Intermediate to Advanced Practices Implemented
- Expanded soil sampling from small 1-acre grid in 2016 to 2.5-acre grid in 2019.
- Fertilizer applications are applied using variable rate equipment.
- All nitrogen applied in-season
This 750-acre corn grain and soybean farm in Wisconsin applies all nutrients and in-season applications using a variable rate spinner spreader. The farm does not apply livestock manure. The farm went from using intermediate 4R practices in 2016 to an advanced 4R nutrient management plan in 2019. The data from individual fields shows how the farm has adapted practices and enhanced the crediting for nitrogen from the previous soybean crop. In field 3 nitrogen rates are lower following the soybean crop.
The average annual cost of 4R practices for corn grain production decreased as the farm moved to advanced 4R practices from 2016 to 2019. During this time, nitrogen use efficiency improved, decreasing below one pound of nitrogen per bushel in 2018 and 2019. The nitrogen balance for corn grain also decreased as the farm changed from intermediate to advanced practices. The combination of these practice changes also resulted in an 18 percent reduction in CO2e pounds per bushel when the 2019 crop year is compared to 2016.
The cost per acre for 4R practices is much lower in soybean on average because of the lower rates of fertilizer applied.