Annual report of the North Carolina Agricultural Experiment Station

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THIRTY-FIRST ANNUAL REPORT
OF THE
NORTH CAROLINA
Agricultural Experiment Station
OF THE
COLLEGE OF AGRICULTURE AND MECHANIC ARTS
FOR THE
Year Ending June 30, 1908
Including Scientific Papers and Bulletins Nos. 197, 198, 199
West Raleigh, North Carolina
RALEIGH:
Presses of Edwards & Broughton Printing Company
1909
N. G. COLLEGE OF AGRICULTURE AND MECHANIC ARTS
THE NORTH CAROLINA
AGRICULTURAL EXPERIMENT STATION
UNDER THE CONTROL OF THE
TRUSTEES OF THE A. AND M. COLLEGE
Governor R. B. Glenn, ex officio Chairman, Raleigh
R. H. Ricks Rocky Mount
W. D. Turner Statesville
O. M. Gardner Shelby
Locke Craig Asheville
C. W. Gold Raleigh
E. M. Koonce. . . Jacksonville
T. W. Blount Roper
D. A. Tompkins Charlotte
J. T. Ellington Smithfield
W. E. Daniel. . Weldon
W. H. Ragan High Point
W. B. Cooper Wilmington
M. B. Stickley Concord
jl. T. Ballenger Tryon
N. B. Broughton Raleigh
0. L. Clark. Clarkton
STATION STAFF
George T. Winston, President of the College
C. B. Williams Director and Agronomist
W. A. Withers Chemist
F. L. Stevens Vegetable Pathologist
J. S. Jeffrey Poultryman
F. C. Reimer Horticulturist
R. S. Curtis Animal Husbandman
John Michels Dairy Husbandman
R. I. Smith Entomologist
William Kerr Assistant in Field Experiments
W. A. Syme Assistant Chemist
J. G. Hall Assistant in Plant Diseases
W. C. Etheridge .Assistant in Farm Crops
J. C. Temple Assistant Bacteriologist
A. F. Bowen Bursar
C. P. Franklin Secretary and Stenographer
The Bulletins and Reports of this Station will be mailed free to any resident
of the State upon request.
Visitors are at all times cordially invited to inspect the work of the Station,
the office of which is in the new Agricultural Building of the College.
Address all communications to
N. C. AGRICULTURAL EXPERIMENT STATION.
WEST RALEIGH. N C
North Carolina Agricultural Experiment Station,
Office of the Director,
West Raleigh, N. C, June 30, 1908.
To His Excellency, Robert B. Glenn,
Governor of North Carolina.
Sir :—I have the honor to submit herewith the report of the opera-tions
of the North Carolina Agricultural Experiment Station of the
North Carolina College of Agriculture and Mechanic Arts for the
year ending June 30, 1908.
Trusting that this report will prove satisfactory to your Excellency,
I am,
Yours very truly, C. B. Williams,
3 f % O 5 Director.
TABLE OF CONTENTS
Page.
Board of Trustees and Experiment Station Staff 2
Letter of Submittal 4
Report of Director and Agronomist 5-12
Report of Chemist 13-14
Report of Biologist 15-19
Report of Poultryman 20-21
Report of Horticulturist 22-23
Report of Animal Husbandman 24-25
Report of Dairy Husbandman 26
Report of Entomologist - 27-28
Financial Statement 29
Scientific Papers
—
Experiments Upon the Effect of Formalin Upon the Germination of
Oats 30-36
A Study of Corn Mold - 37-39
Studies in Soil Bacteriology .^~, „v... 40-63
The Colormetric Determination of Nitrates in Soil Solutions Con-taining
Organic Matter 64-65
Notes on Plant Diseases Occurring in North Carolina 66-82
Bulletins
—
No. 17 (Press Bulletin)—The Grape Black Rot 83-84
No. 197—Some Insect Enemies of Garden Crops.
No. 198—Handling and Marketing of Milk and Cream.
No. 199—Feeding Experiments With Cows and Calves.
THIRTY-FIRST ANNUAL REPORT
OF THE DIRECTORS OF THE
N. C. AGRICULTURAL EXPERIMENT STATION
For the Year Ending June 30, 1908
By the Director
Upon assuming the duties of Director of the Station at the begin-ning
of the year, careful consideration with the different workers was
made of plans of all experiments being conducted and of those subse-quently
inaugurated. In all branches of the Station new and im-portant
lines of investigation have been started, and this work in most
cases is progressing in a satisfactory manner. Herewith is presented
a brief statement regarding the work in progress in the several Di-visions
of the Station, which is made up partly from the reports of
the different workers and partly from observations made by the
Director.
DIVISION OF AGRONOMY.
The experimental work of this Division has been materially aug-mented
and strengthened during the year, both by the addition of new
lines of work and by the extension of experiments in progress. Much
attention is being devoted to a determination of the best fertilizer
combinations and the most economical quantities to use per acre ; the
most prolific varieties; the best methods of cultivation and handling;
and the most profitable rotation for corn, cotton, wheat, oats, cowpeas
and soy beans, for the conditions of climate and soil under which the
experiments are being conducted. Experiments are being carried on
to ascertain the best fertilizer and lime treatment for legumes. With
oats, varieties are being grown both from fall and spring sowings to
determine the relative value of these different sowings and the best
varieties to use for seeding at the respective seasons. Much work has
been put out to aid in study of the effect of proper methods of seed
selection of cotton, wheat and corn upon their prolificacy and yield.
This year, the variety tests will embrace a comparison of sixty-eight
varieties of corn, thirty-eight of cotton, fifteen of wheat, sixty-two of
oats and about fifty of cowpeas and soy beans. In addition to these,
variety-distance tests are being conducted with three leading typical
varieties of corn and three of cotton to determine the optimum dis-tancing
of these when grown under different conditions. In response
to a popular demand for information on alfalfa and clover growing,
field studies on small plats are being made to determine under what
6 THIRTY-FIRST ANNUAL REPORT, 1908.
conditions of soil, fertilization and cultural management these dif-ferent
legumes make their best and most profitable growth. Inves-tigations
are being conducted to ascertain the factors which promote
the growth of suckers on different varieties of corn, and the relation
their undisturbed development sustains to total yield of grain per
acre. More than fifty combinations of grasses and legumes are being
experimented with to study their comparative value for hay and pas-turage.
A thorough. system of terraces over the whole farm has been
laid off and constructed at an expenditure of considerable effort
and time.
DIVISION OF CHEMISTRY.
The Chemical Division has maintained a close cooperation with
the Biological Division in a study of nitrogen-fixation, ammonifica-tion,
nitrification and denitrification. In this cooperation the Chem-ist
confines his attention to the chemical analyses, while tha Bacteri-ologist
looks after the bacteriological examinations. Efforts are being
made to determine the nature, distribution and conditions most and
least favorable for the growing of nitrogen-fixing, nitrifying, ammo-nifying
and denitrifying bacteria. In these investigations, an espe-cial
effort is made by the Bacteriologist to isolate and identify the
bacteria concerned.
DIVISION OF BIOLOOY.
The research work of the Biological Division has progressed ac-tively
along the same general course as previously reported, but has
been greatly enlarged by the extension of old lines and the addition
of new ones. The cooperation which has been maintained by this
Division with the National Bureau of Plant Industry in a Plant
Disease Survey of North Carolina and in an effort to secure melons
of high eating and shipping qualities that could be grown upon land
affected with watermelon wilt will be continued, and experiments
have been put out on a badly infected field near Auburn. Efforts
are being directed largely toward the production by hybridization
and selection of strains of melons that will be wilt-resistant. The
results obtained along this line during the past year have been exceed-ingly
encouraging, as the wilt-resistant melons, which now comprise
practically all that are being worked with, have been found to possess
decidedly higher edible and commercial values than has been secured
heretofore.
The tobacco wilt experiments which have been conducted for a
number of years in the old bright tobacco belt of Granville County,
for the purpose of securing wilt-resistant strains of high commercial
value, will be continued. Up to this time, the resistance to this dis-ease
of about seventy varieties has been determined. On the infected
areas native types of tobacco are practically wiped out by the ravages
of this disease. Attention is being confined this year in these ex-
REPORT OF DIRECTOR. 7
periments to a study of six highly resistant strains, the resistance of
which was brought out by last year's work. These promising strains
which have been developed are two from Sumatra; two from Turk-ish
; one from Italian ; and one from local bright leaf tobacco.
The study of fungi or bacteria causing new or little known apple
diseases, occurring in the State, have been continued and extended.
During the period covered by these investigations, two new diseases
have been discovered and several new ones have been described and
much information concerning their mode of life, relation of plant
growth and best methods of treatment has been worked out and pub-lished.
For the present in this line of work, attention is being con-fined
largely to morphological and physiological studies of apple rot,
canker, leaf-spot and two diseases that affect the twigs, with the hope
of evolving practical remedial measures.
In the lettuce drop investigations, by the construction of cold
frames on the Station farm, it has been possible to prosecute the work
more completely under control conditions. Outdoor experiments are
being carried on which are designed to determine the longevity of
the vegetative and reproductive parts of the causal fungus in the
soil and in the atmosphere ; under what conditions the spores infect
the leaves; and the resistance of the fungus to treatment by different
chemicals in varying concentrations. These experiments are being
supplemented by laboratory work. The soil bacteriology investiga-tions
in cooperation with the Chemical Division have been enlarged
and continued. A large number of organisms have been isolated and
studied with a disclosure of the extreme variety of the presence of
nitrifying power in most soils workeel with. Study is being made
of ammonifying organisms and the comparative rate of activity of
nitrogen-fixing bacteria in soils and in solutions. Efforts are being
directed towards determining the relative availability and accepta-bility
of ammoniacal nitrogen to some of our general farm crops as
compared with nitrate nitrogen. During the year, new research
work on the development of poisons in milk has been started for the
purpose of ascertaining the conditions under which these are pro-duced
and to determine from what source bacteria producing the
toxins are derived. Attention will be given to an isolation and study
of the organisms responsible for the production of these toxic prin-ciples.
This work, with slight modifications, will be continued. The
value of the work of this Division is attested by the large correspond-ence
it maintains with farmers and fruit growers on plant diseases.
DIVISION OF POULTRY.
Work in the main of the Poultry Division has been conducted
along the general lines of testing the relative efficiency of different
breeds in food utilization, as shown by egg-production and increase
in weight; various methods of handling and feeding chickens; and
8 THIRTY-FIRST ANNUAL REPORT, 1908.
different styles of incubators and brooders under different systems
of management. In the pedigreed breeding experiments which have
now been conducted for two years the results seem to indicate an
increased percentage of good layers over previous years. With care
ful and intelligent breeding and selection along the right lines it is
expected to secure strains of greater prolificacy ; of higher percentage
of egg hatching; and of hardier and more robust constitution. Ex-periments
to determine the value of disinfecting incubators and add-ing
moisture artificially have been carried on with six machines.
There seems to be a material increase in the percentage of chickens
hatched from fertile eggs under these two conditions combined or
separately over those hatched made in dry machines, although the
incubators used were of the non-moisture type. In this connection it
might be mentioned that the poultryman has secured in these mois-ture
and disinfection experiments two hatches which have proven to
be decidedly the best ones that have been made during his five years
connection with the Station.
Feeding experiments have just been started to test the value of
cottonseed meal for poultry feeding, when fed in different quantities
and in different combinations in conjunction with corn and wheat
bran. A study of the effects of inbreeding in poultry is being made
to determine if it can be carried on indefinitely without producing
deterioration in the flock in point of prolificacy, size and vigor, if
due attention is given to these characters in mating and selecting
breeding stock. This work has not progressed very far, but at this
time a marked improvement in the laying capacity of many indi-viduals
has been noted.
DIVISION OF HORTICULTURE.
The Horticulturist has devoted his attention largely during the
past year to outlining and getting started work of an original nature
with blackberries and dewberries. At present he is confining his
energies chiefly to a study of the causes and best methods of treat-ment
of that faseiculation commonly known as "double flower/' to
which these are subject wherever grown commercially in North Caro-lina.
The investigations will consist largely of a study of the struc-ture
and growth of the fascicle to determine the causes for its for-mation,
whether due to disease, insects, physiological conditions, cul-tural
treatment, soil or weather. The growing of blackberries in this
State for market purposes was started in a small way about twenty
years ago in the section around Ridgeway. From this modest be-ginning,
the growing of these and dewberries has gradually devel-oped,
until to-day the sale of these crops bring thousands of dollars
into the communities where this industry is carried on and where a
few years ago there were practically no horticultural interests. This
REPORT OF DIRECTOR. 9
industry is centered chiefly in Warren, Moore, Cumberland, Colum-bus
and Harnett counties, and is established in many cases on soils
which are now returning annually in profit per acre fifteen to twenty
times the original purchase price of the land. There are thousands
of acres of sandy and sandy loam soils located in the coastal plain
section of the State which, as they are at present affording little or
no income to their owners, may be purchased very cheaply and which
might be given over to remunerative blackberry and dewberry cul-ture.
At present, one of the most serious drawbacks to the mainte-nance
and extension of this branch of farming is the greatly decreased
yield, frequently caused by "double flower" or "rosette." Especially
menacing to profitable blackberry growing is the reduced production
experienced by many growers. The Wilson blackberry, the only va-riety
grown for general market purposes, because of its appearance,
edibility, shipping qualities and its date of maturity, is ordinarily so
badly affected with sterility in the large number of abnormally de-veloped
flower parts as to surfer usually a reduction of about seventy-five
per cent in total yield. The trouble, while not nearly so serious
with dewberries, can only be held in check by costly cultural meth-ods,
such as cutting off all the young canes immediately after the pick-ing
has been finished. The determining of the cause of "rosette" will
have wide practical bearing on the working out of remedial measures
not only for blackberry and dewberry growers in North Carolina,
but for those located in other sections of the country where these are
affected with this abnormality of growth.
The work which this Division is conducting on anthracnose and
self-sterility in dewberries is fraught with economic features and
possibilities.
DIVISION" OF ANIMAL HUSBANDRY.
As this is a new Division of the Station, a considerable portion of
the time of the Animal Husbandman has been taken up in planning,
providing animals and new equipment and getting under wray lines
of experimentation. ~No phase of the work has been completed, but
all that has been started is being prosecuted as expeditiously as is
consistent with expediency. Much effort has been devoted to a study
of the effects of feeding cottonseed meal and linseed meal as supple-mentary
feeds to corn to young and thrifty pigs with a mean average
of about 100 pounds live weight, during the experiments. These ex-periments
are designed to determine the amounts of cottonseed meal,
which may be safely fed in conjunction with corn to hogs; the
economy of gains made; ancl the quality of the pork produced, in
comparison with that secured with rations of corn alone and corn and
linseed meal combined. With the completion of the first half of the
experiment which had been running for ninety days, it was demon-strated
that 0.6 pound of cottonseed meal mixed with the other por-
10 THIRTY-FIRST ANNUAL REPORT, 1908.
tion of the ration and fermented may be fed safely during this length
period in conjunction with corn in the proportion of five parts of
corn to one of meal and secure a pound of gain at less than one-half
the cost of those obtained by feeding corn aloue under tue same con-ditions.
