京郊农田不同植被的土壤风蚀模数比较

为了研究京郊地区农田植被土壤风蚀变化规律，提出京郊防尘的农作制度，笔者采用野外风洞原位测试方法定量评价北京周边不同植被冬春季节的土壤风蚀状况。结果表明：植被覆盖在冬春季可以明显降低农田土壤风蚀量，5种植被均表现为100 cm的土壤风蚀模数略大于20 cm的。在风速20 m/s的条件下，3月中旬冬小麦、小黑麦的农田抗风蚀能力＞紫花苜蓿＞油菜、菠菜；小黑麦和冬小麦分别在20 cm和100 cm处地表抗风蚀能力强。4月中旬菠菜的农田抗风蚀能力＞油菜＞紫花苜蓿＞冬小麦、小黑麦、小黑麦和冬小麦分别在20 cm地和100 cm抗风蚀能力最弱。翻耕地比免耕地风蚀模数高，其中留根茬翻耕地最高，立秆免耕最低；3月份秸秆粉碎免耕风蚀模数大于留根茬免耕，4月份则相反。不同植被下土壤风蚀模数与土壤含水量呈负相关，且随着土层的增加相关系数逐渐降低；不同秸秆残茬处理下土壤风蚀模数与5~10 cm土层含水量和土壤覆盖度相关性较高，且均呈负相关。一年两作区越冬作物能提高土壤抗风蚀力；春玉米区立秆免耕抗风蚀里最强，免耕和秸秆还田等也均能提高土壤抗风蚀力。

Comparation of Soil Erosion Modulus between Different Vegetation Farmland around Beijing Suburb

To study the soil erosion changes under different vegetation farmland around Beijing suburb and propose dust farming systems in Beijing suburb,the research was carried out on the farm land surface by means of the movable wind tunnel in order to evaluate quantitatively erosion effects of different farm land.The results showed:vegetation cover could significantly reduce the amount of soil erosion in the winter and spring,When wind speed was constantly 20 m/s,the anti-erosion ability of five vegetations in the...