在大搞水土保持中,不论采取哪种措施,都程度不同地影响耕作层。“修地三年穷”的说法,就充分反映了修地不注意保留表土的害处和保留表土的重要性。现在介绍几种“保留表土”的办法。(一)整地担壕:“壕”有大小、深浅,有方形的,也有长形的,各不一样。在壕的位置、大小、深度、运土方向确定之后,未开挖之前,将计划起壕处的表土铲向周围或两旁堆存;铲除面积大小,视壕的大小、深浅而定;表土不能堆在壕边,离壕边要有一定的距离,一般不 In vigorously promoting soil and water conservation, no matter what kind of measures are taken, the tillage layers will be affected to different degrees. The saying of “three years of cultivation is poor” fully reflects the importance of the cultivation land not paying attention to preserving the topsoil and preserving topsoil. Now introduce several ways to “retain topsoil.” (A) site preparation trenches: “trench” size, depth, square, long, and not the same. After determining the location, size, depth and direction of earth mooring, the topsoil to be planted as a moat shall be piled around or on both sides before being dug; the size of the eradication site shall be determined by the size and depth of the moat; Heap in the trench edge, from the trench to have a certain distance, generally not