INCREASING DDGS IN RATIONS WILL INCREASE THE CRUDE PROTEIN % AND % PHOSPHORUS IN THE DIET.

1. MANAGING P IN CATTLE DIETS WITH DISTILLERS GRAINS – THE IMPLICATIONS FOR CROP PRODUCTIONGeorge Cummins, ISU Extension Crop Specialist • Manure is a valuble resource that should be utilized for economic, environmental and social reasons.

2. INCREASING DDGS IN RATIONS WILL INCREASE THE CRUDE PROTEIN % AND % PHOSPHORUS IN THE DIET.

3. INCREASING THE DDGS IN THE RATION WILL INCREASE THE NITROGEN AND PHOSPHORUS EXCRETED IN THE MANURE INCREASING DDGS IN THE RATION WILL INCREASE THE NITROGEN AND PHOSPHORUS EXCRETED IN THE MANURE

4. THE NITROGEN CYCLE

5. ARE YIELD AND WATER QUALITY GOAL COMPATIBLE?

6. $2.20/bu $0.11/lb N $0.22 $0.33 $0.44 MRTN LOW HIGH Maximum Return To N and Most Profitable N Rate Range

7. Maximum Return To N and Most Profitable N Rate Range

9. Nitrogen fertilizer recommendations for manured soilsa and corn after alfalfa(from Blackmer, Voss, and Mallarino, 1997)

10. N P K Where is the Phosphorus?Where is it Going? Sources Transport Destination Runoff Critical Source Areas? High Source & High Delivery Erosion P leaching Tile flow Water Body Subsurface flow Adapted from Beegle, 1999

11. Critical value for P loss “the gap” Critical value for yield Determining “the Gap” P loss in surface runoff Crop yield Low Medium Optimum High Soil test P

12. DECADES CENTURIES Effects of Land Use on Eutrophication Natural process Accelerated by land use

13. Good News on Soil & Phosphorus Losses: Impact of Slope and Pastures (60-80% of P can come from <5% of the land)

14. Field Reference and Recordkeeping Booklet ICM 1

15. PM 1688 Revised November, 2002

16. Nutrient Content of Harvested Crops

17. APPLYING MANURE ACCURATELY AND UNIFORMLY IS SOMETIMES DIFFICULT

18. Availability of nitrogen in animal manure • Nitrogen is present in both organic and inorganic forms in animal manure. • The total amount of N present and the proportion of organic to inorganic N depends on animal species and how the manure is handled and stored. • Recent research suggests: • About 35% of the total N in dry cattle and dairy manure is available to plants the year of application • About 100% of the N in liquid swine manure is plant-available the year of application.

19. Application losses of nitrogen • The two forms of inorganic N in animal manure are ammonium (NH4+) and urea. • If manure is left on the soil’s surface, ammonium and urea will form ammonia gas and be lost to the atmosphere. This process is called volatilization. • You must make adjustments for volatilization losses of N.

20. Use correction factors to account for nitrogen volatilization during land application of animal manure Correction factors to account for N volatilization during land application of animal manures. Application Method Correction Factor Direct injection 0.98 Bdcst & incorp. w/in 24 hrs 0.95 Bdcst & incorp. after 24 hrs 0.80 Bdsct liquid, no incorp. 0.75 Bdcst dry, no incorp. 0.70 Irrigation, no incorp. 0.60 Source: Iowa Department of Natural Resources

21. Volatilization example -- solid manure You have solid manure from a beef operation that contains 12 lb N, 6 lb P2O5, and 12 lb K2O per ton. The manure will be broadcast onto the land; it will not be incorporated. Correction for field volatilization loss: 12 lb N x 0.7 = 8.4 lb N/acre The amount of N available the year of application is: 8.4 lb X 0.35 = 2.9 lb N/ton of manure.

22. Availability of phosphorus in animal manure • P is present in both inorganic and organic forms. • If the soil test for P is “high” or “very high” consider that 100% of the P is available. • If the soil test for P is “very low,” “low,” or “optimum” consider that 60% of the total P will be available the year of application.

23. Availability of potassium in animal manure • K is present in animal manure as the inorganic ion K+. This is the form of K used by plants, so assume that 100% of the total K is available to plants in the year of application.

24. Nutrient requirements for crop production • Manure application rates can be determined using either N, P, or K, depending on which set of regulations you fall under. • N and P are used most frequently to determine application rates.

25. N requirement exampleN supplied by cattle feedlot manure N Fertilizer Requirement = 160# Manure rate = 160 lb N/acre  2.9 lb N per ton = 55 tons/acre [55 tons x 6 lb P2O5/ton = 330 lb P2O5/acre]

26. DDGS Additional Concerns • From Table 2, “Use of Distillers Grain in Feedlot Diets” • 15% DDGS in diet increases excreted P2O5 by 20% • 25% increases excreted by 40% • 40% increase by 70% • Additional Concern regarding Application Dry manure spreaders are not calibrated often enough Dry spreaders aren’t always very uniform in application.

27. My Suggestions for Manure Management • 1. Sample the manure. • 2. Plan for where, how much, and how to apply it. The biggest step! • 3. Monitor it’s performance during the year – late spring N tests when in doubt? • 4. Get a “report card” of how you did. Use the end of season stalk N test.

33. RUNOFF WHERE DOES IT GO?

37. HYPOXIA ZONE - 2005 JULY 9 JUNE 20 JULY16 AUGUST 1

39. Multi-species Riparian Systems Combines woody and non-woody plant materials to reduce surface runoff Betts, NRCS

40. Constructed Wetlands Specifically constructed to intercept chemically-loaded discharge from field tiles Betts, NRCS