Study On Nitrogen Utilization Of Wheat Based On Canopy Spectrum

The nitrogen utilization and yield response to nitrogen application of late rice-stubble wheat were studied in the area of rice and wheat rotation in jianghuai,anhui province.Five nitrogen application levels(0,90,180,270,360 kg·hm-2)were used to analyze the effects of different nitrogen application rates on carbon metabolism,nitrogen utilization and yield of late sown wheat.at the same time,in order to improve the precision fertilization technology of wheat in anhui province,the response of wheat canopy spectrum to different nitrogen fertilizer application modes was studied,and the accuracy of the canopy spectral growth monitoring model was established to compare the dry stubble wheat area in huaibei and the rice stubble wheat area in jianghuai.The main research results are as follows:1,Increasing nitrogen fertilizer can significantly optimize the canopy structure of rice stubble wheat in each growth period and improve leaf photosynthesis.proper application of nitrogen was beneficial to the accumulation and transport of dry matter.2.The accumulation and transport of nitrogen and the activities of nitrogen anabolism enzymes in wheat organs could be significantly increased by increasing N application.excessive nitrogen application is not conducive to the coordination of carbon and nitrogen metabolism and the improvement of nitrogen anabolism enzyme activity and nitrogen utilization rate.3.Spike number,grain number per spike and yield of wheat increased with the increase of nitrogen application.continue to increase the nitrogen fertilizer to 360 kg·hm-2 yield did not increase but decreased.It is recommended that the appropriate nitrogen application amount for rice stubble wheat in jianghuai region under late sowing condition is 180～270 kg·hm-2 lower limit,which is the most appropriate nitrogen application amount for both yield and production efficiency.4.The spectral reflectance of nir region is positively correlated with the amount of nitrogen application and seeding density,but not significantly correlated with the ratio of fertilizer application.the correlation between vegetation index and wheat growth index was good.the accuracy of the altimeter in monitoring wheat growth index is higher than that of the dual-band altimeter.the precision of spectrograph used to monitor dry stubble wheat is better than that of rice stubble wheat.