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在室内用非稳定流水平土柱法对新疆生产建设兵团石河子121团灌区膜下滴灌棉田不同粒径沙壤土水分扩散率进行了实验研究。结果表明:当土壤体积含水率处于0.25~0.30cm~3/cm~3时,Boltzmann变换参数随土壤体积含水率的增大而缓慢降低;当土壤体积含水率低于0.25cm~3/cm~3时,Boltzmann变换参数随土壤体积含水率的增大而迅速降低。当土壤体积含水率接近饱和时,Boltzmann变换参数为零;当土壤体积含水率接近初始含水率时,Boltzmann变换参数趋于无穷大。土壤体积含水率与土壤水分扩散率呈单调递增关系。不同粒径沙壤土的水分扩散率为:0.5~1.0mm>1.0~2.0mm>小于0.5mm。对于同一容重,相同水平距离情况下粒径不同时沙壤土的累计入渗时间和总入渗水量也不同。不同粒径沙壤土累计入渗时间和总入渗水量从大到小排序是:小于0.5mm>0.5~1.0mm>1.0~2.0mm。
The indoor diffusivity of sandy loam with different grain sizes of drip irrigation under plastic film in irrigated area of Shihezi 121, Xinjiang Production and Construction Corps, was experimentally studied with the non-steady flow horizontal soil column method. The results showed that the parameters of Boltzmann transformation slowly decreased with the increase of soil water content when the soil water content was in the range of 0.25-0.30 cm 3 / cm 3. When the volumetric water content of soil was lower than 0.25 cm 3 / cm 3, 3, the Boltzmann transformation parameters decreased rapidly with the increase of soil water content. When the soil moisture content is close to saturation, the Boltzmann transformation parameter is zero. When the soil moisture content is close to the initial moisture content, the Boltzmann transformation parameters tend to infinity. Soil volumetric moisture content and soil moisture diffusivity showed a monotone increasing relationship. The moisture diffusivities of sandy loam with different particle sizes are as follows: 0.5 ~ 1.0mm> 1.0 ~ 2.0mm> less than 0.5mm. For the same weight, the same horizontal distance under different particle size of sandy loam soil infiltration time and total infiltration of water is also different. The cumulative infiltration time and total infiltration water of sandy loam with different particle sizes are in descending order: less than 0.5mm> 0.5 ~ 1.0mm> 1.0 ~ 2.0mm.