Why Consider Grid Sampling for Manure Application?
Grid soil sampling for phosphorus and potassium can identify areas in fields with nutrient deficiencies and other areas with sufficient or excess nutrients. Nutrient maps can be used to define areas for manure application or exclusion, using supplemental fertilizer where manure is not applied or does not meet the crop requirements. The overall effect is to increase the fertilizer-replacement value of the manure, conserving its use for nutrient deficient fields and field areas. Related: LPELC Manure Nutrient Management
Each of the case studies was conducted on a Minnesota farm and presents the method to:
- determine crop nutrient needs
- create manure application and exclusion zones from nutrient maps
- estimate the value of manure under whole-field vs zoned application, and
- evaluate practices to reduce off-site soil and nutrient loss for the specific field analyzed.
Videos
- Part 2: Case study of grid soil sampling for manure application on a dairy farm
- Part 3: Case study of grid soil sampling for manure application on a hog farm
- Part 4: Four brief examples of grid soil sampling for manure application on livestock farms
- Part 5: Nutrient availability from manure and crop nutrient guidelines in Minnesota
- Part 6: Problems of excess or poorly applied phosphorus from manure
The case studies do not discuss variable rate manure application, but do assume capability for supplemental fertilizer application, with or without variable rates.
For More Information
https://portal.nifa.usda.gov/web/crisprojectpages/0099228-agricultural-impacts-on-water-quality.html
Les Everett, Agronomist, University of Minnesota Water Resources Center evere003@umn.edu