Soil carbon dynamics under organic farming: Impact of tillage and cropping diversity

Ecological indicators are herculean contrivance for assessing management practices' impacts on environmental changes. Soil organic carbon (SOC) potentially regulates the agricultural sustainability. Unfortunately, the SOC has been widely degraded through unsustainable land uses and agricultural practices. Hence, the efficacy of conservation tilling and diversified cropping were assessed in terms of restoration of SOC and associated soil properties in fixed plots, which are related with farm productivity and other ecosystem services under organic production systems of the Indian Himalayas. Three tillage management were selected as treatments of the study: i) conventional tilling (CT), ii) reduced tilling (RT), and iii) Zero tilling (ZT) applied to four diversified cropping systems [CS1- maize–black gram–toria, CS2 maize–black gram–buckwheat, CS3- maize–rajmash–toria and CS4 maize–rajmash–buckwheat]. The ZT had the highest SOC content (19.58 g kg−1) as well as the C pool (25.24 Mg ha−1) at a soil depth of 0–10 cm. On the contrary, ZT had the lowest ρb (1.29 Mg m3) and soil penetration resistance (1.32 MPa) at 0–5 cm and 5–10 cm soil depth. Concerning SOC partitioning, regardless of soil depth, it had been evident that more SOC were allocated in the active pool over the passive pool. Out of the diversified cropping systems, the CS2 produced a considerably higher total carbon pool of 24.98, and 23.0 Mg ha−1 at 0–10 cm, and 10–20 cm soil depths, respectively, and active and passive C pools. Hence, abolition of tillage and cultivation of legume embedding cropping systems resulted as a sustainable management system under organic farming for SOC restoration and soil quality improvement in the Himalayan ecosystem. Thus, the study suggested that the cultivation of CS2 under ZT may be promoted for efficient land resource management planning in the study region of the Indian Himalayas.