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Energy use pattern and potential for energy saving in rice-wheat cultivation
Energy in Agriculture, 4 (1985) 271--278 Elsevier Science Publishers B.V., Amsterdam -- Printed in The Netherlands
271
E N E R G Y USE P A T T E R N A N D P O T E N T I A L F O R E N E R G Y S A V I N G IN RICE-WHEAT CULTIVATION
B.S. PATHAK and A.S. BINING
School of Energy Studies for Agriculture, Punjab Agricultural University, Ludhiana (India) (Accepted 6 June 1985)
ABSTRACT Pathak, B.S. and Bining, A.S., 1985. Energy use pattern and potential for energy saving in rice-wheat cultivation. Energy Agric., 4: 271--278. The paper reports and discusses the pattern of energy use in rice and wheat production in a cluster of three villages in the Punjab, India. The energy consumption in rice production was found to be much higher than the energy consumption in wheat production, primarily due to the high irrigation requirements of rice, The increase in size of operational holdings and power source ownership did not increase the indirect commercial energy consumption which reflected an increasing standardization of indirect energy input-based production techniques irrespective of the size of farm. Savings of over 50% in the consumption of diesel fuel in lift irrigation and considerable savings in electric energy and fertilizers were found to be feasible through improvement in the quality and maintenance of irrigation equipment and improved water and fertilizer management practices.
INTRODUCTION
Rice a n d w h e a t a c c o u n t for over 75% o f the t o t a l cereal p r o d u c t i o n in India. T h e i n t r o d u c t i o n o f i m p r o v e d varieties o f rice a n d w h e a t in the sixties started a chain o f t e c h n o l o g i c a l changes w h i c h m a d e it feasible to increase f o o d p r o d u c t i o n b y well over 50% in a p e r i o d o f 15 years. Most o f these t e c h n o l o g i c a l c h a n g e s d e m a n d a d d i t i o n a l e n e r g y inputs, particularly o f c o m m e r c i a l energy. F o r e x a m p l e , t h e r e was a 13-fold increase in the c o m m e r c i a l e n e r g y i n p u t t o the p r o d u c t i o n agriculture o f Punjab, an i m p o r t a n t w h e a t and rice g r o w i n g State, b e t w e e n the years 1 9 5 5 - - 5 6 and 1 9 8 0 81 (Pathak, 1982). This increase was m a i n l y d u e to greater c o n s u m p t i o n o f diesel oil, electricity, chemicals a n d fertilizers. D u r i n g t h e y e a r 1 9 8 0 - - 8 1 , t h e e s t i m a t e d i n p u t s o f c o m m e r c i a l e n e r g y t o I n d i a n p r o d u c t i o n agriculture i n c l u d e d 1 8 3 . 1 8 0 PJ in the f o r m o f diesel oil a n d electricity (primarily f o r irrigation), 4 8 . 4 5 9 PJ in t h e f o r m o f e q u i p m e n t and m a c h i n e r y , and 2 4 9 . 0 0 2 PJ in t h e f o r m o f fertilizer a n d chemicals. In view o f t h e o b s e r v e d c o r r e l a t i o n
0167-5826/85/$03.30
© 1985 Elsevier Science Publishers B.V.
272 between the commercial energy inputs and agricultural productivity (Pathak, 1983) the demand for commercial energy in the agricultural sector is likely to increase very rapidly in the next 15--20 years. On the other hand, the global availability of conventional energy resources is expected to diminish sharply by the turn of this century. The combination of these two factors, namely, the increasing demand for commercial energy inputs and the probability of serious restrictions on commercial energy supplies will force the planners and technologists to give increasing attention to more efficient utilization of energy in production agriculture. Keeping the above corisideration in mind, it was decided to conduct a study in Punjab, Haryana, Himachal Pradesh and Western Uttar Pradesh to record the current state of energy use in production agriculture and to identify the potential for energy conservation. This paper seeks to present the results of the study carried out in Ludhiana district of Punjab in 1981-82. METHODOLOGY The inputs of commercial and non-commercial and direct and indirect energy to each crop production operation on 74 farms in a cluster of three villages in Ludhiana district were measured and recorded