HYDERABAD: In a research finding that will be music to the ears of both environmentalists and the farmers, a team from the ICRISAT has come up with the ways to enhance soil carbon in the drylands where it is relatively less.
Soil carbon is critical for crop yield as it helps in increasing plant nutrient reserves, available water for longer periods and also plays a crucial role in global carbon cycling through representing the largest pool of carbon.
The result of a modelling study conducted by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) team between 2020 and 2022 revealed that with the right combination of fertiliser, biochar and irrigation, the soil carbon can potentially be increased by as much as 300 per cent over 30 years in 13 districts of Odisha and Maharashtra, contributing to global efforts to combat climate change.
Speaking to TNIE, Dr Girish Chander, co-lead of the project who studied the carbon sequestration, said: “Soil carbon is an important soil property as it is closely related to crop yield and aids sustainability. Most of agricultural soils in drylands are low in carbon, and have the potential not only to reduce its own emissions, but also from other sectors as well to enhance the quality of soil and water resources.’’
“Contrary to popular belief, soil is a storehouse of carbon as it contains about 2,500 billion tonnes, whereas air and plants together consist of about 1,350 billion tonnes of carbon. Thus in drylands where soil carbon levels are low, sequestering carbon in soil is critical to boost crop productivity and contribute to climate adaptation and mitigation. Managing agricultural soil as carbon sinks is vital as agricultural systems account for greenhouse emissions though the levels are not as high as non-agricultural practices like vehicular pollution and others,’’ he added.
Referring to use of fertilisers, he said: “We require a holistic and need-based approach for crop nutrient applications. Farmers usually opt for indiscriminate use of urea and DAP when the production is reduced. Instead attention should be given to widely deficient macro and micronutrients, like deficiency of zinc, boron, sulphur and other essential minerals.”
Elaborating on biochar, he said: “Crop residue of plants like cotton, pigeon pea and other plants which cannot be used as fodder or for any other purpose can be recycled either directly or through composting. By using futuristic technology, the biomass can be made into biochar, which will lead to long-term storage of carbon in soil and help in fixing the atmospheric carbon thus reducing the pollution as well as global warming induced climate change.”
“Profile sampling of long-term experiments found that carbon sequestration increased by 100 kg per ha per year with the improved practices of landform management, fertilisers and crop varieties over 45 years. It is enhanced by 300 kg per ha per year with addition of residue over nine years,” he added.