作 者 ：林超文,罗春燕,庞良玉,黄晶晶,付登伟,涂仕华,蒲波
期 刊 ：生态学报 2010年 30卷 22期 页码：6091~6101
Keywords:cultivation, mulching, purple soil, nutrient loss,
摘 要 ：采用随机区组试验，研究了四川紫色丘陵区坡耕地不同耕作和覆盖方式对玉米生育期中水土及养分流失的影响。结果表明：秸秆覆盖对减少水土流失和增加玉米产量的效果均优于地膜覆盖。秸秆覆盖能显著减少地表径流(73.9%-86.2%), 但增加了壤中流(15.4%-156.4%);使径流总量降低32.5%-66.6%，并极显著降低土壤侵蚀总量达96.4%-98.1%。地膜覆盖虽能在一定程度上减少壤中流和径流总深，但差异未达到显著水平。土壤N平均损失量达37.4 kg/hm2，其中70.1%经由壤中流流失。秸秆覆盖虽然增加了一定的壤中流N损失，但能减少N流失总量达12.8%-65.1%。土壤P素损失量相对较小，仅为9.32 kg/hm2，并主要随侵蚀泥沙迁移，占流失总量的92.1%。土壤K损失量达183.3 kg/hm2，其流失载体也主要是侵蚀泥沙，占96.5%。因此，两种覆盖方式均能显著控制土壤P和K的损失。无论是秸秆还是地膜覆盖，与顺坡垄作相比，横坡垄作均能减少地表径流、地下径流、土壤侵蚀量及氮、磷、钾素总流失量，同时还能提高玉米产量。从简便、增产和防治面源污染的角度考虑，紫色土区坡耕地最适宜的种植方式为平作+秸秆覆盖。
Abstract:Increasingly aggravated non-point source pollution resulting from intensified farming activities has drawn wide concerns from the society. Among the farming activities, overdose of chemical fertilizers has been blamed the most. Sichuan Basin is one of major grain production basis in China where farming on sloping lands is prevailing and intensive with increased fertilizer use. This has put great pressure on the widespread water eutrophication, particularly in the summer when heavy rains usually cause serious soil loss and water runoff that carry away large amounts of nutrients from the farmlands. Previous studies have well addressed the patterns of soil erosion and surface runoff with which how and how much soil nutrients are lost from the sloping lands, however, there is still lack of research on effects of surface mulching with crop straw or plastic film on soil nutrient losses through soil erosion and water runoff. Therefore, the objectives of this field study were to investigate effects of different cultivation and mulching methods on different types and amounts of soil erosion, pathways and amounts of nutrient losses during corn growing season from a purple soil located on a sloping landscape in the Sichuan basin. The experiment was carried out with a randomized block design consisting of nine treatments and three replications. There nine treatments included (1) conventional down slope ridge cultivation, (2) flat cultivation (non-ridged), (3) contour ridge cultivation, (4) contour alley cropping, (5) down slope ridge cultivation + straw mulching, (6) flat cultivation + straw mulching, (7) contour ridge cultivation + straw mulching, (8) down slope ridge cultivation + plastic film mulching, and (9) contour ridge cultivation + plastic film mulching. The results indicated that the effect of straw mulching on reducing soil and water losses and on improving corn yield was superior to the use of plastic film. The straw mulching significantly reduced surface runoff by 73.9% -86.2% in spite of the increase in underground runoff by 15.4%-156.4%, resulting in reduction of total runoff by 32.5%-66.6% and soil erosion by 96.4%-98.1%. Though use of plastic film alleviated the underground runoff and total runoff to some extent, the difference was not significant compared to the traditional cultivation. Amount of N lost from the soil was 37.4 kg/hm2, of which N losses through underground runoff accounted for 70.1%. The straw mulching decreased total N losses by 12.8%-65.1% in spite of some increase in N loss through underground runoff. Amount of P lost from the soil was relatively small (9.32 kg/hm2) but it was mainly moved out of the field with sediments, accounting for 92.1% of total P losses. Amount of K lost from the soil reached 183.3 kg/hm2 of which the loss through sediments that were the main carrier of K account for 96.5%. Mulching soil surface with either straw or plastic film effectively controlled P and K losses. Compared to the traditional, down slope ridge cultivation, the contour ridge cultivation produced higher corn yields while it lowered nutrient, soil and water losses associated with surface and underground runoff and soil erosion. The integration of flat cultivation and straw mulching can be an improved practice as it does realize straw recycling, improve crop yields and reduce losses of soil and water and plant nutrients.
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