for 1 year. The sample farms were chosen at random after completing an inventory of the three villages. However, care was taken to ensure that the study sample was representative of operational holdings of different sizes. Also, a numerical balance was maintained between the operational holdings owning different types of farm power sources. Data on each operation were processed to yield information on energy inputs to various crops on individual farms and to work out the average energy consumption of farms falling in different categories of holding sizes and power source ownership. The energy requirements of the operations which consumed large quantities of energy were examined in order to ascertain the potential for conservation of energy. The information presented in this paper pertains to the energy use patterns and potential for energy conservation in rice-wheat cultivation, the most important crop rotation in Punjab. RESULTS AND DISCUSSION
Direct commercial energy inputs Table 1 gives the direct commercial energy input (MJ/ha) to rice and wheat production on different types of farms. The operational holdings owning tractors (TOF) and bullocks (BOF) used nearly the same a m o u n t of direct commercial energy to produce rice on 1 ha of land. The consumption of direct commercial energy on small operational holdings (NOF) depending entirely on hired tractors/buUocks
273 TABLE 1 Direct commercial energy input to rice and wheat production Farm
Direct Commercial Energy Input (MJ/ha) Rice
TOF BOF NOF
Wheat
Diesel
Electricity
Total
Diesel
Electricity
Total
6513.7 2192.8 4 693.1
16122.8 20927.7 27 669.2
22636.5 23120.5 32 362.3
6672.9 3652.5 4 802.2
1 168.2 959.7 1 056.4
7 841.1 4612.2 5 858.6
TABLE 2 Indirect commercial energy inputs to rice and wheat production Farm
Indirect commercial energy inputs (MJ/ha) Nitrogen
Phosphorus
Potash
Chemicals
Machinery
Total
10516.8 12198.9 10890.2
630.8 712.9 682.2
98.5 180.6 161.0
727.2 578.6 735.5
433.6 272.4 476.1
12406.9 13943.4 12945.1
7 359.1 7 580.6 7 486.4
824.5 877.8 753.1
130.3 111.8 124.4
109.0 162.0 31.4
331.4 121.7 183.4
8 757.3 8 853.9 8 578.7
Rice
TOF BOF NOF Wheat
TOF BOF NOF
was higher. Excessive irrigation resulting f r o m individual irrigation p u m p s a n d limited c r o p p e d area was the m a j o r reason f o r high direct c o m m e r c i a l e n e r g y c o n s u m p t i o n o n N O F holdings. The direct c o m m e r c i a l e n e r g y i n p u t s to w h e a t p r o d u c t i o n s h o w a d i f f e r e n t trend. T h e c o n s u m p t i o n o f this c a t e g o r y o f e n e r g y o n the T O F was observed t o be t h e highest, m a i n l y because o f a m o r e m e c h a n i z e d s y s t e m o f seed bed p r e p a r a t i o n o n these holdings. T h e t o t a l direct c o m m e r c i a l e n e r g y i n p u t to w h e a t p r o d u c t i o n was 1/3 or less o f the i n p u t s t o rice p r o d u c t i o n . This d i f f e r e n c e is to be a t t r i b u t e d t o the d i f f e r e n t irrigation r e q u i r e m e n t s o f the t w o c r o p s u n d e r the c o n d i t i o n s prevailing in L u d h i a n a district. N i t r o g e n a c c o u n t e d for a m a j o r p o r t i o n o f the c o m m e r c i a l e n e r g y i n p u t t o the p r o d u c t i o n of b o t h rice and wheat. C o n t r a r y t o t h e general belief, t h e indirect e n e r g y i n p u t in the f o r m o f e q u i p m e n t a n d m a c h i n e r y even in t h e S t a t e o f P u n j a b is relatively small. The differences in the q u a n t i t y o f indirect c o m m e r c i a l e n e r g y i n p u t per unit area b e t w e e n d i f f e r e n t t y p e s o f
274 o p e r a t i o n a l holdings are o n l y marginal. This is an i n d i c a t i o n o f t h e f a c t t h a t t h e i n d i r e c t e n e r g y i n p u t - b a s e d t e c h n o l o g i e s in a progressive agriculture t e n d t o d e v e l o p size n e u t r a l i t y . Perusal o f T a b l e s 1 a n d 2 leads t o t h e c o n c l u s i o n t h a t in t h e s a m p l e villages t h e b e n e f i t s o f t e c h n o l o g i c a l changes c o n n e c t e d w i t h t h e use o f c o m m e r c i a l e n e r g y i n p u t s w e r e r e a c h i n g all g r o u p s o f o p e r a tional holdings.
