通过选取干热河谷区典型发育的3种原位土壤(燥红土、变性土和新积土)剖面平台,采用“浇水—曝晒”循环的方法模拟研究区干湿交替的气候条件,设置0,1,3,5次干湿交替频度,以探明不同干湿交替处理对干热河谷冲沟发育区3种典型土壤的崩解性差异及其影响因素。结果表明:(1)3种土壤的崩解过程有所差异,燥红土崩解速度较慢,崩解持续时间短,崩解残留土较多;变性土崩解速度极慢,崩解持续时间长,崩解残留土量最多;新积土崩解过程迅速,土壤崩解速度极快,几乎无残留土量。(2)3种土壤的崩解性差异明显,最大崩解指数从大到小依次为新积土(97.56%)>变性土(38.67%)>燥红土(12.92%);平均崩解速率表现出相似结果。(3)干湿交替对3种土壤崩解性均有一定增强作用,对燥红土和变性土崩解性增强作用主要表现为提高其最大崩解指数和增大其崩解速率2个方面,而对新积土崩解性的影响则主要表现为缩短其崩解完成所需时间。研究结果从干湿交替的角度为冲沟土壤的崩解性研究提供一定的理论参考,为认知该区水土作用过程及开展水土保持工作奠定理论基础。

3 different types of soil(dry red soil,vertisols soil and alluvial soil)in gully-development region of Dry-hot Valleys were chosen to study the influence of dry-wet alternation on the disintegration of different types of soils in the Dry-hot Valleys,which was conducted by the method of“water-exposure”cycle to simulate dry-wet alternate weather in study area,based on 0,1,3 and 5 times Dry-wet Alternate frequency.The results showed that soil disintegration processes were different for 3 types of soil.In comparison,the disintegration of dry red soil was slower in speed,shorter in time,and more in residual soil;the disintegration of vertisols soil was the slowest in speed,the longest in time,and the most in residual soil;the disintegration of sandy soil was fastest in speed and shortest in time,without any residual soil.There were also clear differences among disintegrations of 3types of soil.The biggest disintegrative indexes were described as:alluvial soil(97.56%)>vertisols soil(38.67%)>dry red soil(12.92%).The average disintegration rate showed the similar results as the biggest disintegration index,namely,alluvial soil>vertisols soil>dry red soil.(3)The dry-wet alternation could strengthen soil disintegration of 3different types of soil.For the disintegration of dry red soil and vertisols soil,the dry-wet alternation could enhance their biggest disintegration index and average disintegration rate. For the disintegration of alluvial soil,the dry-wet alternate could shorten disintegration time.All in all,the above results can provide some theoretical references for researching the disintegration of gully soil and cognizing soil and water conservation function process,and can also lay the foundation for soil and water conservation work.