Sarhad J. Agric. Vol. 23, No. 3, 2007 WATER AND ENERGY INPUTS FOR WHEAT PRODUCTION UNDER PERMANENT RAISED BEDS Muhammad Azam Khan *, Muhammad Shafeeq ** and Inayat Ullah Awan * ABSTRACT A study was performed at the Mardan field station of Water Resources Research Institute, National Agricultural Research Center, Islamabad during 2002-03. The objective of this study was to investigate the pattern of energy use and find its relationship with crop production under three methods of irrigation. Methods of irrigation were Basin Complete Irrigation System (BCIS), Narrow Bed Irrigation System (NBIS), and Broad Bed Irrigation System (BBIS). Sources of energy input were human labour and tractor. Water, energy and economic use efficiencies were calculated for each method. It was observed that BBIS consumed maximum energy and produced the highest yield. Water use efficiency was also highest in case of BBIS. Similarly combined (water and energy) use efficiency remained the highest in BBIS with 0.55g/m 3 -kwh. The combined efficiency in case of NBIS (0.51 g/m 3 -kwh) was higher than BCIS (0.35 g/m 3 -kwh). Higher water use efficiency of BBIS i.e. 1.25 and higher energy use efficiency of BBIS i.e., 31.69 produced the good effects on economic efficiency and therefore benefit: ratio of BBIS was also the highest (0.97) compared to NBIS (0.73). The lowest benefit: cost Ratio was observed in BCIS (0.42). INTRODUCTION Water and energy are the two commodities that can boost the yield of any crop. The country has experienced a golden era of water resources development during eighties. She has well developed canal irrigation system. However, time to time droughts lower down the outcome which could have been achieved in the presence of this marvelous system. This results the over use of ground water, which requires energy. Unfortunately, the country is also deficient in this commodity. Regarding water shortage, the country has recently come out from eye opening shock of drought, which remained from 1999 to 2002. In agrarian country, agriculture without water or acute shortage of water is suicidal step of economy, especially when the agriculture is the largest sector of the economy of the country (Pakistan Economic Survey 2003-04). The sector contributes 23.3 % in GDP and engages 42.1 % of the total employed labor force. It is the largest source of foreign exchange earning by serving as the base sector for the county s major industries like textile and sugar. The surface and ground water reserves in Pakistan have been significantly deleted by the prevailing conditions of drought. This has seriously unbalanced the water supply and demand relationship in the country. Moreover, meteorological department is again warning for more severe drought in near future. Therefore, water management and conservation are fast emerging as critical issues and need to be tackled through a collective and sustained effort. Similarly, as Pakistan is also deficient of energy resources. The country pay substantial amount of foreign currency for the import of energy sources (Pakistan Energy Yearbook 2003). As the wheat is staple food of the country, no one can ignore its importance. On the other hand water and energy are the two commodities that have direct effect on its production. Therefore, it is imperative to study the effect of two mentioned commodities on the said crop and efforts are required to find out the best possible combination for maximum growth of better economic efficiency. The present study compares the three methods of irrigation water application i.e. Basin Complete Irrigation System, Narrow Bed Irrigation System, and Broad Bed Irrigation System in terms of water and energy use efficiency for the production of wheat. The energy budget would provide additional information in terms of energy inputs and outputs along with energy efficiency. MATERIAL AND METHODS Location of the Study Area The study was conducted at Mardan Field Research Station of Water Resources Research Institute (WRRI), National Agricultural Research Center (NARC), Islamabad. The site is located at Latitude 33 12 / N and longitude 73 08 / E, which is around 15 km from the district headquarters. The soil of the area is developed from piedmont plain and its texture is mostly silty-clay-loam. The climate is subhumid continental. On average base it is sub-humid in the Kharif and semi-arid to sub-humid in the Rabi season. The mean annual rainfall during the period of 1960-90, as normal of 30 years was around 1000 mm (PMD, 1992). Due to the prolonged drought from 1999 to 2001, the rainfall has reduced considerably. * ** Faculty of Agriculture, Gomal University, Dera Ismail Khan - Pakistan Water Resources Research Institute, NARC, Islamabad - Pakistan Corresponding Author s Email: k_mazam@yahoo.com
