浙江红壤坡面菜地养分流失模拟试验及模型建立

Simulating and modeling of nutrient loss from sloping vegetable field on red soil in Zhejiang Province

以室内人工模拟降雨试验为研究手段,以强降雨过程中红壤丘陵区坡菜地随径流、泥沙迁移的养分流失规律为研究目的,分别在不同坡长(2m,3m,4m,5m)、不同植被覆盖度(0%,30%,60%)和不同表层土壤养分含量条件下进行了有效模拟降雨试验共计25场次,每个场次降雨试验的产流历时设计为30 min,固定雨强为120 mm·h^(-1)。将径流量、产沙量和原表土中各养分的含量作为影响养分流失的主要因子,进行了氮,磷和有机碳流失量的多元回归模型的拟合,并通过对拟合模型验证,得出TN,TP和TOC流失量80%的计算值和实测值之间的相对误差均小于20%,同时,通过实际情况验证,发现TN,TP流失量75%的计算值与实测值之间的相对误差均小于20%。因此,该模型可适用于浙江红壤区坡面菜地养分流失的预测。

To analyze and investigate laws of nutrition （nitrogen, phosphorus and total organic carbon） loss and sediment through runoff from sloping vegetable fields of red loam, 25 indoor simulated rainfall experiments on 4 slope lengths （2m, 3m, 4m, 5m） were carried out, considering 3 levels of vegetation coverage ratio （0% ,30%, 60% ） and different nutrient content in top soil conditions. Each simulated rainfall lasts 30 min and specific rainfall intensity is 120mm . h-1. Multi-variant regression model of nitrogen, phosphorus and TOC loss caused by runoff and sediment was built with runoff amount, sediment yields and nutrition （ nitrogen, phosphorus and total organic carbon） as main influencing factors. Verification with 10 other groups of experimental data showed that, errors of TN, TP and TOC between tested values and simulated values are less than 20% for 80% samples. Also, the com- parison with real field investigation showed that, errors of TN, TP between tested values and simulated values are less than 20% for 75% samples. Thus, the model is suitable for predicting TN, TP and TOC loss from sloping veg- etable field on red soil in Zhejing Province.