Energy consumption by operation T a b l e 3 gives c o n s u m p t i o n o f d i r e c t c o m m e r c i a l e n e r g y b y o p e r a t i o n . T h e direct c o m m e r c i a l e n e r g y c o n s u m p t i o n in s o m e o f t h e o p e r a t i o n s like t h r e s h i n g a n d t r a n s p o r t is yield d e p e n d e n t . T h e e n e r g y c o n s u m p t i o n figures given in T a b l e 3 relate to an average yield o f 4.5 t o f rice and 2.5 t o f w h e a t p e r ha. In t h e case o f rice, irrigation c o n s u m e s t h e largest a m o u n t o f d i r e c t c o m m e r c i a l energy. T h e a b n o r m a l l y high c o n s u m p t i o n o f d i r e c t c o m m e r c i a l e n e r g y f o r irrigation o n N O F f a r m s has b e e n e x p l a i n e d earlier. In t h e case o f w h e a t , h a r v e s t i n g a n d t h r e s h i n g c o n s u m e a little m o r e e n e r g y t h a n irrigation. TABLE3 Direct commercial energy input to each operation in the cultivation of rice and wheat on different farms Operation
Direct commercial energy input (MJ/ha) Rice
Seed bed preparation Sowing Irrigation Fertilizer and chemical application and interculture Harvesting and threshing Transportation Total
Wheat
TOF
BOF
NOF
TOF
BOF
NOF
2 904.1 0.0 18 747.9
250.2 0.0 22 735.7
1 592.9 0.0 30 633.5
2 714.3 331.4 2 080.6
761.6 76.1 1 824.3
1 288.1 107.0 1 720.4
0.0
0.0
0.0
0.0
0.0
0.0
97.4 887.1 22636.5
0.0 134.6 23120.5
0.0 135.9 32362.3
2 532.3 182.8 7841.1
1 932.3 17.9 4612.2
2 712.3 30.8 5858.6
Energy ratio T h e e n e r g y ratio was c a l c u l a t e d b y dividing t h e h e a t value o f t h e m a i n p r o d u c t s (rice a n d w h e a t grains) b y t h e c o m m e r c i a l a n d t o t a l e n e r g y i n p u t s to e a c h c r o p . T h e results are p r e s e n t e d in T a b l e 4.
275 TABLE 4 Energy ratio of rice and wheat on different farms Farm
Energy ratio Rice
TOF BOF NOF
Wheat
Commercial
Total
Commercial
Total
energy
energy
energy
energy
1.78 1.81 1.40
1.59 1.52 1.26
2.45 3.17 3.02
2.18 2.57 2.54
The average yield of rice on the sample farms was observed to be about 25% higher than the state average yield of this crop. The average yield of wheat on the sample farms was, on the other hand, about 15% lower. In spite of a relatively higher o u t p u t for the rice crop the energy ratios were f o u n d to be very low compared to wheat. This is attributed to the large expenditure of energy for irrigating the rice crop. In this respect rice production was a relatively energy-expensive activity of the sample farms.
Energy saving The scope for saving commercial energy in rice-wheat production is related to the magnitude of energy consumption in different production operations. These two crops accounted for 86.4% of the total commercial energy input to production agriculture in the villages included in the study. Irrigation and fertilizers accounted for about 80% of the total commercial energy input to wheat and paddy production on the sample farms. The scope for reducing direct energy expenditure in lift irrigation and indirect energy expenditure in the form of fertilizers is discussed below. T w e n t y three pumping sets with diesel prime movers were randomly selected in a separate study but in the same group of villages for determination of their efficiency. All the pumping sets were found to be highly inefficient (Pathak et al., 1984). The study concluded that the specific fuel consumption of the small diesel engines used on the pump sets could be reduced from the observed level of 365.5 g per kWh to 306.6 g per kWh through proper adjustments and maintenance. The specific fuel consumption could be further reduced to 234.6 g per kWh by replacing the locally assembled engines with standard engines. The average efficiency of the pump and flat belt transmission system in the field was observed to be 39.2%. It was reported to increase to about 50% after adjusting the suction lift, pump speed, belt tension, etc. It was considered practical to achieve an average pump and transmission system efficiency of 65% through proper
276 selection of the system components, correct installation and o p t i m u m adjustments. The above study concluded that more than 50% of diesel fuel and the substantial percentage of electricity n o w consumed in lifting water for irrigation in the three villages could be saved if good quality equipment was selected, correctly installed and properly operated. The potential for saving diesel fuel through pumping system improvement in Punjab was estimated to be of the order of 200 000 m3/year. Improvements in water management in the field offer further possibilities for saving energy in lift irrigation. Experiments conducted under similar conditions (Sandhu and Prihar, 1983) have shown that the number of irrigations for both the rice and wheat crops could be reduced by 1/3 without affecting the yields. This is expected to result in a proportionate saving in energy. It has been reported that 50--70% of fertilizer nitrogen is lost due to leaching, denitrification, volatilization, etc. (Prasad and Subbiah, 1982). Simple practices like drilling of fertilizers at the time of planting can substantially increase the fertilizer use efficiency. Equipment for drilling of fertilizers in measured quantities at the appropriate depth and distance from the seed is available, both for close grown and row planted crops. The use of such equipment with the wheat crop is increasing in Punjab. The techniques for efficient application and utilization of fertilizer under wet land conditions are yet to be introduced. Studies on deep placement of fertilizer with the rice crop