Muhammad Azam Khan et al. Water and energy inputs 694 Experimental Design Experimental area comprising of 0.4 hectare was divided into three blocks for the sowing of wheat and application of water. Three irrigation practices i.e., Basin Complete Irrigation System, Narrow Bed (1.35 m center to centre of furrow) Irrigation System and Broad Bed (1.80 m) were randomly distributed in these blocks. Near by canal water was sufficient to fulfill the water requirement of the crop. One presowing and two subsequent irrigations were employed at an interval of around 30 days to meet crop water requirement. Irrigations were measured using broad-crested weir type flume. The irrigations were scheduled based on soil moisture contents as dried at a temp range of 100 120 C. Criteria for time of irrigation was 5% depletion of available water in top 30 cm depth. Volumetric moisture contents of available water in the root zone (90 cm depth) were used to estimate depth of net irrigation. The data generated were analyzed statistically for descriptive analysis. The three treatments used in the study are summarized as under: i. Basin complete irrigation System (BCIS); ii. Narrow Bed Irrigation System (NBIS); iii. Broad Bed Irrigation System (BBIS). Fertilization and Planting of Wheat Sowing and fertilization operations at the experimental site were mechanized on two treatments comprising of NBIS and BBIS. Whereas, under BCIS fertilizer was applied through broadcast and sowing was done by drill. Constant dose of inorganic fertilizer was applied to all the three treatments. In general, one to two harrowing was done for the seedbed preparation. The seed rate of 110 kg/ha was used. The crop was manually harvested in all the treatments. Casual labor was also engaged for harvesting operation. Energy Inputs For each plot, information was collected for energy inputs and outputs. Sources of physical energy used on this farm were human labor, and tractor. To compute the energy inputs from these power sources, the following procedures were adopted. a. The energy input for human labor was calculated as a product of man-hours and its estimated power. It was set equal to 0.075 kw or 0.1 hp (Khan and Singh 1996). b. The energy consumption by tractor was calculated using the following formula (Khan 1994). E c = F c * F cv * M t Where; E c - Energy consumption by tractor (kwh/ha); F c - Fuel consumption of tractor per hour (l/h); F cv - Caloric value of diesel (kwh/l) M t - Number of hours the machine (tractor) worked per hectare (h/ha). c. The caloric value of diesel in Pakistan is around 10.46 (ENERCON 1989). d. The energy inputs from seed and the crop output was calculated on the caloric content basis. Energy input by fertilizer was calculated on the caloric content of the inputs to their manufacturing process (Khan 1994). e. The energy efficiency ratio used in this paper is the ratio of dietary energy value of agricultural output to the fossil energy expended to obtain it (Bonny 1993). f. The grain and straw yield of wheat crop was recorded from 3.6 m 2 area representing the grids. Under furrow bed system 3.6 m 2 area represented two furrow and two beds of one meter length. Whereas, under basin irrigation system, distance from centre of two rows was used as the measuring point. g. Computations of energy input for all operations were made on per hectare basis. Energy and Water Use Efficiency The water use efficiency was computed in terms of yield of marketable product per unit of water used (kg/m 3 ). The energy use efficiency was computed using yield of the marketable product per unit of energy consumed (kg/kwh). Combined effect of water and energy on crop yield was computed by dividing grain yield with the total amount of water used (m 3 ) and total amount of energy consumed (kwh). This is termed as water-energy use efficiency (g.m -3.kWh -1 ) (Khan et al 2005). Economic Efficiency All treatments were economically analyzed. The analysis was performed to examine the gross margin and return to the family labour. The cost of production for the crop included the cost of all operations performed with various power sources. value of output included the value of crop (wheat) and by product (straw). margin was defined as the gross value of product minus the cost of production (Abbot and Makeham. 1979). Benefit cost ratio is the ratio of gross margin (net return) and total cost of production.
