Studies on the regime of soil moisture under different microhabitats in Huajiang karst valley

Soil physical characters and soil moisture regime law under different microhabitats on afforestation land in karst stony hill area of the Huajing river valley are studied. The result shows that water condition of stone gully is best and soil surface is between stone gully and stone pit, but stone pit is worst. The time of high moisture condition period and that of low moisture condition period under different microhabitats obviously changes annually. Times, extent and dates of water stress under different microhabitats is also actually different in one year. Loss of soil moisture is fast in stone pit, but slow on soil surface, and in stone gully it is between stone pit and soil surface at three small sites within continuous drought dates, which is separately 17.30%, 14.49% and 13.87% in seven days. Time of slight stress on soil surface, in stone pit emerged in seven days. Therefore, soil water stress under different microhabitats emerged in Huajiang karst valley in seven days. This data may be regarded as the time for supplement of water to plants. In general, soil moisture condition in stone gully is superior to soil surface and stone pit. Directing at soil moisture regime character under different microhabitats, suggestion for choosing and allocating tree spices and management to soil water is put forth in the paper.