| Spatial variation of soil moisture on the grass and shrub land under multiple rainfall's supplement in Loess hilly area |
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| DOI：10.7606/j.issn.1000-7601.2012.04.02 |
| Key Words: Loess hilly area soil moisture spatial variation grass land and shrub land |
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| Abstract: |
| Based on the observation data of soil moisture under 42 simulated rainfalls in Yangou watershed of the Loess hilly area, responses of soil moisture to the simulated rainfalls on grass land and shrub land under two slopes with different management methods (undisturbed, cutting, plowing) were studied. The results were as follows: Under five supplementary rainfalls, acco
rding to the standard deviation and variation coefficient of soil moisture, the effect of land management on soil moisture in the 0～100 cm soil layers showed that: the soil moisture in undisturbed grassbush land could be divided into active layer, relatively steady layer and sub-active layer; the whole soil profile o
f cutting land was a relatively steady layer; plowed land was divided into active layer and relatively steady layer. Under a single rainfall, the active and relatively steady layers would become thinner gradually or disappear with the increase of precipitation, while the sub-active layer increased, changes of the mois
ture content in the whole soil profile tended to be uniform. It was suggested that more sensitive descrimination sandards which were standard deviation and variation coefficient should be used to divide the soil layer according to moisture variability under high intensity supplementary rainfall: active layer, standard deviation＞1.4%, variation coefficient＞12%; sub active layer, 1.4%＞standard deviation＞0.9%, 12%＞variation coefficient＞8%； relatively steady layer, standard deviation＜0.9%, variation coefficient＜8%. Soil moisture increased with the decreasing of slope. Slope had a more siganificant effect on soil moisture in undisturbed land and cutting land compared to plowed land, and the effect of slope on soil moisture in 50～100 cm soil layer was more siganificant than that in 0～50 cm soil layer. In conclusion, soil moisture in depth of 0～100 cm graduall
y increased after a single rainfall, and soil moisture of the profile became gradually stable. Land management as well as slope had siganificant effects on both the change intensity of soil moisture and changes of that in different soil depth. |
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