1. Nutrient Budgets For CNMPs Nutrient Management Planners Training March 31, 2009 Bobby Smith County Extension Coordinator UGA Cooperative Extension Morgan County

2. Animal manures used for centuries as fertilizer Benefits:micronutrients slow release of N an P  SOM  soil structure  CEC carbon sink (global warming)

3. Nutrients in organic form N P K is not in same proportion that crops need – usually 1-2-2 instead of 3-2-1.

4. Balancing Manure nutrient inputs Crop needs

5. Nutrient Budgets N-based budgets –Minimize NO3 leaching Manures supply more P than crops need –Excess P leads to eutrophication Will have P-based budgets Determine priority nutrient

6. Nutrient Budgets Two methods – Spreadsheets – QuattroPro & Excel Ag Pollution Prevention page http//www.agp2.org –Nutrient Management Planning in Georgia –CNMP Tools –Worksheet In notebook

7. Nutrient Budgets Both methods are Field Scale –Calculate budgets for each field and sum for farm Proper rate for each field Simulate different scenarios

8. Three Steps Determine crop needs Determine nutrients supplied Balance

9. Crop Needs Need crops to use nutrients Crops have to fit in production system Crops needs vary –Table in Notebook –Crop recommendations Based on SOIL TEST –Maintain nutrient balance –Maintain pH

10. Nutrients Available from Manure Nutrients in organic form Not all available to plants Nitrogen –Mineralization Waste characteristics, temperature, moisture –Losses to volatilization pH, temperature, how applied

11. Nutrients Available from Manure Definitions Total N = Organic N + NO 3 + NH 4 Plant available N % Organic N + NO 3 + NH 4 TKN (Total Kjeldalh N) Organic N + NH4

12. Example – Fresh Dairy Manure (wet basis) TKN = 10.4 lbs/ton NH 4 = 1.9 lbs/ton NO 3 = 0.03 lbs/ton What is Total N? TKN + NO 3 = 10.4 lbs/ton What is PAN? (%mineralized*(TKN-NH 4 )) + NH 4 + NO 3 = 2.6 + 1.9 +0.03 = 4.53 lbs/ton

13. Nutrients Available UGA manure test results give total nutrients Determine Plant Available Nutrients –Use Availability Coefficients Depends on manure and application method Incorporates losses through volatilization and form of nutrient

14. Nutrients Available UGA lab reports on wet basis –Dry basis need % solids To use spreadsheet need results –Wet basis –Total N, P2O5, K2O

15. Balancing Needs Go to Spreadsheet

16. Summary Manure –Improves Soil Organic Matter –Improves Soil Structure –Increases Cation Exchange Capacity –Provides Micronutrients –Not all nutrients are available to plants Manure is not in the correct ratio for crop use (usually 1-2-2 instead of 3-2-1)

17. Summary Continued Nutrient Budgeting is balancing manure nutrients supplied with crop needs Nutrient Budgets are field scale Availability coefficients according to manure application and storage method determine percent available

18. AGRICULTURAL POLLUTION PREVENTION PROGRAM UGA Cooperative Extension UGA Cooperative Extension Biological & Agricultural Engineering Dept. College of Agricultural & Environmental Sciences University of Georgia University of Georgia Sponsored by the GA Pollution Prevention Assistance Division-AgP2 Bobby Smith- rcsmith@uga.edu