Evaluation of midseason sensor based nitrogen fer

Authors: Jacob T Bushong Jeremiah L Mullock Eric C Miller William R Raun D Brian Arnall

Publish Date: 2016/01/14

Volume: 17, Issue: 4, Pages: 470-487

PDF Link

Abstract

Optical sensors coupled with mathematical algorithms have proven effective at determining more accurate midseason nitrogen N fertilizer recommendations in winter wheat One parameter required in making these recommendations is inseason grain yield potential at the time of sensing Four algorithms with different methods for determining grain yield potential were evaluated for effectiveness to predict final grain yield and the agronomic optimum N rate AONR at 34 siteyears The current N fertilizer optimization algorithm CNFOA outperformed the other three algorithms at predicting yield potential with no added N and yield potential with added N R2 = 046 and 025 respectively However no differences were observed in the amount of variability accounted for among all four algorithms in regards to predicting the AONR Differences were observed in that the CNFOA and proposed N fertilizer optimization algorithm PNFOA under predicted the AONR at approximately 75  of the siteyears whereas the generalized algorithm GA and modified generalized algorithm MGA recommended N rates under the AONR at about 50  of the siteyears The PNFOA was able to determine N rate recommendations within 20 kg N ha−1 of the AONR for half of the siteyears whereas the other three algorithms were only able recommend within 20 kg N ha−1 of the AONR for about 40  of the siteyears Lastly all four algorithms reported more accurate N rate recommendations compared to nonsensor based methodologies and can more precisely account for the year to year variability in grain yields due to environment

Keywords: