Microbial Biomass and Activity in Relation to Accessibility of Organic Carbon in Saline Soils of Coastal Agro-Ecosystem
Microbial Biomass and Activity in Relation to Accessibility of Organic Carbon in Saline Soils of Coastal Agro-Ecosystem
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DOI：
10.1007/s40011-016-0801-4
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发表时间：
2018-06
期刊：
影响因子：
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通讯作者：
S. Deb;B. Mandal;P. Bhadoria;E. Schulz;Subhadip Ghosh;M. Debnath
中科院分区：
文献类型：
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作者：
S. Deb;B. Mandal;P. Bhadoria;E. Schulz;Subhadip Ghosh;M. Debnath
在沿海农业生态系统中，土壤盐度从沿海边缘向内陆递减，这种盐度变化影响碳(C)动态和土壤生物学。在此基础上，研究了印度东部沿海盐碱地不同水稻种植制度下土壤微生物生物量和活性与有机碳可及性的变化规律。研究结果表明，随着土壤盐分的增加，土壤微生物生物量和活性降低。另一方面，絮凝Ca2+的优势随着盐分的增加而增加，导致土壤团聚体增加，在大团聚体中形成更多的土壤微团聚体，从而导致团聚体相关碳的增加。土壤有机碳（SOC）含量随着土壤电导率的增加而增加，而单位有机碳（SOC）含量则减少。随着盐度诱导的高渗透胁迫，土壤团聚度的提高和稳定有机C的相对减少可能是这些土壤中微生物生物量和活动受到抑制的原因，因为土壤微生物对C的可利用性受到限制。由于长期淹水导致有机碳分解缓慢，稻-稻-休耕制土壤的稳定有机碳积累量高于其他稻作制土壤。
In coastal agro-ecosystems, soil salinity follows a decreasing gradient from coastal margin towards inland and this variation of salinity influences carbon (C) dynamics and soil biology. Following this trend, an experiment was conducted to study the changes in soil microbial biomass and activities in relation to organic C accessibility along salinity gradient and under different rice based cropping systems in coastal saline soils of eastern India. Findings inferred reduced soil microbial biomass and activities with increase in soil salinity. On the other hand, preponderance of flocculating Ca2+with increase in salinity resulted in higher soil aggregation, formation of greater number of soil micro-aggregates within macro-aggregates and subsequent increase in aggregate-associated C. Further, there was increase in soil organic C (SOC) content but decrease in labile C per unit SOC with increase in soil electrical conductivity. Along with salinity induced hyper-osmotic stress, this higher soil aggregation and relative reduction in labile organic C might be accountable for curbed microbial biomass and activities in these soils, by restricting the availability of C for soil micro-organisms. Slow decomposition of organic C under prolonged submergence resulted higher accumulation of stable organic C under rice–rice-fallow cropping system as compared to soils under other rice-based cropping systems.