Competency Area 6: Nutrient Management and Planning
PO 49. Distinguish P-based from N-based manure application and describe implications.
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Most manures contain approximately three times as much N as P. Thus, applying manure to meet crop N needs will result in overapplication of P and K. Unused P can be lost due to leaching, erosion, and runoff, and can contaminate groundwater and cause eutrophication. Meanwhile, applying manure to meet crop P needs runs the risk of underapplying N, resulting in deficiencies for the growing crop and a poor yield. It requires more land, as smaller manure applications will be utilized on each field, and requires supplemental N in some form, which can be expensive. For example, compare nutrient content of poultry and dairy manure to crop needs: |
When applied to meet N needs (left), both poultry and dairy manure provide much more P and K than needed.
When applied to meet P needs (right), both poultry and dairy manure fail to provide adequate N.
Quick Links
- Competency Area 1: Basic Concepts of Plant Nutrition
- Competency Area 2: Basic Concepts of Soil Fertility
- Competency Area 3: Soil Testing and Plant Tissue Analysis
- Competency Area 4: Nutrient Sources, Analyses, Application Methods
- Competency Area 5: Soil pH and Liming
- Competency Area 6: Nutrient Management and Planning