Differences in soil organic carbon pools and biological activity between organic and conventionally managed rice-wheat fields.

Autor: Benbi, D. K., Sharma, Shivani, Toor, A. S., Brar, Kiranvir, Sodhi, G. P. S., Garg, A. K.
Zdroj: Organic Agriculture; Mar2018, Vol. 8 Issue 1, p1-14, 14p
Abstrakt: Regular input of organic matter under organic system of agriculture may bring about quantitative and qualitative changes in soil organic matter (SOM) and could impact microbial and biochemical properties of soil. While the effect of organic amendments on quantitative changes in soil organic C (SOC) is fairly well-documented, the relationship between physical fractions of SOM and microbial and biochemical activity of soils is relatively less quantified. Using an on-farm approach, we studied the effect of organic and conventional systems of agriculture on soil microbial and enzyme activities and microbial community composition in order to establish their relationship with physical fractions of SOC in rice-wheat sequence. Organic system of management improved SOC stocks by 2.2 Mg ha−1 in the top 15-cm soil, and the accrued C occurred as coarse particulate (cPOC) and mineral-associated organic C (MinOC). Organic production systems were characterised by higher microbial biomass C (MBC), mineralisable C, enzyme activities and population of bacteria, fungi and actinomycetes in soil than the conventional system of management. A regression model, which included dehydrogenase, cellulase, xylanase, MBC and clay, could predict differences in SOC between organic and conventionally managed fields, indicating the need for using several indicators together for characterising the two systems of management. Organic agriculture favourably impacted microbial and C-cycle enzyme activities, which regulated organic matter decomposition and stabilisation in soil. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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