论文部分内容阅读
通过对紫色丘陵区不同种植模式下植被覆盖度的测定,结合标准径流小区天然降雨径流泥沙观测数据,分析不同种植模式下基于UELE模型的植被覆盖与管理因子(C值)的取值变化规律。试验结果表明:(1)不同小区降雨侵蚀差异较大,10次降雨累积产沙规律为:对照小区侵蚀量最大,达到999.6 g,其次为顺坡耕作,其累积值为660.4 g,横坡植物篱耕作小区最小,产生累积值为349.8 g;(2)利用文献模型计算小区2、3、4的C值分别为:0.081、0.075和0.011,三个小区实测C值分别为:0.175、0.172、0.146,实测值能更好反映紫色丘陵区的C因子变化,模型值与实测值差别较大,说明该计算模型不能直接运用于紫色丘陵区C因子的计算,模型值和实测值都反映了不同土地利用类型C值的相似变化规律,即:顺坡耕作>横坡耕作>横坡植物篱耕作。(3)对于坡耕地而言,分析不同种植模式下的C值大小及在年内变化特点,从而实现在降雨集中分布时期保持较大的地表盖度,可有效地控制水土流失,减少土地退化。
Through the determination of vegetation coverage under different planting patterns in purple hilly region and the observation data of runoff and sediment of natural rainfall in standard runoff plots, the changing rules of vegetation coverage and management factors (C values) under different planting patterns based on UELE model . The results show that: (1) There is a great difference in rainfall erosion in different communities. The law of cumulative sediment yield in 10 rainfalls is as follows: the erosion amount of the control plot is the largest, reaching 999.6 g, followed by slope farming, with a cumulative value of 660.4 g, (2) According to the literature model, the C values of plots 2, 3 and 4 were 0.081, 0.075 and 0.011, respectively. The measured C values of three plots were 0.175 and 0.172, respectively, 0.146. The measured values can better reflect the change of C factor in the purple hilly region. The difference between the model value and the measured value shows that the model can not be directly applied to the calculation of the C factor in the purple hilly region. Both the model value and the measured value reflect the difference Similar variation of land use type C value, namely: slope farming> cross slope farming> horizontal slope hedgerow planting. (3) For sloping farmland, the C value under different planting patterns and its variation characteristics during the year were analyzed to achieve a large surface cover during the period of concentrated rainfall distribution, which could effectively control soil erosion and reduce land degradation.