基于加热实验的凉山干旱河谷土壤斥水性研究

Soil Water Repellency in Dry River Valleys of LiangshanBased on Lab-heating Experiment

森林火灾影响地表覆被和土壤性质,改变土壤斥水性,而土壤斥水性被认为是影响土壤水文和侵蚀过程的直接原因。本文采集四川省凉山干旱河谷区表层原状森林土样,通过加热实验,分析不同温度和时间土壤斥水性的变化特征。结果显示:未加热情况下,土壤斥水性具有较强的空间异质性,随着加热温度升高和时间延长,空间异质性减弱。土壤斥水性随温度升高而降低,300℃后土壤斥水性被破坏。土壤斥水性随加热时间延长而降低,前30 min最为明显,60 min后基本保持稳定,但温度达到300℃后,加热时间对表层土壤斥水性的影响减弱。

Soil water repellency(SWR)is altered when forest fires affect surface cover and soil properties,which is considered to be the direct cause of affecting soil hydrology and erosion process.This paper employs lab-heating experiment to analyze the variation characteristics of SWR at different emperature and time in the undisturbed forest soil samples collected from dry river valleys of Liangshan Yi Autonomous Prefecture in Sichuan province.The results indicate that SWR has strong spatial heterogeneity under unheated conditions,which will decrease with the increase of temperature and time;as the temperature build up,SWR will be reduced and destroyed after 300℃;SWR will decrease most obviously with the extension of heating time in the first 30 minutes and remain stable after 60 minutes;however,when the temperature reaches 300℃,the effect of heating time on SWR in topsoil is weakened.