in The Philippines have shown that fertilizer use efficiency can increase by 50% or more over the split broadcast practices if suitable deep applications are used (Khan, 1984). Substantial saving in fertilizer use could be effected in Punjab by introducing the deep placement technique. The balanced use of fertilizer is in itself an important energy conservation measure. Field experiments conducted over many years have shown that under Punjab conditions, wheat yields obtained from the application of 80 kg of nitrogen plus 40 kg of P2Os would normally be higher than the yields obtained from the application of 120 kg of nitrogen alone (Rana and Singh, 1982). Substitution of 1 kg of nitrogen by 1 kg of P2Os saves a b o u t 50 MJ of energy in manufacture. Application of large doses of nitrogenous fertilizer w i t h o u t soil testing, commonly observed in the sample farms, is a likely contributor to low efficiency of fertilizer use. Tillage and threshing operations were also found to be important consumers of commercial energy in rice and wheat production. While there has already been some improvement in the seed bed preparation techniques in recent years, resulting in a reduction in the number of tillage operations, there appears to be a distinct possibility to affect further saving in the energy consumption in tillage of rice and wheat fields. Studies carried o u t at Punjab Agricultural University (Mittal et al., 1983) showed that nearly 50% of the tillage energy could be saved without affecting yields. A review of the test reports of different types of threshers in Punjab has
277
shown that the specific energy requirement varies from 10.00 kWh/t to more than 50.00 kWh/t of threshed wheat grain {Kaul and Kumar, 1975). Chopthreshing was f o u n d to consume the least a m o u n t of energy. A large number of inefficient threshers with high specific energy requirement are apparently in use in the wheat growing regions of Punjab and neighbouring States. Considering the wide variations in the specific energy consumption of different threshers and the fact that over 8 million t of wheat is threshed with small- and medium-sized machines every year in Punjab alone, there is substantial potential for reducing the energy consumption in wheat threshing by using energy-efficient stationary machines. On the other hand, there is not much scope for saving energy in rice threshing. It was observed that more than 80% of the rice crop on the sample farms was threshed manually. Energy saving devices in manual threshing are not available. CONCLUSIONS
The study of energy use patterns on the 74 sample farms in Ludhiana district of Punjab and of the possibilities for saving energy in rice and wheat production leads to the following conclusions: The commercial energy inputs to rice production ranges from 35 000 MJ/ha to over 45 000 MJ/ha compared to 13 500 MJ/ha to 16 000 MJ/ha in the case of wheat. High irrigation requirements of rice are mainly responsible for this difference. The increase in size of farm and power source ownership does n o t increase the energy requirements. In fact the small farmers (NOF) use more energy for rice production per unit area due to the tendency to over-irrigate the rice crop. The rice crop, in spite o f a good yield, gives a low energy ratio, indicating that it is an energy~xpensive crop under the conditions prevailing in the three villages. Over 50% of the diesel fuel consumed in lift irrigation and a large amount of electrical energy can be saved if the quality and maintenance of irrigation equipment and fittings are improved and better water management practices are introduced at the farmers' level. Improved fertilizer management particularly of nitrogenous fertilizer can yield considerable reduction in energy expenditure in rice and wheat production. Rationalised tillage practices and proper selection of stationary threshers for wheat can reduce the energy requirements.
REFERENCES Kaul, R.N. and Kumar, R., 1975. Types and usages of wheat threshers in Punjab. Rep. FPM1/75, Department of Farm Power and Machinery, Punjab Agricultural University, Ludhiana, 9 pp.
278 Khan, A.U., 1984. Deep placement fertilizer application for improved fertilizer use efficiency. Agric. Mech. Asia, Afr. Latin Am. (AMA), 25(3): 25--32. Mittal, V.K., Panesar, B.S., Gill, B.S., Jindal, R.K., Singh, M.P. and Bakhshi, R., 1983. Biennial report, Energy requirements in agricultural sector -- an ICAR coordinated project, 1981--83. Department of Farm Power and Machinery, Punjab Agricultural University, Ludhiana, 208 pp. Pathak, B.S., 1982. Energetics of a developing agriculture -- a case study of the production agriculture of Punjab. Report, Energy Agriculture Project, Punjab Agricultural University, Ludhiana, 19 pp. Pathak, B.S., 1983. Energy for agricultural development. Background note presented during Seminar, 20 January 1983, Management of Agriculture with Special Reference to Green Revolution, Punjab Agricultural University, Ludhiana. Pathak, B.S., Bining, A.S., Nischal, D.P. and Sondhi, S.K., 1984. Energy efficiency of diesel engine pumpsets in Punjab. Report, Energy Agriculture Project, Punjab Agricultural University, Ludhiana, 22 pp. Prasad, R. and Subbiah, B.V., 1982. Nitrogen -- the key plant nutrient in Indian Agriculture. Fert. News (India), 27(2): 27--42. Rana, D.8. and Singh, N.T., 1982. Annual report of the All India Coordinated Agronomic Research Project. Department of Soils. Punjab Agricultural University, Ludhiana, 60 pp. Sandhu, B.S. and Prihar, S.S., 1983. Irrigation scheduling to crops in Punjab. Department of Soils, Punjab Agricultural University, Ludhiana, 8 pp.