A combination of linseed meal with corn in the proportion
of one to five produced gains at about one-half the cost of corn fed
alone; in other words, this lot by eating a little more than one-third
more feed made three and one-third the amount of gain in the same
length of time. These experiments which have been conducted with
hogs confined in pens will be duplicated, using the same feeds com-bined
in the same way, with hogs allowed to range on different green
crops, such as rape, rye, etc., alone and in combinations. Also,
cottonseed meal feeding experiments have been started with the mules
and horses which are being worked on the farm. During the pre-liminary
periods, after a few days trial, they have been found to eat
from one to one and one-half pounds of meal per day with relish.
DIVISION OF DA IKY HUSBANDRY.
A portion of the time of the Dairy Husbandman has been taken
up in conducting feeding experiments to determine the relative value
of cottonseed hulls and corn stover as roughages ; and dried brewers'
grains, and crushed corn in conjunction with cottonseed meal as con-centrates
with corn stover as the sole roughage for milk and butter
production. The first part of these experiments has been finished
and show that inferior corn stover, which product is usually left in
the field to rot, still had a feeding value for dairy cows equal to that
of cottonseed hulls. As a result of a carefully conducted experiment
in calf-feeding, it has been demonstrated that a reduction of about
sixty per cent in the cost of feeding young calves during the first
fourteen weeks may be effected by a gradual substitution of rolled
oats for whole milk after the first week when fed in conjunction with
a grain ration consisting of one part each of corn meal, linseed
meal and wheat bran after the fourth week. The practical bearing
of these results will be appreciated when it is considered that one
pound of rolled oats, costing about four and one-half cents, contains
the same nutritive value as one gallon of milk, which will sell for
thirty to forty cents. Some effort has been given to planning and
constructing an ice-box, a milk and cream cooler anel a sterilizer that
would be cheap and efficient for small dairies. With each of these
as devised greater efficiency has been secured at greatly reduced cost
over the means and appliances ordinarily employed. The cooling
investigations have brought out the fact that to a large extent the
delivery of the milk may be made entirely independent of the time
of milking. Milk kept cool for fifteen hours before delivery has
been found to reach the consumer in better shape than milk taken
REPORT OF DIRECTOR. 11
from the same cows under the same conditions and put into his hands
immediately upon milking without cooling. The value of these re-sults
will be appreciated by dairymen who have had to begin milking
at two to three o'clock in the morning in order to have their product
come upon the market in satisfactory shape, because the milk handled
in the usual way will only keep in good condition for a very few
hours, especially during the summer months. By cooling to 45 de-grees
Fahr. and keeping the milk at this temperature, delivery may
be delayed for twenty-four hours under the most trying weather con-ditions,
thereby obviating the absolute necessity for milking earlier
than a convenient hour by those who are engaged in the milk-supply
business.
A study has been made of the relative efficiency in maintaining
low temperatures of four different types of shipping cans for cream.
Unfinished cooling and sterilizing experiments are being continued
in the dairy laboratory.
DIVISION" OF ENTOMOLOGY.
Much of the time of the Entomological Division during the past
year has been taken up in planning and starting new lines of investi-gations,
as the new Entomologist began work on October 1 without
practically any equipment or work in progress. Studies are being
made largely on the life history of the harlequin bug, cabbage web-worm,
cabbage aphis, corn weevil, plum curculio and peach tree borer,
supplemented by experiments designed to work out more successful
and practical methods for their control. Early in October the En-tomologist
discovered on cabbage and turnips a new species of the
cabbage webworm for North Carolina, it probably having been intro-duced
into the State during the past two years.
An insect collection, representing all the injurious forms occurring
in the State, with records of date and places of occurrence, is being
gradually made. During the year a Bulletin treating of about forty
insects has been prepared, which gives a description, life history and
remedies for the control of these insects which attack the leading
truck crops grown in North Carolina. .
CORN SPECIAL.
The Station, in cooperation with the Norfolk and Southern Rail-way,
operated a Corn Special train through the Eastern portion of
the State. The Special started from Raleigh on March 22 and re-turned
on April 1. While out, visits of two hours or more were
made to twenty villages and towns and talks on matters pertaining to
corn growing were made. The object in running this train was to
try to stimulate farmers to the production of larger yields of corn
per acre by impressing upon them the importance of the adoption of
12 THIRTY-FIRST ANNUAL REPORT^ 1908.
better methods of selecting seed, fertilizing, cultivating, harvesting,
handling and combating the insect and disease enemies of this crop.
The train consisted of two audience cars and an exhibition car, and
the lectures were sometimes delivered in the audience cars, some-times
in school or court-houses, and sometimes in the open where
buildings were not accessible sufficiently large to accommodate the
crowd. The smallest attendance was forty, and the largest between
four and five hundred, and an average of one hundred and forty-five.
At four places evening meetings were held, and these were devoted to
lectures on the applications of Science to Agriculture and on general
agricultural and educational matters. The train was furnished and
operated free by the Norfolk and Southern Railway.
In the exhibition car were carried two to four type-ears of
fifty-odd varieties of corn which we have been testing comparatively
in the State during six or eight years, and which the farmers have
heard of but which most of them have never seen. In addition to
these, seed of varieties of oats, wheat and cowpeas and samples of the
leading types of soil found in the State were neatly arranged in
museum jars to emphasize those salient points which it was especially
desired to bring out and impress. On board were also specimens of
the insects and diseases which are doing most damage to the crops
and orchards of North Carolina, affected plants and seeds, and spray-ing
mixtures and apparatus that should be used in combating them.
At each stop, as far as possible, the crops and orchards were ex-amined
and affected specimens were brought into the cars and dis-cussed
and remedies recommended. It is believed that in this way
the farmers in the localities visited were impressed with the im-portance
and practical value of the work of the Station.
BULLETINS.
Bulletins have been issued as follows
:
No. 197.—Some Insect Enemies of Garden CropSj by R. I. Smith.
No. 198.—Handling and Marketing of Milk and Cream, by John
Michels.
No. 199.—reeding Experiments with Cows and Calves, by John
Michels.
No. 17.—(Press Bulletin)—The Grape Black Rot, by E. L. Ste-vens.
The reports of the heads of the several Divisions and financial
statement follow:
REPORT OF CHEMIST. 13
EEPOET OF CHEMIST.
During the past year the Chemical Division has made analyses of
four hundred and eighty-six samples, of which four hundred and
fifty-five related to the work in investigation and thirty-one were mis-cellaneous.
The miscellaneous samples consisted of:
Soils 3
Marls 3
Fertilizing materials 9
Feeding stuffs 6
Lemon oil and extract 3
Drinking water 1
Solutions for standardization 6
These thirty-one miscellaneous samples involved ninety-five deter-minations,
as follows:
Chlorine 1
Sulphuric acid 1
Total nitrogen 24
Free ammonia 1
Albuminoid ammonia 1
Total phosphoric acid 15
Soluble phosphoric acid 8
Insoluble phosphoric acid 10
Silver 1
Potash 8
Lime , 5
Moisture 3
Total solids 1
Insoluble matter 4
Volatile matter 1
Ash 1
Alkalinity 4
Acidity 1
Citral 3
The miscellaneous work was for the Divisions of Administration,
Agronomy, Botany, Dairy Husbandry and Poultry Husbandry of
the Station.
The four hundred and eighty-five samples, relating to the work
in nitrogen, involved nine hundred and seventy-three determinations,
as follows:
Ammonia by the Kjeldahl and Nessler methods 54
Ammonia by the Kjeldahl method 6
Ammonia by sodium hydroxid 68
Ammonia by magnesia 274
14 THIRTY-FIRST ANNUAL REPORT, 1908.
Nitrites colormetrically 284
Nitrates colormetrically 4
Nitrates by the Tiemann-Schulze method 283
This work on nitrogen has occupied the greater part of the time
and energies of the Chemical Division and has consisted of a study
of nitrogen fixation, ammonification, nitrification and denitrifica-tion
in soils and in solutions, under different conditions and with dif-ferent
organisms and nutrients. The details of the work will be set
forth more fully in bulletin form and in the report of the Botanical
Division, in cooperation with which this work is done.
Among other conclusions reached, it has been found that the or-ganisms
concerned with nitrogen metabolism do not act the same in
soils and in solutions and that there is no relation between the re-sults
in these two media. This shows that the use of soils themselves
for this investigation as originally planned by this Division several
years ago was wise.
This Division has devised a method for getting rid of organic
matter in soil extracts so that the amount of nitrates may be deter-mined
colormetrically without interference from this cause. A pap: r
embodying the results of this work is submitted herewith for pub-lication.
This Division is very much handicapped for lack of room, and it
is to be hoped that the next General Assembly will provide a Chemi-cal
Building for the Station and College work. In the meantime
more space is very desirable.
The analytical work of this Division was performed by W. A.
Syme mainly, and to a small extent by A. J. Wilson, both of whom
have shown commendable zeal and corresponding success in their
efforts.
Very respectfully,
W. A. Withers,
Chemist.
REPORT OF BIOLOGIST. 15
EEPOET OF BIOLOGIST.
I beg to submit a report of the work of the Division under my
charge for the fiscal year now closing:
INVESTIGATIONS CONCERNING APPLE DISEASES.
Work concerning apple diseases began in 1906 under the Adams
fund, has been continued throughout the year.
Apple Twig Disease, which prevails in most sections of the State,
has been closely studied. The fungus which causes it has been iso-lated
and its character studied in pure culture. It proves to be a
species of Pliyllosticta or Phoma, which has been very destructive to
fruit in Arkansas, West Virginia, and several other States. As yet
the disease seems to be limited to the twigs, and has not been noted
upon fruit here.
A second apple twig disease has been found in destructive abund-ance
in many sections of the State. It proves to be a species of
Jlypochnus, which has not been recognized heretofore except in Bra-zil,
where it was reported by Noack in 1898.
Apple Leaf Spot, which is very destructive, especially in the moun-tains,
has been studied, anel will be the subject of further investiga-tion.
Cankers of apple and pear branches are exceedingly abundant and
destructive, and scores of specimens have been received. These can-kers
have been studied and it has been determined that, in most in-stances,
they are due to SpJicvropsis. Sphseropsis canker of the apple
is an old enemy, but it seems to be especially destructive here. Spha>
ropsis canker of the pear has not, to my knowledge, been known
before. Both of these cankers, in addition to causing injury to the
twig and branch, also bring about ripe rot of the fruit.
Monilia fructigena, causing rot of the apple, has been found and
studied somewhat. This is the first time, to our knowledge, that this
disease, which is exceedingly destructive in Europe, and which has
been reported in some other parts of the United States, has been
found in North Carolina.
INVESTIGATIONS CONCERNING LETTUCE SCLEROTINOSE.
Investigations of this exceedingly serious lettuce disease, begun
under the Adams fund a year ago, have been continued throughout
the past year. Two large cold frames for the raising of lettuce under
canvas have been constructed on the Station farm, and a small crop
of fall lettuce and a large crop of spring lettuce was raised for the
purpose of studying the disease. Hundreds of plants wrre inocu-lated
and the progress of the disease carefully noted. The fungus
16 THIRTY-FIRST ANNUAL REPORT, 1908.
was also studied in the laboratory, receiving close attention as to the
manner of infection by means of spores and mycelium ; as to the life
history of the fungus ; number of spores formed and the condition of
spore formation ; action of poisons upon the fungus ; its growth at
normal temperatures; and other points of morphological and physi-ological
interest. Much was learned concerning the fungus and the
disease. This matter will be presented for publication in bulletin
form soon. The lettuce beds, now thoroughly infected with the dis-ease,
are in excellent condition to begin a study of methods of com-bating
the disease, using to this end the knowledge which we have
gained concerning it in this year's study.
OTHER PLANT DISEASES.
Cotton Anthracnose.—Many complaints have been received from
various portions of the State concerning cotton anthracnose. Some
attention has been given to it in the laboratory, and some tests con-cerning
the transmission of this disease from year to year, by seed,
are under way.
A New Siveet Potato Disease.—A sweet potato disease that we are
calling the "soil rot," which seems not to have been described in
literature before, has been repeateelly submitted to this laboratory by
sweet potato growers from various sections of the State. We have
found a fungus (Fusarium) which is constantly associated with this
disease, and which seems probably to be the cause of it. Experi-ments
are under way to determine whether this is actually so.
An Unknown Tobacco Disease was reported to us from Hillsboro.
An examination of the disease was made on the ground. Numbers
of plants were dead in certain regions of the field. No cause could
be assigned. Material was brought to the laboratory for further
study and no fungus or parasite was found associated with this dis-ease.
If this disease should prove of permanent importance, further
study will be given to it.
Corn Mold.—Samples of moldy corn have been received from
about fifty farmers, and in nearly every case the mold seems to be
due to a species of Diplodia. A report of this work on corn mold
will be published soon.
Bean Anthracnose.—Material for study of seed transmission of
this disease, which prevails throughout the trucking section of the
State, has been secured, and a study will be made of the transmission
of the disease from year to year by seed, and also of the possibility of
preventing such transmission.
Cucumber Mildew.—Cucumber mildew has been very destructive
in several portions of the State on both cucumbers and cantaloupes.
We have planted encumbers in our lettuce beds and will conduct
spraying experiments upon them this spring.
REPORT OF BIOLOGIST. 17
Pea?' Septoria.—In the neighborhood of Wilmington, pear trees
suffering very seriously from some disease were found. Laboratory
study showed this disease to be caused by a species of Septoria.
COLLECTION OF PLANT DISEASES AND FUNGI.
An effort has been made to enlarge the Station collection of all
kinds of parasitic fungi, either on weeds, cultivated plants, or wild
plants. Also to secure typical specimens of diseases of cultivated
plants.
GERMINATION OF OAT SEED.
This has been a subject of rather extensive investigation. Oats
were submitted to formalin at different strength, for various lengths
of time, under various conditions, using different qualities and dif-ferent
varieties of oats. It was found that different varieties would
withstand the action of formalin differently ; that the seed of poor
quality are killed to a much larger extent than are seed of better
quality. It thus appears that the few seed lost in the formalin treat-ment
are undesirable ones.
PLANT BREEDING FOR DISEASE RESISTANCE.
Watermelon Wilt.—The work of testing and selecting melons with
the object of securing a variety resistant to the wilt, was continued
this year. Ten varieties resulting from previous selections were
tested on isolated plats on sick soil at Auburn. There was a very
much larger percentage of resistance this year than last, more of
the plats produced edible melons and there was a very much larger
percentage of edible melons on the plats, than in previous years,
nearly three-fourths of the melons in some plats being of high quality.
Twenty-nine selections of seed from melons of high resistance to
the disease and of highly desirable quality were made for further
tests next year.
