EssentIaI PIant NutrIents:
тЬеШ
PRESENCE iN INoRth CAROLINA soils ANd RoU iN plANT NUTRiTioN
M. RAyTuckER, AqRONOMisT
OcTobtR 1 999
Baron Justus von Liebig, a German scientist in the mid- 19th century, showed that nutrients are essential
for plant life. He stated, "We have determined that a number of elements are absolutely essential to plant life.
They are essential because a plant deprived of any one of these elements would cease to exist. . . ." He also
authored the term "law of the minimum," which states that "plants will use essential elements only in
proportion to each other, and the element that is in shortest supply — in proportion to the rest — will determine
how well the plant uses the other nutrient elements."
Knowing the nutrients required to grow plants is only one aspect of successful crop production. Optimum
yield also requires knowing the rate to apply, the method and time of application, the source of nutrients to
use, and how the elements are influenced by soil and climatic conditions.
There are 16 nutrient elements required to grow crops (Table 1). Three essential nutrients — carbon (C),
hydrogen (H) and oxygen (O,) — are taken up from atmospheric carbon dioxide and water. The other 13
nutrients are taken up from the soil and are usually grouped as primary nutrients, secondary nutrients and
micronutrients.
Tire primary nutrients — nitrogen (N), phosphorus (P) and potassium (K) — are commonly found in
blended fertilizers such as 10-10-10, or equivalent grades. Primary nutrients are utilized in the largest
amounts by crops, and therefore, are applied at higher rates than secondary nutrients and micronutrients.
The secondary nutrients — calcium (Ca), magnesium (Mg) and sulfur (S) — are required in smaller
amounts than the primary nutrients. The major source for supplementing the soil with calcium and
magnesium is dolomitic lime (aglime), although these nutrients are also available from a variety of fertilizer
sources. Sulfur is available in fertilizers such as potassium and magnesium sulfate, gypsum (calcium sulfate)
and elemental sulfur.
Micronutrients — iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), boron (B) and molybdenum (Mo) —
are required in even smaller amounts than secondary nutrients. They are available in manganese, zinc and
copper sulfates, oxides, oxy-sulfates and chelates, as well as in boric acid and ammonium molybdate.
ТаЫе
1 . NutrIents essentIaI For pIant qrowtIi
NutrIents
From
аш
& water
NuTRieNTS From
pRiMARy NUTRIENTS
soil, Ume ANd commercIaI FertIUzers
SECONdARy nutrIents mIcronutrIents
carbon (C)
nitrogen (N)
calcium (Ca)
boron (B)
hydrogen (H)
phosphorus (P)
magnesium (Mg)
chlorine (Cl)
oxygen (0)
potassium (K)
sulfur(S)
copper (Cu)
iron (Fe)
manganese (Mn)
molybdenum (Mo)
zinc (Zn)
