Enhanced soil carbon storage by arbuscular mycorrhizal fungi in a long-term nutrient management under soybean-based cropping system

Abstract To ensure the sustainability of crop production and ecosystem functioning, a thorough understanding of the mechanisms governing soil carbon (C) -sequestration and soil health is essential. This study examined the effects of three nutrient management practices (organic, inorganic, and integrated and two cropping systems (soybean-wheat and soybean-chickpea), on arbuscular mycorrhizal fungi (AMF) and soil C-sequestration in a long-term (12 years) field experiment. We measured the stocks of soil organic carbon, total-glomalin-related soil protein, pertinent soil quality parameters such as microbial biomass carbon, β-glucosidase activity along with AMF biomass [microscopic parameters and 16:1ω5cis phospholipid fatty acid (AM. PLFA) and neutral lipid fatty acid (AM. NLFA)]. It was observed that the measures of AMF biomass were positively correlated with the soil organic carbon stocks, total-glomalin related soil protein stocks, and soil quality parameters. Organic practice recorded significantly higher AMF spores, mycorrhizal colonization percentage, AM. PLFA (2.58 nmoles g⁻ ¹ soil), AM. NLFA (7.95 nmoles g⁻ ¹ soil), soil organic carbon stocks (15.78 Mg ha⁻ ¹), total-glomalin related soil protein stocks (2.10 Mg ha⁻ ¹), and soil quality parameters such as microbial biomass carbon, β-glucosidase activity than inorganic and integrated practices. In comparison to soybean-chickpea, C-sequestration was higher in soybean-wheat. Principal component analysis validated the said results and differentiated soybean-wheat under organic practice from the rest of the treatments. In conclusion, our results suggest that organic management in conjunction with soybean-wheat crop rotation enhances AMF and can be recommended for improving soil quality and C sequestration without compromising crop yield.