Sarhad J. Agric. Vol. 23, No. 3, 2007 695 RESULTS AND DISCUSSION Total Energy Input Total energy input of human labor was the highest for the plots of NBIS (59 kwh) followed by BBIS (50 kwh) and BCIS (45 kwh) (Table 1). This high use of energy occurred in the treatment of NBIS and BBIS for land preparation and sowing. No suitable machinery was available for complete land preparation in plots of NBIS and BBIS. Therefore, after plowing with tractor and its implement human labour was employed for bed preparation. In case of sowing operation, only human labour was used in NBIS, due to non availability of suitable machinery for sowing crop in these plots. In case of BBIS, sowing operation consumed the highest energy due to tractor. The movement of grain drill was very difficult in BBIS compared to BCIS. Energy used in fertilizer application was almost same in all the three treatments, as the same quantity of fertilizer was applied in these plots. Weeding was a big problem in the area. This operation was not only performed manually but weedicide was also applied. Much difference in energy consumption was observed between BCIS and NBIS. As the large quantity of weeds were destroyed during narrow bed formation in NBIS. Flood irrigation is the commonly used method of irrigation; and that took longer time in plots of BCIS compared to the other treatments. Seed energy remained the same for all the three treatments (Table II). The only difference visible in total physical energy consumption was high use of inanimate energy in BBIS. Noteworthy difference was observed in energy efficiency ratio between BBIS and NBIS compared to BCIS. However, minor difference was observed in energy efficiency ratios of NBIS and BBIS. Water use efficiency was highest in BBIS and lowest in BCIS; however, the difference was non considerable. This water use efficiency was notably higher only in BBIS compared to BCIS (Table III). The data was analyzed to see the combined effect of energy and water use efficiencies. The highest energy and water use efficiency (0.55 g/m 3 kwh) was observed in BBIS followed by NBIS (0.519 g/m 3 kwh) and BCIS (0.35 g/m 3 kwh). Therefore, it can be concluded that BBIS was most efficient in terms of both energy and water use (Table III) Economic Efficiency An appreciably higher gross margin was observed in the plots of BBIS compared to NBIS and BCIS (Table IV). Even in NBIS higher gross margin and benefit cost ratio was observed compared to BCIS. Therefore, in terms of economic efficiency, BBIS is the best system among the three systems in the area, whereas NBIS is better than BCIS. CONCLUSION The study conducted for production of wheat revealed that concept of BBIS is efficient in terms of energy consumed, water use and economic at the farm level. The gross margin were also comparable to NBIS, however, Benefit ratio was appreciably higher in BBIS compared to the other two irrigations systems. Considering the acute shortage of irrigation water and higher cost of energy, it is advisable to have BBIS instead of BCIS. BCIS not only demands higher amount of water but also consumes more energy in land preparation operation.
Muhammad Azam Khan et al. Water and energy inputs 696 Table I. Physical Energy Inputs in Various Methods of Irrigation for Wheat Treatments Operation Energy Sources (kwh.ha -1 ) Human Tractor Total BCIS Land Preparation 1.150 310.325 311.475 Sowing 3.987 115.510 119.497 Fertilize Application 0.690 0.000 0.690 Weeding 20.697 0.000 20.697 Irrigation 5.091 0.000 5.091 Harvesting 13.798 0.000 13.798 Total 45.413 425.835 471.248 NBIS Land Preparation 16.115 147.333 163.448 Sowing 18.866 0.000 18.866 Fertilize Application 0.452 0.000 0.452 Weeding 11.398 0.000 11.398 Irrigation 2.555 0.000 2.555 Harvesting 9.433 0.000 9.433 Total 58.819 147.333 206.152 BBIS Land Preparation 18.533 263.809 282.342 Sowing 0.938 351.745 352.683 Fertilize Application 0.470 0.000 0.470 Weeding 15.717 0.000 15.717 Irrigation 2.835 0.000 2.835 Harvesting 11.260 0.000 11.260 Total 49.753 615.554 665.307 Table II. Total Energy Inputs in Various Methods