Tobacco Wilt.—Several varieties of tobacco have been developed
in our previous breeding work to such an extent that they will grow
with high resistance upon infected soil on which none of the ordi-nary
varieties of tobacco will grow at all. AVe now have five such
varieties. With one only forty plants out of nine hundred and fif-teen
wilted; another fifteen out of three hundred and fifty-nine;
another twenty-five out of three hundred and five. These strains of
tobacco will be tested again this year.
STUDY OF SPORE MEASUREMENT.
A study of spore measurement has been made with the object of
ascertaining the degree of variability existing among fungi when
grown under different conditions with different nutriment, etc. Ke-suits
of this work are about ready for publication.
2
18 THIRTY-FIRST ANNUAL REPORT, 1908.
SOIL BACTERIOLOGY.
Nitrification.—Work on soil bacteriology under the Adams fund
has been continued. Nitrifying organisms, both the nitrate makeis
and the nitrite makers, have been isolated, enabling us to study them
in pure culture. An improvement upon various methods of tech-nique
has been made regarding the preparation of silicate jelly. An
account of this was published in the Centralblatt fur Bakteriologie,
ParoLsitenhunde u. InfeMionskrankheiten, Volume XXI, No. 13,
1908. Very numerous tests have been made of the nitrifying power
of various soils under various conditions, and a critical study has
been made of the methods of determining nitrifying power of soils,
and the factors which effect the nitrifying power. The relation of
temperature, aeration, degree of moisture and chemical composition
of the medium to nitrification has been closely considered. Careful
study has been made of the behavior of nitrifying organisms when in
solution and when in soil. It has been ascertained that there is a
very great difference in the behavior of these organisms in the soiii-tion
and in the soil. An attempt has been made to ascertain the
reason for this difference.
Ammonification.—Ammonifying organisms have been studied
much as have nitrifying organisms, to ascertain what proportion of
soil organisms are ammonifiers, under what conditions they am-monify
most rapidly, and the behavior of these organisms in soils
and in solutions.
Nitrogen Fixing Bacteria.—Some attention has been given to these
organisms, particularly as to their ability to fix nitrogen in soils, as
compared with their ability to fix nitrogen when in solutions.
Availability of Amnwniacal Nitrogen as Compared with that of
Nitrite Nitrogen.—This fundamentally important question has ben
made the subject of study in pot tests and in the field. Jt seems
very probable, from other studies, that our soils are deficient in ni-trifying
power. If this be so, it is very important to know whether
nitrogen in the form of ammonia is fully as acceptable to the plant
as nitrogen in the form of nitrate. If the nitrate be for any reason
better suited to plant nutrition, it then becomes important to devise
some mode of increasing the nitrifying power of our soils.
LEGUME INOCULATION EXPERIMENT.
Tests are planned and are partially under way to determine
whether the root tubercle organism of burr clover is capable of pro-ducing
root tubercles upon alfalfa.
PTOMAINE INVESTIGATION.
Investigations have been begun to determine under what condi-tions
poisonous products are formed in milk, and what source of con-
REPORT OF BIOLOGIST. 19
tamination is most likely to produce such poisons. The work has
not yet been carried to completion.
PLANT SURVEY.
This work is carried on in cooperation with the Bureau of Plant
Industry. Hundreds of letters have been sent to farmers throughout
the State, in order to ascertain the prevalence of certain diseases of
plants, and to secure information concerning their distribution. On
pages G6-82 are given the results of this work.
CORRESPONDENCE.
Numerous inquiries concerning plant diseases and other botanical
questions have been received and answered. In all, about 4,000
pieces of mail matter have been sent out from this Division.
CORN TRAIN.
One member of this Division accompanied the corn train on its
ten day trip to speak on "The Prevention of Plant Diseases." Ap-proximately
3,000 farmers were in this way reached, concerning this
important subject.
COMPLETED WORK.
There is now ready for publication a Bulletin on oat smut, con-taining
the results of some six years' work on this subject. There
was published, during the past year, a Press Bulletin on the Black
Pot of the Grape. A technical article on the prevention of diseases
of small fruits is also practically ready for publication.
I wish to acknowledge the efficient aid of J. C. Temple, Assistant
in Soil Bacteriology, and J. G. Hall, Assistant in Pathology, each of
whom is an exceedingly capable and well-trained man, enthusiastic
and devoted to his work.
P. L. Stevens,
Biologist.
20 THIRTY-FIRST ANNUAL REPORT, 1908.
REPORT OF POULTRYMAN.
I beg to submit the following report of the work in the Poultry
Division for the year ending June 30, 1908
:
For the past two seasons we have been pedigree breeding from a
large number of hens in an effort to improve the laying qualities of
our flock. The work done in this direction shows us that it is neces-sary,
if we are to get the best results, to have more information about
our breeders than simply how many eggs they each lay during the
year, and for this reason we have for the past year been keeping rec-ords
of the number of eggs laid by each hen, the fertility of the eggs,
chicks hatched and the number living until four weeks old. The
system that we have adopted of keeping the pedigree of the chicks
will also give us the age of each chick, and this data should in a few
years afford valuable information as to the best hatching season for
profitable egg-production.
Work has also been commenced during the year to determine if in-breeding
can be practiced for a number of years without detriment
to the health and vigor of the stock, if proper attention is given to
these characters in selecting stock.
There is a belief quite prevalent, especially among farmers, that
inbreeding is detrimental in poultry work, or for utility poultry at
any rate, and that if the practice is of any value it is only in the
breeding of exhibition poultry.
It is believed that if it is an advantage for one class of breeders
it may be just as useful to the others if properly used, and that many
breeders are losing a great deal on account of their prejudice against
this practice.
In order to test this we are breeding two different strains of Barred
Plymouth Rocks, keeping each line pure, and as a check crossing the
two from time to time to see if there is any advantage in the introduc-tion
of new blood.
Realizing that cottonseed meal is one of the cheapest and best stock
feeds obtainable, we have undertaken some experiments to determine
if it can be as successfully used in poultry feeding as in feeding other
kinds of stock, and if so, in what proportion and combinations it will
give the best results.
Considerable work has been done in artificial incubation, special
attention being given this season to the question of whether it is
beneficial to disinfect the incubator before each hatch, also whether
the addition of moisture helped the hatch, either from the standpoint
of the number of chicks hatched or the vitality of the chicks.
Six incubators were used in this work, all of one size and make,
and machines which are sold as non-moisture machines, that is ma-
REPORT OF POULTRYMAN. 21
chines that do not need any supplied moisture. Results varied con-siderably
from one hatch to another, and it is thought best to con-tinue
this work another season, trying as far as possible to eliminate
the conditions that we think were most largely responsible for the
varying results from the same machines in different hatches.
It has been the almost universal custom to raise chicks that are
hatched in incubators, in brooders with artificial heat, but during the
past year considerable interest has been aroused in a method of rais-ing
the chicks without supplied heat, in what is known as a fireless
brooder. If this system is a success it can readily be seen that it
will mean quite a saving in the cost of raising chicks artificially, sav-ing
the cost of the kerosene and the time of an attendant in looking
after the lamps. Information as to this system is at present time
confined almost exclusively to the claims of the parties advertising
the system, and it is our intention to try this system the coming
season so that we can give information as to its use to parties who
are interested and want information from a disinterested source.
Respectfully submitted,
J. S. Jeffrey,
Poultryman.
22 THIRTY-FIRST ANNUAL REPORT, 1908.
EEPOET OF HORTICULTUEIST.
Since no experimental work had been done by the Horticultural
Division for a number of years previous to my appointment, the
work has of necessity been largely of a formative nature. No line
of work has been carried to completion. This Division is now con-fining
itself to the following lines of investigation:
DOUBLE FLOWER OF THE BLACKBERRY AND DEWBERRY.
This trouble, generally known as "double flower" or "double blos-som"
among our dewberry and blackberry growers, gets its name
from the fact that there is usually a doubling of the flower. The
term "rosette" would be equally applicable because of the rosette-like
growth produced from the buds in spring.
The Horticulturist began studying the trouble during the summer
of 1907. It was found in several sections of the State, and in each
section the blackberry industry has been practically wiped out.
Experiments at Cameron.—The trouble v/as such a serious one
that the horticulturist at once began cooperative work on a small scale
with three of the leading growers at Cameron, N. C. This was to
determine the nature of the abnormality, to get the growers inter-ested,
and to get the work started, since it would require at least one
year before the work could be undertaken at the Experiment Station.
The experiment is being conducted as follows in each field:
Four typical adjacent rows were selected in each field. The entire
growth, both old and new canes, of two rows, was entirely destroyed
early in July immediately after the picking season. These plants
must produce sufficient new cane growth during the remainder of
the season for the following year. Only the old growth (fruiting
canes) was cut out of the other two rows, leaving the young cane
growth made during the spring to produce the next year's crop.
This was done to determine what influence the different methods
of destroying the old growth will have on the "double flower," and
second, whether it is necessary to go to the heavy expense of destroy-ing
all of the cane growth, and then fertilizing heavily to produce the
second growth of new canes the same season. The plants have been
carefully studied since the work was started and valuable data have
been obtained. Photographic records are being made of the develop-ment
of the normal and abnormal buds and growth. While valuable
data have already been obtained, the most important data during this
season will be obtained during the fall months. Furthermore, it
will require further study and experimentation before conclusive
statements can be made regarding the cause and best method of con-trolling
the trouble.
Experiments at Station Farm.—Extensive experiments with
"double flower" are now being conducted on the Station farm. Six
REPORT OF HORTICULTURIST. 23
plots of Wilson blackberry and six plots of Lucretia dewberry, each
plot consisting of three rows, are being devoted to this work. These
plots were planted during January of the present year. These par-ticular
varieties were selected because they have been the most im-portant,
commercially, in the State and are bidly affected. It will
require one season to get the plants well established before any real
experimental work can be undertaken. Each plot will then be treated
differently in the way of pruning and destroying the old and young
canes to see what effect it will have on the "double flower."
Aside from this, we are testing twenty-two other varieties of black-berries
and fourteen of dewberries to determine what varieties are
affected.
SELF-STERILITY OF DEAVBERRIES AND BLACKBERRIES.
Many of our varieties of dewberries and blackberries give unsatis-factory
results when planted by themselves. This appears to be due
in many cases to self-sterility.
We are now testing fifteen varieties of dewberries and twenty-three
of blackberries to determine to what extent they are self-sterile;
the cause of this self-sterility, and the varieties that will be the best
to use for the pollination of self-sterile varieties.
Since these plants were just planted during the past winter, no
data can be obtained until they come into bearing next year.
CONTROLLING1 ANTIIRACNOSE BY CULTURAL MEANS.
The Horticulturist is now carrying on cooperative work with five
of the leading dewberry growers to determine the best cultural means
of controlling this disease. It is the most serious disease Avith which
dewberry growers have to contend at the present time.
The present methods of controlling the disease are very costly. I
believe that this cost can be considerably reduced by improving and
modifying the present cultural methods.
These experiments are to determine how often the canes should be
cut off ; the best depth to cut them, and the best tools for this purpose.
The work was started last summer and accurate records have been
kept of the rate and character of new growth. This year records
will be kept of the amount of fruit yielded by each plot.
MISCELLANEOUS WORK.
The Division is giving considerable study to several of our leading
fruits. Photographs are being made and notes taken on the various
methods of propagation, planting, cultivation, and marketing of the
more important fruits. The Division has made a fairly complete
survey of the dewberry industry of the State, including localities,
names and addresses of growers, and acreage. A similar survey of
other leading fruits is now well under way.
Respectfully submitted, F. G. Reimer,
Horticulturist
24 THIRTY-FIRST ANNUAL REPORT, 1908.
KEPOKT OF ANIMAL HUSBANDMAN.
I beg to submit the following report of the operations of this Di-vision
for the year just closed:
It will be necessary to say at the outset that the brief report fol-lowing
is simply a general status of the work now in progress by this
Division. No line of work has been fully completed during the past
year, owing to the fact that it was necessary to provide entirely new
equipment on the Station farm.
The first line of work undertaken was a determination of the
amount of fermented cottonseed meal which could be fed safely in
conjunction with corn to young and growing hogs ; to determine the
economy of gain ; and the quality of the product when compared with
corn alone, and corn and linseed meal.
The length of the feeding period was six months. The check lot
of pigs fed on corn remained in an unthrifty condition all during
the experiment. The two lots of pigs fed on corn and cottonseed
meal in varying proportions made larger gains as the amount of
cottonseed meal was increased. This was true, however, only during
the first period of three months. The lot which made the largest
gain received the most cottonseed meal, though none of the pigs were
fed more than .62 pound per day. The gains made were clearly in
favor of the ration composed of four parts of corn and one part of
cottonseed meal. The limit of profitable feeding was three months
or thereabouts. During the last three months of the feeding period
the gains were materially decreased with all pigs fed cottonseed meal,
which would seem to indicate that this material should not be fed
longer than seventy-five to ninety days. If fed to hogs, great care
should be taken to measure or weigh the amount fed each time, and
discontinue feeding after the time stated. While it is possible that
the feeding period could be lengthened, it would not seem to be a
safe venture for the farmer to make.
A second line of work was undertaken to determine the relation
between feeding hogs in dry lots and on forage crops. The ration for
each lot consisted of three parts of corn and one part of fermented
cottonseed meal. With three lots, this ration was fed in conjunction
with green crops; with the fourth lot, the corn and cottonseed meal
were fed alone in the same proportion in a dry lot. This experiment
is now nearly completed, and bids fair to give valuable data in favor
of the green crops, which can be produced so abundantly by North
Carolina farmers. The first grazing crop furnished was fall rye,
after which oats and Canada peas; oats and rape were given as a
second series in the succession. For the third series of forage crops,
cowpeas and corn, cowpeas and sorghum, sweet potatoes and peanuts
were fed. These crops all made rapid growth and furnished feed for
the greater part of the summer and fall months.
This is one line of work which the Station expects to thoroughly
REPORT OF ANIMAL HUSBANDMAN. 25
investigate, as swine raising is one of the paying lines of work for
the farmers in this State. The pigs in this experiment are all thrifty
and will be ready for market by the latter part of December, after
which the results of the experiment will be reported in detail.
The third line of work undertaken was the feeding of cottonseed
meal to horses and mules to determine:
1. The possibility of using such a supplementary feed with corn.
2. The economy of the ration.
3. The amounts and condition in which it could be most satisfac-torily
fed.
4. The effect on the condition of the animal.
The work mules of the Station are being used in this experiment,
and each mule will receive one of the rations fed each of the other
mules during the experiment.
The preliminary period of the experiment, lasting from April 6 to
May 20, proved conclusively that the meal was relished by the mules
in quantities as large as one pound, and in some cases one and one-half
pounds per day. The meal was mixed with ear-corn for two
mules, and with corn and cob-meal for three mules during the first
part of the final feeding period. The final ration which is being fed
at the present time, is composed of ear-corn and cottonseed meal, the
meal fed ranging from three-fourths of one pound to two and one-fourth
pounds per day.
The above experiment is to be run one year exclusive of the pre-liminary
period. The ration will be reversed at the end of every
two months to eliminate individuality. During the first part of the
experiment the same amount of meal was substituted for the corn
that was taken out of the ration. At present, however, one pound
of cottonseed meal is being substituted for as much as two pounds of
corn, to determine the efficiency of the cottonseed meal in furnishing
protein, in replacing the corn and balancing the ration.
