Why rain water harvesting skills, is critical in arid and semi-arid regions

With the current drought, training smallholder farmers, especially in arid and semi-arid regions on rain water harvesting skills, is critical.

According to researchers, farmers can harvest rainwater by building small planting basins and ‘half-moon’ trenches, or create stone and earth bunds or grass strips that redirect runoff towards crops – an approach called contour farming.

“Kenya’s rainwater potential is more than 350 billion cubic meters. If captured and managed, the water is enough to support 233 million people or close to four times the country’s population in 2022,” said Maimbo Malesu, a Water Scientist with the Centre for International Forestry Research and World Agroforestry Centre.

In Kenya, 80 per cent of land is classified as arid or semi-arid – much of which is being rapidly degraded.

Farmers can also minimise soil tillage, and use cover crops and mulch to limit the amount of soil and water lost through evaporation, rain splash erosion, and runoff.

They can practice water harvesting and conservation in farm ponds, sand dams, and tanks to provide a source of irrigation during dry periods.

Groundwater can be recharged using trenches and percolation pits, and organic manure can be used to improve soil fertility and structure.

These low-cost technologies manage to boost yields by capturing rainwater and keeping it within the root zone of their crops, along with other simple approaches to increase soil moisture and green water, and reduce water and soil nutrient losses.

“Efficient use of water where every drop counts will lead to improved yields, economic growth and job creation, enhanced livelihoods, social benefits and improved climate resilience,” noted Malesu.

Researchers also believe that investing in green water management practises will help curb serious food shortages that has been occasioned by climate change.

“At an estimated Sh30,000 to Sh60,000 per hectare, investing in green water management in rain fed smallholder farming is a cost-effective and sustainable way to increase productivity, with added benefits,” said Dr Catherine Muthuri, who is the centre’s Kenya Country Director. Incorporating agroforestry techniques can also help in efficient use of water for crops.

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