随着三十年代风蚀灾害的发生,半干旱大平原处于气候反常和难于预测的情况下,残茬覆盖因能防止风蚀而在旱地耕作制中发展起来(Mccalla and Army,1961)。一般说来,农户们都重视进行残茬覆盖,但在实践上由于使用的犁耕工具不同,耕后残茬遗留在土表的百分率有很大的不同,在土壤表面垂直切下的农具,不搅动或不翻转耕层,每次耕作仅能混合残茬5—15％,而搅动土层时,如用铁锹或凿形中耕铲和园盘耙时,每次耕作可把表层的残茬30—50％混入 With the onset of wind-induced disasters in the 1930s and the semi-arid Great Plains in climatic anomalies and unpredictable conditions, stubble cover was developed in dry farming systems to prevent wind erosion (Mccalla and Army, 1961). In general, farmer households attach importance to stubble coverage, but in practice due to the different plowing tools used, the percentage of remaining stubble residues on the soil surface varies widely. Tools that are cut vertically on the soil surface, Without agitating or inverting the topsoil, only 5-15% of the stubble can be mixed with each tillage. When agitating the stratum, such as shoveling or chiseling tillage shovels and disc harrows, 30-50% mixed