Most farmers are feeding an all-corn ration, which is very expen-sive
and undesirable, to say the least. The purpose of this experi-ment
has been to work out a cheaper, practical and more efficient
ration.
In addition to the above work, there has been considerable im-provement
made at the Station farm in the way of buildings and lots.
A number of farrowing pens have been built, feeding floors, pens
and hog pastures.
The Station has also purchased several high grade Poland Clrna
brood sows and a pure bred boar, which are to be used for raising hogs
of uniform type for future experimental work.
Considerable correspondence has been carried on, this being mostly
in reference to breeds of live stock best adapted to the conditions of
the State ; questions in regard to breeding, feeding and management
of live stock ; and the laying out lots for pasture purposes.
R. S. Curtis,
Animal Husbandman.
26 THIRTY-FIRST ANNUAL REPORT, 1908.
KEPOET OF DAIRY HUSBANDMAN.
The data obtained on the relationship of cold to the keeping quality
of milk prove conclusively that it is feasible for dairymen to deliver
their morning's milk in the afternoon and the night's milk the follow-ing
morning, thus making the milking independent of delivery. In-deed
they prove that sweet milk may be furnished by making only
one delivery a day. The data, therefore, point the way to saving a
great deal of labor as well as much unnecessary drudgery.
The feeding experiments showing that rolled oats may be gradually
substituted for milk in calf rearing, are of far-reaching importance
in that the reduced cost resulting from such substitution will undoubt-edly
be a strong factor in inducing dairymen to raise enough calves
to build up and replenish their h^rcls.
In the stover and huH experiments conducted by this Division, the
fact is brought out that dairymen will save thousands of dollars an-nually
by raising and feeding corn stover instead of buying and
feeding cottonseed hulls.
In another experiment, it was demonstrated that dried brewers'
grains have the same feeding value as corn meal when both are used
to supplement a grain ration consisting of one-half cottonseed meal
and one-quarter corn meal. Since the dried brewers' grains can
usually be purchased at a much lower price than corn meal, the
economy of using them is evident.
The original plans presented for the construction of cheap ice
boxes and sterilizers will, if adopted generally, save thousands of dol-lars
to our dairymen, besides resulting in more efficient cooling and
sterilizing than would be possible without them.
The Division has also worked out a new method for making cot-tage
cheese, which is especially adapted for making this cheese on a
commercial scale.
Cottage cheese has been made for centuries, but this is the first
time, so far as known to the writer, that any successful effort has
been made to place the making of this cheese upon a commercial and
scientific basis. The method of manufacture, as well as the method
of marketing, as worked out by us, insures absolute uniformity of
product, and makes it possible to manufacture cottage cheese on as
large scale as is done with many other kinds of cheese.
This new method opens the way for an extensive and profitable use
of skim milk.
Respectfully submitted,
John Miciiels,
Dairy Husbandman.
REPORT OF ENTOMOLOGIST. 27
REPOKT OF ENTOMOLOGIST.
When I came to the Station on the first of last October, I found
the Entomological Division practically without laboratory, library
and office equipment. Some little time was required to get things
in shape before any investigational work could be taken up. The
insect collection was found to be small, poorly arranged and contained
few of the more common species. My time, therefore, for the past
nine months, has been devoted largely to making insect collections
—
both by collecting and by breeding—to attending to correspondence,
and to getting under way new lines of investigation.
publications.
A Bulletin, entitled "Insects Injurious to Garden Crops,'7 which
contains sixty-four pages, has been prepared. This was written with
especial reference to the needs of gardeners, truckers and farmers in
North Carolina.
INVESTIGATIONS.
Life history studies, and in some instances experiments with
remedial measures, have been conducted with insects as follows:
Harlequin Bug (Mvrgantia histrionica) .—Commencing when the
bugs first appeared this spring, careful observations and notes were
made to determine the following points:
(1) Egg laying record; (2) period of incubation of eggs; (3)
length of life cycle; (4) number of generations; (5) parasitism of
eggs and nymphs; and (6) general habits.
Various direct remedies have been tested and the kerosene emul-sion
treatment of fifteen per cent strength has proved quite effective
against young and half-grown bugs, while it also prevents some of
the eggs from hatching. The egg-laying record of the hibernating
brood has been secured, one female laying one hundred and seventy-nine
eggs between April 7 and June 9. Other individuals under
observation laid from ninety-six to one hundred and twenty eggs dur-ing
a shorter period. Many interesting and important facts about
terrapin bugs have been noted, but this line of investigation is yet
in progress.
Cabbage Web-worm (Hellula undalis).—Plans were made this
spring to study the life history of this insect, which was first discov-ered
in North Carolina by the writer during the past October. Up
to June 30 no web-worms have put in their appearance, but it is
expected they will be present certainly by late summer or early fall.
Cabbage Aphis (Aphis brassicce).—Gratifying results have been
secured from the use of a spray of common soap solution as a remedy
against the cabbage aphis. During the year tests have been made
28 THIRTY-FIRST ANNUAL REPORT, 1908.
both on the College and Central Hospital farms, using various soap
solutions of different concentrations in comparison with ten and
fifteen per cent kerosene emulsion and tobacco decoctions, with the
results indicating the superiority of common soap solution, both in
efficiency and economy.
Plum Curculio (Conotrachelus nenuphar).—This insect was made
the subject of a life history study during the spring and the length
of egg, larva and pupa stages were determined for North Carolina
conditions. A common species of parasite (Sigalphus curculionis)
was reared in considerable numbers from the curculio larvae. Ob-servations
on the egg-laying and feeding habits were made and re-corded.
The scope of this experiment is also to be increased, and
it is to be continued during the coming year.
Fumigation Against Com Weevils.—Because of numerous com-plaints
of poor results coming from the use of carbon bisulphid as
a remedy against corn weevils, the writer has undertaken to find
some other substance or substances that will be cheap and effective.
A number of tests were made during February and March, but the
results, while encouraging, indicate that much further work of an
enlarged nature should be carried on before attempting to draw
definite conclusions. Extended work is planned to be taken up in
a vigorous manner during the coming year.
Respectfully submitted,
R. I. Smith,
Entomologist.
RECEIPTS AND EXPENSES. 29
North Carolina Agricultural Experiment Station in Account with the
United States Appropriations, 1907-1908.
Dr.
To receipts from the Treasurer of the United States, as per appropriations for the
fiscal year ending June 30, 1908, under Acts of Congress, approved March 2,
1887, and March 16, 1906:
Hatch Fund $15,000.00
Adams Fund 9,000.00
Cr.
By Salaries
Labor
Publications
Postage and stationery
Freight and express
Heat, light, water and power
Chemical supplies
Seeds, plants and sundry supplies.
Fertilizers ,
Feeding stuffs
Library
Tools, implements and machinery. ,
Furniture and fixtures
Scientific apparatus
Live stock
Traveling expenses
Contingent expenses
Buildings and land
Hatch Fund. Adams Fund.
. $6,945.83 $6,780.00
2,624.90 508.57
938.54
434.98
258.59
58.79
36.81 406.94
445.97 367.91
218.10 308.77
733.04
109.00 143.29
350.86
566.30
1.23 162.05
457.00 200.00
467.05 122.47
15.00
338.01
Total $15,000.00 $9,000.00
We, the undersigned, duly appointed auditors of the corporation, do hereby
certify that we have examined the books and accounts of the North Carolina Ex-periment
Station for the fiscal year ending June 30, 1908; that we have found the
same well kept and classified as above, and that the receipts for the year from the
Treasurer of the United States are shown to have been $24,000, and the corre-sponding
disbursements $24,000; for all of which proper vouchers are on file and
have been by us examined and found correct, thus leaving nothing.
And we further certify that the expenditures have been solely for the purposes
set forth in the Acts of Congress, approved March 2, 1887, and March 16, 1906.
(Signed)
J. T. Ellington,
O. L. Clark,
T. T. Ballenger,
P. H. Ricks,
Auditors.
(Seal.)
Attest: A. F. Bowen, Custodian.
30 THIRTY-FIRST ANNUAL REPORT, 1908.
SCIENTIFIC PAPERS.
EXPERIMENTS UPON THE EFFECT OF FORMALIN UPON
Th|E GERMINATION OF OATS.
By F. L. STEVENS.
Many different strengths of formalin are or have been at various
times recommended for the prevention of oat smut; also many dif-ferent
modes of application and different lengths of exposure to the
formalin fumes.
The two factors which must control in the selection of the strength
to be employed, and the time and the mode of application, are the
fatality to the smut spores and the effect upon the germination of
the grain.
While the strength of one ounce to one gallon of water is employed
by many with success, it occasionally results in a loss of the crop,
clue to its killing the seed ; therefore this strength is to be regarded
as within the danger limit, and is not to be recommended.
In order to ascertain whether one ounce to two gallons of water
is dangerous to seed, tests were made during May, 1905, with one
hundred seeds, employing three different strengths of formalin, as
indicated in the following table, and with the fertilizer in one c~se
put in the drill, in the other well mixed with the soil, and in the
third using no fertilizer:
Table I.
—
Showing the Effect Upon Germination of Formalin Solutions
of Different Concentrations.
O n e Ounce
Formalin
to one
Gallon.
One Onnee
Formalin
to Two
Gallons.
One Ounce
Formalin
to Three
Gallons.
Average. No
Formalin.
No fertilizer _
Per Cent.
38.5
03.
08. 5
Per Cent.
80.5
00.5
57.
5
Per Cent.
37.5
67.5
53.5
Per Cent.
52.
2
63.
7
59.8
Per Cent.
38
With fertilizer mixed with soil
With fertilizer unmixed with soil 100.0
Average 50.7 60.2 52.8' 58.7 69.0
The results are so irregular and discordant that no conclusion
seems justified unless it be that in such tests a much larger number
of seeds should be used to give more reliable averages. The test was
therefore modified and repeated on a larger scale in June, 1-105.
In each instance one pint of seed was treated with the formalin solu-
EFFECT OF FORMALIN UPON GERMINATION OF OATS. 31
tion at the rate of one gallon of solution to one bushel of seed. After
treatment two hundred seeds were taken for the germination test,
with the following results
:
Table II. -Showing Effect Upon Germination of Formalin Solutions of
Different Concentrations.
One Ounce
l'orinalin
to One-ualf
Gabon.
One Ounce
l oruialin
to One
(J til. on.
One Ounce
1 orniiilin
to I wo
Gallons.
One Ounce
i onnaiiu
to Tiirte
Galioi.s.
Cloth-covered 12 hours after treatment then plant-ed
immediately
Planted immediately after treatment
Dried 48 hours after treatment before planting
Cloth-covered 12 hours then dried with lime before
planting
Average «
Per Cent.
25
47
43
35
i'er Cent.
95
99
96
94
Per Cent.
97
88
98
94
Per Cent.
93
37 96 91 93
It comes out clearly from this experiment that the strongest solu-tion
injures germination seriously, though no injury is apparent
from the treatment by the other solutions under any of these condi-tions.
There is even an indication of increased germination with
the increase of the formalin, as shown by the averages, 93, 94 and 96
per cent. Whether such stimulation is a fact or whether the differ-ences
shown in the table are due to accidental variation in the s< eds
it is impossible to say. There is no significant difference resulting
from the modes of treatment with any of the strengths unless it be
with the strongest solution, which showed greatest fatality when cov-ered
12 hours and when planted immediately. This is to be expected,
since both of these modes of treatment tend to retain the formalin
fumes in contact with the seed for a longer time than do the other
treatments.
The solution of one ounce of formalin to one gallon of water did
no appreciable injury to these seeds with any of the modes of treat-ment
followed. In field practice, however, this solution and even
weaker solutions are known under some conditions to deplete the
stand. It seemed, therefore, that some other factor must at times
enter into the question ; that probably there is a difference between
different varieties of oats or between oats of the same variety under
different conditions. A more extensive experiment was therefore
planned to test the following points:
Do different varieties of oats offer different decrees of resistance
to formalin ? What percentage of the seed is killed by formalin of
the strengths usually employed? Does formalin have anv stimu-lating
effect upon germination? Are seeds of inferior quality more
32 THIRTY-FIRST ANNUAL REPORT, 1908.
susceptible than those of medium or excellent quality? Does the
fatality increase with the increase of the time of application ? While
many tests have been made bearing upon these points, they have
usually been made with one or two factors only in mind, and the re-sults
are neither concordant nor conclusive. 1
A series of crucial experiments was planned with the hope of gain-ing
conclusive answers to these questions. 2
In all cases 1,000 seeds of average quality were taken and treated
for twelve hours. They were treated with formalin of the strength
indicated, employing 1 cc. of the solution to 9.3 cc. of seeds, this
being equivalent to the usual practice of using one gallon of liquid
to one bushel of seed. The seed, after being thoroughly wetted by
the solution, were placed in glass capsules, of suitable size, to pre-vent
loss of formalin by evaporation. Great care was taken to have
the lots exactly alike, except as regards the factor under observation.
After treatment the seeds were planted in flats in clean sifted sand
in rows one-half an inch apart, with the seeds evenly distributed in
the rows. In this manner, it was possible to account for every seed.
The final record of germination was taken two weeks after planting,
since experience showed that all viable seeds germinated in that time.
All seeds designated as of average quality were gotten by discard-ing
from a clean commercial sample of considerable size, all foreign
seeds and empty chaff, but retaining all actual oat seeds, each of
which, in case of any possible doubt, was inspected as to its integ-rity.
This sample was thoroughly mixed and the 1,000 seeds for
the test were taken absolutely without selection by always taking the
seed lying nearest at hand, be it large or small. The strengths most
used in practice, .26 per cent, .39 per cent, and .78 per cent of for-malin,
or as more commonly designated, one ounce to three gallons,
one ounce to two gallons, and one ounce to one gallon, were employed
;
also a weaker solution, one ounce to four gallons (.2 per cent forma-lin).
The first of these is mostly used, the second often, and the
third rarely.
•A summary of much that has been done is presented by G. Kotik Uber die
Bedeutung- des Formaldehyds als, Pfianzenschutzmittel U. S. V. Zeit. f. Land—
Versuchswesen, Oest—. Jahr IX 1906 811.
2 In carrying out these tests I am indebted to the efficient assistance of F. H.
Brown.
EFFECT OF FORMALIN UPON GERMINATION OF OATS. 33
INFLUENCE OF DIFFERENT STRENGTHS UPON WHITE
SPRING, RED RUST PROOF, VIRGINIA WINTER
GRAY, APPIER, BURT, BLACK SPRING OAT OF
AVERAGE QUALITY TREATED TWELVE HOURS.
Table III.
—
Test of the White Spring Oat, 1,000 Seeds.
Flat
No.
Strength of Solution. Number
Germinated.
Per Cent
Germinated.
Per Cent +
Due to
Treatment.
