تجزیه و تحلیل اقتصادی انرژی آب و بستر بزرگ شده تولید گندم و سیستم های آبیاری معمولی: یک مطالعه موردی از یک منطقه نیمه خشک از پاکستان

The project's aim was to reduce Pakistan's water use and consequently its costs in semi-arid crop production system by increasing awareness, benchmarking water use and targeting practical solutions for optimising water use with raised bed irrigation system. The aim of this study was to compare water as well as energy used in wheat production on raised bed (RB) and conventional farming systems in Pakistan in terms of energy ratio, energy and water productivity and benefit/cost ratio of the two systems. The values of all energy inputs and output were converted to energy farm. Economic analysis was performed for each crop. The total energy requirement under RB farming on two understudy sites were 3653 kWh ha−1 and 4455 kWh ha−1, whereas 3910 kWh ha−1 and 4752 kWh ha−1 were consumed under conventional farming, i.e. 6% higher energy inputs were used on conventional farming than RB farming system. Average energy ratios of 6.3 and 4.6 were achieved under the RB and conventional farming systems, respectively. The main conclusion of the study is that in RB farming system, water, seed and fertilizer energies applied were properly utilized but in the conventional (basin) system some parts of the applied energies vanished due to many reasons.

It is a well-known fact that nothing is more important to human beings than sustainable and reliable food production. In this respect availability of water and energy is and will continue to be an important foundation in agriculture that can assure sustainable and reliable food production. However, the conservation and management of water and energy are the two key issues for researchers who need proper consideration to reduce the cost of these two commodities in such a way that the reduction in price should not result the decrease in agricultural productivity. Pakistan has experienced a golden era of water resources development during eighties with well-developed canal irrigation system. However, time to time droughts lower down the outcome which could have been achieved in the presence of this marvellous system; the country hardly could come out from eye opening shock of drought, which remained almost 3 years (1999–2002). The drought caused the over use of ground water, which required energy (the country is deficient in this commodity) (Economic Survey of Pakistan, 2008-09). Moreover, it has been noted that water availability to agriculture is expected to fall from 72% in 1995 to 62% by 2020, globally, and 87% to 73% in developing countries (Khan et al., 2006). In agrarian country like Pakistan, agriculture without water or acute shortage of water will have detrimental effects on economy, as the agriculture sector directly contributes almost one-fourth of its GDP and engages more than 40% of the total employed labour force of the country (Economic Survey of Pakistan, 2008-09). Traditionally crops, especially wheat, in Pakistan are sown on flat basins which are flooded for irrigation. Conveyance and deep percolation losses causing water shortage to crops associated with overexploitation of groundwater has prompted a search for alternative methods of water application to the crops, like raised bed (RB) technology, to meet agricultural water demand. It is believed that RB technology was first adopted for the wheat crop to save water in Mexico (Sayre and Hobbs, 2004). In Yaqui Valley of Mexico almost all farmers adopted furrow-irrigated bed planting systems for more or less all crops in the last more than 30 years. In around 1998 the technique of planting various crops, including wheat, on raised bed with irrigation water confined to furrows between the beds was imported to Pakistan from Australia under Australian Centre for International Agricultural Research (ACIAR) program. With this program studies were conducted under a national project to simulate the adaptation of raised bed in wheat, maize and cotton crops in the country. Besides water saving for the crops, this water application method was also considered as one of the causes of reduced water logging and improved seed rate of crops (Hobbs et al., 2000, OFWM, 2002, Talukder et al., 2002 and Sayre and Hobbs, 2004). Therefore, it is popular in many developed countries including Australia (Fischer et al., 2005). RB faming system was also considered as energy saving technology, due to improved methods of mechanical weeding and fertilizer application (as water along with fertilizer is delivered more efficiently to the root zone of plants in RB system than many other forms of irrigation system). RB technology also reduced lodging and consequently facilitated harvesting. Singh et al. (2009) understand that the additional benefit of the technology includes zero or reduced tillage and consequently reduction in diesel, labour and machinery cost, with improved soil structure in wheat–rice crops production system. However, almost all the authors confined their studies to see the water saving in RB system of irrigation; whereas, energy is equally an important aspect for study in the system while comparing it with tradition basin method. Moreover, these authors and many other restricted their studies to see the merit of RB. There is no doubt that RB system has been proved better system than basin in many studies but what the demerits of basin are and what the benefit we can take with those demerits, is a big question mark. A study was conducted with the aim to evaluate the performance of water and energy parameters of raised bed irrigation system for the production of wheat grown on two sites (Mardan and Swabi) of the NWFP, Pakistan having some what different soil conditions. The specific objective of the study was to examine and compare water and energy consumption in crop production operations, in raised bed irrigation system and basin irrigation system, and in result of production process, out put of the crop (grain and biological yields), and water and energy use efficiencies for the above-mentioned irrigation methods. The economic budget provided information in terms of monitory inputs and outputs on farmer side.

In this study, the energy requirements of inputs and output for RB and conventional basin production systems were examined in the North West Frontier Province of Pakistan. Data for the production of wheat were collected from two farm pairs on both production systems. The research results revealed that the energy input use on RB production system was 7% lower than that on conventional basin production system. The energy input of chemical fertilizer (52–67%) on both production systems has the biggest share in the total energy inputs. On basin, the energy input of machinery (21.55%) has the most shares in the total energy inputs in Sawabi; whereas, on Mardan this share was 12.51% of the total energy. On average, consumption of machinery energy was higher on RB than basin on the wheat production, indicating that both the systems depend mainly on fossil fuels. Furthermore, it implies that conventional farming system is very sensitive to possible changes in prices and availability of fossil fuels. Agriculture sector has increased its fossil resources consumption enormously to achieve higher yields. Therefore, any positive change in energy consumption will bring a positive revolution in the sector.