苏打盐碱土的改良是东北松嫩平原土壤治理的重要目标。综合前人的研究结果，归纳总结了改良剂的作用机理和改良效果，主要类型及应用，以及改良剂在实际使用中存在的问题，也展望了改良剂的应用前景，为今后改良剂的深入研究提供参考。改良剂可分为无机改良剂、有机改良剂、微生物菌剂，组合改良剂的使用效果好于单一改良剂，改良剂的应用对土壤理化性质、结构、养分含量以及微生态环境都有改善，并促进植物生长。提出针对北方旱田盐碱土的改良，新型有机改良剂以及配套改良技术的研发是今后研究的重点。

酸杆菌是土壤中一类重要的细菌类群。基于16S rRNA基因序列分析发现，酸杆菌一般占细菌总量的20%左右，甚至高达50%以上，表明酸杆菌在土壤生态过程中起到重要的作用。从植被、海拔高度、氮肥管理及二氧化碳升高对土壤酸杆菌分布的影响，以及酸杆菌根际效应等几方面论述了土壤酸杆菌门细菌生态学研究进展；综合分析揭示出不同分类单元酸杆菌细菌分布与环境因子间的关系；阐述了部分酸杆菌细菌的潜在生态功能。最后指出在土壤酸杆菌研究中应强化分离培养、细化分子生态、采用宏基因组学和单细胞测序新技术的重要性。

The severe environmental stresses of the Arctic may have promoted unique soil bacterial communities compared with those found in lower latitude environments. Here, we present a comprehensive analysis of the biogeography of soil bacterial communities in the Arctic using a high resolution bar-coded pyrosequencing technique. We also compared arctic soils with soils from a wide range of more temperate biomes to characterize variability in soil bacterial communities across the globe. We show that arctic soil bacterial community composition and diversity are structured according to local variation in soil pH rather than geographical proximity to neighboring sites, suggesting that local environmental heterogeneity is far more important than dispersal limitation in determining community-level differences. Furthermore, bacterial community composition had similar levels of variability, richness and phylogenetic diversity within arctic soils as across soils from a wide range of lower latitudes, strongly suggesting a common diversity structure within soil bacterial communities around the globe. These results contrast with the well-established latitudinal gradients in animal and plant diversity, suggesting that the controls on bacterial community distributions are fundamentally different from those observed for macro-organisms and that our biome definitions are not useful for predicting variability in soil bacterial communities across the globe.© 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.

Despite recognition of the importance of soil bacteria to terrestrial ecosystem functioning there is little consensus on the factors regulating belowground biodiversity. Here we present a multi-scale spatial assessment of soil bacterial community profiles across Great Britain (> 1000 soil cores), and show the first landscape scale map of bacterial distributions across a nation. Bacterial diversity and community dissimilarities, assessed using terminal restriction fragment length polymorphism, were most strongly related to soil pH providing a large-scale confirmation of the role of pH in structuring bacterial taxa. However, while α diversity was positively related to pH, the converse was true for β diversity (between sample variance in α diversity). β diversity was found to be greatest in acidic soils, corresponding with greater environmental heterogeneity. Analyses of clone libraries revealed the pH effects were predominantly manifest at the level of broad bacterial taxonomic groups, with acidic soils being dominated by few taxa (notably the group 1 Acidobacteria and Alphaproteobacteria). We also noted significant correlations between bacterial communities and most other measured environmental variables (soil chemistry, aboveground features and climatic variables), together with significant spatial correlations at close distances. In particular, bacterial and plant communities were closely related signifying no strong evidence that soil bacteria are driven by different ecological processes to those governing higher organisms. We conclude that broad scale surveys are useful in identifying distinct soil biomes comprising reproducible communities of dominant taxa. Together these results provide a baseline ecological framework with which to pursue future research on both soil microbial function, and more explicit biome based assessments of the local ecological drivers of bacterial biodiversity.© 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.