Change of the Microorganisms Quantity in Irrigative Gleyey-Yellow under Vegetable Soils

The results of the long-term investigations in dynamics for study of the conditions of taxonomic groups of microorganisms of irrigated gleyey-yellow soils of the subtropical zone under vegetable crops in rotation with the continuous growing of these cultures have been presented. The results of the researches study demonstrated an important vibration of the microorganisms quantity under growing cultures happens. The most quantity of microorganisms, consuming organic nitrogen is observed in irrigative gleyey-yellow soils of the humid subtropical zone. Intensity of mineralization of organic matters was lower in irrigative gleyey-yellow soils. A quantity of microorganisms was lower, but a coefficient of mineralization was higher under continuous cultures as compared the analogous soils under crop rotation. These data show that a type of the soil influence on the rhizosphere microflora insignificantly, while plant shows a significant effect on its quantity and compositions.

Composition and Spatial Distribution of Soil Mesofauna Along an Elevation Gradient on the North Slope of the Changbai Mountains, China

The Changbai Mountains, located in northeastern China, show clear vertical zonation of vegetation types. Six different habitats,namely Pinus koraiensis mixed broad-leaved forest, Pinus koraiensis-Picea forest, spruce-fir forest, Betula ermanii forest, alpine meadow and alpine semi-desert, at elevations ranging from 780 to 2 480 m, covering almost all ecosystems on the north slope of the Changbai Mountains, were investigated to determine: i) whether or not the community composition of soil mesofauna varied significantly at different elevations; ii) if different soil mesofauna groups would respond differently to elevation and iii) which factors influenced the spatial distribution of soil mesofauna along elevation. Soil mesofauna were collected from each habitat in spring(May),summer(July) and autumn(September) of 2009. The soil mesofauna communities were comprised of at least 44 groups and were dominated by Acari and Collembola, followed by Coleoptera, Diptera larvae and Enchytraeidae. The composition, diversity and abundance of soil mesofauna varied among the six habitats. Meanwhile, significant seasonal variations were observed in the composition,abundance and diversity of the soil mesofauna in each habitat. The taxonomic richness and Shannon index were affected by elevation and soil properties, while the abundance was only significantly affected by soil properties. With regard to taxa, the habitats and seasons had significant effects on almost all the abundances of the major taxonomic groups. The abundance of more taxonomic groups was significantly influenced by the soil properties, while those of Geophilomorpha, Araneae and other taxa were affected by elevation.It is concluded that the composition and spatial distribution of the soil mesofauna varied along the elevation gradient on the north slope of the Changbai Mountains, which might be largely related to the variations of the plant community, soil properties and climate change resulting from the elevation gradient.