Energetics and environmental costs of agriculture in a dry tropical region of India

The present article, based on a study of five village ecosystems, assesses the energy efficiency of rain-fed agriculture in a dry tropical environment and the impact of agricultural activity on the surrounding natural ecosystems. Agronomic yield is insufficient to meet the food requirement of the human population, hence 11.5%–49.7% of the required amount of food grains are imported from the market. Energy requirements of five studied agroecosystems are subsidized considerably by the surrounding forest in the form of fodder and firewood. Natural ecosystems supply about 80%–95% of fodder needs and 81%–100% of fuelwood needs. The output-input ratio of agriculture indicated that, on average, 4.1 units of energy are expended to obtain one unit of agronomic energy. Of this, 3.9 units are supplied by the natural ecosystem. In addition, 38% of the extracted firewood is marketed. The illegal felling and lopping of trees result in ever-increasing concentric circles of forest destruction around the villages and together with excessive grazing results in savannization. The forests can be conserved by encouraging fuelwood plantations (0.7 ha/ha cultivated land) and developing village pastures (1.6 ha/ha cultivated land) and reducing the livestock numbers. Agricultural production in the region can be stabilized by introducing improved dry farming techniques such as intercropping, planned rainwater management, and adequate use of fertilizers.