植物篱对土壤养分流失的控制机理研究

IMPACT OF HEDGEROW ON THE CONTROL OF SOIL NUTRIENT LOSS

植物篱是一种能有效减少地表径流、保土蓄水的水土保持措施,但其控制土壤养分流失相关机理的研究甚少。2001年在长江上游支流吒溪河的二级支流王家桥小流域设立的6个香根草(Vetiveriazizanioides)植物篱试验小区中进行地形测量及采样分析,拟通过局部地形变化、土壤颗粒和养分在小区内的空间分布变化来分析植物篱对紫色土区土壤养分流失的控制机理。坡型测量结果表明,植物篱带前出现泥沙堆积,说明植物篱能有效阻止侵蚀泥沙的向下搬运;机械组成分析结果表明,侵蚀影响下的土壤颗粒粒径在空间上出现分布差异,侵蚀剧烈的局部>0.2mm土壤颗粒明显富集,而植物篱对不同粒径的土壤颗粒的流失均有控制效果,但对粒径较大的颗粒的流失控制效果更明显;全量养分和速效养分含量空间分布的分析结果则表明,植物篱对土壤养分流失具有明显的控制作用。

Hedgerow is one of excellent measures for soil and water conservation,to reduce runoff efficiently and hold soil and water strongly.However,its mechanism in controlling nutrient loss is far from well known.Field experiments were implemented in six plots,in which Vetiveria zizanioides was planted in three rows in Wangjiaqiao Watershed in Upper Yangtze River Region.This study aims to understand how hedgerow can control soil nutrient loss(Agroforest System),by measuring changes of micro-topography,distributions of soil particles with different sizes and soil nutrient in different spatial points in the experimental plots.Results shows that hedgerows could flatten slope by a dispositionary zone formed before them,and that they also could influence redistribution of soil particles by retarding soil surface runoff.Furthermore,results of chemical analysis of total and available nutrients demonstrated that hedgerows could indirectly reduce soil nutrient loss.