Mar 2, 2009

Improving water productivity in the agricultural sector

Pakistan’s economy heavily depends on the output of the agricultural sector which constitutes 20-25 per cent of GDP. Apart from providing input to a large portion of manufacturing sector, it provides direct employment to more than 40 per cent of the labour force. The agriculture sector in Pakistan is plagued with a number of issues which includes flat yields, low water productivity. And underinvestment in rural infrastructure and research and technology. Despite all its challenges, the sector has been providing sustenance to country’s economy so far.
Today, arguably the single largest threat to the agricultural sector of Pakistan is shortage of irrigation water. Pakistan is already a water stressed country with large scale degradation of resource base groundwater is now being overexploited in many areas and dependence on ground water is increasing every year. Climate change and political fallout of building large reservoirs provide no solace to the scenario.
It appears that unless some drastic measures on water productivity are taken, agriculture sector in Pakistan will go further down in its productivity. Fortunately, there have been some encouraging developments in this regard with introduction of water conservation technologies which include High Efficiency Irrigation Systems (HEIS) and PVC geomembrane for lining of delivery system and reservoirs.
HEIS refers to irrigation methodology which optimises the use of water by allowing water to drip slowly in root zone of the plant through a network of pipes, valves, and emitting devices. It is an established methodology of increasing water productivity by avoiding seepage and evaporation losses. It has been successfully demonstrated all over the globe, particularly in countries where water resources are scarce.
HEIS involves designing and installation of demand-based system in the farm to provide right quantity of water to each plant. A typical system considers crop’s water requirement, condition of soil and water, climatic conditions, and other factors like farm size etc at the design stage. The designer designs the suitable solution for the farm which includes the type of emitting device suitable for the crop. There is a wide variety of emitting devise with different discharge rate like droppers, micro tubes, bubblers, and sprinklers etc.
HEIS offers a large range of benefits at the farm level. It brings in efficiencies in virtually all farm inputs most important being the water efficiency. Flood irrigation the traditional method in use in Pakistan normally achieves 30 per cent efficiency whereas efficiency through HEIS can go as high as 95 per cent. With uniform and consistent water supply, crop or orchard does not go under stress and produces more fruit of uniform size. More yield and greater produce of high grades has direct impact on improving farmers’ economics. Payback period of a typical HEIS system, having a life of 15-20 years, ranges from one year to three years. Additionally, efficiency is also achieved in fertiliser application. PVC geomembrane on the other hand offers a seepage proof lining arrangement for the storage and delivery mechanism of water. It can be used in lining canals, watercourses, and reservoirs. PVC geomembrane offers affordable and easy to install solution for water conservation for delivery system losses. Typically, earth covered geomembrane linked reservoir costs one-third the cost of concrete reservoir with a longer life.
The challenges for HEIS industry are still tremendous. The shortage of skilled manpower, rising cost of imports, and adaptation of systems to local infrastructure are among the greatest challenges. Agriculture universities and skill development in situations need to start offering certification courses for the industry to develop the adequate local knowledge base. Local manufacturing of components also needs to be promoted to bring the overall cost of system down and increase the appeal of HEIS for an average Pakistani farmer. With introduction of modern farming practices and technologies, Pakistan’s agriculture sector can overcome current challenges and perform to its full potential, helping Pakistan achieve self sufficiency in food production and earn precious foreign exchange through exports. By Rutaba

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