不同耕作方式对宁南旱地土壤团聚体的影响

Effects of different tillage on soil aggregates in the arid areas of South Ningxia

在宁南旱区对试验耕地定位实行连年传统翻耕（CT）、隔年免耕—深松（NT→ST）及深松—免耕（ST→NT）三种不同处理。用干筛法和湿筛法对连续3年处理后土壤团聚体的变化进行测定,分析结果表明,干筛法中NT→ST处理在0~40 cm土层中〉0.25 mm的机械稳定性团聚体比处理前和CT处理分别高33.11%、29.51%;ST→NT处理在0~40 cm土层中〉0.25 mm机械稳定性团聚体含量比处理前和CT处理分别高40.51%、36.91%。湿筛法中NT→ST处理在0~30 cm土层中〉0.25 mm的水稳性团聚体含量比处理前高7.33%,NT→ST处理在0~10 cm土层〉0.25 mm的水稳性团聚体比CT处理高1.47%,而在10~40 cm土层NT→ST处理和CT〉0.25 mm的水稳性团聚体含量差异不显著;ST→NT处理在0~40 cm土层中〉0.25 mm水稳性团聚体含量比处理前和CT处理分别高10.75%、10.12%。分析结果同时说明,采用深松—免耕（ST→NT）轮耕方式更有利于土壤团聚体含量和稳定性的增加。

In this study,three different tillage treatments of conventional tillage（CT）,the following year no-tillage-subsoiling（NT→ST） and subsoiling-no-tillage（ST→NT） were conducted on the arid areas of South Ningxia.After 3 years of consistent tillage treatment,using dry sieving and wet sieving methods,the changing of soil aggregates was analyzed and tested.The results showed that the content of 〉0.25 mm mechanical aggregates in 0～40 cm layers of NT→ST increased by 33.11% and 29.51% and ST→NT increased by 40.51% and 36.91% compared with those of natural soil and CT.The content of 〉0.25 mm water-stable aggregates of NT→ST in 0～30 cm layers increased by 7.33% compared with that of natural soil,and that in 0～10 cm layers increased by 1.47% compared with CT,but that in 10～40 cm layers had no significant difference compared with CT;Compared with those of natural soil and CT,the content of 〉 0.25 mm water-stable aggregates in 0～10 cm layers of ST→NT increased by 10.75% and 10.12%. The results also show that subsoiling-no-tillage（ST→NT） is more conducive to increase the stability of soil aggregates content.