考虑初始含水率沿程不均匀分布的畦灌技术要素调控

畦田土壤初始含水率是影响灌水质量的重要因素之一，由降雨产流导致的畦田土壤含水率沿程不均匀分布是华北平原农田常见的现象。为探究土壤初始含水率空间变异性对畦灌水流运动以及灌水质量的影响，本文开展一维土柱入渗试验与二维土槽灌溉试验，结合WinSRFR地面灌溉模拟模型，优化求解初始含水率沿程不均匀条件下的畦灌技术要素。结果表明：畦田土壤初始含水率沿程增幅越大，畦灌田面水流推进速度越快，田面水流消退速度越慢；相较于初始含水率均匀分布，畦田土壤初始含水率沿程不均匀分布条件下，灌水效率和灌水均匀度有所下降，储水效率无明显变化；当畦田土壤初始含水率沿程增加时，灌水效率和储水效率受畦田长度、入畦单宽流量及改水成数的影响，而灌后土壤水分均匀度仅受畦田长度和单宽流量的影响；当畦田土壤初始含水率沿程由0.189 0 m³/m³均匀增大至0.464 3 m³/m³时，畦田长度L为85 m、改水成数G为6、单宽流量q为7.0 L/(m·s)时可取得最优灌水质量。本研究结果可为降雨产流带来的畦田土壤初始含水率不均匀条件下的灌水技...

Regulation of Border Irrigation Technical Elements Considering Condition of Uneven Initial Soil Moisture Content along Border

Soil initial moisture content is one of the important factors affecting border irrigation quality. The uneven distribution of soil moisture content caused by runoff is a common phenomenon in the farmland of North China Plain. In order to explore the influence of spatial variability of initial soil moisture content on flow movement and irrigation quality of border irrigation, one-dimensional soil column infiltration test and two-dimensional soil tank irrigation test were carried out in this study. Combined with WinSRFR surface irrigation simulation model, the technical factors of border irrigation under the condition of uneven initial moisture content were optimized and solved. The results showed that the greater the increase of initial soil moisture content along the border, the faster the surface water flow of border irrigation, and the slower the surface water flow of border irrigation. Compared with the uniform distribution of initial moisture content, under the condition of uneven distribution of initial moisture content along the border soil, the irrigation efficiency and irrigation uniformity will decrease, and the water storage efficiency will not change significantly. When the initial soil moisture content increased along the border, the irrigation efficiency and water storage efficiency were affected by the length of the border, the flow rate per unit width of the border and the number of water improvement, while the soil moisture uniformity after irrigation was only affected by the length of the border and the flow rate per unit width. When the initial moisture content of the border soil increases uniformly from 0.1890m3/3 to 0.4643m3/m3, the optimal border irrigation quality can be obtained when the border length L=85m, the number of water change G=6.0, and the unit width flow q=7.0L/(m·s). The results of this study can provide a scientific basis for the regulation of irrigation technology elements under the initial moisture content of border soil caused by rainfall runoff.