期刊
SOIL RESEARCH
卷 60, 期 6, 页码 590-600出版社
CSIRO PUBLISHING
DOI: 10.1071/SR21151
关键词
cover crops; legumes; microbial residues; no-till; organo-mineral associations; plant residues; soil carbohydrates; soil management; soil organic carbon accumulation
类别
资金
- National Council for Scientific and Technological Development (CNPq)
- Foundation for Research Support of Rio Grande do Sul State (Fapergs)
- Coordination for the Personnel Improvement of Graduate Education (CAPES)
- Agriculture and Agri-Food Canada (AAFC)
No-tillage and legume cover cropping can promote carbon accumulation and stabilization in highly weathered subtropical agricultural soils. Both practices result in the accumulation of plant-derived carbohydrates in the surface soil layer, and conservation management methods can also increase carbon content in deeper soil layers.
Context Knowledge of the impacts of no-tillage and cover cropping on carbon accumulation and stabilisation in highly weathered agricultural soils of subtropical regions is scant. We hypothesised that implementation of no-tillage coupled with high-quality legume residues in highly weathered agricultural soils would result in high carbon accumulation rates, mainly as microbe- and plant-derived materials in fine mineral-organic complexes. Aims and methods We sampled soil profiles down to 100 cm in a long-term field experiment and used density and particle size fractionation in combination with carbohydrate analyses to compare the effect of conventional tillage vs no-tillage, combined or not with legume cover cropping, and combined or not with mineral nitrogen fertilisation. Key results Both no-tillage and legume cover crops favoured the accumulation and enrichment in plant-derived carbohydrates in the surface soil layer, due to the accumulation of plant residues. The ratio of microbe- to plant-derived carbohydrates increased with soil depth indicating that the soil carbon (C) was more microbially processed than at the surface. Conservation management systems also increased soil C at depth and this was most visible in the clay fraction. The additional clay-size C accumulating at depth under conservation treatments was of both microbial and plant origin. Conclusions Our results support the hypothesis that mineral-associated C is composed of both plant and microbial residues and is positively influenced by conservation management practices. Implications Our results demonstrate that no-till and legume cover cropping are efficient practises to foster C accumulation and stabilisation in heavily weathered agricultural soil profiles in a subtropical climate.
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