CLAY-BASED irrigation could reduce water use by more than half in semi-arid Botswana

DIVAGRI researchers from Botswana University of Agriculture and Natural Resources (BUAN) are experimenting with Self-regulating, Low Energy, Clay-based Irrigation (SLECI) systems on maize to test if it is more efficient at saving water than standard drip irrigation systems.

The SLECI system uses the actual suction force of the soil for the regulation of the system’s water release. The water is kept in the irrigation pipes that are connected to water tanks on a platform. The clay tubes at the end of the irrigation pipes remain damp and only release more water when there is a higher suction tension in the soil.

Many small farmers in Botswana struggle with access to sufficient water for their crops. “We predict that using SLECI as an irrigation system could lead to about 60- 80% water savings,” says Prof Khumoetsile Mmolawa from BUAN’s Department of Agricultural and Biosystems Engineering (ABE). He specializes in irrigation engineering.

Moreover, because the SLECI pipes do not need to be switched on but rely on the suction force of the soil, small farmers don’t need to regularly check their irrigation.

“If this works, small farmers could also significantly reduce the amount of time they spend being in the field,” says Prof Mmolawa.

The Buan research ream is currently manually and remotely collecting data about the soil water dynamics under the SLECI system in comparison with  Conventional Drip Irrigation.

Above: Mr Thomas Koetelas from IPT connects the SLECI tubes underground in a maize field at BUAN experimental farm in Botswana.