Objective Exploring the leaching mechanism of soil water and nitrogen migration under drip spring irrigation, which may provide a theoretical basis for salt control and nitrogen conservation in saline-alkali land.
Methods The effects of different irrigation quotas (W1: 750 m3/hm2, W2: 1200 m3/hm2, W3: 1500 m3/hm2, W4: 1800 m3/hm2, W5: 2250 m3/hm2) on soil water and nitrogen leaching in 0～100 cm soil layer were compared and analyzed by field experiments, and 2 250 m3/hm2 was used as control.
Results The soil moisture content under drip irrigation was as follows: narrow rows > wide rows between > films, and the moisture content of the corresponding positions increased with the increase of irrigation quotas, and the positions of wide rows and narrow rows in the membrane gradually approached, tending to the maximum soil water holding capacity. The nitrate nitrogen content in the soil profile showed that the intermembrane > furrow irrigation > in the membrane, and the larger the irrigation quota, the lower the nitrate nitrogen content of the corresponding soil layer. Under the same irrigation conditions, the nitrate nitrogen leaching in the membrane was larger under the drip irrigation method, and the inter-membrane aggregation or a small amount of leaching was greater, and the total nitrate nitrogen leaching was > in the intermembrane > than that in the furrow irrigation under the irrigation rate of 2 250 m3/hm2, and the nitrate nitrogen leaching was reduced by 8.11% compared with the furrow irrigation under the irrigation quota of 2 250 m3/hm2.
Conclusion In the good irrigation or canal irrigation areas with water source guarantee and complete drip irrigation system, the spring irrigation method of film drip irrigation can reduce the spring irrigation quota by more than 20% and reduce the nitrogen leaching loss by 35.77%, which will effectively prevent and control nitrogen pollution of groundwater and indirectly improve the reuse efficiency of soil residual nitrate nitrogen.
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