Whipker
В.
1998. Submission procedures
for root substrate, water, fertilizer solution
and plant tissue samples. Raleigh (NC): N.C.
State University Department of Horticultural
Science and N.C. Cooperative Extension
Service. Horticulture Information Leaflet
560. Available at www.ces.ncsu.edu/depts/
hort/floriculture/hils/HIL560.pdf (verified 9
Dec 2008).
Table 1. Expected range of values for soilless
media parameters analyzed according to SME
procedure (Warncke 1998)
Parameter
Range
Nutrient
Balance 1
pH
5. 0-6.5
—
tn
О
и
<300 mhosx 10'Vcm
—
ЕС
< 3 mS/cm
—
IN-N
40-200 ppm
—
NO,-N
40-200 ppm
8-10%
NH -N
4
0-20 ppm
<3%
P
0-20 ppm
К
30-300 ppm
1 1-13%
Ca
20-250 ppm
14-16%
Mg
15-150 ppm
4-6%
Na
—
<10%
Cl
—
<10%
1 Nutrient balance =
[nutrient concentration (ppm) x 1 00] ■*- EC (ppm)
EC (ppm) = EC mhos x lO ’/cm x 6.7
or
EC (ppm) = mS/cm x 670
2 The NCDA&CS Agronomic Division measures
EC in units ofmhosxlO Vcm.
North Carolina
Department of Agriculture
and Consumer Services
Steve Troxler, Commissioner of Agriculture
Agronomic Division
Colleen M. Hudak-Wise, Ph.D., Director
www.ncagr.gov/agronomi/
(919) 733-2655
Mailing Address
1 040 Mail Service Center
Raleigh NC 27699-1040
Physical Address [DHL, FedEx, UPS]
4300 Reedy Creek Road
Raleigh NC 27607-6465
Agronomic Sampling
Folder No. 9
prepared by
Michelle McGinnis, Brenda Cleveland,
Catherine Stokes
January 2009
Sampling for
Soilless
Media Analysis
Floriculture, Nursery & Greenhouse Crops
Soilless media are light-weight substrates used
in containerized production of floriculture
and nursery crops, greenhouse vegetable and
tobacco transplants. Common components of
soilless substrates include compost, peat moss,
perlite, pine bark, sand and/or vermiculite.
Unlike mineral soils, soilless substrates tend
to have little capacity to supply or retain
nutrients or to buffer pH. Consequently,
container nutrient levels and pH are dynamic
and can change quickly. As a result, regular
monitoring of pH and nutrient levels can help
fine-tune fertilization programs.
Saturated media extract (SME) procedure is
used by the Agronomic Division for soilless
media analysis. It is preferred over traditional
soil testing for laboratory analysis of container
substrates (Warncke 1998). The Division
offers the SME procedure through its Plant,
Waste and Solution laboratory.
Methods and measures
SME measures electrical conductivity (EC),
nitrate-nitrogen (NO,-N), ammonium-nitrogen
(NH4-N), phosphorus (P), potassium (K),
calcium (Ca), magnesium (Mg), sulfur (S),
sodium (Na) and chloride (Cl ). EC units are
mhosx 1 0 -7cm, and nutrient concentration units
are parts per million (ppm). pH is measured
on a 1:1 sample-to-water (by volume) slurry.
