Research on nitrogen application rate of spring wheat in Xining area of Qinghai province based on DNDC model
The aimed to alleviate the Groundwater pollution caused by the leaching of surplus nitrogen fertilizer in farmland,and to find the appropriate amount of nitrogen under the conditions of high yield of wheat and agronomic efficiency of nitrogen fertilizer.The DNDC(Denitrification Decomposition)model was calibrated and validated based on 2-year experimental data from the Xining region of Qinghai.The model was calibrated using data from 2020 and validated using data from 2021.The sensitivity of wheat yield and nitrate leaching to irrigation amount,irrigation frequency,tillage depth,nitrogen application rate,and fertilization frequency was first evaluated to explore the effects of different nitrogen application rates on wheat yield,nitrate leaching amount and nitrogen fertilizer utilization efficiency in farmland.The results showed that:(1)DNDC model could simulate wheat yield and nitrate nitrogen leaching amount well.The normalized root-mean-square deviation of wheat yield and nitrate nitrogen leaching amount was 0.16-0.28 and 0.18-0.26,respectively.The standard deviation ratio of root-mean-square deviation was 0.55-0.68 and 0.48-0.57,and their coefficient of determination was greater than 0.80.(2)Wheat yield and nitrate nitrogen leaching were the most sensitive to nitrogen application,with sensitivity indices(SI)of 0.753 and 1.946,respectively.Nitrate nitrogen leaching was less sensitive to fertilization and irrigation frequency,with sensitivity indices(SI)of-0.360 and 0.152,respectively.The irrigation amount(SI=-0.007,SI=0.085)and tillage depth(SI=0.013,SI=0.078)had almost no effect on wheat yield and nitrate nitrogen leaching.(3)Based on the high yield of spring wheat,the agronomic efficiency of nitrogen fertilizer and the safety of groundwater,the optimal nitrogen application range for wheat in Xining,Qinghai was 160.73-176.83 kg/hm2.The above results can provide a theoretical basis for green production in agricultural areas on the Qinghai Plateau.
万方数据
维普
