Form taken up by plant: NH4+, NO3-
Mobility in soil: NH4+: no; NO3-: yes:
NO3- water soluble, not influenced by soil colloids
Mobility in plant: Yes
Deficiency symptoms: Chlorosis in older leaves, under severe deficiency lower leaves are brown, beginning at the leaf tip and proceeding along the midrib.
Soil pH where deficiency will occur: None due to nitrate's mobility
Role of nutrient in plant growth: N assimilation into amino acids for protein and amino acid synthesis, component of chlorophyll, vegetative growth
Enzymes that require N: Nitrate reductase, nitrite reductase, nitrogenase
Role of nutrient in microbial growth: Necessary for the synthesis of amino acids
Concentration in plants: Wheat 1.7 - 3.0%
Forage 3.0 %
Corn 2.7 - 3.5%
Soybeans 4.2 - 5.5%
Grain sorghum 3.3 - 4.0%
Peanuts 3.5 - 4.5%
Alfalfa 4.5 - 5.0%
Bermudagrass 2.5 - 3.0%
Effect of pH on
Precipitated forms (low pH): none
Precipitated forms (high pH): none
at pH>8, no nitrification; at pH>7, NO2- accumulates
Interactions with other nutrients: Si: enhances leaf erectness, thus neutralizing the negative effects of high nitrogen supply on light interception (leaf erectness usually decreases with increasing nitrogen supply); P: symbiotic legume fixation needs adequate P or a N deficiency can result; Mo: component of nitrogenase therefore could have Mo induced N deficiency in N2 fixing legumes (especially under acid soils conditions); Fe: necessary for nitrogenase and ferredoxin (electron carrier), legume hemoglobin, deficiency reduces nodule mass, and nitrogenase;
Fertilizer sources: ammonium sulfate, anhydrous ammonia, ammonium chloride, ammonium nitrate, ammonium nitrate-sulfate, ammonium nitrate with lime, ammoniated ordinary superphosphate, monoammonium phosphate, diammonium phosphate, ammonium phosphate-sulfate, ammonium polyphosphate solution, ammonium thiophosphate solution, calcium nitrate, potassium nitrate, sodium nitrate, urea, urea-sulfate, urea-ammonium nitrate, urea-ammonium phosphate, urea phosphate.
Burford, J.R., and J.M. Bremner. 1975. Relationships between the denitrification capacities of soils and total, water-soluble and readily decomposable soil organic matter. Soil Biochem. 7:389-394.
Marschner, Horst. 1995. Mineral Nutrition in Higher Plants. Academic Press, London.
Tisdale, S.L., W.L. Nelson, J.D. Beaton, and J.L. Havlin. 1993. Soil Fertility and Fertilizers. MacMillan Publishing Co., New York, N.Y.
Authors: Heather Lees, Shannon Taylor, Joanne LaRuffa and Wade Thomason