271
E N E R G Y USE P A T T E R N A N D P O T E N T I A L F O R E N E R G Y S A V I N G IN RICE-WHEAT CULTIVATION
B.S. PATHAK and A.S. BINING
School of Energy Studies for Agriculture, Punjab Agricultural University, Ludhiana (India) (Accepted 6 June 1985)
ABSTRACT Pathak, B.S. and Bining, A.S., 1985. Energy use pattern and potential for energy saving in rice-wheat cultivation. Energy Agric., 4: 271--278. The paper reports and discusses the pattern of energy use in rice and wheat production in a cluster of three villages in the Punjab, India. The energy consumption in rice production was found to be much higher than the energy consumption in wheat production, primarily due to the high irrigation requirements of rice, The increase in size of operational holdings and power source ownership did not increase the indirect commercial energy consumption which reflected an increasing standardization of indirect energy input-based production techniques irrespective of the size of farm. Savings of over 50% in the consumption of diesel fuel in lift irrigation and considerable savings in electric energy and fertilizers were found to be feasible through improvement in the quality and maintenance of irrigation equipment and improved water and fertilizer management practices.
INTRODUCTION
Rice a n d w h e a t a c c o u n t for over 75% o f the t o t a l cereal p r o d u c t i o n in India. T h e i n t r o d u c t i o n o f i m p r o v e d varieties o f rice a n d w h e a t in the sixties started a chain o f t e c h n o l o g i c a l changes w h i c h m a d e it feasible to increase f o o d p r o d u c t i o n b y well over 50% in a p e r i o d o f 15 years. Most o f these t e c h n o l o g i c a l c h a n g e s d e m a n d a d d i t i o n a l e n e r g y inputs, particularly o f c o m m e r c i a l energy. F o r e x a m p l e , t h e r e was a 13-fold increase in the c o m m e r c i a l e n e r g y i n p u t t o the p r o d u c t i o n agriculture o f Punjab, an i m p o r t a n t w h e a t and rice g r o w i n g State, b e t w e e n the years 1 9 5 5 - - 5 6 and 1 9 8 0 81 (Pathak, 1982). This increase was m a i n l y d u e to greater c o n s u m p t i o n o f diesel oil, electricity, chemicals a n d fertilizers. D u r i n g t h e y e a r 1 9 8 0 - - 8 1 , t h e e s t i m a t e d i n p u t s o f c o m m e r c i a l e n e r g y t o I n d i a n p r o d u c t i o n agriculture i n c l u d e d 1 8 3 . 1 8 0 PJ in the f o r m o f diesel oil a n d electricity (primarily f o r irrigation), 4 8 . 4 5 9 PJ in t h e f o r m o f e q u i p m e n t and m a c h i n e r y , and 2 4 9 . 0 0 2 PJ in t h e f o r m o f fertilizer a n d chemicals. In view o f t h e o b s e r v e d c o r r e l a t i o n
0167-5826/85/$03.30
© 1985 Elsevier Science Publishers B.V.
272 between the commercial energy inputs and agricultural productivity (Pathak, 1983) the demand for commercial energy in the agricultural sector is likely to increase very rapidly in the next 15--20 years. On the other hand, the global availability of conventional energy resources is expected to diminish sharply by the turn of this century. The combination of these two factors, namely, the increasing demand for commercial energy inputs and the probability of serious restrictions on commercial energy supplies will force the planners and technologists to give increasing attention to more efficient utilization of energy in production agriculture. Keeping the above corisideration in mind, it was decided to conduct a study in Punjab, Haryana, Himachal Pradesh and Western Uttar Pradesh to record the current state of energy use in production agriculture and to identify the potential for energy conservation. This paper seeks to present the results of the study carried out in Ludhiana district of Punjab in 1981-82. METHODOLOGY The inputs of commercial and non-commercial and direct and indirect energy to each crop production operation on 74 farms in a cluster of three villages in Ludhiana district were measured and recorded for 1 year. The sample farms were chosen at random after completing an inventory of the three villages. However, care was