黄土高原半干旱区人工林地土壤水分环境的研究

对黄土高原半干旱丘陵沟壑区主要造林树种林地水分进行了研究。结果表明,该区域不同树种林地土壤含水量很低,接近于凋萎湿度,2002年5月,6 m深土壤平均含水量为5.02%~5.12%,2003年5月为4.65%~6.35%,降水作用仅发生在地表至2 m左右土层内,在1.8~4.0 m有明显的土壤干化现象,含水量保持在凋萎湿度。土壤干层的存在是该区域林地和荒坡土壤水分分布的普遍规律,主要是由特殊的气候条件造成的土壤水分收支长期亏损的积累结果,并非林木生长的必然现象。

The Research of Artificial Forestland on Soil Water in the Semi-arid of the Loess Plateau

The condition of soil water of main forestation trees in semi-arid vegion on the Loess Plateau was studied,the results were as the following:(1) the soil moisture contents of forestland were low,near to the wilting humidity.In May 2002,soil moisture within 6m depth was 5.02%~5.12%,in May 2003,the soil moisture was 4.65%~6.35%.The influence on soil moisture only took place within 2m depth,in 1.8~4.0m layer,there was obvious soil desiccation,and the soil moisture was on the wiltin humidity.(2) the distribution of soil moisture in different forestlands and wastelands indicated that the existence of dried soil layer was a general common phenomenon in this region.The cause of this phenomenon was from the long-term deficit of soil moisture due to the special climate conditions in this region,not from the growth of forest trees.