Claire Browne1, Seb Ie2
2 Birchip Cropping Group (BCG), 73, Cumming Avenue, Birchip, VIC, 3483
Knowing how much soil nitrogen (N) is available to crops is critical for effective nitrogen management. In 2015, six barley varieties were grown with five varying rates of nitrogen (N). The decile one rainfall season resulted in well below average yields for Victoria’s Wimmera region. By October 2015 symptoms of extreme moisture stress were evident across the trial, which had a mean yield of 0.7t/ha. As a result of haying off, there was a negative relationship between N rate and yield. There was not an interaction between varieties and N rate.
In 2016 a single wheat variety was sown across all plots, with additional N applied to half of each plot. A nitrogen balance was calculated to ascertain the difference between the soil test results and estimated amount of N in residual. The 2016 wheat yields were higher where the higher N applications had been applied in 2015, showing a significant interaction between 2016 and 2015 N treatments. In paddocks where crops have hayed off, these results suggest that deep soil N testing may give a better indication of available N for a subsequent crop than paddock history.