模拟降雨对3种类型土壤氮、磷素空间分布及其颗粒组成的影响

Effect of Simulated Rainfall on Spatial Distribution of Nitrogen and Phosphorus and Its Particle Composition of Three Types Soils

采用模拟降雨的方法,研究降雨对3种类型土壤氮、磷素坡面空间分布的影响及其降雨前后土壤颗粒组成的变化。结果表明,模拟降雨条件下,3种类型土壤表层和下层土壤氮素流失量均为褐土显著高于棕壤和红壤,且红壤氮素流失量最少;3种类型土壤表层和下层氮素流失严重的坡位均为坡上部和坡下部,坡中部流失量较少而为残留量峰值部位;模拟降雨对红壤表层和下层有效磷的空间分布影响显著大于棕壤与褐土;3种类型土壤表层有效磷为棕壤与褐土坡下部及红壤坡上部流失严重,而下层有效磷流失最严重的坡位均为坡上部;红壤泥沙流失量分别高出棕壤和褐土45.47%,83.05%,且模拟降雨前后其质地变化也最显著,由粉粘壤土变为粘壤土,其他类型土壤质地未发生变化,而颗粒组成的变化是棕壤明显高于其他2种土壤类型。

Spatial distributions of nitrogen, phosphorus and its particle composition of three kinds ot soil be- fore and after rainfall were conducted by simulated rainfall experiments. The results showed that under simu- lated rainfall, the nitrogen loss on both surface and lower of cinnamon soil was significantly higher than that of brown soil and red soil in the three kinds of soil, and the red soil nitrogen loss was the least. The slope position＇s nitrogen loss serious on both surface and lower were all up and bottom slope of the three kinds of soil, and the nitrogen loss of the middle slope was less so it came to be a peak area of the nitrogen amount of residue. Effect of simulated rainfall on spatial distribution of available phosphorus of red soil was significant- ly greater than that of brown.soil and cinnamon soil. three kinds of soil were brown soil and cinnamon soil The available phosphorus loss serious on surface of the at bottom slope and red soil at up slope but the available phosphorus on lower of the three kinds of soil were all up slope loss serious. After simulated rainfall the red soil had the largest sediment runoff, which was 45.47% and 83.05% higher than that of brown soil and cin- namon soil respectively, but also its texture type changed, which changed from clay loam to silky clay loam, beside, the other two kinds of soil＇s texture type did not change. The change of soil particle composition of brown soil was significantly higher than that of the other two kinds of soil compared with before rainfall.