Minimal soil disturbance and residue retention increasing soil organic stocks and soil microbial biomass in Typic Ustochrept soil: A review

Soil organic carbon (SOC) and its fractions (labile and non-labile) including particulate organic carbon (POC) and its components [coarse POC and fine POC], light fraction organic carbon (LFOC), readily oxidizable organic carbon, dissolved organic carbon (DOC) are important for sustainability of any agricultural production system as they govern most of the soil properties, and hence soil quality and health. Being a food source for soil microorganisms, they also affect microbial activity. Tillage regimes that contribute to greater aggregation also improved soil microbial activity. Soil OC and MBC were at their highest levels for 1.0–2.0 mm aggregates, suggesting a higher biological activity at this aggregate size for the ecosystem. Compared with CT treatments, NT treatments increased MBC by11.2%, 11.5%, and 20%, and dissolved organic carbon (DOC) concentration by 15.5% 29.5%, and 14.1% of bulk soil, >0.25 mm aggregate, and 0.25 aggregate, and 0.25 mm aggregate (11.3%), and 0.25 mm aggregate, and 0.25 mm aggregate, and <0.25 mm aggregate in the 0−5 cm soil layer, respectively. In conclusion, soil organic carbon fractions (SOC), and microbial biomasses in the macro-aggregates are more sensitive to conservation tillage (CT) than in the micro-aggregates. Soil aggregation regulates the distributions of SOC and microbial parameters in Typic Ustochrept soil.