黑钙土不同土层在两种材质负压渗水器下的吸渗特性

基于–5 k Pa负压灌水条件下的一维垂直水分吸渗试验,分析了陶土和聚乙烯醇缩甲醛泡沫塑料(PVFM)两种材质负压渗水器在黑钙土A、B层的渗水性能,测定累计吸渗量、吸渗率、湿润峰及土壤含水率等指标,并利用它们考察了Kostiakov,Horton、Philip 3种常用的土壤水分吸渗模型及垂直一维非饱和土壤水分运动代数模式描述负压吸渗过程的适用性,进一步比较了不同处理下的模型参数。结果表明:(1)–5 k Pa灌水条件下,PVFM渗水器和陶土渗水器的累计吸渗量没有明显差异,前者能有效替代后者作为负压渗水器;(2)黑钙土B层土壤水分吸渗特性比A层差,同时间内累计吸渗量较少,吸渗率降低速度更快;(3)短时间负压灌溉条件下,不同土层的累计吸渗量与湿润峰、吸渗率与湿润峰倒数、湿润峰平方与时间均存在明显的线性关系;(4)负压灌溉后距离渗水器上下各15 cm范围内,土壤含水率维持于20%~33%范围内,变异系数均在10%左右;(5)拟合结果表明,Kostiakov与Philip模型能很好地描述–5 k Pa负压灌溉下不同处理的水分吸渗特性,而Horton模型描述黑钙土A、B层较长时间的吸渗效果较差。

Infiltration Characteristics of Two Kinds of Negatively Pressurized Infiltration Devices in Different Layers of Chernozem

Based on the vertical one-dimensional infiltration under the condition of –5 kPa, the water permeability of pot clay and PVFM in Chernozem zone A and zone B were analyzed. And the infiltration capacity, infiltration rate, humid peak and soil moisture content were measured and used to test the applicability of Kostiakov model, Horton model, Philip model and algebraic method of vertical one-dimensional unsaturated soil water movement in evaluating negative pressure infiltration, and further compared the model parameters under different treatments. The results indicate: 1) PVFM can replace pot clay as negative pressure infiltration device due to no significant difference in their measured accumulated infiltration; 2) Chernozem zone B has worse infiltration characteristics, less cumulative infiltration capacity and faster infiltration rate decrease compared with zone A in the same time; 3) In short time negative pressure irrigation, significant linear correlation exist between infiltration capacity and humid peak, between infiltration rate and reciprocal humid peak, between humid peak squared and time; 4) When using negative pressure irrigation, soil moisture contents within 15 cm up and down from infiltration device keep within 20%—33% with a variation coefficient of about 10%; 5) Fitting calculation proves that Kostiakov model and Philip model describe better the infiltration characteristics, while Horton model describes poorly in later period.