Conservation agriculture’s impact on total and labile organic carbon pools in calcareous and non-calcareous floodplain soils under a sub-tropical rice-based system

• Published in: PloS one 2023-11, Vol.18 (11), p.e0293257-e0293257
• Main Authors: Sarker, Rakhi Rani, Rashid, M. H, Islam, Md. Ariful, Jahiruddin, M, Islam, Khandakar Rafiq, Jahangir, Mohammad Mofizur Rahman
• Format: Article
• Language: English
• Subjects: Agricultural conservation; Agricultural management; Agriculture; Air pollution; Beans; Brassica nigra; Calcareous soils; Carbon; Carbon content; Cereal crops; Conservation; Conservation tillage; Crop residues; Cropping systems; Crops; Efficiency; Emission standards; Emissions; Evaluation; Experiments; Fertilizers; Field tests; Floodplains; Greenhouse gases; Lability; Legumes; Lens culinaris; Microorganisms; Mimosaceae; Mustard; No-tillage; Organic carbon; Organic soils; Oryza sativa; Phenolphthalein; Productivity; Residues; Retention; Rice; Sea level; Soil conservation; Soil erosion; Soil fertility; Soils; Subtropical climates; Sustainability; Tillage; Triticum aestivum; Wheat; Wind
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0293257

To evaluate the effects of conservation agriculture (CA) on SOC pools and their lability, field experiments (2015-2020) were conducted on contrasting soils under subtropical climates. The experiment on non-calcareous soils, was comprised of tillage (minimum [MT] vs. conventional [CT]) in main plots, cropping systems (Wheat [Triticum aestivum]-Aus and Aman rice [Oryza sativa L.], WRR; Lentil [Lens culinaris]-Aus and Aman rice, LRR; and Mustard [Brassica nigra]- Boro and Aman rice, MRR) in the sub-plots, and crop residue (with or without 20% residue) in the sub-sub plots. The experiment on calcareous soils, was comprised of tillage (strip-till, ST; no-till, NT; and CT) and crop residue (high residue, HR at 50% by height vs. low residue, LR at 15%). Results showed that the MT had higher SOC contents by 18.8% than the CT in non-calcareous soils. Likewise, SOC was 12.5% and 6.7% higher in the NT and ST, respectively, than in the CT in calcareous soils. Significantly higher particulate organic (POC), permanganate oxidizable (POXC), and microbial biomass carbon (MBC) were observed in the MT, NT, and ST than in the CT at both locations. Reduced tillage with residue retention under LRR had a higher SOC, including labile C pools compared to WRR and MRR systems. Similarly, carbon management index (1.2-1.5 and 1.0-1.2) in both soils had significant positive correlations with SOC lability via POXC, POC, and MBC pools, indicating a SOC sequestration potential. In conclusion, our results showed positive effects of CA on SOC and its lability across soils.