In Rural India, most of the families depend on wood and kerosene to satisfy their daily energy needs. Families in remote tribal villages of the Nalgonda District of Andhra Pradesh mainly depend on wood as fuel for cooking. As forests become depleted, villagers have to go further and further to collect wood, taking time and energy that could be put to more productive use. Those who have to buy wood pay high prices, which strains household budgets.
Wood is collected several times a week by both women and children, leading to the reduction of wood resources. And, apart from the time, effort and money spent in obtaining wood, cooking fires cause indoor pollution which is harmful for infants. The use of traditional cooking stoves leads to a high chance of respiratory/ lung infections among users. In India, use of huge amounts of chemical fertilizers is reducing soil fertility and crop yields; therefore the construction and distribution of biogas digesters and the production of vermicompost are available options which might provide a real solution to these various problems.
Biogas: clean, renewable fuel for rural homes
The potential for biogas is enormous. It can be generated from cattle dung, which is readily available, as most villagers own cattle. Unlike wood whereby the smoke from wood fires can lead to asthma, lung cancer and bronchitis, biogas is a clean and smokeless fuel. Switching to biogas stoves means cleaner, healthier homes, particularly benefiting women and children.
Biogas stoves are also more efficient, whereby women have better control over gas stoves than wood stoves and food can be prepared more quickly. They can start cooking as soon as they turn on the gas and turn it off immediately when they finish without the effort involved in lighting wood fires, an especially difficult task when wood is wet. Much time and effort is also saved as the women no longer have to gather wood and stockpile it for the rainy season. They are also relieved of the heavy work of carrying.
It is a composite unit consisting of a digester and gas holder. The digester is a chamber containing the animal waste in the form of the slum. It is normally situated below the ground level. It is made of masonry work. There is a partition wall in the middle of the digester which divides the digester into semi-circular compartments. There is one inlet opening to recover digested material and another outlet opening to feed the system. The outlet opening is lower than the inlet opening. The gas holder is a drum-like structure, it is a like cap on the mouth of the digester where it dips in the slurry and rests on the suitable base inside the digester.
Benefits of Biogas
• Biogas is a clean fuel. It produces no smoke and cuts down on pollution, especially indoors.
• Biogas is almost twice as efficient as wood in producing energy and, biogas stoves are five times more efficient than traditional stoves. Biogas stoves light instantly in all weathers, making cooking quicker by using less fuel.
• Families save money as their dependence on wood is reduced.
• Biogas reduces the workload; women are freed from the chore of gathering wood.
• Biogas is sustainable. The raw materials to produce biogas (cattle dung and water) are readily available renewable resources.
• Biogas produces manure as a by-product; Waste slurry from biogas plans is an excellent starting material for vermicompost preparation.
• Biogas helps conserve forests by replacing wood as a fuel, thereby reducing pressure on forests.
Crop residue burning
Crop residues like paddy straw/green manures are vital resources for sustaining soil productivity. They not only replenish soil organic matter, which is a key indicator of soil quality but also supply essential nutrients upon mineralization (N, P, S and Si) and even on soaking (K) and improve physical properties (Surekha et al. 2003). It has been estimated that in India alone, burning of crop residues releases CO2, CO, CH4, N2O and SO2 gases, equivalent to 6606 thousand tonnes of CO2 annually (INCCA, 2007). Improving the management of crop residues as animal feed and restricting its wastage through burning, should be one of the main priorities. Thus, there is an urgent need to optimize the use of the limited feed resources, especially straws for ruminant feeding. The burning of crop residues is quite common in tribal districts of Andhra Pradesh (Fig. 6). In Dupahad cluster of Nalgonda district, crop management practices.
- Centrial institue of dryland agriculture