半干旱高寒区保护性耕作法对土壤孔隙状况和微形态结构特征的影响

Effect of Protctive Tillage on soil Pore Space STatus and Character of Micromorphological Structure

少免耕保护性耕作较传统耕作土壤紧实度增加，＞１２００ｕｍ的通气孔隙度降低，小孔隙（＜５ｕｍ）和毛管孔腺增加，持水能力增强，提高了土壤的保水性能，且＞０．０５ｍｍ微团聚体含量、结构系数和团聚水平明显高于传统耕作，保护性耕作处理具有较明显的多级团聚体，其形状呈近似圆形或椭圆形，棱角不甚明显，轮廓清晰．另外，还明显促进了水稳性团聚体的形成，同传统耕作相比坡梁地少、免耕处理＞０．２５ｍｍ水稳性团聚体含量分别增加８．１６％和２１．５６％，旱滩地免耕较传统耕作则增加１２．０７％。

The protectective tillage such as min-till or no-till raises soil compaction as compared with the tradition tillage,reduces> 1200um aeration porosity and raises small pore space and capillary porosity,increases water retention and conservation abilities, and increases >0.05mm microaggregate,structural index, and the level of aggregation. The protective tillage has clear multiple-drop aggregate whose shape is similar to circle or ellipse, whoseedes are no clear but the outline is clear.Otherwise, protective tillage obviously promotes the formation of waterstable aggregate,As compared with tracditon tillage, the min-till and no-till respectively increase 8.16 and 21.56 percent on >0.25mm waterstable aggregate in sloping ridge land, but in shooly land,the no-tillage only increases 12.07 percent.