 Part of › Amino Acids: Building blocks of proteins › Enzymes: responsible for all biological process › Nucleic Acids › Cholorphyll  Needed for Carbohydrate use  Increases root growth

 Excess nitrogen flowing down the Mississippi each year is estimated to be worth $750,000,000 (Science, Malakoff, 1998)  NUE in cereal production must be improved

Raun and Johnson, Agron J. 91:

 Growth is controlled not by the total of resources available, but by the scarcest resource. › Only by increasing the amount of the limiting nutrient (the one most scarce in relation to "need") was the growth of a plant or crop improved. Justus von Liebig

Nutrient limitation expressed as a % of potential yield, or “sufficiency”, and independent of the environment Nutrient limitation directly related to yield potential, and dependent on the environment Mobile Nutrients Immobile Nutrients Plants respond to the total amount of mobile nutrients present Plants respond to the concentration of immobile nutrients present

Yield Goals: average of last 5 years +20% average of the last 3 best years. Yield Goal includes, grain and forage/lbs of meat Nebraska study showed that farmers overestimated yield by 2 Mg ha -1 (32 bu ac -1 ), resulting in an excess of 35 kg N ha -1 (Schepers et al., 1986) Over-optimistic yield goals were the largest contributor to excess N applications with average yield goals exceeding actual yields by over 15%, only about 30% of the fields were within 5% of the yield goal (Daberkow et al., 2001)

 Nitrogen Recommendation = Yield Goal N rate – Residual N  Residual N is › 0-6” (Top-soil) Soil Test NO3 › 6-18” (Sub-soil) Soil Test NO3 › NO3 from irrigation › Cover Crop Credits.

Long-Term Winter Wheat Grain Yields, Lahoma, OK Ave Yld 42 bu/ac

“After the FACT” N Rate required for “MAX Yields” Ranged from 0 to 140 lbs N/ac

1.Right Source 2.Right Place 3.Right Rate 4.Right Time IPNI: International Plant Nutrition Institute

 Anhydrous Ammonia NH3  Urea  Liquid UAN  DAP, MAP, APP  Coated N (sulfur and Polymer)

 Corn vs wheat vs forages

 Cereal Grains, Cotton, Sugar Beets Malting Barley  Yield Goal  Soil Testing  Sensors

 Pre plant and Top-dress/ Side-Dress › Winter Wheat › Corn  Forage Systems › Spring, summer, fall

Brian Arnall 373 Ag Hall Presentation YouTube Channel : OSUNPK