吴旗县不同植被类型土壤干层特征分析

吴旗县位于黄土高原暖温带半干旱地区，由于降雨量较少以及地表的蒸发和植物的蒸腾，使土壤水亏损严重，部分植被下的土壤中出现了土壤干层。为了系统比较不同植被类型下土壤干层特点，通过对吴旗不同植被0～9.0m土壤水分的实地测量和分析，得出以下结论:除农地外，其它植被类型下都不同程度的存在着土壤干层，干层严重程度，林地大于灌木林地，灌木林地大于草地；草地存在临时干层和永久干层，永久干层深度可以达到4.0m。测量当时，灌木林没有临时干层，存在永久干层，深度3.0～8.4m；杏树林不存在临时干层，油松林临时干层则很严重，杏树林和油松林永久干层深度分别在8.0m和9.0m以上。临时干层的出现取决于降水的补充，因此可能与采样时间有关。通过对吴旗县土壤干层的分析可以为进一步研究土壤干层和植被建设提供借鉴。

Analysis of Dried Soil Layer of Different Vegetation Types in Wuqi County

Wuqi County lies in the warm temperate zone and semi-arid area. Because of less precipitation, soil evaporation and vegetation transpiration, the soil water is seriously lossed and dried soil layer appears in parts of vegetation’s ground. In order to systematically compare the characteristic of dried soil layer in different vegetation types, according to the local investigations and analysis of 0~9.0 m soil water of different vegetations, the following conclusions are drawn. Except the farm ground, other vegetations’ grounds have dried soil layers of different degree. To the dried extent of layer, arbor ground is drier than shrub ground and shrub ground is drier than grass ground.At the time of investigation, it is found that there are temporary and perpetual dried soil layer in grass ground and the depth of perpetual dried soil layer is 4.0 m, and shrub ground has no temporary but perpetual dried soil layer and the depth of perpetual dried soil layer is 3.0~8.4 m, and almond ground has no temporary dried soil layer but the perpetual dried soil layer of pine is seriously dry and the perpetual dried soil layer depth of almond is over 8.0 m and the pine’s is over 9.0 m. Precipitation determines the existence of temporary dried soil layer, so the temporary dried soil layer is related to the sampling time. This analysis of the dried soil layer in Wuqi will provides references for further study of dried soil layer and vegetation planting.