Diagnosing Plant nutrient deficiencies Dr. Ellen Paparozzi Department of Agronomy and Horticulture University of Nebraska-Lincoln Nitrogen Deficiency corn sorghum Old to young (left to right) Nitrogen Deficiency wheat Sugar beets wheat Causes • Cold, very wet or very dry soils accentuate symptoms • Most universally deficient nutrient in non- leguminous crops • A mobile element • Required in the highest concentration (linear response) • pH not an issue is most soils Phosphorus Deficiency Corn Sorghum P deficiency due to herbicide injury to corn roots Phosphorus Deficiency • Most pronounced on young plants • Older plants may grow out of symptoms • Cold, very wet or very dry soils accentuate symptoms • Often mistaken for other stresses such as insects, temperature or herbicides Potassium Deficiency Potassium Deficiency Yellowing followed by necrosis of leaf margins • OR, small chlorotic spots progress to necrosis and are scattered on older leaves • Internodes are shorter • Plants susceptible to diseases • Drought/irregular irrigation corn sorghum Corn Magnesium Deficiency • 0.5% dry weight • Yellow to white interveinal striping or chlorosis of older leaves • Older leaves may become purple • Leaf edges and tips may turn brown and die • Accentuated in acid, sandy soils with high rainfall • Agronomic crops, hard to distinguish from disease or other nutrient deficiencies; tissue test !! Magnesium Deficiency Magnesium deficiency Corn Calcium Deficiency • 1% dry weight • Immobile macronutrient • Incomplete formation of developing tissue • Severe stunting • Tips of emerging leaves often “stick” together • Not often seen in legumes • Fruit lacks rigidity Calcium Deficiency Sulfur deficiency • Accentuated in cold, wet soils which are acid or sandy with high O.M. content • Legumes and some vegetables have a higher requirement than small grains • Non-linear (linear plateau) response to application • Sulfur-induced N-deficiency ??? Sulfur Deficiency Sorghum Sugar beets Tobacco Iron Deficiency • 0.02% dry weight • Occurs in calcareous soils • Interveinal chlorosis of younger tissue • Brown, necrotic spots may occur (soybeans) • In dicots and non-graminaceous - shortened lateral roots, more root hairs Manganese Deficiency Sorghum Corn Tissue test or soil test ??? Nutrient in excess Induced Deficiency NH4, K, Ca, Mg, Na Same except Na Cl NO3, SO4 + N K (NH4 blocks K uptake) Ca Mg and B PO4 Fe, Mn, Zn, Cu Fe Mn (and the reverse) Mo Cu 3 List of Apps available Yara CheckIT - - free app See the catalog from International Plant Nutrition Institute or visit their website www.ipni.net .