巢湖马鞍山西北坡土壤侵蚀及其N、P时空变异研究

Soil Erosion and Spatial-Temporal Variability of Nitrogen and Phosphorus on Northwest Slope of Ma an Mountain of Chaohu

以马鞍山西北坡土壤作为研究对象,利用不同时间不同海拔高度土壤的试验数据,分析了坡面土壤氮磷含量的时空变异特征和次降雨前后土壤颗粒组成与氮磷含量的变化特征,进行了坡面土壤及氮磷元素移失量的估算。结果表明,速效磷含量由1月到7月呈增加趋势;土壤全磷含量随着时间变化而逐渐降低,在空间上随海拔高度降低而逐渐增加;土壤的全氮与水解氮在季节上表现出春季较高,而夏季较低的特点,在空间上呈从山体下部向上逐渐降低的趋势;降雨后,坡地表层土壤氮磷含量会有一定程度的降低,其中速效磷和水解氮降幅明显高于全磷和全氮,土壤颗粒组成呈现出粘粒和粉粒含量减少,砂粒含量相对增加的趋势;坡面土壤的平均流失厚度为0.41 cm/a,平均流失量为5 412 t/(km2.a),氮素和磷素的平均移失量分别为9.12,2.30 t/(km2.a)。

The soil on northwest slope of Maan mountain was taken as study object. Through using trial data in different time and different height to analyze the characteristics of spatial-temporal variability of soil nitrogen and phosphorus , and also to analyze the change characteristics of soil particle size distribution and the contents of soil nitrogen and phosphorus before rainfall and after rainfall on slope, then the transport estimation of soil and its nitrogen and phosphorus on slope was discussed. The results showed that the rapidly available phosphorus contents had the trend to increase from January to July, and the total phosphorus contents declined gradually with time but increased gradually from upside of mountain to downside of mountain. The contents of total nitrogen and hydrolysable nitrogen was both highest in spring and lowest in summer, and decreased gradually from downside of mountain to upside of mountain. After rain, the contents of nitrogen and phosphorus on the slope surface declined, and the declined rate of rapidly available phosphorus and hydrolysable nitrogen was higher obviously than that of total nitrogen and total phosphorus. Also after rain, the clay and silt contents of the surface soil decreased and the sand contents increased. The transport thickness of soil was 0.41 cm/a,the transport estimation of soil was 5 412 t/（km^2·a）, the transport estimation of nitrogen and phosphorus was 9.12, 2.30 t/（km^2·a） on slope.