11 Control
One ounce to four gallons i
998
996
993
985
941
99.8
99.6
99.3
98.5
94.1
14 —.2
15
13
12
One ounce to three gallons 2
One ounce to two gallons 3
One ounce to one gallon *
—.5
—1.3
—5.7
1 .2 per cent formalin, .08 per cent formaldehyde.
2 .26 per cent formalin, . 104 per cent formaldehyde,
3 .39 per cent formalin, . 156 per cent formaldehyde.
4 .78 per cent formalin, . 312 per cent formaldehyde.
Table IV.
—
Test of Eed Rust Pboof Oat, 1,000 Seeds
Flat
No.
Strength of Solution. Number
Germinated.
Per Cent
Germinated.
Per Cent +
Due to
Treatment.
16 Control
One ounce to four gallons
One ounce to three gallons
One ounce to two gallons
One ounce to one gallon
989
984
984
973
925
98.9
98.4
98.4
97.3
92.5
17
20
19
18
—.5
—.5
-1.6
-6.4
Table V.
Test of Virginia Gray Oat, 1,000 Seeds.
Flat
No.
Strength of Solution. Number
Germinated.
Per Cent
Germinated.
Per Cent +
Due to
Treatment.
30 Control
One ounce to four gallons
One ounce to three gallons
895
883
855
821
790
89.5
88.3
85.5
82.1
79.0
29
28
—.2
—.4
27 One ounce to two gallons _ —7.4
26 One ounce to one gallon _ _ —10.5
Table VI.
—
Test of Appler Oat, 1,000 Seeds.
Flat
No.
Strength of Solution. Number
Germinated.
Per Cent
Germinated.
Per Cent +
Due to
Treatment.
10 966
977
958
933
912
96.6
97.7
95.8
93.3
91.2
8 +1.1
9 One ounce to three gallons _ . —.8
7 One ounce to two gallons _ —3.3
6 One ounce to one gallon —5.4
34 THIRTY-FIRST ANNUAL REPORT, 1908.
Table VII.
—
Test of Burt Oat, 1,000 Seeds.
Flat
No.
Strength of Solution. Number
Germinated.
Per Cent
Germinated.
Per Cent +
Due to
Treatment.
1 Control _ _ _ 903
922
930
901
730
90.3
92.2
93.0
90.1
73.0
2
3
One ounce to four gallons
One ounce to three gallons _
+1.9
+2.7
4 —.2
5
One ounce to two gallons
One ounce to one gallon _ —17.3
Table VIII.
—
Test of the Black Spring Oat, 1,000 Seeds.
^Jj
1
; Strength of Solution. Number
Germinated.
Per Cent
Germinated.
Per Cent +
Due to
Treatment.
25 Control _ _ 934
959
949
903
911
93.4
95.9
94.9
90.3
91.1
24 One ounce to four gallons _ _ _ +2.5
23 One ounce to three gallons +1.5
22 One ounce to two gallons —3.1
21 One ounce to one gallon —2.3
It will be noted that the White Spring, Red Rust Proof and Vir-ginia
Gray oats give perfectly consistent results, showing increasing
fatality with an increase in the strength of the solution employed,
the loss ranging from .2 to 5.7 per cent with the White Spring oat
and from .2 to 10.5 per cent with the Virginia Gray oat.
The Appier, Burt and Black Spring oats show with the weaker of
the two weakest strengths slight evidences of stimulation and an in-creased
germination over that obtained without treatment, this vary-ing
from 1.1 per cent with the Appier to 2.5 per cent with the Black
Spring oat.
Increase in fatality with increase in strength is shown with the
two stronger solutions in Tables VI and VII.
The Burt oat with a loss of 17.3 per cent in germinating power,
being the one when the strongest solution is considered, showing
greater susceptibility than any other tested.
In Table VIII the Black Spring oat presents some inconsistencies,
notwithstanding the large number of seeds used and the carefulness
of the test. These may be explained, however, by the very high re-sistance
of this oat to all strengths of solutions, thus reducing the
total of fatalities to such a small number as to unduly magnify error
from accidents. The high resistance offered by this oat is probably
attributable to its smooth, shiny, black, hard glumes of extraordinary
thickness.
It may be concluded from this series that formalin of the strength
of one ounce to four gallons or one ounce to three gallons of water
may be used without detriment to germination of these varieties, but
EFFECT OF FORMALIN UPON GERMINATION OF OATS. 35
that greater strength will appreciably injure the germinating power of
some of them, and that the stimulating effect, if any, is insignificant.
TEST OF DIFFERENT TIME OF EXPOSURE TO FOMA-LIN
AND OF THE USE OF LIME.
Table IX.
—
Appler Oat, 1,000 Seeds.
Flat
No.
Strength of Solution. Time
Treated.
Number
Germinated.
Per Cent
Germinated.
10 Control _ _ _ 966
955
934
911
912
893
96.6
49 2-101
2 hours
6 "
12 "
24 "
95.5
31
41
6
One ounce to one gallon
One ounce to one gallon
93.4
91.1
91.2
35 89.3
i Formalin two hours, lime ten hours.
Table IX indicates a gradual increase in fatality with increase of
the time of application, and shows slightly beneficial effect from the
use of lime. Comparison of Tables IX and XI brings out the fact
that the one ounce to one gallon solution may be used for two hours
with greater safety than the one ounce to two gallon solution for
twelve hours, and that with lime the one ounce to one gallon solution
for two hours is no more injurious than the one ounce to four gallons
solution for twelve hours. While no experimental evidence is at
hand regarding the resistance offered by the smut spores to these
solutions of different strengths for different times, it is probable that
owing to the minuteness of the spores the strong solutions for the
short time would be more often fatal to them than would a weaker
solution for a longer time. It is probable, therefore, that in practice
it will be found best to increase the strength of the solution and to
use lime, rather than to increase the time.
EFFECT OF QUALITY OF SEED OX RESISTANCE TO
FORMALIN.
Table X.—Appler Oat, 1,000 Seeds.
Flat
No. Strength of Solution. Quality of
Seed.
Number
Germinated.
Per Cent
Germinated.
Per Cent
Loss Due to
Treatment.
10 Control Average
Average
Good
Good
Medium
Medium
Poor
Poor
966
912
991
954
976
920
937
780
96.
6|
91.2)
99.1^
95.4j'
97.
6|
92. 0]
93.7"|
78.0)
6
45
46
43
One ounce to one gallon
Control
One ounce to one gallon
Control
5.4
3.7
47
44
One ounce to one gallon
Control _ _
4.6
48 One ounce to one gallon
15.7
36 THIRTY-FIRST ANNUAL REPORT, 1908.
Table XL
—
Virginia Gray Oat, 1,000 Seeds.
Flat
No.
Strength of Solution.
Qualitv of
Seed.
Number
Germinated.
Per Cent
Germinated.
Per Cent
Loss Due to
Treatment.
30 Average
Average
Good
Good
Medium
Medium
Poor
Poor
895
790
924
826
909
801
859
659
89.
5
1
79.0 J
92.4)
82. 6 J
90.9)
80. lj
85.9)
65.9|
26
36
One ounce to one gallon
Control _
10.5
32
37
33
38
One ounce to one gallon
Control
One ounce to one gallon
Control
9.8
10.8
34 One ounce to one gallon
20.
Seeds such as were used in the preceding tests were carefully
graded into three classes, each seed being examined individually.
The largest, plumpest grains were designated as "good," the next
lower class as "medium," and the smaller shrunken ones as "poor."
Especial care was taken that no empty glumes, but only actual seeds,
be included in this last class. With the Appier oat, Table X, it is
seen that in the controls the seeds germinated according to quality,
99.1, 97.6, 93.7 per cent respectively, and that when treated with
formalin, one ounce to one gallon, the loss of germinating power was
little with the good seeds, a trifle more with the medium seeds, but
very great with the poor seeds. The average has little or no signi-ficance,
since no record was kept of the percentage of seed of each
quality in the average sample.
With the Virginia Gray Oat, Table XI, less concordant results
were secured. The main fact, however, comes out clearly that there
is much greater fatality from treatment among the poor than among
the better seed.
The fact brought out in these two last tables is very significant, in
that it shows that even the slight diminution in germinating power,
resulting from the formalin treatment of oats, is of benefit in that ic
is in effect a form of seed selection resulting in a partial elimination
of the poorest seed, to the betterment of the sowing. It is probably
to this fact, in part at least, that we may attribute the beneficial
effects of the formalin treatment, so frequently noted, even when no
smut appears in control plats.
In view of these facts, it may be desirable in practice to use the
strongest solution employed in these experiments, or even stronger,
as a means of culling out the poor seed, to then test the germinating
power in order to ascertain the loss of live seed, and to regulate
accordingly the amount of seed to use per acre for sowing. Mechani-cal
separation might, however, attain more economically the same end.
EFFECT OF FORMALIN UPON GERMINATION OF OATS.
A STUDY OF CORN MOLD.
By F. L. STEVENS and J. G. HALL.
The disease of corn known throughout the State as "mold," "mil-dew,"
"rot," "souring," attracted particular attention in 1906, and
study of the disease was begun at that time.
The disease affects the ear, manifesting itself as a whitish growth
of mold over the surface of the grains, sometimes affecting the whole
ear and at other times portions only of it. The amount of fungus
visible upon the superficial parts of the grain is not large, but upon
breaking open the ear, it is found that the spaces between the bases
of the kernels are often densely packed with masses of pure white
mycelium.
Externally, no signs of fruiting bodies of any kind are apparent,
but close examination at the point of attachment of the grains to the
cob, in many instances, reveals the presence of exceedingly minute
black specks, which under the microscope prove to be the fruiting
organs (pycnidia) of the fungus.
Numerous mail inquiries have been received concerning this dis-ease,
and in response to letters, a large number of specimens, repre-senting
many different sections of the State, were received and ex-amined.
While other fungi were occasionally present, in nearly
every instance the symptoms given above were predominant,- and the
fungus with the white mycelium and the black pycnidia was the only
one that was noticed in constant association with the disease.
The pycnidia, upon examination under a microscope, were seen
to be filled with rather long, slender, smoky, usually two-celled, occa-sionally
three-celled, spores. These spores were slightly thicker at
one end than at the other, and were darker in color at the thicker end
than at the narrow end.
This fungus was readily isolated in culture by means of agar plates,
and it has been under cultivation in the laboratory for nearly two
years. It grows rapidly, producing abundant loose, floccose, aerial
mycelium, and a sparse sprinkling of the characteristic pycnidia with
its characteristic spores.
While longer in proportion to the thickness than is usual in the
genu? Diplodia, this fungus must be regarded as a Diplodia; in its
relationship, however, verging toward the genera Septoria and Henr-dersonia,
particularly toward the dark spored, short-spored septoria,
such as Septoria piricola Desm., which grows upon the pear.
Three species of Diplodia have been described upon Zea ; 1, D.
Maydis (Berk.) Sacc. Syll. Fung. Ill 373; 2, D. Frumenti E. & E.
Syll. Fung. X 292; 3, D. Macrospora Earle Syll. Fung. XIV 939.
38 THIRTY-FIRST ANNUAL REPORT, 1908.
These were originally described as growing upon stems and probably
were saprophytic.
The species which we mention above agrees well with the descrip-tion
of Diplodia Macrospora Earle, and is without question to be re-garded
as Diplodia Macrospora, although that species has not hereto-fore
been reported as occurring upon the ears of corn.
A second species of Diplodia was also found in some instances on
the molding ears, evidently as a cause of the mold. This species,
while to the naked eye showing no difference from Diplodia Macro-spora
as to its mycelium or pycnidia, was markedly different in shape
and size of its spores, which were regularly linear-oval, evenly col-ored
throughout and much shorter than the spores of the Diplodia
Macrospora, This latter species agrees completely with the descrip-tion
of the Diplodia Maydis and is to be regarded as that species.
The latter species has recently been the subject of investigation
in Illinois, 1 and was also reported upon at the last meeting of the
American Association for the Advancement of Science. 2
It is estimated that in 1906, the year in which there was the great-est
amount of dry rot, so far as any records have been made, the loss
was 4.5 per cent of the entire crop in Illinois. This represents a loss
of over 15,000,000 bushels, having a value of more than $5,000,000.
The loss in 1907 was less than 2 per cent of the crop or about
$2,000,000.
In order to glean from the farmers as many facts as possible con-cerning
this disease, several hundred letters were sent out to leading
corn growers throughout the State, asking the following questions
:
1. Under what conditions of weather does it do most damage, dur-ing
wet seasons or dry seasons ?
2. Is it most damaging in corn standing alone on the stalk or in
corn which is put up in the shock ?
3. Does it appear before the corn is husked or after?
4. If it shows before husking, does it continue to develop after
husking ?
5. Is there any particular variety which is more susceptible than
other varieties ?
6. Does the time of ripening of corn affect the rotting?
7. Estimate the amount of damage as follows
:
a. Dollars per acre.
b. Per cent of crop.
c. Damage in your county.
In response to these letters we select for analysis twenty-four re-plies,
representing the twenty-three separate counties, Jackson, Mitch-ell,
Ashe, Madison, Caswell, Halifax, Henderson, Pasquotank, Gas-
I IU. Agricultural Experiment Station Circular 117.
2 ScienceN. S. XVII, No. 684, p. 212. Dry Rot of Corn and its Causes. James
T. Barrett.
EFFECT OF FORMALIN UPON GERMINATION OF OATS. 39
ton, Stokes, Sampson, Burke, Forsyth, Northampton, Yancey, Davie,
Wilson, Watauga, Buncombe, Macon, Chatham, Catawba and Ala-mance.
In ten instances, these replies were accompanied by samples
of diseased corn, which proved to be unquestionably the disease
under consideration. While no certainty exists that the other four-teen
replies relate to this disease, it is most highly probable that they
do, since the disease was carefully described, since there appears to
be no hesitation on the part of the farmer as to his recognition of it,
and since in the ten instances where samples were submitted, no error
was noticed.
As to the first question: there was an unanimity of opinion that
the disease was worse in wet seasons than in dry ones. In one in-stance,
the reply was that it was that it was worse in warm, wet
weather.
As to the effect of shocking : three replies stated that there was no
difference whether the corn was in shock or still standing, six replied
that the disease was worse in the shock, and six replied that the dis-ease
was worse when it was not in shock, so that in all probability the
disease is independent of this condition.
Regarding question number three: fifteen stated that the disease
appears before the corn is shucked, while only two stated that the
disease comes upon the corn after shucking. One stated that it con-tinues
to develop after shucking, eighteen state that it does not.
As to specially susceptible varieties: eleven replies were to the
effect that some varieties were more subject to the disease than others.
Three replies stated that there was no difference in susceptibility in
the varieties. Among the varieties named as being more susceptible
than others were the following:
Any early varieties, Iowa Silver Mine, Boone County White, Hick-ory
King, Any red variety, Large Cob, Dent, Strawberry Corn,
Sugar Corn, Soft Varieties, Yellow, Large Cob, Large Kernel.
