Appl#dEnergy30(1988) 235-243
Energy Norms and their Measurement in Agriculture A. R. Rao Department of Veterinary Physiology, Haryana Agricultural University, Hisar--125004, India
ABSTRACT 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%0 of a l l the energy consumed in India. Energy conservation in agriculture therefore warrants a deeper study. 235 Applied Energy 0306-2619/88/$03"50 © 1988 Elsevier Applied Science Publishers Ltd, England. Printed in Great Britain
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INTRODUCTION Energy inputs in production agriculture are often considered only as fuels, or materials derived from fuels (such as fertilisers), which are used. The enormous input of solar energy is of little consequence because alternative options for its utilisation in any terrestrial area are usually regarded as limited. This approach is adequate for situations where energy sources are only the common fuels like oil products, electricity, etc. However, in the developing countries like India, the role of non-dommercial sources of energy and power is enormous and their applications in various rural or urban activities are diverse. In several situations, the entire input of production agriculture consists only of these non-commercial sources of power and energy. In such a situation, an assessment of energy utilisation in agriculture by the common western model will be grossly misrepresentative. We have discovered the anomalies of using the standard method for computing the energy utilisation in Indian agriculture. MATERIALS AND METHODS Our studies 1-7 concerning the pattern of energy utilisation in crop production in Haryana have led us to the following procedure based partly on experience and much more on 'best approximations'. Detailed physical data were collected for 31 individual farms of the Ambala district, where the area under maize cultivation ranges from 0.41 to 3.24 ha, with light to medium type soil and rainfall of about 100 cm per year (of which 75-80% occurs during the maize growing season). Supplementary irrigation was obtained from electricity-stimulated wells. The data were transformed into energy equivalents. 2 Comparative data for the different districts 8 suggested that only a few variables affected the energy-use efficiency. The energy behaviours of farms showing extreme values for these variables were analysed in detail. Thus, the six farms showing maximum and minimum data for area under crop, use of tractors, fertiliser use, use of farmyard manure, irrigation, as well as grain yields, were selected for detailed analyses of energy utilisation.
RESULTS In the smallest farm (see Table 1), farm yard manure (FYM) has been used liberally, thus maximising the energy inputs. However, the yield was not high and therefore the energy utilisation in maize cultivation remained low. The maximum input of about 77% is accounted for by the often ignored
Energy norms and their measurement in agriculture
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traditional input of FYM. By comparison, the magnitude of all other inputs is insignificant. This waste of energy is apparent also for the other farms shown in Table 1. The recommended plant nutrients of 120kg of urea, 197 kg of superphosphate and 50 kg of muriate of potash 8 would consume a total energy input of 917 Mcal/ha. On the other hand, the recommended amount of nitrogen as FYM for this crop would be 12 tonnes per ha, which is equivalent to 15 624 Mcal. Thus, the input of FYM, in terms of energy, is wasteful as far as the supply of plant nutrients is concerned. We should now evaluate whether a minimum requirement of FYM is necessary 15 for each crop in the crop cycle. It would be desirable to limit the use of FYM to that necessary for maintaining soil structure, humus, etc. This study, as well as several of our previous studies, has shown that the use of FYM as a source of plant nutrients is highly wasteful and, by using only about 5% of the embodied energy of FYM, chemical fertilisers can be produced and transported to supply equivalent plant nutrients. In the Indian context, the use of dung as manure is of doubtful value because it can be readily used for such an essential purpose as domestic fuel in the form of dung cakes. ~6 In the second farm, the irrigation inputs were doubled. As a result, a substantial improvement in the grain output and production efficiency was achieved. Considering that the additional irrigation does not cost much in terms of energy, this may be a worthwhile input. Farm no. 3 had the highest grain output. However, the reasons for the improved performance in yields are not apparent from these selected inputs; it may simply be a characteristic of the soil. On the other hand, the fourth farm had the lowest output. The only possible reason for this minimal productivity is low labour use, especially in farm operations such as weeding and hoeing. Urea application was at a maximum on farm no. 5, which used just half of the FYM of Farm no. 1: this has not affected the productivity (compared with farm no. 1), but has improved substantially the energy-use efficiency. On the largest farm (no. 6) observed, tractorised equipment and diesel fuel were used, whereas chemical fertiliser, FYM or irrigation were not employed, thus minimising the total inputs. The use of machinery has not done much for farm productivity, perhaps because of other deficiencies such as plant nutrients and irrigation. However, in so far as the energy inputs are concerned, the efficiency of the farm has been maximised. In reviewing the data, we conclude that limiting the use of FYM and increasing irrigation would improve productivity. Increasing fertiliser use will have little effect on the efficiency of energy utilisation. Mechanisation p e r se will not be of much use, although it adds substantially to the energy inputs. Some of these points have been concluded previously. 8 The same rates of production were obtained in the two adjacent districts of Karnal and Kurukshetra, which have similar soils, but where extremes existed in the
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A. R. Rao
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range of use of F Y M . The higher average yield at Ambala may be accounted for by the higher use of fertiliser. However, the increased irrigation applied in Kurukshetra has not borne fruit.
