西部黄土丘陵区降雨特征及其对坡地土壤侵蚀的影响

以甘肃省定西市安家沟流域的大型径流观测场为依托,以2009—2011年天然降雨在不同土地利用条件下产流产沙特征数据为依据,研究了黄土高原西部黄土丘陵区降雨特征及其对坡地土壤侵蚀的影响。结果表明,在次降雨条件下不同处理径流过程分别经历了产流、峰值、稳定、消减4个表征时刻,土壤侵蚀过程分别经历了发生、峰值、消减3个表征时刻。次降雨条件下,不同处理其径流总量、侵蚀总量排序均为:15°春小麦10°春小麦10°油松林15°荒地15°沙棘林10°荒地15°油松林10°沙棘林。通过层次聚类分析得出,在10°,15°的坡度下,灌木林沙棘、乔木林油松分别具有明显的水土保持效应。所以结合试验地的气候和环境特点,10°坡面适宜种植沙棘林,15°坡面适宜退耕还林。

Rainfall Characteristics and Their Effects on Slope Erosion in Western Loess Hilly Region

Rainfall characteristics and their effects on loess slope erosion in the loess hilly region of the western Loess Plateau were studied using the runoff plots located in the Anjiagou watershed, Dingxi City, Gansu Province and the data observed from 2009 to 2011. Results showed that in the condition of natural rainfall, runoff process under different treatments could be divided into runoff producing, maximum runoff, stability of runoff and disappearance of runoff and soil erosion, into erosion producing, maximum erosion amount and curtailment erosion. The eight treatments, in order of the decreasing total amounts of runoff and soil loss, were 15° spring wheat, 10° spring wheat, 10° Pinus tabulaeformis arboreal forest, 15° waste land, 15° Hippophae rhamnoides shrub forest, 10° waste land, 15° Pinus tabulaeformis arboreal forest and 10° Hippophae rhamnoides shrub forest. From the hierarchical clustering, on the 10° slope, Hippophae rhamnoides shrub forest had an obvious effect of soil and water conservation, while on the 15° slope, Pinus tabulaeformis arboreal forest had an obvious effect of soil and water conservation. Therefore, combined with the climate and environment of test site, 10° slope is suitable for planting Hippophae rhamnoides and 15° slope, for returning farmland to forest.