Nutrient Management

1. Nutrient Management Section 5.5 – Phosphorus, Potassium and Heavy Metals Adapted CNMP Core Curriculum Presented by: Roberto Maisonnave, Ag Engineer & M. Sc. International Environmental Consultant robermaison@hotmail.com www.ambientagro.com

2. Objectives • Understand the P cycle • Learn effects of P in the environment • P management exercise • Understand K+ cycle and management • Review main Heavy Metals related issues

3. Crop Residue The Phosphorus Cycle Crop Harvest Fertilizer P Manure P Solution P Stable Labile Labile Stable Organic P Inorganic P Leaching From: Livestock and Poultry Environmental Stewardship 34-3

4. Critical Maintenance Level Limit Nutrient Rate Buildup Drawdown Soil Test Level Soil Phosphorus • Maintaining the soil solution concentration for plant uptake is important. • Nutrient strategy Range Range Maintenance Range

5. Soil Test Phosphorus • Agronomic soil tests are used to determine plant available P. • The tests are a prediction of the amount of desorbed labile (readily available) P into soil solution from the soil mineral surface, over the growing season.

6. Environmental Concerns • Phosphorus is adsorbed to soil particles and moves with soil • Pathways that transport soil to surface water are the primary pathways for P movement to surface water

7. Pathways for P Loss from Soils

8. Phosphorus in Water • Often limiting nutrient in fresh water systems • Addition stimulates algal growth • Too much P = less dissolved O2 • Excessive P = EUTROPHICATION

9. Managing Agricultural P • Minimize P sources • Diet manipulation • Manure technologies - No reduction in P, but may increase options for hauling greater distances or marketing • Fertilizer Management • Conservation Practices • No direct application of P to water

10. Dietary Manipulation Manure Treatment Less Available P in Manure Agronomic Application Rates Erosion Control Buffer Strips Improved Water Quality

11. CNMP Development • Create a Farm P Balance • Current soil tests • Current manure tests • Determine crop P needs • Use manure and wastewater volumes and manure test to determine P2O5 to be applied • Use risk assessment tools to determine the lowest risk application areas

12. P Based Application Rate • Soil Test Phosphorus (STP) • Application based upon soil test analysis, and crop P needs, based on university recommendations • Fertility strategy • Buildup low P soils • Maintenance • Drawdown

13. Kansas P Field Category & Application Rates

14. Kansas Manure Application Rates Oklahoma Manure Application Rates

15. Phosphorus & Potassium Crop Removal

16. Phosphorus Removal • Corn removes 9 kg P2O5 / ton grain • 9 ton/ac Corn: 81 kg P2O5 / ha • This corn crop would remove approximately 62 kg of P2O5per hectare

17. Example NE 25

18. Example NE25

19. POTASSIUM

20. Potassium • Potassium Cycle • Ruminant considerations • Dairy herds, primarily lactating cows • Potassium management

21. The Potassium Cycle

22. Potassium characteristics • Soils can have > 20.000 kg Total K+ / ha • Almost all fixed in clay bridges and unavailable for plant uptake • Exchangeable K+ is bound to soil particle surfaces, and is desorbed into soil solution at 1-10 ppm • Not easily leached in soils, but can be leached

23. Excess K+ Concerns • Grass Tetany • High levels of K+and N in the plant can cause reduced amounts of plant magnesium (Mg) • This can cause a Mg deficiency in grazing animals, and cause a condition called grass tetany or hypocalcaemia • Avoid over-application of K+to pastures • Environmental Concerns • Generally, excess K+ in surface water has not been a concern • Agronomic considerations • Soil Test • Provide adequate K for crop production

24. N-P-K Summary • Understand the source and transport characteristics of the landscape and the particular behavior of elements • Develop a crop budget using nutrient strategies and risk assessment tools • Evaluate performance using good records • Check (often) laws, permit requirements, and regulations governing nutrient management

25. HEAVY METALS

26. Who are they? Are they important? • Ag+, As • Cd2+, Co2+, Cr, Cu2+ • Fe, Hg2+, Ni2+, Pb2+, V, Zn2+ • Some have no biological function • Others are essential for life but toxic at high concentration levels

27. HEAVY METALS CONCERNS • Started on Bronze Age: melting of Cu & Sn • Drinking water pollution • Products for direct human consumption • Vegetables & Fruits • Grains • Fish: Minamata Bay case, Hg bioaccumulation • Hg water: 2 ppb, Hg fish: 20.000 ppb • Respiratory disease

28. Corn* Crop Removal Source: Kansas State University, Corn Production Handbook * 10 ton / ha yield

29. Swine Manure HM Source: AmbientAgro Swine Effluent Database Anaerobic Lagoon Effluent

30. Swine Manure HM in Northeast China Source: Zhang et. al; 2012. Journal of Environmental Research and Public Health

31. Take home message • Heavy metals are present at your farm • Nutrition science must help reducing concentrations in feed additives • Be aware of their risk especially in relation to direct human consumption crops • Soil thresholds: may be wise to follow Bio solids annual loading rates (EPA)