taken to ensure that the study sample was representative of operational holdings of different sizes. Also, a numerical balance was maintained between the operational holdings owning different types of farm power sources. Data on each operation were processed to yield information on energy inputs to various crops on individual farms and to work out the average energy consumption of farms falling in different categories of holding sizes and power source ownership. The energy requirements of the operations which consumed large quantities of energy were examined in order to ascertain the potential for conservation of energy. The information presented in this paper pertains to the energy use patterns and potential for energy conservation in rice-wheat cultivation, the most important crop rotation in Punjab. RESULTS AND DISCUSSION
Direct commercial energy inputs Table 1 gives the direct commercial energy input (MJ/ha) to rice and wheat production on different types of farms. The operational holdings owning tractors (TOF) and bullocks (BOF) used nearly the same a m o u n t of direct commercial energy to produce rice on 1 ha of land. The consumption of direct commercial energy on small operational holdings (NOF) depending entirely on hired tractors/buUocks
273 TABLE 1 Direct commercial energy input to rice and wheat production Farm
Direct Commercial Energy Input (MJ/ha) Rice
TOF BOF NOF
Wheat
Diesel
Electricity
Total
Diesel
Electricity
Total
6513.7 2192.8 4 693.1
16122.8 20927.7 27 669.2
22636.5 23120.5 32 362.3
6672.9 3652.5 4 802.2
1 168.2 959.7 1 056.4
7 841.1 4612.2 5 858.6
TABLE 2 Indirect commercial energy inputs to rice and wheat production Farm
Indirect commercial energy inputs (MJ/ha) Nitrogen
Phosphorus
Potash
Chemicals
Machinery
Total
10516.8 12198.9 10890.2
630.8 712.9 682.2
98.5 180.6 161.0
727.2 578.6 735.5
433.6 272.4 476.1
12406.9 13943.4 12945.1
7 359.1 7 580.6 7 486.4
824.5 877.8 753.1
130.3 111.8 124.4
109.0 162.0 31.4
331.4 121.7 183.4
8 757.3 8 853.9 8 578.7
Rice
TOF BOF NOF Wheat
TOF BOF NOF
was higher. Excessive irrigation resulting f r o m individual irrigation p u m p s a n d limited c r o p p e d area was the m a j o r reason f o r high direct c o m m e r c i a l e n e r g y c o n s u m p t i o n o n N O F holdings. The direct c o m m e r c i a l e n e r g y i n p u t s to w h e a t p r o d u c t i o n s h o w a d i f f e r e n t trend. T h e c o n s u m p t i o n o f this c a t e g o r y o f e n e r g y o n the T O F was observed t o be t h e highest, m a i n l y because o f a m o r e m e c h a n i z e d s y s t e m o f seed bed p r e p a r a t i o n o n these holdings. T h e t o t a l direct c o m m e r c i a l e n e r g y i n p u t to w h e a t p r o d u c t i o n was 1/3 or less o f the i n p u t s t o rice p r o d u c t i o n . This d i f f e r e n c e is to be a t t r i b u t e d t o the d i f f e r e n t irrigation r e q u i r e m e n t s o f the t w o c r o p s u n d e r the c o n d i t i o n s prevailing in L u d h i a n a district. N i t r o g e n a c c o u n t e d for a m a j o r p o r t i o n o f the c o m m e r c i a l e n e r g y i n p u t t o the p r o d u c t i o n of b o t h rice and wheat. C o n t r a r y t o t h e general belief, t h e indirect e n e r g y i n p u t in the f o r m o f e q u i p m e n t a n d m a c h i n e r y even in t h e S t a t e o f P u n j a b is relatively small. The differences in the q u a n t i t y o f indirect c o m m e r c i a l e n e r g y i n p u t per unit area b e t w e e n d i f f e r e n t t y p e s o f
274 o p e r a t i o n a l holdings are o n l y marginal. This is an i n d i c a t i o n o f t h e f a c t t h a t t h e i n d i r e c t e n e r g y i n p u t - b a s e d t e c h n o l o g i e s in a progressive agriculture t e n d t o d e v e l o p size n e u t r a l i t y . Perusal o f T a b l e s 1 a n d 2 leads t o t h e c o n c l u s i o n t h a t in t h e s a m p l e villages t h e b e n e f i t s o f t e c h n o l o g i c a l changes c o n n e c t e d w i t h t h e use o f c o m m e r c i a l e n e r g y i n p u t s w e r e r e a c h i n g all g r o u p s o f o p e r a tional holdings.
