RZWQM2模型模拟牛场肥水施用夏玉米土壤硝态氮迁移特征

为研究华北平原种养结合中养殖肥水的合理施用,减少典型农田水肥施用后土壤氮淋溶对地下水的影响。该研究以河北省徐水区夏玉米为研究对象,应用RZWQM2模型验证牛场肥水施用玉米农田的可行性,对2014—2016年玉米种植前后数据进行模型参数率定与验证。验证结果表明,土壤体积含水率的均方根误差和平均相对误差值分别在0.000 6～0.070 7 cm~3/cm~3和0.21%～21.44%之间变化,土壤硝态氮均方根误差和平均相对误差值分别在0.000 8～2.617 3 mg/kg和0.03%～18.58%之间变化,其中牛场肥水施用土壤中硝态氮主要在0～120 cm土层发生变化,说明RZWQM2模型可以用来模拟华北平原牛场肥水施用对土壤水分、硝态氮含量及玉米产量的动态变化。利用率定和验证后的模型进行了夏玉米农田硝态氮淋溶的验证与预测,表明硝态氮淋溶浓度随肥水氮量的增加而增加。RZWQM2模型可以应用于牛场肥水施用农田的模拟,为预测和评估土壤适宜的肥水施用提供更合适的方法。

Simulation of the soil nitrate nitrogen migration characteristics of summer maize fertilized with dairy manure and wastewater using RZWQM2

Abstract: The continuous improvement of the intensive breeding of livestock and poultry had resulted in a large amount of livestock waste, which caused seriously affected the sustainable development of animal husbandry. The ecological model of farmland reuse after anaerobic treatment of breeding waste has been widely used. Fertilizer water application increased the cumulative nitrogen utilization rate of the winter wheat-summer corn rotation system and reduced the accumulation of nitrogen in the soil; on the other hand, excessive irrigation of farming fertilizer water increased the intensity of nitrogen leaching losses in the farmland, and nitrate nitrogen leaching affected groundwater and human health. As a result, how to protect groundwater quality and reduce nitrate nitrogen leaching loss while rationally using farming fertilizer and water farmland had become a hot issue for domestic and foreign scholars. This study took summer corn in Xushui District of Hebei Province as the research object, using the RZWQM2 model to verify the feasibility of irrigating the corn on the farmland with dairy effluents, and uses the data from 2014 to 2016 corn to verify the model parameters. The verification results showed that the RMSE values of the water content of each soil layer vary from 0.000 6 cm3/cm3 to 0.070 7 cm3/cm3 and the MRE values from 0.21% to 21.44%, and the RMSE values of the soil layer nitrate-nitrogen from 0.000 8 cm3/cm3 to 2.617 3 cm3/cm3 and the MRE values from 0.03% to 18.58%. The results showed that the RZWQM2 model after calibration and verification can be used to simulate the dynamic changes of soil water, nitrogen and crop yields under the application of dairy effluents on summer corn planting in the North China Plain. The utilization rate and verification model carried out the verification and prediction of nitrate nitrogen leaching, which showed that the application of dairy effluents mainly occurred in the 0-120 cm soil layer, and the leaching amount of the deep layer increased with the increase of nitrogen application. It can be seen from the simulation results that due to the concentration of pre-season rainfall in corn, there is more nitrate nitrogen in the deep soil. The simulation and prediction of nitrate-nitrogen leaching in the 200 cm soil layer further illustrated that the leaching of the root zone over time nitrate nitrogen in deep soil layers increased with increasing nitrogen application rate. The results showed that the RZWQM2 model can be better applied to farms for applying dairy effluents, and provided a more suitable method for predicting and evaluating the appropriate amount of dairy effluents brought into the soil. But in essence, for a model, it was difficult to reproduce the soil layer in the multiple root zone of summer maize. Therefore, the simulation study of the nitrate-nitrogen leaching in the deep soil of the crop should be combined with the specific local conditions. Comprehensive consideration of crop yield and water and fertilizer utilization proves the feasibility of the model for the assessment of soil nitrogen loss after irrigation of cattle farm fertilizer and water, and it was concluded that the replacement of fertilizer with medium-concentration cattle farm fertilizer and water in farmland is more conducive to crop growth.