IFCA continues to survey its members each spring and fall about fertilizer application practices based on the 4R Code of Practice. The 4R metric survey results can be combined with results from the survey conducted by NASS for a better understanding of the adoption of voluntary practices over time to reduce nutrient losses. Results shown are from the IFCA 4R survey for the 2020 crop year.
For nitrogen loss reduction practices, the survey asked about ammonia application to corn acres. Figure 4.29 indicates that 89% of fall applied corn acres received ammonia in accordance with the University of Illinois’ recommended application date and 87% included a labeled nitrification inhibi tor. Results show that 65% of these acres received a rate of applied nitrogen less than the MRTN for corn-corn or corn-soybean rotation, which is an indication of planned split nitrogen application. Seventy-four percent of corn acres had ammonia applied at a total nitrogen rate in the recommended range according to the updated Nitrogen Rate Calculator.
Figure 4.30 shows survey results about phosphorus loss reduction practices. The results indicate that 75% of acres are soil tested at least once every four years and 24% of acres are above critical P soil test values based upon crop removal rates.
