Study on nitrogen fertilizer recommendation based on RapidSCAN CS-45 for drip-irrigated winter wheat in Xinjiang

Abstract

The research goal is to provide a theoretical basis for real-time evaluating nitrogen nutrition and rational nitrogen fertilization of drip-irrigated winter wheat in Xinjiang province through two-year fixed position experiment by using the local popular variety ‘Xindong 22’ as materials under five nitrogen application levels (0, 120, 240, 360, 480 kg·ha^-2); the models of nitrogen fertilizer recommendation of drip-irrigated winter wheat growing stage was constructed based on the analysis of the relationship between the application of nitrogen fertilizer and remote sensing indicators as NDVI and NDRE at different growth stages which was measured by using the portable active remote sensing spectrometer RapidScan CS-45 on canopy. The results show that the values of NDVI and NDRE in drip-irrigated winter wheat canopy increase rapidly during the recovering stage and the booting stage; during the booting stage and the filling stage, the values of NDVI and NDRE increase slowly, and they begin to decrease after entering the filling stage; the dynamic change trend of NDVI and NDRE in drip-irrigated winter wheat canopy is significantly consistent. The values of NDVI and NDRE may be useful in developing fertilizer application guidelines for wheat which compared with conventional fertilizer application may reduce nitrogen application rates, improve fertilizer use efficiency, yields, and economic benefits.