【摘要】 基于近年来黄土丘陵区林地形成大规模土壤干层的事实,为了探索降雨在黄土丘陵区枣林地干化土壤中的入渗、迁移规律,明确干化土壤的修复能力,在陕北米脂试验站建立野外10m大型土柱模拟枣林地干化土壤,采用CS650—CR1000土壤水分自动监测系统对其进行连续定位观测。观测数据分析表明:(1)独立降雨的入渗、迁移深度主要取决于降雨量,大、中、小雨的水分影响深度分别达90~140,70~80,40cm,降雨量一定时还与降雨强度、初始土壤含水量等因素有关,降雨强度越大、初始土壤含水量越高,水分的入渗深度及迁移深度也越大。(2)间歇降雨中几次降雨交互对水分的入渗、迁移产生促进作用。相同雨量下,其入渗深度较独立降雨可提高100%~160%,迁移深度可提高91%~197%。(3)黄土丘陵区并非所有降雨都对土壤水分有影响。观测期内降雨次数与降雨量的有效率分别为36.4%和72.7%。(4)土壤垂向剖面在多次降雨的累积作用下具有层次性,本试验期间降雨影响范围内的土壤剖面主要可以分为3层,0—90cm为降雨入渗敏感层,90—160cm为降雨入渗迟缓层,160—240cm为雨水迁移层。研究结果对于促进黄土丘陵区林地干化土壤的治理与修复,加强土壤水分的科学管理与改善具有重要的理论和实践意义。更多还原

【Abstract】 Based on the fact of the formation of large-scale soil dry layers in recent years,a field soil column up to 10 m was established to simulate the drying soil in jujube forests at the Mizhi experimental station,which is located in the north of Shaanxi Province.The purpose was to explore the regularities of rainfall infiltration and water migration,also to clarify the infiltration capability of dry loess.By using the CS650-CR1000 automatic system,changes of soil moisture within different depths were observed continuously under natural conditions.Meanwhile,the precipitation during the monitoring period was recorded by an automatic weather station.The results showed that both of the depths of infiltration and migration under independent rainfall mainly depended on the precipitation.The depths could reach up to 90-140 cm,70-80 cm,and 40 cm,respectively,when influenced by heavy rain,middle rain,and light rain.With the same precipitation,it was affected by other factors such as rainfall intensity and initial soil water content.The greater the rainfall intensity and the higher the initial soil water content was,the deeper the depths were.Under intermittent rainfall conditions,several rainfall events promoted infiltration and migration interactively.Compared with independent rainfall,the intermittent rainfall could significantly increase the infiltration depth by 100%-160%,and the migration depth by 91%-197% with the same precipitation.In the loess region,not all the rainfall events could influence the soil.During the observation periods,the effectiveness of the rainfall fre-quency and amount were 36.3%,72.7% respectively.Under the influence of multiple rainfall events,the soil profile tended to be layered.According to the changes of soil moisture,the affected soil could be mainly divided into three levels,i.e.the sensitive layer of rainfall infiltration within 90 cm,the delayed layer of rainfall infiltration between 90 cm and 160 cm,and the migrating layer of rainfall between 160 cm and 240 cm.The results are of great theoretical and practical significance to the restoration of woodland drying soil and scientific management of soil moisture in the loess hilly region.更多还原