Critical to have proper in-field drainage systems, say experts

Ashton Mutyavaviri

WHILE there is a general belief that seasons associated with the El Nino weather do not have much rain, there is still room for excessive rains and flash floods that require farmers to prepare proper drainage systems in their fields to save crops from water logging and leaching, experts have warned.

Zimbabwe Farmers Union (ZFU) secretary general Mr Paul Zakariya recently told this publication that there was need for farmers to make proper drainage systems to prevent water logging in their fields.

Mr Zakariya urged farmers to practise rainwater harvesting and conservation, make proper drainage systems and standard contours to divert water and save crops from leaching and water logging.

“El Nino does not mean there is no rain. There can be excessive rains in a space of a week, which can cause flash floods in many fields, hence the need for farmers to create drainage channels that allow water to flow out of their fields and prevent leaching and water logging.

Incessant rains or abnormally high amounts of rain can leach nutrients, especially nitrogen from the soil. Nitrogen added to the soil in the form of granular fertiliser is especially vulnerable to leaching, said Mr Zakariya.

Agricultural experts estimate that 80 percent of arable land in Africa has low soil fertility and suffers from physical soil degradation as a result of massive nutrient loss caused by unsustainable soil management practices.

Nitrogen is responsible for crop growth and yields obtained in agricultural production.

It is also the most limiting nutrient to plant growth on smallholder farms in Africa due to its susceptibility to losses resulting from leaching and run-off or erosion, among other factors.

Meanwhile, Zimbabwe Commercial Farmers Union (ZCFU) president Dr Shadreck Makombe also concurred urging farmers who planted their crops in low lying areas, wetlands and river banks to make efforts and divert water from their fields to save their crops.

“The incessant rains may result in leaching and my advice to farmers is for them to dig trenches and contour ridges. The ridges will divert the water from the fields although it can still be harvested for future use,” Dr Makombe said.

To reduce the impact of late onset of rains, mid-season dry spells and early season termination, there is need to strengthen efforts to promote rainwater harvesting and its efficient use at both household and community levels.

The Agricultural and Rural Development Advisory Services (ARDAS) said effective use and management of groundwater and increasing investment in water storage infrastructure such as dams to retain the reduced precipitation levels was vital to improve crop and livestock production.

ARDAS encouraged farmers to construct standard contours in-field to facilitate appropriate infiltration and drainage.

“Dead level contours and infiltration pits direct run-off into the soil to where it recharges the water table,” ARDAS explained.