【摘要】 种植和管理因子C值作为地表覆盖和耕作管理的关键参数,对我国土壤侵蚀预报模型的基础研究具有重大意义。通过分析三峡库区紫色土坡地玉米、花生等主要农作物的农作期、种植模式、降雨侵蚀力的年内分布以及不同农作期的土壤流失比率,计算得到了22种种植模式下的作物覆盖管理因子C值。结果表明:C值变化范围为0.16～0.65,不同种植模式的C值差别较大,其大小排序为:间/轮作<轮作<单作。在同种种植模式下,生长期和降雨侵蚀力的分布是导致差异的主要原因,而不同种植模式下,间/轮作、轮作可调整作物生长期和降雨侵蚀力分布的组合,使土壤流失率与农作期EI的乘积较小,其中间/轮作情况下土壤侵蚀可能性最小。将计算所得的大部分结果与观测结果和其他经验公式的计算结果进行了比较,基本相符。因此可以利用通用流失方程(USLE)结合降雨侵蚀力分布及作物生长周期和覆盖度变化计算所得的C值定量评价不同种植模式与清耕休闲情况的土壤侵蚀的对比。该研究为三峡库区紫色土坡地土壤侵蚀评价提供了依据。更多还原

【Abstract】 The effects of cropping system on soil loss(C values) were analyzed through calculating crop stage, rainfall erosivity, and SLR in the USLE model. The results reflected that the C values of 22 cropping systems changed from 0.16 to 0.65 in purple soil of the sloping crop land. The C values of different cropping system increased in the order: intercrop/rotation<rotation<monoculture. In the same cropping patterns, the distribution of growth period and rainfall erosion was the main reason for leading to the difference, and in the different cropping patterns, the combination of crop growth period and rainfall erosion distribution could be adjusted to make the product of soil erosion rate and crop EI smaller, indicating that the soil erosion was the least in the case of intercrop/rotation. Most of the results obtained by this calculation method were basically consistent with the results of the observation and other empirical formulas. The C value obtained by this method can be used to quantitatively evaluate the contrast of soil erosion between different cropping patterns and fallow practices. This study can provide a reference for crop configuration on purple soil sloping lands.更多还原