Energy consumption by operation T a b l e 3 gives c o n s u m p t i o n o f d i r e c t c o m m e r c i a l e n e r g y b y o p e r a t i o n . T h e direct c o m m e r c i a l e n e r g y c o n s u m p t i o n in s o m e o f t h e o p e r a t i o n s like t h r e s h i n g a n d t r a n s p o r t is yield d e p e n d e n t . T h e e n e r g y c o n s u m p t i o n figures given in T a b l e 3 relate to an average yield o f 4.5 t o f rice and 2.5 t o f w h e a t p e r ha. In t h e case o f rice, irrigation c o n s u m e s t h e largest a m o u n t o f d i r e c t c o m m e r c i a l energy. T h e a b n o r m a l l y high c o n s u m p t i o n o f d i r e c t c o m m e r c i a l e n e r g y f o r irrigation o n N O F f a r m s has b e e n e x p l a i n e d earlier. In t h e case o f w h e a t , h a r v e s t i n g a n d t h r e s h i n g c o n s u m e a little m o r e e n e r g y t h a n irrigation. TABLE3 Direct commercial energy input to each operation in the cultivation of rice and wheat on different farms Operation
Direct commercial energy input (MJ/ha) Rice
Seed bed preparation Sowing Irrigation Fertilizer and chemical application and interculture Harvesting and threshing Transportation Total
Wheat
TOF
BOF
NOF
TOF
BOF
NOF
2 904.1 0.0 18 747.9
250.2 0.0 22 735.7
1 592.9 0.0 30 633.5
2 714.3 331.4 2 080.6
761.6 76.1 1 824.3
1 288.1 107.0 1 720.4
0.0
0.0
0.0
0.0
0.0
0.0
97.4 887.1 22636.5
0.0 134.6 23120.5
0.0 135.9 32362.3
2 532.3 182.8 7841.1
1 932.3 17.9 4612.2
2 712.3 30.8 5858.6
Energy ratio T h e e n e r g y ratio was c a l c u l a t e d b y dividing t h e h e a t value o f t h e m a i n p r o d u c t s (rice a n d w h e a t grains) b y t h e c o m m e r c i a l a n d t o t a l e n e r g y i n p u t s to e a c h c r o p . T h e results are p r e s e n t e d in T a b l e 4.
275 TABLE 4 Energy ratio of rice and wheat on different farms Farm
Energy ratio Rice
TOF BOF NOF
Wheat
Commercial
Total
Commercial
Total
energy
energy
energy
energy
1.78 1.81 1.40
1.59 1.52 1.26
2.45 3.17 3.02
2.18 2.57 2.54
The average yield of rice on the sample farms was observed to be about 25% higher than the state average yield of this crop. The average yield of wheat on the sample farms was, on the other hand, about 15% lower. In spite of a relatively higher o u t p u t for the rice crop the energy ratios were f o u n d to be very low compared to wheat. This is attributed to the large expenditure of energy for irrigating the rice crop. In this respect rice production was a relatively energy-expensive activity of the sample farms.
Energy saving The scope for saving commercial energy in rice-wheat production is related to the magnitude of energy consumption in different production operations. These two crops accounted for 86.4% of the total commercial energy input to production agriculture in the villages included in the study. Irrigation and fertilizers accounted for about 80% of the total commercial energy input to wheat and paddy production on the sample farms. The scope for reducing direct energy expenditure in lift irrigation and indirect energy expenditure in the form of fertilizers is discussed below. T w e n t y three pumping sets with diesel prime movers were randomly selected in a separate study but in the same group of villages for determination of their efficiency. All the pumping sets were found to be highly inefficient (Pathak et al., 1984). The study concluded that the specific fuel consumption of the small diesel engines used on the pump sets could be reduced from the observed level of 365.5 g per kWh to 306.6 g per kWh through proper adjustments and maintenance. The specific fuel consumption could be further reduced to 234.6 g per kWh by replacing the locally assembled engines with standard engines. The average efficiency of the pump and flat belt transmission system in the field was observed to be 39.2%. It was reported to increase to about 50% after adjusting the suction lift, pump speed, belt tension, etc. It was considered practical to achieve an average pump and transmission system efficiency of 65% through proper
276 selection of the system components, correct installation and o p t i m u m adjustments. The above study concluded that more than 50% of diesel fuel and the substantial percentage of electricity n o w consumed in lifting water for irrigation in the three villages could be saved if good quality equipment was selected, correctly installed and properly operated. The potential for saving diesel fuel through pumping system improvement in Punjab was estimated to be of the order of 200 000 m3/year. Improvements in water management in the field offer further possibilities for saving energy in lift irrigation. Experiments conducted under similar conditions (Sandhu and Prihar, 1983) have shown that the number of irrigations for both the rice and wheat crops could be reduced by 1/3 without affecting the yields. This is expected to result in a proportionate saving in energy. It has been reported that 50--70% of fertilizer nitrogen is lost due to leaching, denitrification, volatilization, etc. (Prasad and Subbiah, 1982). Simple practices like drilling of fertilizers at the time of planting can substantially increase the fertilizer use efficiency. Equipment for drilling of fertilizers in measured quantities at the appropriate depth and distance from the seed is available, both for close grown and row planted crops. The use of such equipment with the wheat crop is increasing in Punjab. The techniques for efficient application and utilization of fertilizer under wet land conditions are yet to be introduced. Studies on deep placement of fertilizer with the rice crop