DISCUSSION Fallacies involved in computing the efficiencies of, energy utilisation in agriculture will be apparent from the two columns of data for farm no. 4 in Table 1. In the usual methodology, most of the inputs described in the table would not be taken into account and so the total inputs of energy into the farm operations would appear to be very low. This would lead to enormous increases in the apparent efficiencies of the systems. F o r instance, farm no. 4 shows great increases in the efficiency of energy utilisation as observed from the last two rows. The data for farm no. 6 illustrate the absurdity of the standard methodology which leads to a total input of zero and substantial productions leading to efficiencies apparently approaching infinity. We should take into consideration sources of power or energy which have alternative options of use. Since human power has infinite uses, the input of man-days of work cannot be ignored. Energy inputs through human labour m a y be assessed with many degrees of precision or imagination. We may assume in a welfare state that the energy inputs to a person or his requirements of citizenship are unrelated to the work output. With such an assumption, we can ignore the energy consumed by him during his lifetime as food, in living, housing, education and the acquisition of skills and what he accounts for as a citizen in national transportation, administration or defence. With such a computation, an American citizen accounts for over 4 2 0 0 0 k c a l per hour of work in a 40-hour week. 1° In the absence of such comprehensive data, we attribute only the dietary energy of the worker for the working day towards the energy inputs of farming (488 kcal/h of work) while many use a figure of 0"1 hp (63 kcal/h) as the work output. Energy inputs due to bullock work have to account for the feed inputs on a life-time basis and in terms of the working days in a year. The main inputs in the Indian situation are crop residues. In the USA, crop residues constitute the largest sources o f 'environmental pollution'. Obviously, crop residues are resources for animal feeds in India. The traditional use of some crop residues as fuels gives an idea of the diverse options available for the use of cereal straw too. Our computations elsewhere 17 show that, on a life-time basis, the efficiency of straw utilisation in bullock work is often a b o u t 4% and cannot be more than a b o u t 8% with a biological ceiling of a b o u t 10%. Alternatively, straw use can have an efficiency of 80% in improved biomass furnaces.
