In February 2019, IFCA surveyed its retail members about fertilizer application practices based on the 4R Code of Practice. This survey captured fall fertilizer application practices for 2018, including the percentage of acres treated with 4R practices. Going forward, IFCA will survey its members every winter and summer to capture fall and spring fertilizer-application practices. The 4R metric survey results can be combined with results from the survey conducted by NASS to get a better understanding of the adoption of voluntary practices over time to reduce nutrient losses.
The results from the first 4R metric survey in the fall of 2018 (for the 2019 crop year) are as
follows:
Nitrogen
- 29% of corn acres received an application of fall ammonia.
- Of the corn acres that received fall ammonia, 89% was applied after October 24.
- Of the corn acres that received fall ammonia, 92% included a labeled nitrification inhibitor.
- Of the corn acres that received fall ammonia, 78% received a rate of applied nitrogen
less than the MRTN for corn-corn or corn-soybean rotation. This is an indication of a
planned split nitrogen application.
Phosphorus
- 46% of acres receive variable rate application of phosphorus.
- 57% of acres received fall-applied phosphorus.
Soil Test
- 79% of acres are soil tested at least once every four years.
- 31% of acres are above critical phosphorus soil test values based on crop removal rates.
