1. Phosphorus Cycle, Fertilizer and Organic P Sources. Fundamentals of Nutrient Management Training. August 2009. Morgantown, WV. Ed Rayburn West Virginia University Extension Service erayburn@wvu.edu

2. Phosphorus P is phosphorus, the mineral essential for energy metabolism and bone formation. P 2 O 5 is the measure of fertilizer plant nutrient. P 2 O 5 = 2.3 x P

3. Soil phosphorus Total P in surface soils (0.005 to 0.15%) Organic P in soils (50% of total P) –RPO 4 +H 2 O--------->HPO 4 - + ROH Soil solution P for optimum crop production 5 to 300 ppb P for algal growth 10 to 30 ppb

4. Plant available forms of P H 2 PO 4 - pH<7.2 HPO 4 -2 pH >7.2

5. Phosphorus fixation Reduction in P availability Precipitaion reactions Low pH –Iron and aluminum phosphates (insoluble compounds) Adsorption reaction High pH –Formation of Calcium phosphates (Insoluble)

6. Phosphorus adsorption Chemisorption Physical electrostatic adsorption Most adsorption on iron and aluminum oxides Kaolinite clay minerals Low pH increases adsorption of P P adsorption higher at high clay content

7. Converting to Mehlich 1 Phosphorus pH<5.6 Weak Bray P ppm x 0.6 = Mehlich 1 P ppm pH 5.6-6.2 Weak Bray ppm x 0.7 = Mehlich 1 P ppm pH 6.3-6.9 Weak Bray ppm x 0.8 = Mehlich 1 P ppm pH>6.9 Weak Bray ppm x 1.2 = Mehlich 1 P ppm Morgan ppm x 1 ~ Mehlich 1 P ppm

8. Forage yield response to soil test P.

9. Fertilizer P affect on forage yield when soils test medium to high in P.

10. Fertilizer P affect on forage yield when soils test low in P.

11. Components of nutrient cycling Mass Balance = Import – Export –Import = forage + grain + minerals + fertilizer + rainfall –Export = animal products + crops + run off + erosion + leaching Recycling within farm –Nutrient content of pasture, crop, and supplements –Nutrients excreted by animal vs. removed in product –Recovery of urine and feces –Uniformity of return to area removed from –Location of areas having a net import or export

12. Nutrient value of pasture, hay, silage, and grains.

13. Nutrient content of pasture crops in terms of fertilizer nutrients. Pounds/Ton at 90% Dry Matter NP2O5P2O5 K2OK2OCaCO 3 MgCO 3 Pasture, grass5816731914 Pasture, mm grass6316603416 Pasture, mm legume6314574518 Pasture, legume6914675419 SD12315103

14. Nutrient content of hay crops in terms of fertilizer nutrients. ------- Pounds/Ton at 90% Dry Matter ------ NP2O5P2O5 K2OK2OCaCO 3 MgCO 3 Hay, grass309382312 Hay, mm grass359403113 Hay, mm legume4811474916 Hay, legume5610516217 Hay, small grain26937189 Straw17533137 corn stalks62773 SD9211133

15. Nutrient content of silage crops in terms of fertilizer nutrients. ------- Pounds/Ton at 33% Dry Matter ------ NP2O5P2O5 K2OK2OCaCO 3 MgCO 3 Silage, corn103844 Silage, grass15418105 Silage, mm grass15417135 Silage, mm legume194 6 Silage, legume21420216 Silage, small grain1451984 Silage, sg and leg18523135 SD31541

16. Nutrient content of grain crops in terms of fertilizer nutrients. ---- Pounds/Bushel at 85% Dry Matter --- NP2O5P2O5 K2OK2OCaCO 3 MgCO 3 Corn, shell0.770.330.270.040.20 Wheat1.140.480.310.170.28 Oats0.580.240.180.070.14 Barley0.850.360.270.080.20 Soybeans3.350.691.170.320.44 SD0.150.100.060.020.07

17. Average nutrient content of manure. Source and FormNP2O5P2O5 K2OK2OCaMgS Poultry (broilers, lb/t)596340301310 Poultry (layers, lb/t)395730101146 Dairy (solid, lb/t)13686151683720 Dairy (liquid, lb/1000 gal)2819252373 Swine (liquid, lb/1000 gal)4037231185 Horse (solid, lb/t)96111662 Adapted from V.A. Bandel. 1988. Univ. MD Fact Sheet 512. Using Manure to cut Fertilizer Costs

18. Animal (mineral) vs. fertilizer (oxide) forms of nutrient measurements

19. CP = 6.25 N P 2 O 5 = 2.29 P K 2 O = 1.20 K CaCO 3 = 2.50 Ca MgCO 3 = 3.47 Mg Conversion from fertilizer nutrient to mineral form.

20. Nutrient value of milk, meat, and wool

21. Nutrient value of animal products

22. Magnitude of nutrient cycling by a 1000 lb. cow.

23. Magnitude of nutrient removal by a 500 lb. steer.

24. Magnitude of nutrient removal by a dairy cow making 10,000 lb. milk.

25. Annual nutrient cycling or removal by different classes of cattle.

26. Nutrient value of fertilizers.

27. Phosphate sources triple superphosphate(0-46-0) DAP(18-46-0) superphosphate(0-20-0)

28. Livestock excrete excess P in manure with little in urine.

29. July 2009 fertilizer prices N from urea $0.50 / lb P2O5 from TSP $0.50 K2O from KCl $0.75

30. The dollar value of plant nutrients (N, P 2 O 5, and K 2 0) passing through a 1000 pound cow each year is ~ $150 to $250.

32. Summary : Components of nutrient management Mass Balance = Import – Export –Import = hay + silage + grain + minerals + fertilizer –Export = milk + meat + wool + surface loss+leaching Recycling in pastures and meadows –Nutrient content of pasture –Uniformity over area (or lack of) –Location of areas having a net manure import –Location of areas having a net manure export

33. Take home lesson: Effective recycling of nutrients in manure is an important way to reduce fertilizer cost and prevent environmental contamination.