混播草带控制水源区坡地土壤氮、磷流失效应

史 静; 卢 谌; 张乃明

混播草带控制水源区坡地土壤氮、磷流失效应

Effects of mixed grass strip on controlling nitrogen and phosphorus loss of slope land in water source region

摘要

摘要: 坡地土壤氮、磷流失是湖库型饮用水源区污染的主要来源。本文以云南最大的城市集中式饮用水源地为研究区域，在昆明云龙水库库区周边的坡耕地红壤上开展了混播草带防治土壤氮、磷流失效应的研究。研究结果表明：选择适宜草种进行混播，所形成的草带控制水土及氮、磷流失效果优于自然植被；对地表径流量、土壤侵蚀量的控制效果均为：混播黑麦草+紫花苜蓿＞混播黑麦草+白三叶＞自然植被＞无草带种植；草带对土壤侵蚀量的控制效果要好于地表径流量。其中处理混播黑麦草+紫花苜蓿、混播黑麦草+白三叶径流量分别比无草带种植降低35.19%、46.26%；侵蚀量比无草带种植降低73.51%、78.13%；坡耕地地表径流中氮素流失形态主要以泥沙中氮流失为主，占到80%～85%左右，磷素流失以颗粒态磷流失为主，占到90%～95%左右；对地表径流中的氮、磷流失量控制效果均为：混播黑麦草+紫花苜蓿＞混播黑麦草+白三叶＞自然植被＞无草带种植, 对总氮流失量的控制效果要好于总磷流失量；混播黑麦草+白三叶处理中径流中总氮、总磷流失量分别降低59.96%、48.57%；混播黑麦草+紫花苜蓿处理径流中总氮、总磷流失量分别降低63.31%、56.91%；自然植被处理中径流总氮、总磷流失量分别降低29.46%、26.03%。

Abstract: Nitrogen and phosphorus loss of slope land is the main pollution resource of lake and reservoir drinking source region. In order to reduce the impact of water and soil erosion of sloping fields on the eutrophication of water and improve sustainability of fragile slopes, the field experiment was conducted in Kunming，Yunnan Province in 2011, where Yunlong reservoir is the largest city centralized drinking resource region of Kunming. And effects of different mixed grass strip treatments on reducing nitrogen and phosphorus losses in slope land of red soil were analyzed. Four treatments, including perennial ryegrass + alfalfa (A), perennial ryegrass+trifolium repens (B), natural vegetation(C) and without grass strip(CK), were designed with three replications in the slopes with 15°. The zone of grass strip standard was 3m*1m and sow seeding rate planted at the upper of slope land of each plot was 10 g/m2. Runoff and sediment were collected during maize growing season from May to October). Results showed that runoff and soil erosion of different grass strip treatments were lower than that of the contrast. The surface runoff and soil control effects of different grass strip were presented a trend of A>B>C>CK, and the control effects of soil erosion were better than those of surface runoff. Compared with CK, A and B decreased the runoff rate by 35.19% and 46.26%, and the erode rate decreased by 73.51%and 78.13%, respectively. N existed in the runoff of slope land was mainly in the form of silt N, which accounted for 80%～85%. P existed in the runoff was mainly in the form of granular P, which accounted for 90%-95%. The effects of different grass strip on preventing N and P loss were：A>B>C>CK. The control effects of total nitrogen loss were better than those of total phosphorus. Compared with CK, B decreased total N and P in runoff by 59.96% and 48.57%, A decreased by 63.31% and 56.91% and C decreased by 29.46% and 26.03%, respectively. This research provides scientific basis for soil erosion and water quality protection.

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