The amount of damage was placed at from 10 to 50 to 75 per cent
of the value of the crop. Estimates as to dollars per acre and the
damage per county were so unsatisfactory as to be undeserving of
analysis. It is certain, however, that the disease causes, in the aggre-gate,
a very large loss in this State. Both species of Diplodia caus-ing
this mold are known to live and flourish upon corn stalks, and it
is not to be doubted that the fungus multiplies on old stalks, making
there enormous quantities of spores, which, spread by the wind, cause
disease to the following crop. It is therefore very important to plow
under, so far as is possible, all old stalks, leaves and shucks, to thus
diminish the amount of infected material.
40 THIRTY-FIRST ANNUAL REPORT, 1908.
I. STUDIES IN SOIL BACTERIOLOGY.1
NITRIFICATION IN SOILS flND IN SOLUTIONS.
By F. L. STEVENS and W. A. WITHERS
Assisted by J. C TEMPLE and W. A. SYME.
Following the lead of Robert Koch in 1881, in the utilization of
his gelatine plate method for enumeration of the bacterial flora of
various soils, came a vast number of researches directed toward a
determination of the numbers of bacteria in soils from various
sources, depths, conditions, etc., and much valuable information was
gained as to the relative numbers of organisms obtaining in soils
under different conditions. But it came to be recognized after a few
years that the method of enumeration of bacterial floras by plate
counts falls far short of furnishing the needed data for a proper
understanding of the functions of bacteria in soils.
Attention was then directed toward methods, not to determine the
number of bacteria in soils, but to determine the abundance or effi-ciency
of the particular kinds of organisms that are known to be
either beneficial or injurious to agricultural soils. This problem
was essayed in two different ways, by Remy in 1902, 2 and Hiltner
and Stormer in 1903. 3
The method of Remy consists in using as an inoculum, weighed
amounts, usually one to ten grams, of the soil under investigation,
and with this inoculating sterile solutions of various composition to
ascertain the chemical changes effected in the solutions by the bac-teria
introduced with the inoculum. In this way, for example, a 1 per
cent peptone solution is inoculated, and the amount of ammonia found
at the end of a given number of days is taken as an indication of the
ammonifying power of the soil. Similarly, solutions containing am-moiiiaeal
compounds are employed to gain an index of the nitrifying
power, and Giltay's solution is used to measure the denitifying power.
The method of Hiltner and Stormer consists in using solutions
similar to those employed in Remy's method, but making in each
analysis a series of inoculations with the inoculum varying from
1000 milligrams to 0.001 milligram of soil. Since, in some in-stances,
the dilution used fails to cause reaction because the quantity
of inoculum is so small as to contain none of the specific organisms
1 The facts set forth in this article were presented in substantially this same form
at the seventh annual meeting- of the North Carolina Academy of Science May 2,
1908. See Science 27 pg. 988. This article also appears in the current volume of
the Centralblatt fur Bakteriologie II ab.
'2 Centr. Bakt. 2 Abt. 8 (11)08) pp. 657-699, 728-761.
3 Studien uber die Bakterienflora des Ackerbodens, Berlin, (1903).
STUDIES IN SOIL BACTERIOLOGY. 41
in question, while in other instances there is reaction, indicating the
presence of the organism, some conclusions are permissible as to the
number of bacteria present of the particular kind in question in the
inoculum used.
The methods of Bemy and of ITiltner and Stormer and modifica-tions
of these, have been used in numerous investigations in soil bac-teriology,
and much knowledge has been gained as to the abilities of
the bacteria of the soil to effect changes of particular kinds in the
solutions employed and under the conditions of the tests.
The use of soil itself as a culture medium in which to study the
activities of bacteria under conditions of bacteriological control seems
to have been singularly neglected, and when employed, has been used
only for special purposes, e. g., Coleman1 and Bazarewski,2 who em-ployed
soil in physiological studies of nitrifying organisms, and by
Wimmer3 and Hoffman. 4
The object of soil bacteriology is to picture clearly the kinds and
intensities of bacterial activity in the soil in order that the effects of
cultural methods, fertilizers, crops, etc., upon the bacterial flora and
its efficiency may be known, to the end that defects may be recognized
and corrective measures employed.
That the methods of Eemy, of Hiltner and Stormer and of their
followers come much nearer to this ideal than mere colony enumera-tion,
can not be doubted, but that either of these methods very closely
approximates actual occurrences in the soil itself is questionable.
Conditions of bacterial life in solution and in soil may be, indeed
they certainly are, fundamentally different, and the most that can be
said with assurance, when isolated species or natural or artificial com-posites
of species, are inoculated into solutions of known composi-tion
and produce certain chemical changes, is that the organisms
present bring about the changes noted under the conditions of the
test, i. e., dealing with solutions of the artificial nature of those that
are employed.
By such tests it has been noted that certain species of bacteria and
certain live soils when placed in solution bring about nitrification,
ammonification, denitrification, etc., with certain degrees of inten-sity.
It by no means follows of necessity that the same organisms
when in soils cause the same chemical changes, or if so-, with the
same intensities.
To picture adequately the functioning of soil bacteria, methods
must be used which show as nearly as possible the effects as they are
actually produced by bacteria in soils. To assume that bacterial
1 Untersuchungen ueber Nitrifikation Cent f. Bak. 2 abt. 20, 401, (1908)
.
2 Beitrage zur Kenntnis der Nitrifikation und Denitrifikation im Boden 1906.
Diss. Gottingen.
3Zeit. f. Hyg. 48, 160 (1904).
4 Relation of Soil Bacteria to Nitrogenous Decomposition, 23rd Rept. Wis. Agr.
Exp. St. (1906) 120.
42 THIRTY-FIRST ANNUAL REPORT, 1908.
changes produced in a solution represent the changes that would be
caused by the same bacteria in a soil, is to base upon the hypothesis
that the action of a given species of bacteria in a solution is the same
in kind, and approximately the same in degree as is the action of the
same species when in a soil.
Both upon a priori grounds and as the result of numerous observa-tions
during the past few years, we were led to doubt the validity of
this hypothesis. 1 A series of experiments was therefore instituted
to test the question: Do soil bacteria act in solutions the same as
they do in soils ? The results of these experiments, with other ex-periments
of collateral bearing we here present and discuss.
We may state in advance that working with pure cultures as well
as with soil composites, there is a great divergence in behavior of
the same organisms when in soils and in solutions as regards nitrifi-cation,
2 denitratation, and ammonification ; that some species or races
affect their chemical changes in each medium, some in one only,
others to different degrees in different media.
Bacteriological Methods.
In all instances strict bacteriological precautions were taken to
avoid contamination of the test cultures. In cases of composite or
crude inoculations with soil, the soil to be used was taken with asep-tic
precautions, and the water, media, glassware, etc., were sterile.
Unless otherwise stated, the cultures were in cotton-stoppered, Erlen-meyer
flasks, and were kept in a dark incubator room at a tempera-ture
varying from 30 degrees to 35 degrees. Calcium carbonate was
added to all cultures. 400 grams of air-dry soil were used with water
sufficient to render one-third saturated, unless otherwise stated.
Before sterilizing, the soil and nitrogenous material (except as-paragin)
were mixed, the water content made as desired, and the
whole flashed, plugged, autoclaved for one hour at 120 degrees, and
inoculated as desired. To sterilize asparagin a definite amount was
weighed into a graduated flask, and enough ether added to cover the
asparagin. After twenty-four hours the ether was evaporated, sterile
water added, the asparagin dissolved and made up to a definite vol-ume.
The desired amount of this solution was taken with a sterile
pipette.
'Since the publication of the brief abstract of this paper in Science, 27, p. 988.
Fraps (Bui. 106, Tex. Agr. Exp. Sta. p. 8) has noted that nitrification does not
proceed in saturated soils, and Lipman in his book "Bacteria in Relation to
Country Lite," p. 338, says that "With too much (moisture) nitrification was
suspended." Failue to nitrify in an almost "waterlogged" sand was also noted
by Hoffman (23rd Rept. Wis. Agr. Exp. Sta).
2 Throughout this article we employ the term nitrification which has by many
writers been used in many divers ways, in what seems its most logical meaning, to
designate the change of ammoniacal nitrogen to nitrate nitrogen, and the term
nitritation and nitratation to mean respectively change to nitrite and nitrate, as
has been done by Winogradsky. The term denitratation is introduced to desig-nate
change from the nitrate to some other form containing less oxygen.
STUDIES IN SOIL BACTERIOLOGY. 43
When it was desired to absorb solutions by soil, the soil to be used
was dried in an air bath at 100-105 degrees, then 200 or 400 grams
of this soil were flashed, plugged, sterilized, and the solution to be
absorbed, previously inoculated, was poured upon it.
Three methods of inoculation have been employed: first the de-sired
quantity of fresh soil (the inoculum) was poured into the flask
on top of the soil to be inoculated and mixed by thorough shaking;
second, the soil inoculum was weighed into a flask containing the
nutrient solution, and this mixture poured onto the soil medium in
the flask and mixed ; third, a bacterial suspension was secured by
adding 100 grams of soil to 200 cc. of sterile water and shaking three
minutes. Inoculations were then made with the desired amount of
the suspension.
Chemical Methods.
Soil Extract.—To the sample of 400 grams of soil were added
10 cc. of chloroform and water sufficient, with that originally in the
soil, to make 1200 cc. Shaking in a shaking machine was continued
for four hours. After standing over night, the solution was (1)
poured off if sufficiently clear, or (2) filtered through a Pasteur-
Chamberland filter,
1 or (3) after an aliquot part had been taken for
the ammonia determination, the remainder ivas treated with lime
and carbon black and filtered after precipitating the lime with a cur-rent
of carbon dioxide.
Ammonia.—When nitrogen was added in the form of ammonium
sulphate, it was expelled by boiling with a solution of sodium hy-droxide.
When it was added in organic forms, it was expelled by
boiling in the presence of magnesium oxide. In either case the dis-tillate
was collected in one-fifth normal hydrochloric acid and titrated
with one-tenth normal ammonium hydroxide solution, using cochineal
as an indicator.
When the amount of nitrogen was less than the equivalent of 0.1
cc. of one-tenth normal ammonium hydroxide solution, the ammonia
was liberated and collected in the same manner, but the amount was
determined by Nesslerizing.
Nitrites and Nitrates.-—The clarified solution was tested with
diphenylamine,2 which is sensitive to one part of nitrogen in the form
of nitrite or nitrate in twenty millions or 0.05 milligrams nitrogen in
one liter. In the case of soils where the dilution of the solution was
approximately twenty times, the method would show 0.1 milligram
nitrogen in 100 cc. of soil solution or about 0.06 milligram in 400
grams of soil.
Nitrites.—The sulphanilic acid method of Griess3 was used for
nitrites.
bureau of Soils U. S. Dept. Agr. Bui. No. 31. (1906) p. 12.
2 TreadwelPs Analytical Chemistry (1906), 1, p. 341.
3 Bui. Soc. Chim. (3) 2, (1889) ; Bureau of Soils, U. S. Dept. Agr. Bui. 31, (1906),
p. 41.
44 THIRTY-FIRST ANNUAL REPORT, 1905.
Nitrates.—Nitrates were usually determined by the Tiemann-
Schulze method,1 deduction being made for nitrites. When the
amount of nitric oxide liberated was small, a correction was made
for the amount insoluble in a concentrated solution of ferrous sul-phate.
When the amount of nitrogen in the form of nitrates was very
small, it was estimated by the phenol-disulphonic acid method. 2
Explanation of Tables.
The amounts of ammonia, nitrites and nitrates are expressed in
terms of the element nitrogen.
The amounts of nitrogen found at the end of the experiment in
different forms of combination are expressed in terms of percentages
of the nitrogen added at the beginning of the experiment and in terms
of milligrams in 100 cc. of solution. In the case of soil, unless other-wise
stated, the total amount of water present with 400 grams of soil
was 60 cc,, which was sufficient for one-third saturation. In pre-paring
the samples for experiment, the amount of water added was
sufficient, together with that originally present in the soil, to make
60 cc. approximately.
Table I.
—
Showing Nitrification of Both Ammonium
s
Date
of
Inocula-tion.
as
1—1 ,_ .
%%<
Q
Medium. Inoculum. Initial Nitrogen.
9
1
Kind. Grams. Kind. Grams. Milli-grams.
Form.
1902 10-17-07 28
28
28
28
28
Live soil 1866
Sterile soil 1866
400
400
240
240
240
240
127.3
(N H^2 S 4
1903 (N H4I2 S O*
1904 Live soil 1866 ! 400
Sterile soil 1866 400
C S. M.
1905 C. S. M.
1905a Omelianski's solu___ 300 Soil 1866 5 (N H4)g S 4
NITRIFICATION IN SOILS AND IN SOLUTIONS.
Experiment No. 32.—400 grams of soil, No. 1866, from the bed
of the greenhouse were placed in a liter Erlcnmeyer flask. Water,
containing ammonium sulphate to amount of 240 milligrams of
nitrogen, was added to make one-third saturation. Another flask was
similarly prepared, except that the nitrogen was in the form of cotton-
1 Treadwell's Anal. Chem. (1904), Vol. 2., p.
p. 401.
2 Jour. Am. Chem. Soc. 16, (1894); 122, 193.
Bui. 31, (1906) p. 39.
360. Zeit. f. Anal. Chem. 14 (1870)
Bureau of Soils, U. S. Dept. Agr.
STUDIES IN SOIL BACTERIOLOGY. 45
seed meal. Check flasks similarly prepared, but sterile, were pro-vided
in each instance. The flasks were kept in the incubator room
four weeks at 30-35 degrees.
At the same time Omelianski's solution,3 containing ammonium
sulphate, was inoculated with 5 grams of the same soil and main-tained
under the same conditions as were the soil cultures. The re-sults
appear in Table I.
It is here evident from the soil tests, both with ammonium sul-phate
and with cottonseed meal, that this soil is in a vigorous nitri-fying
condition, yet the tests by inoculation in solution give no indi-cation
of the presence of nitrate, even by diphenylamin, capable of
indicating one part of nitrate in two millions. It may be added that
this soil has never nitrified in solution sufficiently to give the dipheny-lamin
reaction, though in soil tests it has repeatedly showed itself to
be in reality a vigorous nitrifier.
The entire absence of ammonia in the cultures with cottonseed
meal was so striking and unexpected that the samples were again
analyzed on December 5, with confirmation of the fact that neither
of the cottonseed meal flasks contained ammonia.
This raised the question whether the soil under study had any
Sulphate and Cottonseed Meal in Soils but Not in Solutions.
?4
CD Percentage of Initial Nitrogen. Miliigrams of Nitrogen in 100 cc. Solution.
-ti
PI
O o
O
OS'S
P
Recovered as "3 Recovered as
1
CO
Ammonia. Nitrites. Nitrates. Ammonia. Nitrites Nitrates.
1902
1903
Net
10.00
12.40
90.00
87.60
34.00
82.00
tr.
0.20
56.00
5.60
50.40
46.00
40.0
49.6
360.0
350.4
136.0
328.0
tr.
