[Effects of Biochar Application on Physicochemical Properties and Bacterial Communities of Microplastic-contaminated Calcareous Soil].

Microplastics are widely distributed in the soil environment, threatening the soil ecological environment system and changing soil physicochemical properties and microbial characteristics. Biochar is often used as a soil amendment to improve soil quality due to its special pore structure and good soil nutrient retention ability. However, the understanding of the effects and mechanisms of biochar application on the physicochemical properties and bacterial communities of microplastic-contaminated soils is still very limited.

[Diversity of Soil Eukaryotic Microbes in Different Succession Stages in Maolan Karst Forest of Guizhou].

As an indispensable part of the Maolan karst forest soil microorganisms, eukaryotic microbes play an important role in ecosystem material and energy flow. To investigate the composition and diversity of soil eukaryotic microbial communities under different succession stages in the Maolan karst forest, we explored the diversity and composition of soil eukaryotic microbes under four succession stages of primary forests (YSL), shrub forests (GML), bushes (GMC), and grassland (CD) via high-throughput sequencing (HTS) of the 18S rDNA. The results showed that the composition of soil eukaryotic microbial communities was similar in different succession stages under different classification levels.

[Soil bacterial community characteristics under different microhabitat types on Maolan karst forest, Guizhou, Southwest China].

We analyzed the diversity, community composition and relative abundance of soil bacteria communities in five different types of microhabitats (included stone caverns, stone crevices, stone gullies, stone grooves, top-soils) in Maolan karst forest, Guizhou Province, China. Bacterial 16S rRNA V3-V4 variable regions were analyzed by high-throughput sequencing technique. We examined the effects of soil physicochemical factors on bacterial community structure.

[Effects of Chinese prickly ash orchard on soil organic carbon mineralization and labile organic carbon in karst rocky desertification region of Guizhou province].

Taking 5-year-old Chinese prickly ash orchard (PO-5), 17-year-old Chinese prickly ash orchard (PO- 17), 30-year-old Chinese prickly ash orchard (PO-30) and the forest land (FL, about 60 years) in typical demonstration area of desertification control test in southwestern Guizhou as our research objects, the aim of this study using a batch incubation experiment was to research the mineralization characteristics of soil organic carbon and changes of the labile soil organic carbon contents at different depths (0-15 cm, 15-30 cm, and 30-50 cm). The results showed that: the cumulative mineralization amounts of soil organic carbon were in the order of 30-year-old Chinese prickly ash orchard, the forest land, 5-year-old Chinese prickly ash orchard and 17-year-old Chinese prickly ash orchard at corresponding depth. Distribution ratios of CO2-C cumulative mineralization amount to SOC contents were higher in Chinese prickly ash orchards than in forest land at each depth.

[Effects of land use and abandonment on soil labile organic carbon in the Karst region of southwest China].

Effects of land use and land abandonment on labile organic carbon (LOC) in whole soils and different aggregate sizes were studied by sampling analysis of the soils in some typical land uses of the Karst region, southwest China. Results showed that the content and degree of dispersion of labile organic carbon decreased with soil depth, and the content of LOC was highly significant (P < 0.01) in 0-10 cm than in 10-20 cm and 20-30 cm.

[Relationships between soil and rocky desertification in typical karst mountain area based on redundancy analysis].

Redundancy analysis (RDA) was employed to reveal the relationships between soil and rocky desertification through vegetation investigation and analysis of soil samples collected in typical karst mountain area of southwest Guizhou Province. The results showed that except TP, TK and ACa, all other variables including SOC, TN, MBC, ROC, DOC, available nutrients and basal respiration showed significant downward trends during the rocky desertification process. RDA results showed significant correlations between different types of desertification and soil variables, described as non-degraded > potential desertification > light desertification > moderate desertification > severe desertification.

[Variation of soil organic carbon under different vegetation types in Karst Mountain areas of Guizhou Province, southwest China].

This paper studied the variation characteristics of soil organic carbon (SOC) and different particle sizes soil particulate organic carbon (POC) in normal soil and in micro-habitats under different vegetation types in typical Karst mountain areas of southwest Guizhou. Under different vegetation types, the SOC content in normal soil and in micro-habitats was all in the order of bare land < grass < shrub < forest, with the variation range being 7.18-43.