of Irrigation for Wheat Energy Parameters BCIS NBIS BBIS Human Energy (kwh.ha -1 ) 45.413 58.819 49.753 Tractor Energy (kwh ha -1 ) 425.835 147.333 615.554 Total Physical Energy (kwh. ha -1 ) 471.248 206.152 665.307 Seed Energy (kwh. ha -1 ) 1617 1617 1617 Total Energy Input (kwh. ha -1 ) 2088.248 1823.152 2282.307 Table III. Parameters Analysis of Energy Inputs and Output, Energy and Water Use Efficiencies Under Three Methods of Irrigation Treatments BCIS NBIS BBIS Water Used (m 3 ) 5250 4180 3940 Grain Yield (tones. ha -1 ) 3.81 3.86 4.92 Total Energy Inputs (kwh) 2088 1823 2282 Total Energy Output (kwh) 56007 56742 72324 Energy Efficiency Ratio 26.82 31.12 31.69 Energy Use Efficiency (kg.kwh -1 ) 1.82 2.12 2.16 Water Use Efficiency (kg.m -3 ) 0.73 0.92 1.25 Energy and Water Use Efficiency 0.35 0.51 0.55 (g.m -3. kwh -1 )
Sarhad J. Agric. Vol. 23, No. 3, 2007 697 BCIS Table IV. Wheat (Rs/ha) Under Three Methods of Irrigation Variables Human (hours used and ) Tractor (hours used and ) Total (hr) (hrs.ha -1 ) (Rs) (hrs) (hrs.ha -1 ) (Rs) (Rs) Land 2.50 15.41 41.67 256.88 2.50 15.41 775 4778.05 817 5035 Preparation Sowing 8.67 53.45 144.50 890.88 0.67 4.13 167.5 1032.68 312 1924 Fertilizer 1.50 9.25 25.00 154.13 - - - - 25 154 Application Irrigation 11.07 68.23 184.45 1137.18 - - - - 184 1137 Weeding 45.00 277.44 750.00 4623.92 - - - - 750 4624 Harvesting 30.00 184.96 500.00 3082.61 - - - - 500 3083 Seed & Fertilizer Irrigation Water (Grain) (Straw) (Rs.kg -1 ) Margin Benefit: Ratio 6800 6823 29579 3.81 3.95 42134 11.06 12555 0.42
Muhammad Azam Khan et al. Water and energy inputs 698 NBIS Variables Human (hours used and ) Tractor (hours used and cost) Total (hrs) (hrs.ha -1 ) (Rs) (hrs) (hrs.ha -1 ) (Rs) (Rs) Land 41.00 216.02 683.33 3600.28 1.00 5.27 250 1317.18 933 4917.46 Preparation Sowing 48.00 252.90 800.00 4214.96 - - - - 800 4214.96 Fertilizer 1.15 6.06 19.17 100.98 - - - - 19 100.98 Application Irrigation 6.50 34.25 108.33 570.78 - - - - 108 570.78 Weeding 29.00 152.79 483.33 2546.54 - - - - 483 2546.54 Harvesting 24.00 126.45 400.00 2107.48 - - - - 400 2107.48 Seed & 6800 Fertilizer 3425 Irrigation Water 24683 3.86 (Grain Tons.ha -1 ) 3.97 (Straw Tons.ha -1 ) 42636 11.05 (Rs.kg -1 ) 17953 Margin Benefit: 0.73 Ratio
Sarhad J. Agric. Vol. 23, No. 3, 2007 699 BBIS Variables Human (hours used and cost) Tractor (hours used and cost) Total (hrs) (hrs.ha -1 ) (Rs) (hrs) (hrs.ha -1 ) (Rs) (Rs) Land 33.90 213.21 565.00 3553.46 1.50 9.43 425 2672.96 990 6226.42 Preparation Sowing 8 50.31 133.33 838.57 2.00 12.58 500 3144.65 633 3983.23 Fertilizer 1.00 6.29 16.67 104.82 - - - - 17 104.82 Application Irrigation 6.04 37.99 100.67 633.12 - - - - 101 633.12 Weeding 33.50 210.69 558.33 3511.53 - - - - 558 3511.53 Harvesting 24.00 150.94 400.00 2515.72 - - - - 400 2515.72 Seed & 6800 Fertilizer 3799 Irrigation Water 27574 4.92 (Grain) 5.02 (Straw) 54280 11.03 (Rs.kg -1 ) Margin 26706 Benefit: Ratio 0.97 REFERENCES Abbot, J.C. and J.P. Makeham. 1979. Agricultural economics and marketing in the Tropics. Longman Group Limited, Essex, England. Govt. of Pakistan 2003-04. Pakistan Economic Survey, Finance Div. Econ. Advisor Wing, Islamabad. Govt. of Pakistan. 2003. Pakistan Energy Yearbook, Hydrocarbon Dev. Instt. of Pakistan. Ministry of Petroleum and Natural Resources, Islamabad. Govt. of Pakistan. 1992. Pakistan Metrological Department (PMD) Climatic Normals of Pakistan for 1961-1990. Computerized Addition, Pakistan Met. Deptt., Karachi. Khan, M.A. and G. Singh. 1996. Energy Inputs and Crop in Western Pakistan. Energy 21(1): 45-53 pp. Khan, M.A. 1994. Energy inputs and Crop in D.I. Khan Distt. Pakistan. Dissertation, Asian Instt. of Tech. Bangkok, Thailand. ENERCON. 1989. Tube-well Energy Audit Manual; Ministry of Planning and Dev. Govt. of Pakistan, Islamabad. Bonny, S. 1993. Is agriculture using more and more energy? A French case study. Agric. System. 43: 51-66. Khan, M.A., S. Ahmad, Z. Hussain, M. Yasin, M. Aslam and R. Majid. 2005, Efficiency of water and energy use for production of organic wheat. J. Sci. Tech. and Dev. PCST. 24(1).