植物篱对红壤坡耕地的水土保持效应及其机理研究

摘要

在浙江诸暨红壤丘陵山区的野外径流小区条件下,设计5种不同植物篱种植模式,结合自然降雨、人工模拟暴雨试验、稀土元素(REE)示踪、土壤抗蚀性评价等方法,研究植物篱的减流减沙效应和控制机理.结果显示,与裸坡相比,自然降雨下麦冬双行植物篱处理地表径流量降低39.4％,土壤流失量降低65.8％,效果最佳.降雨前土壤含水量能显著影响径流和土壤流失的发生特征.土壤容重和孔隙度可作为衡量植物篱控制水土流失效应的最佳指标.根据17个抗蚀性指标建立植物篱条件下红壤抗蚀性的综合评价指标体系,评价结果表明土壤综合抗蚀性由高到低依次为麦冬双行、黄花菜+麦冬双行、黄花菜双行、麦冬单行、黄花菜单行和裸坡.不同坡位植物篱对土壤抗蚀性的影响存在差异,侵蚀泥沙主要来源集中在中下坡位.%A field run-off experiment having five different patterns of hedgerows was carried out to explore effects and mechanisms of the hedgerows conserving soil and water in a red soil sloping farmland in a hilly region of Zhuji, Zhejiang, making use of natural rainfalls, simulated storms, rare earth element tracing technique ( REE) and soil erosion resistance index system. Results show that under natural rainfall, ihe hedgerow of Double rows of Ophiopogon japonicas reduced runoff and soil loss by 39.4% and 65. 8% respectively, ranking first among the five patterns in efficiency. The pre-rainfall soil water content could significantly affect occurrence of runoff and soil losses. Regression models were established to simulate the relationships between runoff and soil loss. Changes in soil physical properties under the different patterns were significant and bulk density and porosity were found to be the premier indicators in evaluating effects of the hedgerows controlling soil and water losses. On the basis of the seventeen indices for soil erosion resistance, a comprehensive evaluation index system was established to evaluate red soil erosion resistance as affected by hedgerows. Evaluation using the system indicate that the soil erosion resistance of hedgerows followed the order of double rows of Ophiopogon japonicas ( MM ) > one row of Ophiopogon japonicas plus one row of Hemerocallis citrina (MM) > double rows of Hemerocallis citrina (HH) > a single row of Ophiopogon japonicas (M) >a single row of Hemerocallis citrina (H) > plot without hedgerow (L). Position of hedgerows on the slope also affects their effect on soil and water losses because the middle and down slopes are the major sources of sediments.