陕西省长武县黑垆土斥水性的影响因素

Factors Influencing Water Repellency of Heilu Soil in Changwu County,Shaanxi Province

[目的]分析改性黑垆土出现斥水性的条件及其影响因素,为研究气候暖干化背景下当地降雨入渗行为对斥水性的响应问题提供参考。[方法]试验在黄土旱塬陕西省长武县农田试验场进行。选取玉米地和苜蓿地0—20 cm土壤作为试验对象,对2种作物下的土样设计4水平土壤含水量、3种容重和3水平十八烷基伯胺(OCT)添加量进行组合配制土样,用滴水穿透时间法进行斥水性测试。[结果]土壤斥水性(SWR)随着土壤含水量(0%~6%范围)和容重的增加及OCT添加量的增加而增大,其中土壤含水量、OCT添加量和土壤容重对SWR的影响存在多因素交互效应。在逐步回归分析中,OCT和含水量共同参与下的拟合模型更优。1.3 g/cm^(3)土壤容重下,在0%含水量和0.15%OCT添加量及2%含水量和0.10%OCT添加量条件时,非斥水的黑垆土土壤会转变为轻微斥水性土壤。[结论]在黑垆土低水条件下的降水入渗过程中,应更多关注不同土地利用土壤含水量和极性物质的积累变化对斥水风险的影响。

[Objective]The conditions and factors influencing soil water repellency(SWR)of Heilu soil was explored in order to provide a reference for research on the response of local rainfall infiltration behavior to water repellency under the background of climate change.[Methods]The experiment was conducted on farmland from Changwu County on the Loess Plateau.Measurements were made on soil samples from the 0—20 cm soil layer of a maize field and an alfalfa field.Soil samples from the two crop fields were brought to a laboratory and tested at four soil moisture contents,three bulk densities,and three levels of added octadecylamine(OCT).Water repellency tests were conducted by measuring drip penetration time.[Results]SWR increased with increasing soil moisture content(ranging from 0%to 6%),bulk density,and OCT addition.Soil moisture content,OCT addition,and soil bulk density exhibited multi-factor interaction effects on SWR.Stepwise regression analysis determined that the best model occurred with OCT and water content as regression parameters.Under a soil bulk density of 1.3 g/cm^(3) at 0%moisture content with 0.15%OCT addition,2%moisture content and 0.10%OCT addition,the non-water-repellent Heilu soil would turn into slightly water-repellent soil.[Conclusion]More attention should be given to the impact of soil water content and accumulation of polar substances on water repellency risk under different land uses during the process of precipitation infiltration for a Heilu soil under low-water conditions.