紫色土坡地果草种植模式的水土流失特征研究

紫色土坡耕地是三峡库区重要的土地资源。以研究降雨强度对紫色土坡地产流产沙的影响为基础,以紫色土坡地示范推广的果草模式为研究对象,对其水土流失特征进行了野外定点监测研究。研究结果表明:(1)短历时、高强度降雨对紫色土坡地的产流产沙影响最强烈,降雨历时与产流产沙存在明显的负相关,而雨强参数与产流产沙则存在明显的正相关;(2 )在降雨特征参数中,平均雨强是反映紫色土坡地径流系数、泥沙量和径流含沙量的最好特征参数,I3 0 则能最好的反映紫色土坡地径流量的变化;(3)在不同降雨强度下,果草模式对产流量、径流系数、产沙量和径流含沙量都有非常明显的减少或降低作用,特别在低强度降雨时,其减水减沙效应更明显,种植年限对其效应也有影响;(4)在短历时、高强度典型次降雨情况下,果草模式具有明显延迟产流时间和延缓产流过程的作用;(5 )果草模式降低了紫色土降雨前后表土养分的衰减,减少了表土养分的流失;(6 )果草模式对速效养分的流失具有较好的减弱作用,因而其对保持地力,提高土地生产力具有较好的作用

Study on Soil and Water Loss Characteristics of Intercropping Orchard-Pasturage Model in Purple Soil Slopeland

Purple soil sloping farmland is the important land resources in three gorges reservoir region. Based on the research of rainfall intensity influencing on runoff yield and sediment yield, the demonstrated and popularized intercropping orchard-pasturage model was taken as research object, and its characteristics of soil and water loss was studied through opening and locating monitor experiment. It's showed that:(1)The short period and high intensity rainfall has the strongest influence on runoff yield and sediment yield, there was obvious negative correlation between rainfall period and runoff yield and sediment yield, and obvious positive correlation between rainfall intensity parameters and runoff yield and sediment yield;(2)Among the rainfall characteristic parameters, average rainfall intensity is a best one to reflect runoff coefficients, silt amount and silt content of runoff, and I_(30) is the best one to reflect the change of runoff amount in purple soil sloping farmland;(3)Under different rainfall intensities, intercropping orchard-pasturage model can obviously reduce the runoff amount,runoff coefficient,silt amount and silt content of runoff, especially under the low intensity rainfall, its effect of water and sediment reducing is more obvious, and growing year also has influence on its effect;(4)Under the typical short duration and high intensity rainfall, intercropping orchard-pasturage model play an important role in time-delaying and postponing process of runoff yield and sediment yield;(5)Intercropping orchard-pasturage model has reduced surface soil nutrient waning after rainfall, and surface soil nutrient running off was decreased;(6)Intercropping orchard-pasturage model can reduce nutrient loss effectively,so as to keep soil fertility and improve soil productivity of purple soil sloping land.