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Nitrogen Management. Intro to Soils. Nitrogen in the Plant . Part of Amino Acids: Building blocks of proteins Enzymes: responsible for all biological process Nucleic Acids Cholorphyll Needed for Carbohydrate use Increases root growth. SCIENCE Magazine.
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Nitrogen Management Intro to Soils
Nitrogen in the Plant • Part of • Amino Acids: Building blocks of proteins • Enzymes: responsible for all biological process • Nucleic Acids • Cholorphyll • Needed for Carbohydrate use • Increases root growth
SCIENCE Magazine 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
N that is not used is lost Raun and Johnson, Agron J. 91:357-363
Liebig's Law of the Minimum 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 Liebig1803 - 1873
Bray’s Nutrient Mobility Concept Plants respond to the total amount of mobile nutrients present Plants respond to the concentration of immobile nutrients present Mobile Nutrients Immobile Nutrients Nutrient limitation directlyrelated to yield potential, and dependent on the environment Nutrient limitation expressed as a % of potential yield, or “sufficiency”, and independentof the environment
Yield Goals 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)
N rate recommendation • 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
4 R’s Right Source Right Place Right Rate Right Time IPNI: International Plant Nutrition Institute
Nitrogen sources • Anhydrous Ammonia NH3 • Urea • Liquid UAN • DAP, MAP, APP • Coated N (sulfur and Polymer)
Nitrogen Placement • Corn vs wheat vs forages
Right Rate • Cereal Grains, Cotton, Sugar BeetsMalting Barley • Yield Goal • Soil Testing • Sensors
Right Time • Pre plant and Top-dress/ Side-Dress • Winter Wheat • Corn • Forage Systems • Spring, summer, fall
Thank you!!! www.extensionnews.okstate.edu Brian Arnall 373 Ag Hall 405-744-1722 b.arnall@okstate.edu Presentation available @ www.npk.okstate.edu Twitter: @OSU_NPK YouTube Channel: OSUNPK