Characteristics of soil nitrogen transport under moisture measurement and supplemental irrigation in winter wheat

Abstract

【Objective】 To explore reasonable water and nitrogen management practices in the main winter wheat producing areas of North China. 【Method】 A field experiment was carried out at the Irrigation Experiment Centre Station of Shandong Province from 2020 to 2021 using "Qimai No.1" wheat as the material. Four irrigation treatments were set up, with the upper and lower limits of irrigation at 60%-70% (W1), 70%-80% (W2), 80%-90% (W3) and no irrigation (CK) of the field water holding capacity, and the application rate of nitrogen was 240 kg/hm2. The data from the experiments were used to determine the rate of the parameters of the RZWQM 2 model and to validate the model, and the model was applied to simulate the effects of the water and nitrogen regulation on the accumulation of soil nitrate nitrogen and nitrogen use. The model was used to simulate the effects of water and nitrogen regulation on soil nitrate nitrogen accumulation and nitrogen utilisation. 【Result】 The results showed that the standard root mean square errors (NRMSE) of soil profile water content, soil nitrate nitrogen amount and yield ranged from 9.3% to 25.0%, 0.3% to 29.7% and 4.03% to 11.19%, respectively, and the mean relative errors (MRE) ranged from 8.0% to 24.2%, 1.4% to 30.4%, and 5.29% to 11.98%, respectively, with consistency index D were all higher than 0.65; using the corrected RZWQM 2 model, five nitrogen levels (180, 200, 220, 240 kg/hm2and 260 kg/hm2) were set at W1, W2 and W3 moisture measurement and recharge levels, and the soil nitrate nitrogen accumulation produced at the W2 and W3 levels was increased by 30.9%-59.7% and 49.6%-79.6%, respectively, compared with the W1; The simulation concluded that N application of 220-240 kg/hm2 and W2 levels were more favourable for soil nitrate N accumulation in the 0-1 m soil layer, with accumulation of 108.30-125.10 kg/hm2. Nitrogen uptake efficiency and nitrogen fertilizer bias productivity of N application of 220 kg/hm2 and W2 levels were 59% and 23.4 kg/kg, respectively. 【Conclusion】 In conclusion, the RZWQM 2 model can be used to simulate soil nitrate nitrogen accumulation and nitrogen utilisation in the main production area of winter wheat in North China, and moisture supplemental irrigation W2 and nitrogen application of 220-240 kg/hm2 are more reasonable water and nitrogen management measures in this area.

Keywords

• rzwqm 2 model
• supplemental irrigation by measuring moisture
• water and nitrogen regulation
• nitrate-nitrogen accumulation
• nitrogen use efficiency