in The Philippines have shown that fertilizer use efficiency can increase by 50% or more over the split broadcast practices if suitable deep applications are used (Khan, 1984). Substantial saving in fertilizer use could be effected in Punjab by introducing the deep placement technique. The balanced use of fertilizer is in itself an important energy conservation measure. Field experiments conducted over many years have shown that under Punjab conditions, wheat yields obtained from the application of 80 kg of nitrogen plus 40 kg of P2Os would normally be higher than the yields obtained from the application of 120 kg of nitrogen alone (Rana and Singh, 1982). Substitution of 1 kg of nitrogen by 1 kg of P2Os saves a b o u t 50 MJ of energy in manufacture. Application of large doses of nitrogenous fertilizer w i t h o u t soil testing, commonly observed in the sample farms, is a likely contributor to low efficiency of fertilizer use. Tillage and threshing operations were also found to be important consumers of commercial energy in rice and wheat production. While there has already been some improvement in the seed bed preparation techniques in recent years, resulting in a reduction in the number of tillage operations, there appears to be a distinct possibility to affect further saving in the energy consumption in tillage of rice and wheat fields. Studies carried o u t at Punjab Agricultural University (Mittal et al., 1983) showed that nearly 50% of the tillage energy could be saved without affecting yields. A review of the test reports of different types of threshers in Punjab has
277
shown that the specific energy requirement varies from 10.00 kWh/t to more than 50.00 kWh/t of threshed wheat grain {Kaul and Kumar, 1975). Chopthreshing was f o u n d to consume the least a m o u n t of energy. A large number of inefficient threshers with high specific energy requirement are apparently in use in the wheat growing regions of Punjab and neighbouring States. Considering the wide variations in the specific energy consumption of different threshers and the fact that over 8 million t of wheat is threshed with small- and medium-sized machines every year in Punjab alone, there is substantial potential for reducing the energy consumption in wheat threshing by using energy-efficient stationary machines. On the other hand, there is not much scope for saving energy in rice threshing. It was observed that more than 80% of the rice crop on the sample farms was threshed manually. Energy saving devices in manual threshing are not available. CONCLUSIONS
The study of energy use patterns on the 74 sample farms in Ludhiana district of Punjab and of the possibilities for saving energy in rice and wheat production leads to the following conclusions: The commercial energy inputs to rice production ranges from 35 000 MJ/ha to over 45 000 MJ/ha compared to 13 500 MJ/ha to 16 000 MJ/ha in the case of wheat. High irrigation requirements of rice are mainly responsible for this difference. The increase in size of farm and power source ownership does n o t increase the energy requirements. In fact the small farmers (NOF) use more energy for rice production per unit area due to the tendency to over-irrigate the rice crop. The rice crop, in spite o f a good yield, gives a low energy ratio, indicating that it is an energy~xpensive crop under the conditions prevailing in the three villages. Over 50% of the diesel fuel consumed in lift irrigation and a large amount of electrical energy can be saved if the quality and maintenance of irrigation equipment and fittings are improved and better water management practices are introduced at the farmers' level. Improved fertilizer management particularly of nitrogenous fertilizer can yield considerable reduction in energy expenditure in rice and wheat production. Rationalised tillage practices and proper selection of stationary threshers for wheat can reduce the energy requirements.
REFERENCES Kaul, R.N. and Kumar, R., 1975. Types and usages of wheat threshers in Punjab. Rep. FPM1/75, Department of Farm Power and Machinery, Punjab Agricultural University, Ludhiana, 9 pp.
278 Khan, A.U., 1984. Deep placement fertilizer application for improved fertilizer use efficiency. Agric. Mech. Asia, Afr. Latin Am. (AMA), 25(3): 25--32. Mittal, V.K., Panesar, B.S., Gill, B.S., Jindal, R.K., Singh, M.P. and Bakhshi, R., 1983. Biennial report, Energy requirements in agricultural sector -- an ICAR coordinated project, 1981--83. Department of Farm Power and Machinery, Punjab Agricultural University, Ludhiana, 208 pp. Pathak, B.S., 1982. Energetics of a developing agriculture -- a case study of the production agriculture of Punjab. Report, Energy Agriculture Project, Punjab Agricultural University, Ludhiana, 19 pp. Pathak, B.S., 1983. Energy for agricultural development. Background note presented during Seminar, 20 January 1983, Management of Agriculture with Special Reference to Green Revolution, Punjab Agricultural University, Ludhiana. Pathak, B.S., Bining, A.S., Nischal, D.P. and Sondhi, S.K., 1984. Energy efficiency of diesel engine pumpsets in Punjab. Report, Energy Agriculture Project, Punjab Agricultural University, Ludhiana, 22 pp. Prasad, R. and Subbiah, B.V., 1982. Nitrogen -- the key plant nutrient in Indian Agriculture. Fert. News (India), 27(2): 27--42. Rana, D.8. and Singh, N.T., 1982. Annual report of the All India Coordinated Agronomic Research Project. Department of Soils. Punjab Agricultural University, Ludhiana, 60 pp. Sandhu, B.S. and Prihar, S.S., 1983. Irrigation scheduling to crops in Punjab. Department of Soils, Punjab Agricultural University, Ludhiana, 8 pp.