紫色土坡耕地细沟侵蚀的防治

坡耕地是紫色土区域典型的土地利用方式,细沟侵蚀是紫色土坡面侵蚀的主要形式之一。试验研究发现,10°,15°,20°,25°小区细沟侵蚀量占坡面总侵蚀量的比例分别为28.61%,57.66%,80.66%和91.16%;细沟沟头出现的顺坡临界坡长平均值分别为6.19m,4.15m,2.75m,1.57m。在大量野外调查的基础上,采用植物篱、"地埂+植物篱"和"大横坡+小顺坡"3种措施均能控制细沟侵蚀的发生。尤其是"大横坡+小顺坡"模式,兼具了植物篱与"地埂+植物篱"两种措施的优点,且造价低、节省劳力,具有较好的推广前景,特别是暂时无法实施坡改梯的广大偏远山区。

Prevention and control of rill erosion on purple soil slope cultivated land

Rill erosion is one of the main erosion types on the purple soil slope cultivated land.It accounts for 28.61%,57.66%,80.66% and 91.16% when the slope gradients are 10°,15°,20° and 25°,respectively.Thereby,it is necessary to prevent rill initiation using appropriate measures in the interest of conserving soils.In the Five Years Development Project of Eleventh,some prevention and control measures were investigated by the research group of the slope cultivated land management in the Yangtze River area.In sum,the measures included hedgerows,"ridge + hedgerows" and "downslope ridge tillage and cross trenches".Among them,the key technology is to change the runoff flow direction on the critical length of rill initiation so as to prevent the rill erosion.The preliminary effect investigation shows some excellences in the environment and economy.The preferable estimation shows that these measures have advantages of operation and save inputs including investment and labor.Therefore,it is worth extending implemental areas,especially in the underdeveloped mountain regions.