Assessment of Carbon Sequestration Rate and System Productivity under Complementary Bio-Intensive Cropping Systems in an Inceptisol of Southern Telangana Zone

Depletion of soil organic carbon (SOC) is the major cause of the decline in soil productivity and degradation for sustainable crop production arising from elevated CO2 emissions. The adoption of different cropping systems (CSs) is an alternative strategy for soil carbon storage (SCS). Keeping these factors in mind, the current study was conducted in 2019–2020 and 2020–21 to examine the impact of (CSs) on C– sequestration capabilities in the continuing long-term field trial started in 2017. It was conducted at an experimental farm at the College of Agriculture, Rajendranagar. Our findings showed that the impact of effective CSs improved SOC stock above the initial status (7.53 Mg ha-1) in both years. The following cropping order showed a noticeably higher build-up of SOC stock: CS1: Rice – Maize and CS2: Bt cotton – Fallow, respectively, had the lowest values (0.66 Mg ha-1) and (0.60 Mg ha-1) whereas CS5: Maize + Pigeon pea – Groundnut (1.25 Mg ha-1) and CS4: Pigeon pea + Green gram (1:3) – Sesame (1.22 Mg ha-1) had the highest values. The level of SOC in one of the CSs, CS10: Bhendi, Marigold, and Beetroot, demonstrated a detrimental impact on the study’s findings, with depletion (-0.13 Mg ha-1) falling below the original value. Interestingly, the build-up of SOC was more prominent in 2020-2021 in all the CSs as compared to 2019-2020, and SOC accumulation (1.44 Mg ha-1) was more pronounced in CS4, maintaining the same trend as in 2019-2020. However, the higher carbon sequestration rate (CSR) in 2019-2020 was recorded in CS5 (0.42 Mg ha-1 yr-1) and CS4 (0.41 Mg ha-1 yr-1) while a positive increment in CSR in 2020-2021 was observed in all the CSs with higher (2.15 Mg ha-1 yr-1) being under CS7: Fodder sorghum + Fodder cowpea. System productivity in terms of RGEY (40818 kg ha-1) was significantly higher under CS10 after the third year and declined by 18.80% at the end of fourth year. CSR and RGEY reported a negative significant correlation (r= -0.755*) and non-significant correlation in 2019-2020 and 2020-2021, respectively. The salient findings have indicated that CSs involving cover crops (legumes and cereals) had sequestered higher SOC, thus bridging the gap to the farmers towards soil carbon loss by elevated CO2 through the adoption of these complementary bio-intensive CSs mechanisms.