四川卧龙岷江冷杉林小流域土壤水分的时空分布特征及变异性

本文应用CNC503DR型中子土壤水分仪,在四川卧龙亚高山暗针叶林生态系统定位站,研究了林分和小流域尺度上岷江冷杉林土壤水分的时空分布特征及变异性。结果表明：研究期间,小流域土壤平均容积含水量在0.59~0.66之间,不同群落类型之间,差异比较明显,且随时间的变化规律不同;小流域内土壤剖面的平均容积含水量在0.52~0.77之间,平均值为0.60,土壤表层最高,45 cm深度最低;随着海拔升高,土壤含水量增加,但超过3 700 m则减少;不同坡向,土壤含水量在0~30 cm土层半阴坡高于半阳坡,30 cm以下土层则相反;不同坡位,土壤含水量下坡最高,其次是中坡,上坡最低;小流域土壤水分变异系数在0.217 6~0.409 8之间,不同群落类型之间差异显著,随着土层剖面深度增加而减小,随着海拔升高而减小,半阴坡高于半阳坡,下坡大于中坡和上坡。

Spatiotemporal Distribution Characteristics and Variability Coefficient of Soil Moisture in a Small Abies faxoniana Forest Catchment in Wolong, Sichuan Province

In this paper,based on field data collected by a CNC503DR soil moisture neutron probe device in sub-alpine dark coniferous forest ecosystem station during the period from July to October,researches were conducted on quantified spatial and temporal distribution characteristics and variability coefficient of soil moisture in Abies faxoniana forest at both stand scale and catchment scale.The results showed that the mean volumetric soil moisture content in the catchment varied from 0.59 to 0.66 from July to October,which had slightly differences among different communities.The highest soil moisture content occurred in the subsurface soil layer while the lowest soil moisture content was found in below 45 cm soil depth.With the ascending of altitude,an increasing trend was firstly found in soil moisture content（SMC）,however,when altitude exceeded 3 700 m,SMC showed an decreasing trend.Compared with the southwest-aspect slope,the northeast-aspect slope showed higher SMC in 0~30 cm soil depth while lower SMC appeared in soil depth below 30 cm.The soil moisture of the lower slopes was higher than that of the upper slopes.The coefficient of variability（CV） of soil moisture at catchment scale was 0.22~0.41.The CV increased with increasing SMC while decreased with increasing soil depth.The CV at northeast-aspect was higher than that at southwest-aspect,at lower slope higher than that at middle slope and upper slope.