0.8
0.0
0.0
0.0
0.0
224.0
22.4
201.6
1901 51.00
100. 00
46.00 tr. 216.0
400.0
184.0 0.0
0.0
184.0
1905
Net 46.00 184.0
1905a 0.00 0.0
ammonifying power, and tests were conducted, employing both pep-tone
and cottonseed meal separately and inoculating with soil ~No.
1866. Each when tested at the end of eight days gave a consider-able
amount of ammonia, showing the soil to be in normal ammonify-ing
condition. The only probable explanation of the absence of
ammonia in this instance is that it was consumed by the nitrite or-ganisms
as fast as it was made. It appears also that the nitrite was
likewise consumed by the nitrate organisms equally fast.
Centr f. Bak. 2 Ab. 5 537-549.
46 THIRTY-FIRST ANNUAL REPORT, 1908.
Table II.
—
Showing Nitrification of Both Ammonium Sulphate and
1909
1910
1911
1912
1913
1914
1909a
1911a
1913a
o> o
10-30-07
10-30-07
10-30-07
10-30-07
10-30-07
10-30-07
10-30-07
10-30-07
10-30-07
o 2?
Medium.
Kinds.
Live soil 1667
Live soil 1667
Live soil, plat 10—
Live soil, plat 10—
Live soil 1867
Live soil 1867
Omelianski's solu.
Omelianski's solu.
Omelianski's solu.
Grams.
400
400
400
400
400
400
300
300
300
Inoculum. Initial Nitrogen.
Kind.
Soil 1667
soil piat io _::
Soil 1867
Grams.
grams. Form.
240 (NH 4 ) 2S04
240 C.S. M.
240 (NH 4) 2S04
240 C. S. M.
240 (NH 4 ) 2S04
240 C. S. M.
127.3 (NH 4 ) 2S04
127.3 (NH 4 ) 2S04
127.3 ( NH 4) 2S04
Table III.
—
Showing Failure to Nitrify in
Date
of
Inocula-tion.
03
o „
H
Medium. Inoculum. Initial Nitrogen.
B
ft
a
CO
Kind. Grams. Kind. Grams. Milli-grams.
Form.
2546 8-24-08
8-24-08
8-24-08
8-24-08
8-24-08
8-24-08
8-24-08
8-24-08
28
28
28
28
28
28
28
28
Live soil 1931a
Live soil 1931a
Omelianski's
solution.
Omelianski's
solution.
Live soil 1931b
Live soil 1931b
Omelianski's
solution.
Omelianski's
solution.
400
400
377. 12
377. 12
400
400
377. 12
377. 12
240 (NH^,SO.
2547 240 (NHV),SOa
2548
2549
2550
Suspension of
soil 1931a.
Suspension of
soil 1931a.
10
10
160
160
210
240
160
160
(NH4 ) 2S0 4
(NH4 ) 2S0 4
(NH 4 ) 2S0 4
2551 (NH4 ) 2S0 4
2552
2553
Suspension of
soil 1931b.
Suspension of
soil 1931b.
10
10
(NH4 ) 2S0 4
(NH4 ) 2S0 4
Experiment No. 3J/..—Three samples of soils Nos. 1667, 1867 and
plat 10, 400 grams each, were taken. The soils were made to one-third
saturation with water carrying 240 milligrams of nitrogen,
either as ammonium sulphate or as cottonseed meal. Simultaneous
inoculations were made into Omelianski's ammonia solution, using 5
grams of soil as the inoculum. All were done in duplicate. The
results are given in Table II.
It is noted in this instance two of the three samples failed utterly
STUDIES IN SOIL BACTERIOLOGY. 47
Cottonseed Meal by Soil No. 18G7 in Soil but Not in Solution.
Percentage of Initial Nitrogen. Milligrams Nitrogen in 100 cc. Solution.
si
a
eg
o °
Recovered as
naccount-ed
for.
o °
Recovered as
a Ammonia. Nitrites. Nitrates. Ammonia. Nitrites Nitrates
x P H H
1909 12.20 87.80 87.80 tr. 0.00 73.2 526.8 526.
8
tr. 0.0
1910 81.50 18.50 18.50 tr. 0.00 489.0 111.0 111.0 tr. 0.0
1911 20.70 79.30 79 30 tr. 0.00 124.
2
475.8 475.8 tr. 0.0
1912 82.40 17.60 17.60 tr. 0.00 494 4 105.
6
105.6 tr. 0.0
1913 1.70 98.30 42.10 tr. 56.20 6.8 393.
2
168.4 tr. 224.8
1911 7.30 92.30 42. 10 tr. 50.20 29.2 370.8 168.4 tr. 200.8
1909a 0.00
0.00
0.00
tr.
tr.
tr.
0.00
0.00
0.00
0.0
0.0
1911a
1913a
SOLUTION B UT VlGOROUS NlTRIFICATIon in Soils.
Percentage of Initial Nitrogen. Milligrams Nitrogen in 100 cc. Solution.
.
S3
O o
o
PI a>
« S3
Recovered as , -d
3 o
o °
Recovered as
2 Ammonia. Nitrites. Nitrates. Ammonia. Nitrites Nitrates.
£ D EH EH
2546 66.52
67.78
67.15
0.34
1.50
0.92
3.38
8.45
5.92
133.0
135.6
134.3
0.7
3.0
1.8
6.8
2547 16.9
aver. 26.93 73.07 53.9 146.1 11.8
2548 93.78
96.36
95.07
0.00
0.00
0.00
0.00
0.00
0.00
39.8
40.9
0.0
0.0
0.0
2549 0.0
aver. 4.93 95.07 2.1 40.4 40.4 0.0 0.0
2550 53.91
62.46
58.18
0.85
0.88
0.87
33.20
7.39
20. 24
107.8
j
1.6
124.9 1.8
116.3 1.7
66.4
2551 14.6
aver 21.68 78.32 42.7 157.3 41.0
2552 93.60
94.38
93.98
0.00
0.00
0.00
0.00
0.00
0.00
39.8
j
0.0
40.1 ' 0.0
0.0
2553 0.0
aver. 6.12 93.98 2.6 39.9 39.9 0.0 0.0
to nitrify either in soil or in solution, but that one sample, soil ]N"o.
1867, nitrified strongly in soil, though not at all in solution. This
soil itself was known to be nearly free from nitrates.
Experiment No. 108.—Two soils were inoculated in duplicate
into soils, and at the same time in duplicate into Omelianski's solu-tion.
The results in Table III give another instance of failure to
nitrify in solutions, though nitrification in soil was vigorous. Though
no checks were run, it is known that soil JSTo. 1931 contained practi-
48 THIRTY-FIRST ANNUAL REPORT, 1908.
Table IV.
—
Showing Better Nitrification in Soil
S
a3
5
3 5
ft
Date
of
tlon.
2046 2-10-08
2047 2-10-08
2048 2-10-08
2049 2-10-08
2050 2-10-08
2054 2-10-08
2055 2-10-08
28
Medium.
Kind. Grams.
Sterile soil 1867.
Sterile soil 1867.
28 Omelianski's solu.
28 I Wiley's solution __.
28 Extract of soil 1867.
28 Omelianski's solu..
28 Wiley's solution __.
390
390
300
300
300
300
300
Inoculum.
Kind Grams.
Soil 1867 10
Soil 1867 10
Soil 1867 10
Soil 1867 10
Soil 1867 10
Soil 1867 .2
Soil 1867 .2
Initial Nitrogen.
Milli-grams.
Form.
240
240
127.3
12.73
127.3
127.3
12.73
i (NH4) 2 S04
(NH4) 2 S04
(NH4)2 S04
(NH4)2 S04
(NH4)2 S04
(NH4) 2 S04
(NH4) 2 S04
cally no nitrate, and that the nitrate shown in this table is the result
of nitrification during the experiment.
Experiment No. 72.—Cultures were tested by using soil extract
as a medium, to ascertain whether some deficiency in the chemical
constitution of the solutions used, which might not exist in soil ex-tract
itself, was responsible for the failure to nitrify in solutions.
Tests were also made in Wiley's solution1 and Omelianski's solution
using 10 grams of inoculum. The results secured at the end of four
weeks are given in Table IV.
The contrast is here again strong between soil cultures E"os. 2046
and 2047, which either upon a basis of percentage of nitrification or
upon a basis of milligrams nitrified per cc. of solution show a much
greater nitrification than cultures in Omelianski's solution, (Nos.
2048 and 2054), which practically failed to nitrify at all. While
the percentage of nitrification in ISTos. 2049 and 2055 in Wiley's so-lution
is high, this is not significant, since the absolute amount of
nitrates is so small as to be almost negligible. Note initial amounts
of nitrogen present. A more nearly correct comparison regarding
the nitrifying power of these samples is shown in the last column,
indicating only slight nitrification in the liquid medium. While
there was nitrification in the soil extract No. 2050, it fell far short
of that occurring in the soil itself. While this experiment, taken
alone, would tend to indicate that soil extract contains something
favorable to nitrification which is lacking in the artificial solutions,
this conclusion is not supported by other evidence. The conclusion
that soil as a medium furnishes a much more sensitive means for de-tection
of nitrification than do the usual solutions, is, however, sup-ported
by the evidence throughout.
'Wiley, Yearbook, U. S. Dept. Agr. for 1895, p. 97.
STUDIES IN SOIL BACTERIOLOGY. 49
Than in Soil Extract or in the Usual Culture Solutions.
Percentage of Initial Nitrogen. Milligrams Nitrogen Per 100 cc. Solution.
,
§3 £3 o
o °
Recovered as
o v
Recovered as
3 Ammonia, Nitrites. Nitrates. Ammonia. Nitrites Nitrates
5 & H P H
2046 19.00 81.00 59.50 0.10 21. 50 76.0 324.0 238.0 0.0 86.0
2047 10.00 90.00 64.40 0.00 25.60 40.0 360.0 257.6 0.0 102.4
aver. 14.50 85.50 61.95 0.05 23.55 58.0 342.0 247.8 0.0 94.2
2048 1.20 98.80 97.00 0.00 1.80 0.5 42.0 41.2 0.0 0.8
2049 12.90 87.10 42.90 0.00 44.20a 0.6 3.7 1.8 0.0 1.9
2050 5.70 94.30 81.20 0.10 13.10 2.4 40.1 34.5 tr. 5.6
2054 12.20 87.80 87.10 0.00 0.70 5.5 37.0 37.0 0.0 tr.
2055 9.701 109.70 102. 30 0.00 7.40* 0.41 4.7 4.4 0.0 0.3
i Excess.
2 This percentage has slight significance because of the small amount of initial nitrogen.
Experiment No. 72.—Duplicate cultures of this experiment were
analyzed at the end of sixty-four days. During this additional time
some slight nitrification had occurred in the cultures which showed
no nitrification at first analysis, but the superiority of soil as a me-dium
for nitrification is even more apparent at the second than at
the first analysis. (Compare Tables IV and V, last column.)
Basing nitrification upon the amount of nitrate produced per 100
cc. of solution, it is seen that the process is sixty-eight times as rapid
in the soil water in situ as it is in Omelianski's or Wiley's solutions,
and thirty-nine times as fast as it is in an extract of the same soil.
It seems clear from this experiment that not only are results of
four week tests in solutions, such as those of Wiley, Omelianski or
Ashby, worthless as indicative of the nitrifying powers of soils tested
by them, but that results which are negative at the end of four weeks
may indicate some nitrification if the cultures be allowed to stand for
a longer time.
Experiment No. 73.—To 400 grams each of live soils Nos. 1867,,
1667 and 2069 were added in the usual way 240 milligrams of nitro-gen
as cottonseed meal.
Flasks of Omelianski's and of Wiley's solutions were also inocu-lated
with each of these soils. Determinations were made upon all
after four weeks' incubation.
The results are presented in Table VI.
In the last column of Table VI it is noted that soils JSTos. 1867
and 2069 gave a large nitrification in soil, but a nearly negligible
quantity in Omelianski's or Wiley's solutions, while the third soil
failed to nitrify to any extent in any medium.
50 THIRTY-FIRST ANNUAL REPORT, 1908.
Table V.—-Showing Results of Nitrification
Lber.
ula-ba-
Medium. Inoculum. Initial Nitrogen.
CD
!
oc
a> o
Q
an
en
l!
Kind. Grams. Kind. Grams. Milli-grams.
Form.
2165
2166
2167
2168
2169
2173
2174
2-10-08
2-10-08
2-10-08
2-10-08
2-10-08
2-10-08
2-10-08
64
64
64
64
64
64
64
Sterile soil 1867 ___
Sterile soil 1867 ___
Omelianski's
solution.
Wiley's solution__
Extracts of soil
1867.
Omelianski's
solution.
Wiley's solution,.
390
390
300
300
300
300
300
Soil 1867
Soil 1867
Soil 1867
Soil 1867
Soil 1867
Soil 1867
Soil 1867
10
10
10
10
10
.2
.2
240
240
127.3
12.73
127.3
127.3
12.73
(NH 4 ) 2S04
(NH4 )2S04
(NH 4 ) 2S04
(NH4 ) 2S04
(NH 4 ) 2S04
(NH4 ) 2S04
(NH 4 ) 2S04
Table VI.—-Showi]vg Nitrification
ooa
M
o> o
P
03
O -
So
Medium. Inoculum. Initial Nitrogen.
a
o3 m
<v Kinds. Grams. Kind. Grams. Milli-grams.
Form.
2060 2-13-08
2-13-08
2-13-08
2-13-08
28
28
28
28
Live soil 1867
Sterile soil 1867 ___
Live soil 1667
Sterile soil 1667
400
400
400
400
240
0.12
240
0.12
C. S. M. 2
2057 C. S. M.
2061 C. S. M.
2058 C. S. M.
2062 2-13-08 28 Live soil 2069 400
,
240 C. S. M.
2059 2-13-08
2-13-08
28
28
Sterile soil 2069
Wiley's solution-
400
300
0.12
12.7
C. S.M.
2063 Soil 1867 .2 ( NH4 ) 2S04
2064 2-13-08 28 Wiley's solution^ 300 Soil 1667 .2 12.7 (NH 4 ) 2S04
2065 2-13-08 28 Wiley's solution— 300 Soil 2069 .2 12.7 (NH 4 ) 2S04
2066- 2-13-08 28 Omelianski's sol— 300 Soil 1867 .2 127. (NH4 ) 2S04
2067 2-13-08 28 Omelianski's sol— 300 Soil 1667 .2 127. (NH4 ) 2S04
2068 2-13-08 28 Omelianski's sol- 300 Soil 2069 .2 127. (NH 4 ) 2S04
STUDIES IN SOIL BACTERIOLOGY. 51
Tests in Solutions and in Soils at 64 Days.
Percentage of Initial Nitrogen. Milligrams Nitrogen in 100 cc. Solution.
PcST3
P
no
Recovered as
o
p
9%
H
Recovered as
Ammonia. Nitrites. Nitrates. Ammonia. Nitrites Nitrates.
