凉山干热河谷典型坡耕地土壤入渗能力动态变化特征研究

Study on the Dynamic Change of Soil Infiltration Capability in Typical Slope Farmland of the Liangshan Dry-Hot Valley Region

为探明凉山干热河谷典型坡耕地土壤入渗性能的动态变化特征及其影响因素,选用微型圆盘入渗仪(mini disk infiltrometer)探究不同地表处理和不同时段(5、8、10月)的土壤入渗特征.研究结果表明:坡耕地连续休闲处理的土壤属性和入渗性能动态变化不大,而5月份雨季初期的翻耕扰动是导致土壤属性突变和导水率急剧增加的主要原因,翻耕后的土壤属性和入渗性能至8月可恢复至连续休闲对照的水平;坡耕地种植玉米可显著降低土壤容重和增加团聚体水稳性,从而提升土壤入渗性能;土壤累积入渗量可以用入渗时间的二次多项式方程进行模拟,在Kostiakov、Philip和Green-Ampt 3种常用入渗过程模型中,GreenAmpt模型用于模拟坡耕地土壤水分入渗过程的效果最优.研究结果可为凉山干热河谷地区的坡耕地水分管理及土壤保持措施布设提供依据.

This study aimed to clarify the dynamic change characteristics and influential factors of soil infiltration in slope farmland of the Liangshan dry-hot valley region.Mini disk infiltrator(MDI)was selected to conduct field experiments and measure infiltration rates in plots of three different treatments at different time periods(May,August,October).The results showed that soil properties and infiltration rate of the continuous fallow treatment varied little throughout the wet season,implying the natural dry-wet dynamic effect on sloping farmland soil infiltration was not significant.However,the tillage disturbance in May of the early rainy season caused the major change of soil properties and the sharp increase in hydraulic conductivity.After that,soil properties and infiltration rate tend to be restored to the level of continuous fallow in August.The corn plants on sloping farmland can significantly reduce soil bulk density and increase aggregate water stability,thus improving water infiltration capability.The cumulative infiltration amount of soil can be simulated by the quadratic polynomial equation of infiltration time.Among the three commonly used infiltration process models,i.e.Kostiakov,Philip and Green Ampt,the Green Ampt model has the best effect in simulating the infiltration process in sloping farmland.The above results would be helpful for water management and soil conservation measures in sloping farmland of the Liangshan dry-hot valley region.