Abstract:

As the basic unit of soil structure, soil aggregates are important indicators of evaluating soil quality, furthermore soil microbes are the most active biological factors of the formation of soil aggregates. Conservation tillage has been applied widely in China, exploring the effects of conservation tillage on soil aggregates and soil microbiological characteristics will contribute to the sustainable development of agriculture. The research progress on the effects of different conservation tillage methods on soil aggregates and microbiological characteristics were reviewed in this article, and the effects of conservation tillage on the distribution, stability, organic carbon content, enzyme activities and microbe diversity of soil aggregates as well as the relationship between soil aggregates and soil microbes were analyzed. The results showed that compared to conventional tillage, conservation tillage caused an increase of the mean weight diameter (MWD) and geometric mean diameter (GMD) of soil aggregates, and the content of water stable aggregates in surface soil, promoted the formation of large soil aggregates and strengthened the stability of soil aggregates. Conservation tillage also increased the soil organic carbon content in the surface layer, which was beneficial to soil organic carbon fixation. Meanwhile, conservation tillage effectively improved soil enzyme activity, but there were different distribution and activity of soil enzyme in different particle-size aggregates. Conservation tillage improved the biomass and diversity of soil microbes including soil fungi/bacteria, and made soil microbial community develop towards fungi-dominated flora. There were different content and composition of soil microbes in different particle-size aggregates, and higher soil bacterial and fungal content existed in microaggregates. Based on the current research status, the promotion of conservation tillage must suit the local conditions with appropriate rotational tillage system and straw returning to field to improve soil quality were proposed, and the future research direction was pointed out.

Key words: conservation tillage, soil aggregates, distributional characteristics, enzymes activities, microbe

摘要：

土壤团聚体是土壤结构的基本单元,是评价土壤质量的重要指标之一。土壤微生物是形成土壤团聚体最活跃的生物因素。保护性耕作在中国已得到广泛应用,探析保护性耕作对土壤团聚体和土壤微生物学特性的影响,有助于农业生产的可持续发展。文章综述了不同保护性耕作方式下土壤团聚体和微生物学特性的研究进展,归纳总结了保护性耕作对土壤团聚体分布特征、稳定性、有机碳含量、酶活性和微生物多样性影响以及土壤团聚体与土壤微生物之间关系。结果表明：与传统翻耕相比,保护性耕作增加了表层土壤团聚体的平均重量直径（MWD）、几何平均重量直径（GMD）和水稳性团聚体含量,促进了土壤大团聚体的形成,提升了土壤团聚体稳定性;保护性耕作提高了表层土壤有机碳含量,有利于土壤有机碳的固定;保护性耕作能有效提高土壤酶活性,土壤酶活性在不同粒径团聚体内分布特征和活性高低存在差异;保护性耕作提高土壤微生物生物量和土壤微生物多样性,提高土壤真菌/细菌比值,使土壤微生物群落向以真菌为优势菌群的方向发展;土壤微生物含量和组成在不同粒径团聚体中存在差异,微团聚体中有更高的土壤细菌和真菌含量。针对目前研究现状,提出了因地制宜推广保护性耕作、适宜的轮耕制度、适量秸秆还田的可能性及未来的研究方向。

关键词: 保护性耕作, 土壤团聚体, 分布特征, 酶活性, 微生物