中文摘要：

基于人工模拟降雨试验,研究了雨型对东北黑土区顺坡垄作坡面土壤侵蚀的影响。根据典型黑土区侵蚀性降雨标准及雨型特征,试验设计了总降雨量相同（降雨量为87.5 mm）的5种不同雨型,即增强型（降雨过程中降雨强度分布为50-75-100-125 mm/h）、减弱型（降雨过程中降雨强度分布为125-100-75-50 mm/h）、峰值型（降雨过程中降雨强度分布为50-75-100-125-100-75-50 mm/h）、谷值型（降雨过程中降雨强度分布为100-75-50-75-100 mm/h）和均匀型（降雨过程中降雨强度保持75 mm/h不变）,以及1个坡度（即顺坡垄作改横坡垄作的临界坡度5°）。结果表明,受前期预降雨的影响,各雨型处理的顺坡垄作坡面径流量差异较小,但坡面侵蚀量存在明显差异,其中峰值型雨型引起的坡面侵蚀量最大,分别是谷值型、减弱型、均匀型和增强型雨型处理下的1.20、1.63、1.78、1.80倍。引起侵蚀量较大的雨型（峰值型、谷值型和减弱型）在典型黑土区天然降雨中出现频次超过70%,这可能是该区夏季顺坡垄作坡面侵蚀作用强烈的重要原因之一。同一降雨强度在不同雨型中出现的时序不同,其产生的径流量和侵蚀量对总径流量和总侵蚀量的贡献率也不相同。除125 mm/h外,同一降雨强度出现在起始阶段产生的侵蚀量对坡面总侵蚀量的贡献率显著大于其出现在其他阶段对坡面总侵蚀量的贡献率。

英文摘要：

Longitudinal ridge,as one of the main tillage management,causes severe soil erosion on hillslope scale and makes great contribution to the soil loss in typical black soil region of Northeast China.Rainfall pattern is one of the main factors influencing hillslope erosion. The simulated experimental study was conducted to investigate the effects of rainfall patterns on hillslope erosion with longitudinal ridge in the typical black soil region. According to the erosive rainfall standard and rainfall pattern characteristics of natural rainfalls in the typical black soil region,the experimental design included five patterns of simulated rainfalls with the same total rainfall amount of 87. 5 mm,covering intensive-type（ rainfall intensity distribution was 50-75-100-125 mm / h）,reduced-type（ rainfall intensity distribution was 125-100-75-50 mm / h）,peak-type（ rainfall intensity distribution was 50-75-100-125-100-75-50 mm / h）,valley-type（ rainfall intensity distribution was 100-75-50-75-100 mm / h） and uniform-type（ rainfall intensity was 75 mm / h）,and the slope gradient was 5° which was the critical slope gradient of changing longitudinal ridge to contour cultivation. The results showed that total runoff volume had little differenceamong five rainfall patterns,while obvious differences in soil loss were observed. Soil loss of the peaktype treatment was 1. 20,1. 63,1. 78 and 1. 80 times higher than those of the valley-type,reduced-type,uniform-type and intensive-type treatments,respectively. Occurring frequency of three rainfall patterns（ peak-type,valley-type and reduced-type） occupied more than 70% of total natural rainfall events,which could be one of the key reasons caused severe hillslope soil erosion with longitudinal ridge in this region. The time sequences of rainfall intensity in each rainfall pattern had great effects on runoff,soil erosion and their contribution rates to total runoff and soil loss. Except for 125 mm / h rainfall intensity,rainfall intensities occurred at the initial s