According to a report, titled Agriculture’s Contribution To Air Pollution And Climate Change, released by the FAO, following are the major sources of agricultural pollution:
Pollution from Biomass Burning
Soot, dust and race gases are released by biomass burning during forest, bush or rangeland clearance for agriculture.
Greenhouse Gas Emissions
For some countries, the contribution from agriculture to GHG emissions is a substantial share of the national total emissions. There is increasing concern not just with carbon dioxide but also with the growth of agricultural emissions of other gases such as methane, nitrous oxide and ammonia arising from crop and livestock production.
Methane from Ruminant and Rice Production
Methane is a principal GHG driving climate change. Its warming potential is about 20 times more powerful than carbon dioxide.
- Rice production currently contributes about 11 per cent of global methane emissions.
- Around 15 per cent comes from livestock (from enteric fermentation by cattle, sheep and goats and from animal excreta).
Nitrous oxide (N2O) is the other powerful GHG for which agriculture is the dominant anthropogenic source. Mineral fertilizer use and cattle production are the main culprits. N2O is generated by natural biogenic processes, but output is enhanced by agriculture through nitrogen fertilizers, the creation of crop residues, animal urine and faeces, and nitrogen leaching and runoff.
Agriculture is the dominant source of anthropogenic ammonia emissions, which are around four times greater than natural emissions. Livestock production, particularly cattle, accounts for about 44 per cent, mineral fertilizers for 17 per cent and biomass burning and crop residues for about 11 per cent of the global total.
How to Reduce Agricultural Pollution?
According to a report, titled, The Challenge of Agricultural Pollution: Evidence from China, Vietnam, and the Philippines , released by the World Bank in 2017, agricultural pollution can be reduced through:
- Improving the livestock industry’s waste management practices and environmental performance.
- Cutting back heavily on the prophylactic veterinary use of antibiotics.
- Bringing farmed aqua-ecosystems into balance, including through the embrace of improved inputs and various kinds of closed-loop systems.
- Reducing fertilizer losses from cereal and specialty crop farming
- Professionalizing the use of pesticides.
- Reducing and repurposing the organic by-products of farming.
- Diffusing rice cultivation techniques that reduce climate-warming greenhouse
Reducing Carbon Emission from Agriculture
The government of India is doing following things to reduce carbon emission from agriculture:
- Increasing the area under System of Rice Intensification (SRI) as an alternative to transplanted paddy.
- Deployment of zero tillage drill machines and other residue management equipment which enable planting of rabi crop in the standing residue of rice crop to avoid its burning.
- Alternate wetting and drying, direct seeded rice system of rice cultivation, use of slow release nitrogen fertilizers, integrated nutrient management practices, leaf colour chart-based nitrogen application, use of urea super granules etc.
- Mandatory Neem coating of urea.
- Promotion of micro irrigation under Pradhan Mantri Krishi Sinchai Yojana (PMKSY)-Per Drop More Crop.
- Planting of trees under National Food Security Mission (NFSM), Bringing Green Revolution to Eastern India (BGREI), Sub-Mission on Agro Forestry (SMAF) and National Bamboo Mission (NBM).
- 45 models of Integrated Farming System (IFS) have been developed for replication in Krishi Vigyan Kendras (KVKs) and in the States for enabling climate resilient agriculture.
- Climate resilient villages have been developed by Indian Council of Agricultural Research (ICAR), one in each of 151 districts. Climate Vulnerability Atlas has been prepared under National Innovations in Climate Resilient Agriculture (NICRA). District Agriculture Contingency Plans have been developed for 633 districts in order to give real time agro advisories for overcoming climate risks.
Getting Rid of Farm Residue
A mechanised technique to get rid of farm residue without burning can reduce pollution from the agriculture to a great extent. The burning of crop residue in Punjab, Haryana and Uttar Pradesh, responsible for severe air pollution in Delhi and northern India in October and November, is declining, but farmers need cheap and effective alternatives like Happy Seeders for it to stop altogether.