Review of Different Composting Methods towards End Product Quality, Cost of Production, Process Adoptability Potential, Post Soil Application Efficacy and GHG Mitigation Potential Fundamental Factors Behind Attending Objectivities of any Regenerative Far
Authors: Bera R. , Saha S. , Datta A. , Mukhopadhyay K. , Barik A. K. , Bhattacharya P. , Mallick R. , Ganguli M. , Narasimhan V. L. , Quah E. 
Published: December 2024

The impacts of climate change on crop productivity and the emerging challenges towards food security have led to the introduction of the regenerative farming approach, which considers regeneration of soil as a prime criterion for sustained food production. Currently, compost is considered as the key component for soil rejuvenation or, more precisely, soil microbial rejuvenation. This is because high-quality compost is the most economical source of diverse microflora. Within the scope of the present study, we reviewed the different composting methods used in large scales in the different Indian tea estates; as per the five-point criteria of end product quality, cost of production, process adoptability potential, post-soil application efficacy and GHG mitigation potential.
In the comparative study, the process adoptability potential was greater for Novcom compost (9.97), which could be primarily due to the shortest biodegradation period, non-selectivity of the raw materials and non-dependency on the infrastructural requirements. The compost quality index (CQI) value was also significantly greater in the case of the Novcom compost (CQI: 5.75) than for Vermi compost (CQI: 2.4) and FYM/Heap compost (CQI: 1.75), which could be due to the presence of a very high microbial population (1016 cfu per g moist compost; or at least 10,000 times greater than that of the other compost) in the Novcom compost.
A there year comparative study regarding post soil effectiveness in terms of crop productivity and soil quality development was performed under the FAO-CFC-TBI project in the Maud tea estate, which revealed higher crop productivity (30.75% higher than that of the control and approximately 11% higher than that of the Vermi & FYM/Heap compost applied plots) and a better value cost ratio under the Novcom compost applied plots. The soil quality enrichment was measured through the soil development index (SDI), which revealed more than 55% higher impact in the Novcom compost applied plots than in the other plots, which was mainly contributed by the increase in the soil microbial population.
Comparative cost analysis on the basis of present material and manday costs revealed that Novcom compost was the most economical (Rs 2345/ton), followed by FYM/Heap compost (Rs 3245/ton) and Vermi compost (Rs 5395/ton), indicating that the Novcom composting method was 60% less expensive than the Vermi composting method.
Most importantly, a comparative study of soil carbon sequestration and GHG mitigation potential under different composting methods evaluated via the IPCC methodology and Century model simulation of EPA revealed the highest soil carbon sequestration potential under Novcom compost (152.9 kg CO2e/ton raw material), followed by FYM/heap compost (69.5 kg CO2e/ton raw material) and Vermi compost (66 kg CO2e/ton raw material). Finally, a comparative study of GHG mitigation potential revealed that Novcom compost was much greater than other composting methods, with a value of 508 kg CO2e/per ton raw material, whereas the nearest value was in the case of Vermi compost, with a value of 277 kg CO2e/per ton raw material. This was due to the shorter biodegradation period and greater microbial population in the Novcom compost, leading to greater scoring in terms of process efficiency and soil carbon sequestration potential. Thus, for any GHG mitigation program, Novcom composting Technology could be a natural choice for sustainable soil management.