Every living organism requires water for its sustainable development and survival. Unfortunately, day to day water is escalating down to scarcity. Presently, Pakistan is rated amongst the water stress countries where per capita water availability is less than 1600m3 per annum, but by the year 2035 water availability should be less than 1000m3 per annum securing its rate among the water scarce countries which is an alarming situation. In this terrible condition its solely need to increase the water productivity meaning that production of more yield per drop to feed inevitable burgeon population.
In agrarian economy of Pakistan, agriculture sector is mainstay by contributing its share of 21-23 percent to Gross Domestic Product (GDP). Agriculture utilizes 93 percent of available water supplies in 80 percent of cropped area and about 90 percent of agricultural output comes from irrigated land.
Traditionally the concept of irrigation efficiency is used for estimating the efficiency of irrigation system. Pakistan’s irrigation efficiency is hardly 50 percent due to wastage of huge volume of water in conveyance, seepage including the application losses. Climatic variability of Pakistan lies under arid to semi-arid region. The productivity per unit land area and per cubic meter of water in Pakistan is less than neighboring same climatic regions. A comparison of Pakistan’s wheat yield with USA and Indian Punjab shows 3:6:10 per unit land area similarly 5:8:10 per cubic meter of water. So the optimization of available water is best option, through adopting improved water management technologies and practices as well as improving use of other inputs. Definition of water productivity is scale dependent. For example a farmer takes water productivity as Yield/Irrigation while and IE (Irrigation Engineer) concern water productivity as Yield/Water Diverted.
Normally expressed as ‘tons per acre per cubic meter of water’ or ‘kg yield per kg water consumed’ or ‘rupees per unit volume of water’.
In Pakistan, flood irrigation is a common practice which is sufficiently inefficient and major contributor to evaporation, runoff, deep percolation and seepage losses, leading to declining of ground water. It should be mandatory to enhance water productivity by described methods such as, high efficiency irrigation systems (HEIS), lining of water courses, promoting laser land leveling and by irrigation scheduling. High efficiency irrigation system includes drip irrigation, sprinkler system, bed and furrow irrigation system or syphon tubes etc. These practices will increases in water use efficiency by 40-50 percent, yield by 34-105 percent and most often enables precise, easy and uniform nutrients application.
Similarly improvement of lining of watercourses includes the cementing and rebuilding according to engineering considerations. Without qualms it improves yield by 2-15 percent, saves irrigation time up to 28 percent, expansion in irrigated area about 21 percent, saving of labor cost in irrigation by 50 percent and prior to these decrease in conveyance losses about 39 percent.
Concept of laser land leveling is a little new, which enables even movement of water in fields. An impact assessment study carried out by Planning and Evaluation Cell of Agricultural Department during 2008 reveals its following impacts:
- Improvement in yield from 10.7 to 12-9 percent
- Increase in irrigated area 34.5 to 42.0 percent
- Saving in irrigation time from 25.1 to 32.1 percent
Reduction in farm culture able waste land by 2.10 percent
Responding to irrigation scheduling, soil water is highly variable component of soil environment in crop production. There is a huge difference between water applied and actual crop water requirement. Number of methods and devices are available to quantify the actual amount of water required by crops like tensiometers, gypsum block, neutron probes, time domain reflectometry and weather stations etc.
Its dare need to literate farmer community relating modern techniques and technologies that revolutionized the agriculture sector. Mostly farmers are ignorant and having little access to new technology. Above discussion can be concluded with the reforming of agricultural extension department acting like a bridge between technology and farmers.
Abdul Rehman . M.Sc. Irrigation & Drainage.
Muhammad Zaeem Mehdi. MSc (Hons) Entomology.
Muhammad Bilal. M.Sc. Irrigation & Drainage.
University of Agriculture, Faisalabad.