陕北黄土高原人工刺槐林生长与土壤干化的关系研究

通过对陕北黄土高原南北 6个人工刺槐林样地进行标准地调查 ,结合树干解析与土壤含水量资料 ,分析了人工刺槐林树高、胸径、材积等指标的生长状况与土壤含水量亏缺的关系。结果表明 ,土壤含水量的亏缺程度与刺槐林的生长有明显的一致性。南部的宜君降雨充沛 ,土壤含水量基本没有亏缺 ,没有产生明显的土壤干化现象 ,相应刺槐林的生长状况良好 ,没有产生衰退迹象。随着降雨量的减少 ,从富县开始 ,土壤含水量发生了严重程度不一的亏缺现象。富县样地因水分亏缺而形成的干化层已影响到了人工刺槐林的生长 ,林分已有了衰退的迹象。样地吴旗、安塞、绥德和米脂则土壤含水量亏缺严重 ,形成了明显的土壤干化层 ,并且严重影响到了人工刺槐林的生长和发育 ,导致人工刺槐林成为低效低产林 ,限制了林分的生态防护效益 ,说明这些地区属于不适宜人工刺槐林生长的分布区。

Study on Relationship between Growth of Artificial Robinia pseudoacacia Plantation and Soil Desiccation in the Loess Plateau of Northern Shannxi Province

Based on the survey for 6 sample artificial %Robinia pseudoacacia% forestland sites and the analysis of soil water content and bole growth ring, the relationship of growing status(about height, DBH and volume and soil water deficit was studied. The results showed that the deficit degree of soil water was related to the growth status of Robinia pseudoacacia. In Yijun County, southern Shannxi, there is no severe soil water deficit, no obvious soil desiccation, the %Robinia pseudoacacia% growth was good. In Fu County, dried soil layer has been formed because of soil desiccation that already has had bad effects on the growth of %Robinia pseudoacacia.% In Wuqi, Ansai, Suide and Mizhi County, soil water deficit become severer, dried soil layer was worse, which caused artificial Robinia pseudoacacia plantation to form into low efficient and productive one and limited the ecological functions of artificial %Robinia pseudoacacia% plantation suggesting that those areas were not suitable for the growth of artificial %Robinia pseudoacacia plantation.