碎石土坡地不同植被配置下的养分流失途径

Soil Nutrient Loss Characteristic of Gravel Soil Slope on Different Vegetation Patterns

为了解不同植被类型及覆盖度对碎石土壤坡地养分流失途径的影响,采用模拟径流小区降雨,研究了6种植被配置模式下地表径流、壤中流及侵蚀泥沙氮、磷养分流失特征。结果表明:植被覆盖坡地氮流失量比裸地减少了0.91~4.60倍,磷流失量减少了6.25~63.9倍,养分控制效果排序为草灌>草本>灌木>裸地。6种植被配置下的地表径流、壤中流及侵蚀泥沙养分流失量存在显著差异,裸地氮、磷的主要损失途径是侵蚀泥沙,灌木是地表径流,草本与草灌结合处理则是地表径流和壤中流;而草本、灌木以及草灌结合土壤磷的主要损失途径是侵蚀泥沙与地表径流共同作用的结果。不同植物覆盖措施对含碎石土裸地氮、磷的流失起到显著的截留作用,主要通过由侵蚀泥沙向非侵蚀泥沙途径转化而实现对氮磷的截留。灌木覆盖度与地表径流的氮磷流失量、径流总量的氮磷流失量之间呈现显著的正相关性,与壤中流的氮磷流失量呈现显著的负相关性。

In order to understand the effects of different vegetation types and coverage on the ways of nutrient loss of gravel soil slope, the characteristics of nitrogen and phosphorus loss through surface runoff, interflow and erosion under six different vegetation patterns were studied by the method of simulating runoff plots rainfall. The results showed that nitrogen loss of vegetation patterns reduced 0.91-4.60 times than bare slope, while phosphorus loss reduced 6.25--63.9 times, and nutrient control effect on slopes with different vegetation listed as follows： Shrub-grass slope〉herb slope〉shrub slope〉bare slope. There was remarkable difference nitrogen and phosphorus loss characteristics through surface runoff, interflow and erosion of six different vegetation patterns. The main way of nitrogen and phosphorus loss in bare slope was eroded sedi- ment, the main way of shrub slope was surface runoff, however, herb slope and shrub-grass slope was sur- face runoff and interflow. The main way of phosphorus loss in slope of herb, shrub and shrub-grass was ero- ded sediment and surface runoff. Vegetation coverage measures had a significant interception in the nitrogen and phosphorus loss on the bare slope of gravel soil. The main loss way of nitrogen and phosphorus trans- formed erosion sediment to non-erosion sediment essentially. Shrub coverage had a significant positive corre- lation with nitrogen and phosphorus runoff loss by surface runoff, and had a significant negative correlation with nitrogen and phosphorus loss by interflow.