How to harness water for dry season farm irrigation

Obeying the law of demand and supply, prices of agricultural produce in dry seasons are often much higher than produce in the rainy seasons because rain-fed agriculture allows all farmers to cultivate and harvest almost simultaneously.

For instance, tubers of yam are ridiculously cheap now, from the perspective of farmers who have invested resources into its production.

About 90 per cent of the farmers in Nigeria do harvest their yam between July and October.

Irrigation facilities enable farmers to beat the law, producing crops at odd periods when rain-fed agricultural products are not available.

Short supply of the irrigated crops always forces the prices up.

Yam, cucumber, maize and watermelon, to mention a few, are more expensive from January to April.

A wise farmer, therefore, would always produce for such periods.

And this is done by digging wells, boreholes, using dams and collection of rain water into tanks for farm irrigation in the dry season.

How to collect water

How then can farmers optimise the present rainy season to produce crops with low gestation periods and make more profit?

Either small or large scale, dry season farming requires adequate planning, and this includes rain water collection from September to November.

Small scale farmers of one or two acres of land can save cost of sinking a borehole or the cost of pumping water for farm irrigation by collecting water into underground reservoirs or plastic tanks.

Several plastic tanks of 6,000 to 10,000 litres could be purchased, put on a slightly elevated floor at the highest points on the piece of land to be used for irrigated farming.

From the elevated floor, water can flow from the tanks to the crops through drip irrigation holes.

With the help of civil engineers and welders, underground or overhead tanks can also be constructed on the farm and rain water collected into them through improvised rain collection devices.

Benefits of rain water collection

Cost of pumping water for farm irrigation with power generators adds up to the cost of production, making the operations unsustainable.

This cost is eliminated or drastically reduced when rain water is tapped and utilised.

If the collected water is inadequate, well water could be daily pumped to supply till harvest times.

And there are solar powered pumping machines that could reduce the cost of pumping water on a small farm, with little initial capital.

Profitability of the farm operations increases with cost-cutting water collection and solar pumping machines.

This increases the disposable income of farmers and their households, meeting their basic needs and improving their living standards.

Crops that can be irrigated

Because of scarcity and the need for economy of water resources, early maturing crops that could be planted in the dry season include cucumber, sweet melon, watermelon, maize and okra.

These crops appear ordinary, but when produced out of the regular season, they become money-spinning.

Drip irrigation maximises water utilization efficiency, eliminating waste, unlike sprinkler or flooding irrigation systems.

Drip system uses tiny holes on the farmland, with drips of water dropping from the calibrated outlets from the holes to the base of the crops.

This way, water is adequately utilised and good results obtained.

Mr Emmanuel Chukwuemeka, an irrigation specialist with Dizengoff Nigeria, said drip irrigation system gives the farmer utmost conservation and judicious utilisation of water in growing crops.

Chukwuemeka added that an outlet or unit in a drip system would dispense one litre of water in one hour, implying that 5,000 plants would consume about 5,000 litres of water in one hour.

One hour of irrigation is enough for the plants in a day, which could be done 30 minutes in the morning and 30 minutes in the evening.

Considering the volume of water needed, early maturing varieties of the said crops are indispensable.

Professor Samuel Olakojo, a maize breeder at the Institute of Agricultural Research and Training (IAR&T), Ibadan, said a variety of maize with 35 to 40 days of maturity is wise, saying people would get returns on their investment, especially in the off-season production.

Cucumbers start fruit yielding around six weeks, making it one of the most suitable crops in this context.

Improved and early maturing varieties of watermelons and sweet melons mature between 65 and 75 days, especially in the dry season with elongated sunshine, making them ideal for dry season small scale irrigation farming.

Economics of water collection

On one plot of land, about 3,000 stands of maize could be planted and reach maturity in 60 to 65 days.

Because fresh maize is always scarce and therefore expensive in dry seasons, farmers can sell a cob at the rate of N40 to retailers or directly to consumers.

3000 cobs of maize sold each at N40 would give the farmer about N120,000, provided he uses a good variety and observes recommended plant spacing.

This could be planted twice or three times before the rainy season sets in, and increasing the number of plots cultivated could mean more income from the farming activities.

About 180,000 litres of water would be needed for 3000 stands of maize for 60 days, and if stored rain water is not adequate, the farmer can supplement with well or borehole water.