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Tillage methods affect soil heat, water, nutrients and soil biology in different ways. Reasonable soil management system can not only improve physical and chemical properties of the soil, but also change the ecological process of farmland soil. Conservation tillage can improve the quality of the soil to different degrees. For example, no-tillage system can effectively improve soil enzyme activity. No tillage and subsoiling tillage can provide abundant resources for soil microbe' s growth and reproduction. No tillage, minimum tillage and other conservation tillage methods exert little disturbance to soil animals, and in turn affect the quantity and diversity of the soil animals as well as their population structure. Effects of different tillage methods on soil physical and chemical properties as well as biological characteristics were reviewed in this article, with the soil physical and chemical indices, enzyme activities, soil microbe diversity and soil animals under different tillage patterns analyzed. The possibility of soil quality restoration with appropriate tillage methods and the future research direction were pointed out.

By using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and sequence analysis, this paper studied the nifH gene diversity and community structure of soil nitrogen-fixing microbes in Hulunbeier sandy land of Inner Mongolia under four years management of five vegetation restoration modes, i. e., mixed-planting of Agropyron cristatum, Hedysarum fruticosum, Caragana korshinskii, and Elymus nutans (ACHE) and of Agropyron cristatum and Hedysarum fruticosum (AC), and mono-planting of Caragana korshinskii (UC), Agropyron cristatum (UA), and Hedysarum fruticosum (UH), taking the bare land as the control (CK). There existed significant differences in the community composition of nitrogen-fixing microbes among the five vegetation restoration patterns. The Shannon index of the nifH gene was the highest under ACHE, followed by under AC, UC, UA, and UH, and the lowest in CK. Except that UH and CK had less difference in the Shannon index, the other four vegetation restoration modes had a significantly higher Shannon index than CK (P < 0.05). The phylogenetic analysis showed that the soil nitrogen-fixing microbes under UA, UH, and UC were mainly of cyanobacteria, but the soil nitrogen-fixing microbes under AC and ACHE changed obviously, mainly of proteobacteria, and also of cyanobacteria. The canonical correlation analysis showed that the soil total phosphorus, available phosphorus, total nitrogen, and nitrate nitrogen contents under the five vegetation restoration modes had significant effects on the nitrogen-fixing microbial communities, and there existed significant correlations among the soil total phosphorus, available phosphorus, total nitrogen, and nitrate nitrogen. It was suggested that the variations of the community composition of soil nitrogen-fixing microbes under the five vegetation restoration modes were resulted from the interactive and combined effects of the soil physical and chemical factors.

By using systematic conservation planning (SCP) method, and taking catchment as planning unit, an optimization of conservation network system for the inter-basin wetland ecosystem in Huang-Huai-Hai Region was conducted, with a comprehensive consideration of 3-dimensional (lateral, longitudinal and vertical) connectivity and Inter-basin Water Transfer Project and by the methods of irreplaceability analysis and gap identification. The efficacy of the optimized conservation network system was evaluated, as compared with the existing conservation network system. According to the principles of irreplaceability and connectivity, the wetland conservation gaps could be divided into two types, i.e. , be conserved in priority and in general. After the optimization, the conservation status of the inter-basin wetland ecosystem in Huang-Huai-Hai Region had an overall improvement. The conserved percentage of the wetland types was from about 20% up to 46.8%, and, for each wetland type, its conserved level increased to some extent, almost above 40%. Both in the near future and in the long term, more attention should be paid to the conservation of lake wetland. In addition, the integration of ecosystem service function and biodiversity and the combination of protection with restoration would be the main task for the wetland ecosystem conservation planning in the future.

By the methods of polymerase chain reaction-denaturing gradient gel electrophoresis and sequence analysis, a comparative study was conducted on the diversity and community structure of soil ammonia-oxidizing bacteria in the Filifolium sibiricum steppe, Stipa baicalensis steppe, Leymus chinensis steppe, Stipa grandis steppe, and Stipa kryrowi steppe in Hulunbeier Grassland, Inner Mongolia. A significant difference was observed in the community structure of soil ammonia-oxidizing bacteria among the five steppes, with the similarity lower than 50%. The diversity of soil ammonia-oxidizing bacteria was the highest in F. sibiricum steppe, followed by in S. baicalensis steppe, L. chinensis steppe, S. kryrowi steppe, and S. grandis steppe. In the five steppes, Nitrosospira cluster 3 was the dominant group, and the Nitrosospira cluster 1, 2, and 4 as well as Nitrosomonas were also found. The community structure of soil ammonia oxidizing bacteria in F. sibiricum steppe was most complex, while that in L. chinensis steppe and S. grandis steppe was relatively simple. Correlation analysis indicated that there existed significant positive correlations between the diversity of soil ammonia-oxidizing bacteria and the soil moisture, total nitrogen, total organic carbon, and C/N ratio (P<0.05).

Traditional culture-dependent method and PCR-DGGE were adopted to investigate the amount of microorganism and bacterial diversity in rhizospheric soil of transgenic Bt cotton in four provinces of Yellow River basin at four growth stages, i.e., 30, 60, 90, and 120 days after sowing. In the same province and at the same growth stage, no significant difference was observed in the amount of microorganism in rhizospheric soils of transgenic and non-transgenic Bt cottons. Within the same province the amount of microorganism was mainly affected by growth stage; while in different provinces, it was greatly affected by regional conditions. In the four provinces, the bacterial diversity in rhizospheric soil of transgenic Bt cotton was abundant; and in the same province and at the same growth stage, there were no significant differences in the Shannon index, evenness, and richness of bacteria in rhizospheric soils of transgenic and non-transgenic Bt cottons. In different provinces, the bacterial diversity in rhizospheric soils was dependent on regional conditions, but the difference was rather small.