Address water quality concerns for sustainable irrigation development

The ongoing campaign by the Ministry of Water and Environment to establish pilot small scale irrigation systems throughout the country so as to promote their adoption at micro levels is a massive opportunity for small holders.

Micro irrigation systems are handy for small land spaces, require comparatively small capital investment, and employ already available family labour.

They are tailored for all-year round production using an already available labour, water and land resources to yield high quality products in quantities sufficient for both domestic and commercial use. This is moreover achieved without need for disruptive displacement procedures such as damming, or extensive water conveyance networks, thereby preserving ecological and social harmonies.

Even so, there are some viable concerns farmers presently have in regard to irrigation water. What type of water is suitable for irrigation? Is it tap, spring, or borehole water? Among the critical factors for irrigation in general to thrive are water quality, quantity and access. In micro irrigation, however, water quality is a fundamental factor, and the farmer’s capacity to guarantee it is one of the prerequisites for its successful adoption.

Because unlike other irrigation systems like sprinkler irrigation, micro irrigation systems apply water directly to plant roots from above or below the soil surface, and they do so in drops conveyed through emitters, tiny holes either punched or installed along water delivery pipes called drip lines.

That drop of water must be applied without clogging these small holes that convey it, thus it must be free of other solids and foreign physical matter, otherwise the farmer has to keep unblocking the pipes, which besides reducing the system lifespan, adds an unnecessary burden to his daily routine.

That drop must also be of a chemical and biological composition that satisfies both plant and soil requirements. This is because plants respond differently to the quality of water, making it imperative to test it before it is released to the garden.

It is the same with soil. Applying poor quality water can lead to soil salinity, and toxicity, and affect water infiltration rates. So the question is: What is the capacity of the rural farmer to carry out tests on his water as a requirement for a profitable micro irrigation cropping enterprise? Because for optimum crop performance, water quality parameters such as PH, electrical conductivity, Sodium, calcium, magnesium each have recommended tolerance levels, beyond which crop performance is negatively impacted.

Currently, there are only three active stations for testing water quality, NWSC laboratories, NARO Research laboratories at Kawanda, and another at Entebbe. If micro irrigation is to thrive, we need more of these facilities, devolved to several parts of the country for cost waivered access by farmers. District water offices should also be well equipped to test water and avail data to farmers.

Also, portable testing equipment should be availed at sub-county levels. Government meanwhile needs to revamp its technical planning structures and agricultural extension service model to incorporate more irrigation professionals, as lead personal in the planning and implementation of irrigation projects, at national, district and sub-county levels.

Otherwise, besides water quality assurance, nearly every other critical factor for micro irrigation development is within the immediate capacity of our rural farmers. Quantity-wise, water from deep boreholes, shallow wells, harvested rain, protected springs and tap stands is sufficient. In my district of Amuria, for example, a borehole, a reliable point source for irrigation water, is found every after 1km radius. It is not different elsewhere. Indeed, MWE rates the national deep borehole functionality throughout the country at a massive 84 per cent.
Mr Enyetu is the Iirrigation engineer at WATESO and Graduate Trainee of Uganda Institution of Professional Engineers.
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