降雨和坡度对植烟坡耕地产流产沙的影响.

This paper explored the characteristics of runoff and sediment yield in purple soil sloping land, and provided a scientific basis for tobacco-growing soil management. [Methods] Long-term positioning observations were carried out on the field outflow plots with different slopes (5°, 10°, 15°, 20°, 25° and 30°), and the characteristics of slope runoff and sediment production with rainfall intensity and slope change were studied. [Results] (1) Through the analysis of rainfall data in the past 10 years, the distribution of rainfall in the study area during the year is extremely uneven. The rainfall from June to September accounts for 80.2% to 92.5% of the annual rainfall; light rain, moderate rain, heavy rain, heavy rain, Heavy rains accounted for 14.6%, 26.7%, 31.5%, 22.5%, and 4.7% of the total rainfall from June to September, and moderate to heavy rains accounted for 80.7% of the total rainfall in the rainy season, which is an important reason for the high intensity of soil erosion; (2) ) The slope runoff coefficient increases with the increase of the maximum 30 min rain intensity. The minimum slope runoff coefficients of 5°, 10°, 15°, 20°, 25° and 30° are 0.033, 0.034, 0.063, 0.092, 0.093, respectively., 0.112, and the maximum are 0.646, 0.666, 0.673, 0.738, 0.742, 0.786, respectively. Under the same rainfall intensity conditions, rainfall can significantly affect the slope runoff coefficient; (3) The sediment yield increases with the increase of the maximum 30 min rain intensity Increase, 5°, 10°, 15°, 20°, 25°, and 30° slope surface sediment yields are 1.7, 1.6, 3.1, 4.8, 2.3, and 1.7 t·km -2 at minimum, and 75.4, 234.7 at maximum, respectively, 440.5, 486.7, 489.5, 477.1 t·km -2, the change of sediment yield with the maximum 30 min rain intensity is affected by vegetation coverage; (4) In light rain (0.14～0.46 mm·min -1 ), medium Rain (0.54～0.88 mm·min -1 ), heavy rain (1.1～1.9 mm·min -1)), the slope runoff coefficient increases with the increase of the slope, and the maximum runoff coefficients are 0.326, 0.565, 0.712, respectively. Under different rain intensities, the sediment yield of the slope varies with the slope. Under light rain and moderate rain, the critical slope of the sediment yield change is 20°, and the maximum sediment yield is 113.8 and 193.5 t·km -2, respectively . The lower critical slope is 25°, the maximum sediment yield is 389.1 t·km -2, and the critical slope changes with the change of rain intensity. [Conclusion] The rainy season is a critical period for the occurrence of regional soil erosion. The slope significantly affects the intensity of soil erosion. Strengthening the water and soil conservation in the rainy season is crucial to the sustainable use of regional soil. [ABSTRACT FROM AUTHOR]