High efficiency irrigation

Irrigated farming occupies a significant place in the country’s economy which is primarily agro-based. Of the total cultivated area of 23 million hectares, about 18 million hectares are irrigated. Important sources of irrigation include surface water, rainfall and underground water. Surface water, however, is largely used to irrigate crops.

Our irrigation system is one of the largest in the world that comprises reservoirs, barrages, inter-link canals, irrigation canals and major and minor water courses. To add to this, groundwater pumped through tube-wells constitute important source of irrigation.

Nevertheless, conveyance, distributive and irrigation efficiency of the canal irrigation system is extremely low due to huge conveyance losses from main canals and their branches, from main watercourses, from farmers’ watercourses and from irrigation fields through evaporation, seepage, percolation and overflow due to unlined canals, poor designed and maintained watercourses, defective irrigation practices, inequity in water distribution and lack of precision land level ing. As a result, crop yields are 50-80 per cent below their potential, contributing to plausible gap between actual and potential yields of arable crops.

This necessitates improving irrigation efficiency of the existing system so as to use available water resources effectively and to prevent wastage of land and water resources. On the one hand, a major project of construction, repair and rehabilitation of barrages, head works and re-modeling of canals, regular desilting of canals, distributa ries and minors, redesigning and improvement of watercourses, post-improvement care by community participation approach and precision land leveling through laser technology needs to be implemented, while on the other hand, the farmers are re quired to adopt recommended methods of irrigation.

Additional area could be brought under cultivation by plugging water losses. For instance, many acres have been brought under cultivation due to availability of additional water in Multan, Bahawalpur, Rahim Yar Khan, Rajanpur and other backward areas of Punjab due to rehabilitation of Taunsa Barrage which is playing a significant role in promotion of agriculture as well as socio-economic condition of the farmers. Likewise, abundant water has become available for crop cultivation in Bhakar, Layya, Khushab, Muzaffargarh and other areas owing to remodeling of the Thal Canal.

Construction of small dams to enhance water storage capacity for agriculture is crucial in the backdrop of lack of national consensus on construction of large dams. Small dams constructed in Rawalpindi, Jhelum, Chakwal and other arid areas are greatly helping in storage of water for agriculture purposes.

The farming community needs to shift from traditional methods of irrigation to modern methods such as drip irrigation, sprinkler irrigation etc. Drip irrigation is an effective technique to improve irrigation efficiency, saving water and protecting land form water logging and salinity. Moreover, this system is of great importance in arid and semi-arid regions such as Balochistan.

Sprinkler irrigation is another technique to utilise water equivalent to the water requirement of a crop and application of excess of water which may cause deep percolation and water logging could be avoided. Thus, this system considerably increases irrigation efficiency.

Lack of precision land leveling has been contributing to application losses up to 50 per cent, uneven distribution of irrigation water, leaching of nutrients, water logging and salinity, loss of cultivated land due to excessive bunds, trouble in cultural practices and lower yield of crops.

Realising the importance of land leveling, the Punjab government has launched a programme of providing the farming community laser sets in irrigated areas for development of irrigated agriculture which is the hub of farming activities. It is estimated that this programme would help in curtailing 50 per cent application water losses and increase in cultivated area.

At the farm level, conservation practices such as zero-tillage sowing of wheat in rice-wheat cropping system could increase water use efficiency by 20 per cent, decrease cultivation cost of wheat by about 82 per cent, reduce energy consumption by 81 per cent and increase yield by 15 per cent.

Likewise, suitable sowing method also helps improving irrigation effi ciency. For instance, bed-furrow sowing of wheat and cotton increase irrigation efficiency up to 30 per cent.

Moreover, appropriate cropping pattern could have considerable effect on water saving. For instance, spring planted sugarcane crop requires 64-80 acre-inch of water per acre, while autumn cane crop requires 80-100 acreinch of water per acre. Thus a crop water requirement is an important yardstick that could be used while selecting a crop in a particular region.

Importantly, the farming community needs to optimise plant population, use recommended irrigation methods, ensure timely sowing of crop, manage weeds free fields, adopt effective plant protection measures, optimal tillage during fallowing, use organic manures and where possible use mulches.

Problems like water theft, conflicts on the issues of water distribution, cutting of trees from canal banks and many other pilfering activities are prevailing unabated.

Therefore, irrigation strategy encompassing appropriate measures for checking water theft from water courses and canals would directly benefit the farmers located at the tail ends. Socio-economic uplift of the farming community in irrigated tract is greatly associated with steady supply of irrigation water essential for increasing farm productivity.