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[Objective] The present paper aimed to investigate the effects of microplastics on the structure and carbon, nitrogen, phosphorus stoichiometric characteristics of red soil with different levels of iron enrichment, and to provide theoretical basis for guiding the improvement of soil quality and pollution management in red soil areas. [Method] Using subtropical red soil as the research object, low density polyethylene (M0, M1, M2) with 0, 0.1%, 1.0% mass and iron (Fe0, Fe1, Fe2) with 0, 10 and 20 g/kg mass were added through indoor cultivation experiments to simulate the pollution level of microplastics and the degree of iron enrichment in red soil. The distribution characteristics of water stable aggregates and the stoichiometric characteristics of carbon, nitrogen and phosphorus in red soil polluted by microplastics under different iron enrichment conditions were studied. [Result] Under the condition of Fe0o, compared with M0, the aggregate content (WSA), mean weight diameter (MWD) and geometric mean diameter (GMD) of M1 with particle size > 0.25 mm decreased, and the WSA, MWD and GMD of M2 increased significantly; Under Fe0, conditions, there was no significant difference in the stability indicators of aggregates among M0, M1 and M2; Under Fe2 conditions, both M1 and M2 significantly reduced the WSA, MWD and GMD of soil aggregates. In terms of carbon, nitrogen and phosphorus content and their stoichiometric characteristics, M1 and M2 under Fe0 conditions could significantly increase soil organic carbon content (SOC); Under Fe0, and Fe2 conditions, microplastic treatment had no significant effect on SOC. The total nitrogen content (TN) of the soil decreased significantly under Fe0, and Fe1, conditions, while microplastic treatment had no significant effect on TN under Fe2 conditions; The total phosphorus content (TP) of the soil showed M0 > M1 > M2. The changes in soil nutrients ultimately led to a significant increase in C/N, C/P and N/P of all microplastic treatments (except for Fe0, M1, Fe2 M1 and Fe2 M2). [Conclusion] The effects of different treatments on the stability of soil aggregates vary. Under the current existing red soil conditions, low micro plastic pollution can reduce the stability of soil aggregates, while high micro plastic pollution can increase the stability of soil aggregates. Under relatively light iron rich red soil conditions, both low and high microplastic pollution have no significant impact on the stability of soil aggregates. Under relatively high iron rich red soil conditions, both low and high microplastic pollution can reduce the stability of soil aggregates. M0reover, the changes in soil aggregate structure under different treatments led to significant differences in the stoichiometric characteristics of carbon, nitrogen and phosphorus in the soil. Overall, microplastic pollution can significantly improve the C/N, C/P and N/P of red soil. [ABSTRACT FROM AUTHOR]

Rural revitalization points out that “industrial prosperity is the key, and ecological livability is the key”. We should always adhere to the concept of “ecology+” and “+ecology” to plan development and take the path of green and sustainable development. Under the requirements of the new era and new ideas, the treatment of biomass waste has been endowed with new connotation. It is not only required to achieve the ecological goal of “zero emissions, no pollution”, but also to pursue the economic potential of “reuse, high-yield value” to achieve the dual effect of ecological revitalization and industrial revitalization. However, China, as a traditional agricultural country, has a huge output of biomass waste mainly consisting of straw and livestock manure, but its ecological industrialization approach is not yet mature, and its resource potential and economic value are far from being developed. Therefore, how to build an efficient industrial system for biomass waste treatment around the “ecological industry” is crucial to realize the good vision of “industrial prosperity and ecological beauty” in rural areas. This paper summarizes the current utilization situation and existing problems of biomass waste, discusses the main path and existing problems of the current ecological industrialization of biomass waste, puts forward corresponding improvement measures and suggestions for the problems, summarizes the steps and components of building an industrial system, in order to provide a reference for the efficient utilization of biomass waste and high-level ecological protection [ABSTRACT FROM AUTHOR]

【Objective】In order to investigate active organic carbon components in 0-40 cm soil layer under comprehensive ecological farming pattern, the sensitivity of active organic carbon (AOC) and characteristics of carbon pool management were examined to provide a theoretical basic for carbon sequestration and nutrient management in paddy field under this pattern.【Method】The soils under three farming patterns, i.e., comprehensive ecological farming mode (EIM), rice-vegetable crop rotation mode (RVM), and conventional rice farming mode (CRM) at the Agricultural Ecological Environment Field Station in Zengcheng District, Guangzhou City, were selected to determine total organic carbon (TOC), dissolved organic carbon (DOC), oxidized organic carbon (EOC), and microbial biomass carbon (MBC), and to explore the factors influencing changes in soil active organic carbon components.【Result】In EIM, TOC was 10.55 g/kg, DOC EOC POC and MBC contents were 0.29, 1.38, 2.09 and 0.11 g/kg, respectively, and those were significantly higher than that of RVM and CRM. Soil microbial entropy was the highest in EIM, and increased by 51.11%-85.72% and 46.04%-223.99%, respectively, compared with RVM and CRM. The most sensitive AOC within the 0-10 cm layer was MBC, whereas within the 10-20 cm layer, EOC exhibited the highest sensitivity. EIM significantly improved soil carbon pool management indexes, with MBC being an important component factor of soil carbon pool management index. The results of redundancy analysis showed that the variation of soil organic carbon components was mainly affected by soil bulk density and pH. 【Conclusion】MBC serves as a sensitive indicator of changes in AOC components and a significant influencing factor in soil carbon pool management indexes. The comprehensive ecological farming mode enhances soil AOC components mainly by affecting bulk density and microbial activities, significantly elevating soil carbon storage. In conclusion, comprehensive ecological farming mode is an effective practice for carbon sequestration in paddy field. [ABSTRACT FROM AUTHOR]