Energy norms and their measurement in agriculture
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Thus, it is easy to see that crop residues may have much higher social advantages as substitutes for commercial fuels like coal or furnace oil than they would have as bullock feed leading to bullock work on the farm or for pulling a cart. Investments of fixed energy are usually ignored and data for traditional farm equipment are scanty. 5 Similarly, fixed energy inputs into tractors and ancillary equipment are often ignored, leading to underestimates of the inputs. Fuel consumption is usually taken as the gross energy value of the product ignoring the other inputs into the mining, refining and transportation of these materials to the point of consumption. We assume the total embodied energy of the fuels.l° In addition to the incorporated energy of fertilisers, we also make some additional assumptions about the transportation costs of these materials to the farm. Farm yard manure has been evaluated in terms of its gross energy and not in terms of the energy requirements for equivalent quantities of nitrogen, phosphorus and potassium (NPK) fertilisers. The energy input as FYM has been grossly under-estimated by most workers, because they were reluctant to give it gross energy values and preferred to use the much lower values obtained when it is assessed for the equivalence of NPK fertilisers. The enormity of such underestimates is apparent from the data for farm 1 where 77% of all the energy inputs are derived from FYM. Energy inputs through seed are often ignored and at best a value equivalent to its dietary energy is attributed. On the other hand, seed production consumes almost double the inputs. Energy inputs into irrigation in our computations take into account the fixed inputs in the material, manufacture and installation of tube-wells and the buildings to house them, the conveyance system on the farm (unlined and lined channels) as well as the coal consumption for the production of electricity. The total energy inputs into irrigation are about eight times the energy estimated from the reading indicated by the electric meter. The primary fuel input in the thermal stations in Haryana is 5"36 times the energy value of the power generated. The effects of the comprehensive assumptions on efficiency estimates are apparent for farm no. 4 (Table 1). Transporation of FYM is rarely taken into account in energy audits and this factor will be a source of error in the assessment of inputs. The farmer's energy inputs into a crop are usually assumed to end when it is transported to the first market. This would be another variable. Transportation by tractor-trailer will consume only about one-fourth of the energy inputs due to transportation by bullock carts. 18 In the evaluation of outputs, the dietary value of the crop is only a small
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part of the crop value in the Indian farming systems. Although the monetary value of the crop residues is much lower, their socio-economic value in the rural Indian context is significant. W h a t is a pollutant in the U S A is a valuable resource in India. In fact, cultivation for the fuel value of the biomass m a y become viable in certain areas in the future. We evaluate the residues on the basis of gross energy which would be appropriate for assessing the by-products as potential fuels, but suitable devaluations will be necessary to appraise them as sources of livestock nutrients.
CONCLUSIONS The m e t h o d o l o g y evolved for this paper has been extraordinary in the sense that the process boundaries have been considerably enlarged from the apparent inputs to include all the inputs from source. When all inputs including man-power and bullock power are taken together, Indian agriculture is not efficient. It is, in fact, worse than that in the industrialised agriculture of the West. So superior technology is really more efficient and should be accepted as such in India also. M o s t of our conclusions are at variance with the c o m m o n opinions regarding energy use in agriculture. However, we are confident, this m e t h o d o l o g y is more relevant and less evasive in evaluating energy utilisation in the Indian context.
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A. R. Rao and I. J. Singh, Urja (Ind. J. Energy), 10 (1981) 305. A. R. Rao and R. K. Malik, Urja (Ind..I. Energy), 11 (1982) 279. R. K. Malik, A. R. Rao and R. R. Gupta, Urja (Ind. J. Energy), 10 (1981) 309. A. R. Rao and R. K. Malik, Energy, 7 (1982) 855. R. S. R. Gupta and A. R. Rao, Energy, 7 (1982) 945. R.S.R. Gupta, R. K. Malik, R. R. Gupta and A. R. Rao, Energy in Agriculture, 2 (1983) 153. R. S. R. Gupta, H. S. Malik, R. K. Malik and A. R. Rao, Energy, 9 (1984) 189. Anonymous, Package of Practices for Kharif, Haryana Agricultural University, Hisar (1982). C. Gopalan, B. V. Ramasastri and S. C. Balasubramanian, Nutritive Value of Indian Foods, National Institute of Nutrition, Hyderabad (1971). D. Pimentel (ed.), Handbook of Energy Utilization in Agriculture, C.R.C. Press, Boca Raton, Florida (1980). R. K. Murty, A Manual on Compost and other Organic Manures, Today and Tomorrow Publishers, New Delhi (1978). C. L. Gupta, K. Usha Rao and V. A. Vasudevaraju, Energy, 5 (1980) 1213.
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