New agriculture modelling study shows atmospheric carbon dioxide can be captured, stored in soil
Soil carbon is critical for crop yield and climate adaptation or mitigation measures. Photo: ISW A agriculture modelling study can help bolster the fight against climate crisis by helping capture atmospheric carbon dioxide and storing it in soil.
Food systems account for nearly one-third of greenhouse gas (GHG) emissions. In 2015, food-system emissions amounted to 18 Gt CO2 equivalent per year globally, representing 34 per cent of total GHG emissions.
International Crops Research Institute for The Semi-Arid Tropics (ICRISAT) has published a modelling study that revealed how the right combination of fertiliser5, biochar, and irrigation could potentially increase soil carbon by as much as 300 per cent and help mitigate climate change.
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The modelling study was conducted in five districts of Maharashtra (Jalna, Dhule, Ahmednagar, Amravati, and Yavatmal) and eight districts of Odisha (Angul, Bolangir, Deogarh, Dhenkenal, Kalahandi, Kendujhar, Nuapada, and Sundegarh).
They have a predominantly semi-arid climate with annual rainfall between 600 millimetres and 1,100 mm. This soil carbon sequestration over 30 years in these 13 districts may significantly contribute to combating global climate change.
ICRISAT scientists, during 2020-2022, collected various data such as weather, soil types, and crop yield, and crop management practices. Based on such data they made projections for carbon sequestration and yields and conducted long-term experiments.
Carbon sequestration is the process of capturing and storing atmospheric carbon dioxide. The researchers also evaluated improved management practices such as biochar, need-based fertiliser, and irrigation.
Biochar is a charcoal-like substance that burns organic material (biomass) from agricultural and forestry wastes in a controlled process called pyrolysis. Although it looks much like ordinary charcoal, biochar has safely reduced contamination and stored carbon.
The modelling study found that biochar increased carbon value in the soil by 130-300 per cent over 30 years with little difference in yield. It also found that the optimal use of fertilizers increased the carbon and output by up to 30 per cent.
The carbon sequestration increased by more than 300 per cent in combination with fertiliser, biochar, and irrigation. The study is aligned with Sustainable Development Goal 13 (SDG 13: Climate Action) which is on taking urgent action to combat climate change and its impacts.
Important crops such as cotton, sorghum, soybean, chickpea, pigeonpea and millet were studied in the region. In addition, soil sampling and analysis of long-term experiments on improved versus traditional farmer practices and tillage and residue management practices were also conducted.
Scientists observed a significant increase in soil carbon with improved nutrients, crop/variety, landform, minimum tillage and residue addition under the climate change scenario till 2100.
Soil carbon is critical for crop yield and climate adaptation or mitigation measures, which are heavily reduced by both intensive agriculture and indiscriminate use of chemicals leading to increased carbon emissions.
“Profile sampling of long-term experiments found that carbon sequestration increased by 100 kg ha per year with the improved practices of landform management, fertilizers and crop varieties over 45 years. It is enhanced by 300 kg ha per year with residue over nine years (Aditi et al. 2021),” said Dr Girish Chander, co-lead of the project, which studied carbon sequestration.
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The German Agency for International Cooperation (GIZ) funded the research. “We would like to analyse how carbon behaves under different agricultural practices,” says Jonas Bartholomay, programme director, GIZ India.
“Agriculture is said to be one of the major factors affecting climate change. However, it can also be a part of the solution. Carbon sequestering can provide an additional source of income for the farmers,” he said.
The study may help policymakers, government, and civil society to implement strategies that incentivise farmers to manage their soils in ways to sequester more carbon.
A new gaming app, ‘Mrida’, has been launched to promote behavioural change among farmers. Dr Melesse Mequanint, co-lead (economics, game app and capacity building), said, “Apart from English, the app will be released in Marathi and Odiya to reach a larger population of farmers in the two states.” (ISW)
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