Abstract
Soil salinization typically inhibits the ability of decomposer organisms to utilize soil organic matter, and an increase in soil clay content can mediate the negative effect of salinity on carbon (C) mineralization. However, the interactive effects of soil salt concentrations and properties on C mineralization remain uncertain. In this study, a laboratory experiment was performed to investigate the interactive effects of soil salt content (0.1%, 0.3%, 0.6% and 1.0%) and texture (sandy loam, sandy clay loam and silty clay soil with 6.0%, 23.9% and 40.6% clay content, respectively) on C mineralization and microbial community composition after cotton straw addition. With increasing soil salinity, carbon dioxide (CO2) emissions from the three soils decreased, but the effect of soil salinity on the decomposition of soil organic carbon varied with soil texture. Cumulative CO2 emissions in the coarse-textured (sandy loam and sandy clay loam) soils were more affected by salinity than those in the fine-textured (silty clay) soil. This difference was probably due to the differing responses of labile and resistant organic compounds to salinity across different soil texture. Increased salinity decreased the decomposition of the stable C pool in the coarse-textured soil, by reducing the proportion of fungi to bacteria, whereas it decreased the mineralization of the active C pool in the fine-textured soil through decreasing the Gram-positive bacterial population. Overall, our results suggest that soil texture controlled the negative effect of salinity on C mineralization through regulating the soil microbial community composition.
Highlights
In the desert-oasis ecotone of China, the transformation of native desert soils to farmlands generally benefits the formation of soil aggregation by increasing soil clay or organic matter contents [1]
Soil texture determines the accessibility of soil organic matter (SOM) to decomposer organisms, and a high clay content generally inhibits the ability of soil microorganisms to decompose soil organic matter [2]
Our result is partly consistent with that presented by Chowdhury et al [29], and we found that C mineralization was more affected by soil salinization with low clay content (6–24%) than in the high clay content (41%)
Summary
In the desert-oasis ecotone of China, the transformation of native desert soils to farmlands generally benefits the formation of soil aggregation by increasing soil clay or organic matter contents [1]. Found a negative relationship between clay content and the decomposition of the active (fast-turnover) carbon (C) pool, whereas soil texture did not affect the decomposition of the stable (slow-turnover) C pool In this region, most of the salt in the irrigation water stores in the field due to high evaporation rather than leaching to the groundwater [3,4]. Setia et al [6] found that the decomposition of the labile C pool was more affected by salinity than that of the stable C pool across different soil textures, but that the rate of active C mineralization was more affected by salinity in a loamy sand soil than in a clay soil This inconsistency was probably attributed to the different responses of the soil microbial community to salinity among different soil textures, which most likely controlled the decomposition process of various
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