2165 6.801 106. 80 30.80 0.00 76.00 27.22 427.2 123.2 0.0 304.0
2166 1.201 101.20 23.80 0.00 77.40 4.82 404.8 95.2 0.0 309.6
aver. 4.001 104. 00 27.30 ! 0.00 76.70 16.02 416.0 109.2 0.0 306.8
2167 3.001 103.00 92.40 0.00 10.60 1.32 43.8 39.3 0.0 4.5
2168 3.40 96.60 6 60 0.00 90.001 0.2 4.1 0.3 | 0.0 3.8
2169 4.70 95.30 77.20 0.00 18.10 2.0 40.5 32.8 0.0 7.7
2173 6.901 106. 90 97.70 1.30 9.20 2.82 45.3 41.4 0.6 3.9
2174 1.601 101. 60 26.40 tr. 75.201 0.12 4.3 1.1 tr. 3.2
i Excess.
2 These percentages have small significance because of the small amount of nitrogen.
in Soils, Not in Solutions-
Percentage of Initial Nitrogen. Milligrams Nitrogen in 100 cc. Solution.
Jh OS
os-d 3S
o °
Recovered as "3
O o
o
^
Recovered as
Ammonia. Nitrites. Nitrates. Ammonia, Nitrites Nitrates
fc P H P H
2060 155.6 244.4 14.0 0.0 230.4
2057 0.4 2.4 2.4 0.0 1.6
net 39.90 60.10 2.90 0.00 57.20 158 242.0 11.6 0.0 228.8
2061 318.0 82.0 78.4 3 6
2058 1.0 1.0 0.6 0.0 0.4
net 79.75 20.25 19.45 0.00 0.80 319.0 81.0 77.8 0.0 3.2
2062 260.0 140.0 33.6 6.4 106.4
2059 1.3 0.7 3 4
net 65.18 34.82 8.32 1.60 24.90 260.7 139.3 33.3 6.4 99.6
2063 41.00 59.00 0.00 3.60 59.001 1.8 2.5 0.0 0.2 2.5
2064 41.90 58.10 33.00 0.00 25. 101 1.8 2.5 1.4 0.0 1.1
2065 50.10 49.90 39.60 tr. 10.301 2.2 2.1 1.7 tr. 0.4
2066 55.10 44.90 40.90 0.20 4.00 23.4 19.1 17.4 tr. 1.7
2067 61.40 38.60 37.60 tr. 1.00 26.1 16.4 16.0 tr. 0.4
2068 50.90 49.10 48.10 tr. 11.00 21.7 20.8 20.4 tr. 0.4
1 Not significant on account of the very small amount of initial nitrogen.
2 C. S. M—Cottonseed Meal.
52 THIRTY-FIRST ANNUAL REPORT, 1908.
Table VII.
—
Showing Nitrification in
CD c3
D
O
o
°a
o> o
ft
3 .
o -
II
Medium. Inoculum. Initial Nitrogen.
B
a
CO
Kind. Grams. Kind. Grams. Milli
grams. Form.
2025
2026
2027
2028
2-10-08
2-10-08
2-10-08
2-10-08
14
14
14
14
Sterile soil 1867 ___
Sterile soil 1867 ___
Peptone water
C. S. M. water
490
490
200
200
Soil 1867
Soil 1867
Soil 1867
Soil 1867
o
o
o
o
120
120
60
60
Peptone.
C. S. M.
Peptone.
C. S. M.
Table VIII.
—
Showing Influence of Number
i &
<s3
ooG
CD O
Q
c3
rO
2 •
i—i ^
if
Medium. Inoculum. Initial Nitrogen.
a
CD
ft
1
CC
Kind. Grams. Kind. Grams. Milli-grams.
Form.
1962
1963
1964
1965
1966
12-2-08
12-2-08
12-2-08
12-2-08
12-2-08
12-2-08
28
28
28
28
28
28
Sterile soil 1867
Sterile soil 1867 ___
Sterile soil 1867 ___
Sterile soil 1867 ___
Live soil 1867
Sterile soil 1867
390
350
300
200
400
400
Soil 1867
Soil 1867
Soil 1867
Soil 1867
10
50
100
200
240
240
240
240
240
240
(NH 4 ) 2 S04
(NH 4 ) 2 S0 4
(NH 4 ) S S0 4
(NH4 ) 2 S04
(NH 4 ) 3 S04
1967 (NH4 ) 2 S0 4
Making proper allowance for the very small quantity of initial
nitrogen in Omelianski's and Wiley's solutions, the same conclusion
is reached from the percentage of nitrogen recovered as nitrates.
Two of the soils could nitrify vigorously in soils but only slightly in
solutions.
Experiment No. 69a.—Four cultures were made ; two in soils,
one with peptone and one with cottonseed meal ; two in solutions, one
with peptone and one with cottonseed meal. They were inoculated
in parallel with the same bacterial suspensions from soil ~No. 1867.
Analysis on the fourteenth day gave the results shown in Table VII.
While nitrification progressed to a marked extent in both soil cul-tures,
the solutions gave no reaction with diphenylamin. Though no
checks were run with this test to determine the amounts of nitrates
in these soils, our constant experimentation with them and frequent
analyses assure us that there was barely a trace, or no nitrate at all,
present in* the soil when the experiment was set up. The amount
shown by the analysis is due to nitrification during the experiment.
Experiments 56 and 57.—It seemed possible that the amount of
STUDIES IN SOIL BACTERIOLOGY. 53
14 Days in Soils, Not in Solutions.
Percentage of Initial Nitrogen. Milligrams Nitrogen in 100 cc. Solution.
u
q
O °
Recovered as q
03-d
q a> al
o °
Recovered as
fit
iq
Ammonia. Nitrites. Nitrates. Ammonia. Nitrites Nitrates.
£ & H P Eh
2025 51.60 48.40 11.20 1.50 37.20 103.2 96.8 22.4 3.0 74.4
2C26 66.30 33.70 2.80 1.50 30.90 132.6 67.4 5.6 3.0 61.8
2027 29.60 70.40 70.40 0.00 0.00 8.9 21.1 21.1 0.0 0.0
2028 61.70 38.30 38.30 0.00 0.00 18.5 11.5 11.5 0.0 0.0
of Bacteria Upon Rapidity of Nitrification.
Percentage of Initial Nitrogen. Milligrams Nitrogen in 100 cc. Solution.
u 1-
8=2
o
o3^3
q o> o °
Recovered as q
o3T3
q & <5 o
o °
Recovered as
q Ammonia. Nitrites. Nitrates. Ammonia. Nitrites Nitrates.
525 P H H
1962 60 90
53.20
0.20
0.20
lost.
17.90
243.6
212.8
0.8
0.8
lost.
1963 29.90 71.10 115.6 284.6 71.6
1964 34.20 65.80 42.70 0.20 23.10 136.8 263.2 170.8 0.8 97.4
1965 21.40 78.60 44.10 0.20 34.50 85.6 314.4 176.4 0.8 138.0
1966 4.601 104. 60 12.60 0.20 91.80 17.61 417.6 50.4 0.8 367.2
1967 31.20 68.80 68.60 0.20 0.00 124.8 275.2 274.4 0.8 0.0
i Excess.
inoculum used might be an important factor in determining the
amount, or at least the rapidity, of nitrification in early stages of
incubation. To throw light upon this point, parallel cultures were
made by mixing the same soil, sterile and alive, in different propor-tions,
thus varying practically only one factor, the quantity of live
organisms present. Experiment 56 consisted of such a series with
nitrogen supplied in the form of ammonium sulphate; experiment
57, with nitrogen in the form of cottonseed meal.
The results are given in Tables VIII and IX.
In Table VIII there is shown a remarkably regular increase in
nitrification as the quantity of inoculum increases. In Table IX,
where cottonseed meal was used, if the third result be disregarded,
the same relation holds true. The discrepancy in the behavior of
soil ~No. 1970 is inexplicable, but it probably does not vitiate the
general conclusions supported by these two experiments, viz, that
with increase in the inoculum there is nearly a corresponding in-crease
in the total amount of nitrification at the end of four weeks.
When tests of nitrifying power are made in the soil itself, by add-
54 THIRTY-FIRST ANNUAL REPORT, 1908.
Table IX.
—
Showing Influence of Quantity of Bacteria
ber.
ula-o
.
a*
O -
U
Medium. Inoculum. Initial Nitrogen.
S
CO
Date
of
Inoc
tion.
Kind. Grams. Kind. *--•& Form.
1968
1969
1970
1971
1972
12-5-08
12-5-08
12-5-08
12-5-08
12-5-08
12-5-08
28
28
28
28
28
28
Sterile soil 1867___
Sterile soil 1867___
Sterile soil 1867
Sttrile soil 1867___
Live soil 1867
Sterile soil 1867
390
350
300
200
400
400
Soil 1867
Soil 1867
Soil 1867
Soil 1867
10
50
100
200
240 C. S. M.
240 C.S.M.
240 C.S.M.
240 ! C.S.M.
240 C. S. M.
1973 240 1 C. S. M.
Table X.
—
Showing no Nitrification in Solutions
1974
1975
1976
1977
1978
1979
0) o
ft
12-12-07
12-12-07
12-12-07
12-12-07
12-12-07
12-12-07
Medium.
Kind.
[Sterile soil 1867.
1 Water
Grams.
200
f Sterile soil 1867 __ 300
1 Water 200
f Live soil 1867. | 400
1 Water
Inoculum.
Kind. Grams.
Sterile soil 1867
Water
f Sterile soil 1867
.
t Water
200
399.5
200
300
200
J Live soil 1867_ I 400
I Water 200
Soil 1867—
.
0.5
Soil 1867— _ 100
1
Soil 1867 _ 0.5
Soil 1867____ _ 100
Initial Nitrogen.
Milli-grams.
Form.
C. S. M.
360 ; C.S.M.
360 I C.S.M.
360 ! (NH 4 ) 2 SO,
360
360
(NH4 ) 2 S0 4
(NH4 ) 3 S0 4
ing the material to be nitrified directly to the soil, it is evident that
there is initially a much larger number of organisms than when 200
milligrams or even 10 grams of the soil are used as an inoculum. We
may regard the direct soil tests in our work as having the equivalent
of an inoculum of 400 grams.
The idea that increase in the quantity of the inoculum brings in-crease
in nitrification arouses the suspicion that perhaps the low nitri-fication,
or entire failure to nitrify, found by the Ashby1 method with
an inoculum of only 200 milligrams of soil, may be due to the small-ness
of the inoculum used.
Experiment No. 58.—This experiment was set up to test this lat-
Jour. Chem. Soc. 85, 1158.
STUDIES IN SOIL BACTERIOLOGY. 55
Upon Rapidity of Nitrification ob Cotton seed Meal.
Percentage of Initial Nitrogen. Milligrams Nitrogen in 100 cc. Solution.
c P
, -: Recovered a.' o
Dtal
Re-covered.
Recovered as
3
rs >
+e 8 Ammonia. Nitrites Nitrates. Ammonia. Nitrites Nitrates
fc P £ p H
1968 76.20 23.80 1 17.50 tr. 6.30 304.8 95.2 70.0 tr. 25.2
1969 70.10 29.90 , 13.30 tr. 16.60 280.4 119.6 53.2 tr. 66.4
1970 74.50 25.50 22.40 tr. 3.10 298.0 102.0 89.6 tr. 12.4
1971 60.20 39.80 \ 4.90 tr. 34.90 240.
8
159.2 19.6 tr. 139.6
1972 53.60 47.00 0.00 tr. 47.00 212.0 188.0 0.0 tr. 188.0
1973 97.50 2.50 0.00 tr. 2.50 390.0 10.0
1
0.0 tr. 10.0
C. S. M.- Cottonseed Meal.
Even When Very Large Inoculum was Used.
Percentage of Initial Nitrogen. Milligrams Nitrogen in 100 cc. Solution.
"5 Recovered as "3 Recovered as
q3
2O uo
o
O °
oOSO o
a <^ o ° 13
Ammonia. Nitrites. Nitrates. Ammonia. Nitrites Nitrates.
fc & H p H
1974 70.60 29.40 29.40 0.00 0.00 97.8 40.7 40.7 0.0 0.0
1975 48.90 51.10 51.10 tr. 0.00 67.7 70.8 70.8 tr. 0.0
1976 78.30 21.70 21.70 0.00 0.00 108.4 30.1 30.1 0.0 0.0
1977 45.40 54.60 54.60 0.00 0.00 62.9 75.6 75.6 0.0 0.0
1978 lost lost lost lost 0.00 lost lost lost lost 0.0
1979 43 20 56.80 56.70 tr. 0.00 60.0 78.5 78.5 tr. 0.0
C. S. M.—Cottonseed Meal.
ter point: to determine whether the failure to nitrify in solutions
can fairly be attributed to the smallness of the inoculum used.
A series of tests was made in solutions, varying the amount of
inoculum. In order to maintain conditions as nearly parallel as
possible, the quantity of soil used in each case was the same, larger
or smaller amounts of it beine; sterilized to sive the desired variations
in the number of live organisms present.
Thus in soil ISTo. 1974, 399.5 grams of sterile soil+0.5 gram of the
same live soil were used, while in No. 1979, grams of sterile soil+
400 grams of live soil were used. The other numbers gave interme-diate
conditions. Solution sufficient to cover the soil to a depth of
2.5 cm. was employed in each case, the solution also carried nitrogen
56 THIRTY-FIRST ANNUAL REPORT, 1908.
Table XL
—
Showing Failure to
Nitrogen 240 Mgs. as Ammonium Sulphate.
o
o
a Medium. Inoculum
d
fc
o
© o 8*
9 «
1/2 » Eh
P.
a Kind. Amount. Kind. Amount.
GO ft Pi
2621 9-10-08 28
[Sterile soil 1549
\ Water to % saturat'n
400
60
Suspension of
Soil number 1867 _.. }
10
2622 9-10-08 28
/Sterile soil 1549
{_ Water to % saturat'n.
400
60
Suspension of
Soil number 1867 }
10
2623 9-10-08 28 f Sterile soil 1549
(Water to saturat'n
400
100
Suspension of
Soil number 1867 ___ }
10
2624 9-10-08 28 [ Sterile soil 1549
\ Water to saturat'n
400
100
Suspension of
Soil number 1867 ___ }
10
2627 9-10-08 28 f Sterile soil 1783
\ Water to % saturat'n
400
100
Suspension of
Soil number 1867 ___ }
10
2628 9-10-08 28 f Sterile soil 1783
\ Water to % saturat'n
400
100
Suspension of
Soil number 1867 ___
I
J
10
2629 9-10-08 28 f Sterile soil 1783
(Water to saturati'n
400
144
Suspension of
Soil number 1867 ___ }
10
2630 9-10-08 28 ( Sterile soil 1783
\ Water to saturati'n
400
144
Suspension of
Soil number 1867 }
10
2631 9-10-08 28
(Sterile soil 1931
\ Water to % satutat'n
400
60
Suspension of
Soil number 1867 ___ }
10
2632 9-10-08 28
{Sterile soil 1931
\ Water to % saturat'n
400
60
Suspension of
Soil number 1867 ___ }
10
2635 9-10-08 28