Decisions used by NSW grains industry advisers to determine nitrogen fertiliser management recommendations

Abstract

Key findings •• Making nitrogen (N) management decisions requires an understanding of soil and plant science, and soil test interpretation. •• Training new agronomists is a priority. •• Senior NSW agronomists identified crop yield expectation as guided by soil moisture at sowing (or at the time of N decision making) as the most important determinant of N fertiliser requirement. •• Further research will increase the understanding of how management practices affect potentially large gaseous N losses. •• Changing from legume pasture-crop sequences to continuous cropping in many central and southern areas of New South Wales is posing new questions for managing N supply. Less frequent pasture legume phases with their N-fixation benefits to the soil is seen as a substantial loss of N-buffering capacity. •• Despite most advisers choosing soil testing as a key approach for determining N fertiliser required, many of their clients had a lower confidence in soil testing, citing ‘high perceived variability in soil nitrate results in the lead up to sowing’.