Energy norms and their measurement in agriculture

Measures of energy inputs to agriculture should include the gross energy, as well as the other inputs embodied in the material/source until it is used on the field. The efficiency of the system should take into account all the inputs of the farmer until the products reach the first market/consumption point. Contributions to agriculture, from say a labourer, may ideally delineate the specific extra energy inputs such as food from his total per capita consumption. Similar assumptions concerning thermally-produced electricity from coal mining to the irrigation pump will enhance perceived inputs by 4 to 5 times. We should discriminate the inputs from the point where other options for use are available and assess their long-term productivity. Thus, wheat straw may have up to 80% efficiency in an improved biomass furnace but only 4% when providing bullock power. Inter-sectoral trade-offs between power/energy sources for the rural folk indicate different imperatives. Replacing optimal levels of farmyard manure by chemical fertilisers may save 2·6 tonnes of coal per hectare of wheat. Similarly, transportation by bullock carts consumes about 4 times more energy than that by trucks. Comprehensive inclusion of inputs into the process boundaries of agriculture gives us the true values and proportions of the various inputs into the energy matrix and helps to identify the major/valuable sources. Pesticides and herbicides, using such analysis, were found to be negligible components, while farmyard manure, irrigation and bullocks formed major components. Evaluation by these methods justifies modern agriculture in India using mechanisation, irrigation, fertilisers and pesticides, notwithstanding the higher requirements of non-renewable fuels and materials. More revealing is the estimate that agriculture consumes about 65% of all the energy consumed in India. Energy conservation in agriculture therefore warrants a deeper study.