Assessment of Organic Carbon Stock and Soil Organic Carbon Fractions Across Different Cropping Systems in the Red and Laterite Soils of Meghalaya, India

ABSTRACT Soil carbon (C) depletion is a prime indicator of land degradation. Cropping system intensification with short‐duration legumes is a perceived important strategy to restore soil C in agricultural land. Hence, the impact of six cropping systems (maize [ Zea mays ]—French bean [ Phaseolus vulgaris ], maize–soybean [ Glycine max ], maize–urdbean [ Vigna mungo ], maize–mungbean [ Vigna radiata ], maize–toria [ Brassica campestris var. toria], and maize–fallow) was evaluated on soil C fractions and pools, C‐resilience, C management index, and soil biological properties in a fixed plot fashion for 7 years in Meghalaya, India. Results showed that the maize–French bean system sequestered maximum C (0.54 and 0.51 Mg ha −1 year −1 ) at 0–10 and 10–20 cm soil depth, respectively. Furthermore, the maize–French bean system had 6.52% and 11.91% higher active soil C pools over the maize–fallow system at 0–10 and 10–20 cm soil depth, respectively. Concerning SOC fractions, soils under the maize–French bean had the maximum VLC (37.66%) and NLC (34.31%) proportion in SOC, followed by the maize‐soybean system at soil depth of 0–10 cm. The upper soil depth (0–10 cm) had more C depletion and lower C recovery over lower soil layers (10–20 cm depth), regardless of cropping systems. The maize–French bean system had 25.7% and 30.2% less soil C depletion over the maize–fallow system at a soil depth of 0–10 and 10–20 cm, respectively. More interestingly, soil under maize–French bean had maximum C‐resilience and C‐sensitivity index. Concerning soil biological properties, the soil in the maize–French bean system recorded maximum SMBC (295.75 μg g −1 soil) and DHA (15.48 μg TPF g −1 soil h −1 ) at 0–10 cm depth. However, acid phosphatase activities were maximum in the maize–soybean cropping system (2.71 and 1.97 μg p‐nitrophenol g −1 soil h −1 in 0–10 and 10–20 cm, respectively). The study inferred that the inclusion of French bean and/or soybean as a succeeding crop in the maize monocropping system is a highly effective approach for restoring soil C and improving soil biological properties in the uplands of Meghalaya region of India.