晋西黄土区典型造林整地措施对土壤水分动态的影响

Soil moisture characteristics under level bench and vegetation in loess area of western Shanxi Province

【目的】探究晋西黄土区典型造林树种和水平阶整地措施对0~180 cm土层土壤水分动态的影响,为植被恢复及流域综合治理提供参考依据。【方法】以晋西黄土残塬区蔡家川流域典型工程措施水平阶以及主要造林树种刺槐Robinia pseudoacacia和侧柏Platycladusorientalis为研究对象,于2019年5—9月生长季开展土壤水分定位监测,并采用配对试验,对自然坡面刺槐林地与侧柏林地土壤水分进行同步观测,分析不同植被和水平阶整地综合影响下的土壤水分特征及对降雨事件的响应,评价典型工程措施对不同植被土壤含水量的影响。【结果】生长季不同植被类型、水平阶整地前后的土壤含水量的变化与降雨量的变化密切相关,不同样地平均土壤含水量由高到低依次为水平阶侧柏林地(18.68%)、自然坡面侧柏林地(16.19%)、水平阶刺槐林地(16.10%)、自然坡面刺槐林地(15.42%)。较之自然坡面,水平阶整地措施能够分别提高侧柏林地和刺槐林地土壤含水量15.38%、4.41%。根据土壤水分垂直变化特征,水平阶整地可以提升土壤水分的活跃层、次活跃层深度:水平阶侧柏林地活跃层、次活跃层深度范围为0~80 cm,相对于自然坡面侧柏林地提升深度33%;水平阶刺槐林地活跃层、次活跃层深度范围为0~140 cm,相对于自然坡面刺槐林地提升深度40%。【结论】土壤含水量的动态变化与降雨量、工程措施、植被作用关系密切,水平阶是开展黄土残塬小流域生态恢复的有效工程措施,且水平阶侧柏林地提升效果要优于水平阶刺槐林地。图3表3参37.

[Objective]This study,with an exploration of the effects of typical afforestation tree species and level bench measure on soil moisture dynamics in 0-180 cm soil layer in the loess region of western Shanxi Province,is aimed to provide a reference for vegetation restoration and comprehensive watershed management.[Method]Taking the level bench,which is a typical engineering measure and the main afforestation tree species(Robinia pseudoacacia and Platycladus orientalis)in Caijiachuan watershed in the loess plateau region of western Shanxi as the research objects,the soil moisture was monitored in the growing season of 2019(May-September),with a synchronous observation made of the soil moisture of natural slopes of R.pseudoacacia and P.orientalis using the paired experimental design before an analysis was conducted of the soil moisture characteristics under the comprehensive influence of different vegetation types and level bench and the response process to rainfall events and the effects of typical engineering measures on soil moisture of different vegetation types were evaluated.[Result]The changes of soil moisture before and after soil preparation with different vegetation types and level bench were closely related to the changes of rainfall and the average soil moisture decreased from level bench-P.orientalis(18.68%),slope-P.orientalis(16.19%),level bench-R.pseudoacacia(16.10%)to slope-R.pseudoacacia(15.42%).Compared with natural slope,level bench could increase the soil moisture of P.orientalis and R.pseudoacacia by 15.38%and 4.41%respectively and according to the vertical variation characteristics of soil moisture,level bench could significantly increase the depth of active layer and secondary active layer of soil moisture:the depth of horizontal active layer and secondary active layer of P.orientalis ranged from 0 to 80 cm,which was 33%higher than that of P.orientalis slope while the depth of horizontal active layer and secondary active layer of R.pseudoacacia ranged from 0 to 140 cm,which was 40%higher than that of R.pseudoacacia slope.[Conclusion]The dynamic change of soil water content is closely related to rainfall,engineering measures and vegetation.Level bench is an effective engineering measure to carry out ecological restoration in small watershed of loess plateau,and the lifting effect of P.orientalis level bench is better than that of R.pseudoacacia level bench.[Ch,3 fig.3 tab.37 ref.]