Changes in carbon pools and biological activities of a sandy loam soil under medium‐term conservation agriculture and diversified cropping systems

Abstract

Summary Conservation agriculture (CA) practices such as zero tillage (ZT) and permanent raised beds (PB) accelerate deposition of soil organic matter and augment associated biological properties of soil through enhanced inputs of organic carbon. However, the potential benefit of CA under intensive cereal‐based systems for key soil health indicators (such as carbon pools and biological activities) is only partially known. Therefore, we analysed the effect of three medium‐term tillage practices and four intensive crop rotations on selected soil organic carbon pools and microbial properties. The tillage practices consist of ZT, PB and conventional tillage (CT) in main plots and four crop rotations (MWMb, maize–wheat–mungbean; MCS, maize–chickpea–Sesbania; MMuMb, maize–mustard–mungbean; MMS, maize–maize–Sesbania) in subplots. The experimental design was split‐plot with three replications. After 6 years, we observed a significant positive effect of CA practices on soil organic carbon (SOC) content, labile SOC fractions, soil microbial biomass carbon (MBC) and dehydrogenase activity (DHA). The total organic carbon (TOC) was greatly affected by medium‐term tillage and diversified cropping systems; it was larger for CA and MCS and MWMb systems. The interaction effect between tillage and cropping systems for SOC content was not significant at all soil depths. Significantly larger contributions (8.5–25.5%) of labile SOC pools to TOC at various soil depths were recorded in PB and ZT. There was a significant positive effect of CA practices and diversified crop rotations on MBC and DHA at all the soil depths and sampling times, but the interaction effect between tillage and cropping systems was not significant. Thus, our medium‐term (≥ 5‐years) study showed that the combination of CA (PB and ZT) practices and appropriate choice of rotations (MCS and MWMb) appears to be the most appropriate option for restoration and improvement of the soil health of light‐textured Inceptisols through the accumulation of soil organic matter (SOM) and improvement in soil biological properties. Highlights Effect of conservation agriculture (CA) on soil labile carbon inputs and biological properties. Observed changes in SOC stock and C‐pools at different soil depths after 6 years. Significant effects of tillage and crop rotations observed for labile‐C pools. Adoption of ZT and PB enhanced SOC stock, C‐pools and microbial activity compared to CT.

Climate smart agricultural practices improve soil quality through organic carbon enrichment and lower greenhouse gas emissions in farms of bread bowl of India

“…Our findings are also consistent with the findings of Choudhary et al (2018a, b) and Parihar et al (2018) who also observed significantly higher TC under CA based practices.…”

Responses of Soil Carbon Pools, Enzymatic Activity, and Crop Yields to Nitrogen and Straw Incorporation in a Rice-Wheat Cropping System in North-Western India

“…Surface retention of crop residues under no-tillage system has been reported to greatly enhance the soil enzymatic activity, which was related to increased microbial biomass in the soil (Hok et al, 2018;Saikia et al, 2019). This has significance in RWCS, where alteration in moisture regimes during two seasons changed the pattern of microbial decomposition of C input into the soil triggered by enzymatic activity (Choudhary et al, 2018;Parihar et al, 2018). The TOC pools and enzymatic activity under different straw management regimes vary substantially depending on climate factors, soil types, and experimental conditions (Wang et al, 2015a;Zhao et al, 2015).…”

Long‐term conservation agriculture helps in the reclamation of sodic soils in major agri‐food systems

“…Higher microbial activity in surface soil under CA‐based management also contributed to higher production of VLC in those scenarios (Choudhary, Datta, et al, 2018; Choudhary, Jat, et al, 2018). Parihar et al (2018) also reported higher VLC as MBC at surface soils under CA‐based management in Northwest India. All CA‐based managements resulted in higher SOC in comparison with CT.…”