Stubbles, stalks, stover, husk, bran, bagasse, and molasses are generally classified under Crop Residue.
Harvesting, threshing, and primary processing of crops leave behind a variety of plant materials that need safe disposal and recycling.
These residues, once thought to be waste, are now regarded as an important natural resource due to their versatile utility.
CRs are primarily used as bedding material for livestock, animal feed, soil mulching, biogas generation, bio-manure and compost, thatching for rural homes, mushroom cultivation, biomass energy production, fuel for domestic and industrial use, etc.
Problem and Perspectives
Every year, in India about 683 million tonnes of CRs are produced, of which nearly two-thirds are contributed by cereal crops.
Among cereal crops, rice generates the most gross residues followed by wheat.
Fibre crops residue accounts for nearly 20 per cent of the total CR generated in the country. Cotton accounts for 74 per cent of total fibre CR among fibre crops.
It is estimated that burning one tonne of rice straw accounts for the loss of 5.5 kg of nitrogen, 2.3 kg of phosphorus, 25 kg of potassium, and 1.2 kg of sulphur, besides organic carbon.
Heat generated from burning of CRs elevates soil temperatures, causing the death of beneficial soil organisms.
The burning of CRs is a potential source of greenhouse gases, which are responsible for aggravating the global calamity of climate change.
When rice straw is burned in open fields, it releases carbon dioxide, carbon monoxide, methane, sulphur oxide, and nitrogen oxide gases.
Reason for paddy stubbles burning:
A shortage of farm labour at a critical time of field operation;
A very short span or window for the preparation of the field for the next wheat crop; and
Large-scale use of a combine harvester for the harvesting of paddy.
Regulations and Solutions
The Central Government has launched various promotional schemes and programmes to encourage environmentally safe management of CRs, and to promote technologies for its alternative uses.
Financial assistance @50% is provided to the farmers for purchase of CRM machinery, and @80% is provided to cooperative societies, Farmer Producer Organisations and Panchayats for the establishment of Custom Hiring Centres in villages.
The scheme promotes usage of machines such as super straw management systems, happy seeders, smart seeders, mulcher, crop reapers, etc. for ‘on-form’ management of CRs, and balers & rakes for straw collection in the form of bales to facilitate its other uses.
Techno-commercial pilot projects will be established under the bilateral agreement between beneficiaries (farmers, FPOs, Cooperative Societies, panchayats etc.) and industries utilising paddy straw.
Financial support @ 65% of the project cost will be jointly borne by the Central and State Governments; 25% will be contributed by the industry; and the balance 10% will be the share of beneficiary.
The Indian Council of Agricultural Research has developed an innovative Pusa Decomposer technology to biologically decompose paddy stubbles in the farm.
It’s a microbial solution available both in liquid and capsule form for accelerated decomposition of straw.
Satellite monitoring and imaging showed that 92% area of the decomposer sprayed plots has been managed through decomposition and only 8% area in these plots was burned.
The application of composted residues to soil adds organic carbon and other essential plant nutrients to the soil and promotes microbial activity in the soil.
During Swachhata (cleanliness) Special Campaign 2.0 (2 Oct 2022-31 Oct 2022), the ICAR- Krishi Vigyan Kendras adopted over 900 villages across the country to demonstrate and promote microbial-based crop residue management and vermicomposting technologies were demonstrated to nearly 22,700 farmers in their fields.
Compared to wheat straw, rice straw is not a preferred livestock feed due to certain nutritional quality issues.
Crop residues can be utilised as animal bedding and then placed in dung pits to make compost.
Paddy straw is a nourishing substrate for mushroom cultivation. Each tonne of dry rice straw can produce 50 to 100 kg of mushroom depending on other conditions.
A special product called biochar can be made from rice straw, which is a carbon-rich material used as a soil amendment.
Rice straw is also a valuable material for surface mulch in various other crops.
Diversification of crops in the traditional wheat-rice system is also one of the technical solutions to minimize CR burning.
The concerted efforts of the Central Government, Government of Punjab, NCR State Governments, and other stakeholders towards better on-farm management of CRs and facilitating various options for their off-site uses have helped significantly in reducing the CR burning events.
Concerned states have prepared action plans to control stubble burning and regular monitoring for effective management of CRs across the region.
In addition to technical and financial support, intensive educational campaigns and awareness camps are also required to have the best impact.