Wednesday April 9 2014

A bumper harvest starts with harvesting rain water

By Andrew Ndawula Kalema

It’s raining, so you would expect farmers to give their usually costly and unreliable water sources a break and harvest the free rain water instead.

But, going by queues at community piped water stands and boreholes, fetching water remains a major activity even at the peak of the rainy season.

Ugandans would rather fetch water from a distant source than harvest rain water from roofs of their houses, other buildings and surfaces. Time and energy spent does not seem to matter.

Visitors from countries such as India, where every drop counts, wonder why Ugandans do not harness the abundant water resources for agricultural production.

Two rainy seasons
Most farmers use either surface water from lakes, rivers and streams, or groundwater from wells and boreholes, which makes up about 40 per cent of the water resources. Rain water makes up the 60 per cent.

Uganda is one of the few countries blessed with two rain seasons a year, thus the expression--rain fed agriculture. But are farmers making the most of this resource?

Unfortunately they are not. Very few farmers are aware that setting up water harvesting systems on their farms can save them a lot of money and boost their production.

According to experts, rainfall offers probably the cleanest water; a product of a natural distillation process, providing pure water for livestock. Surface runoff is the best water for plant irrigation as it carries nutrient-rich silt from eroded top soils.
A dam or pond fed by surface run off from a nearby road or slope can sustain an off-season vegetable growing project. So, why do farmers shun this God-given resource?
Same reason they have not taken advantage of solar technology. They assume it is costly and only rich farmers can afford it.

Use available resources
Of course, they are wrong. Compared to other sources, rain water is a lot cheaper. Piped water comes with a monthly bill, and you are always at the mercy of the service provider. Sinking a borehole to access ground water is costly. Sometimes, the water table is too low, the ground too hard, the water too acidic; unsuitable for farm use.

Harvesting rain water, on the other hand, is something every farmer can do, using the resources around them.

The first resource is the roof of the house where you stay. It is the dream of every farmer to have a decent house. With hard work, many farmers eventually get to realise that dream.

Some people install gutters on the roof to channel rain water into the ground.

With minimum resources, it is possible to set up a reliable rain water harvesting system on your house. Acquiring a storage tank is the hardest part, taking up between 70-90 per cent of the entire cost.

Storage tanks can range from small containers originally intended for other purposes, for example, metallic drums used for motor and cooking oil, paint, and industrial chemicals like acid.

Larger ground-level tanks can be made of sand and cement-lined wire mesh, while plastic-lined underground tanks are another option.

As the only option
Currently, there are several NGOs training communities to make tanks from locally available resources such as clay and bamboo. At the same time, there are several companies manufacturing plastic tanks of different sizes.

In semi-arid areas such as the cattle corridor, where surface water might not be easily available, and groundwater inaccessible because the water table is too low or the ground is too hard, or the water itself is too acidic, rain water is the only option.

People who make the most money in the cattle corridor are not the herdsmen with thousands of animals, but entrepreneurs who invest in rain water harvesting structures such as dams.

During rainy seasons, the dams fill up and during dry seasons, cattle owners pay the dam owners money for their animals to drink from there.

Without a reliable source of water, you might as well forget about farming. Ideally, every farmer should have at least three water sources to ensure a steady supply.

Different water sources
The first one should consist of a system of gutters on all structures, collecting rain water and directing it into a storage tank. The water from here should be for domestic use and for animals.

The second source should be a pond or dam in a low lying area where rain water flows or accumulates. The pond or dam can be built small initially and enlarged until it is big to supply water throughout the year.

The third source should be a well or borehole to access ground water. This can be hand dug or machine drilled, depending on how high or low the water table is and how hard the ground is. This source should serve as a backup for the other two.

It is worrying that many farmers depend on boreholes for all their water needs. This puts a lot of pressure on ground water reservoirs which take long to recharge or recover. Farmers in Uganda need to realise that a bumper harvest starts with harvesting rain water.

The author is a farming journalist and a consultant.