Elita Chikwati-Agriculture News Editor

The 2025/26 rainfall season has been characterised by heavy rains.

By now, most parts of the country have received meaningful rains in terms of drinking water for livestock, pasture replenishment and crop growth and development.

The bulk of the crops, according to updates from the Ministry of Lands, Agriculture, Fisheries, Water and Rural Development, are in good condition.

However, some farmers are beginning to panic as the rains are now causing leaching.

Leaching is the downward movement of vital water-soluble macro and micronutrients from the soil, causing potential deficiencies in crops. It is more common in sandy soils and areas of heavy rainfall.

Rains have also caused waterlogging in some areas as a result of persistent downpours across the country. Poor field drainage is affecting crop health in certain regions.

Signs of nutrient leaching are evident in some parts of the country, with maize and tobacco being the most affected.

In maize, loss of nutrients such as nitrogen is now evident. This is seen through yellowing (chlorosis) of older leaves (starting at the tips), stunted growth, weak stems and poor ear/kernel development.

Some farmers may end up reaping immature leaves that cure green and have poor quality.

Experts urge farmers to take corrective measures to ensure they obtain a high-quality leaf at the end.

For nitrogen leaching and yellowing of leaves, farmers can apply top-dressing fertilisers, or calcium ammonium nitrate once soils begin draining.

Farmers have been urged to apply top-dressing fertilisers in stages and to time applications during breaks in rainfall to reduce the effects of leaching.

The Ministry of Lands, Agriculture, Fisheries, Water and Rural Development, in a recent advisory, said heavy rains pose a risk of fertiliser leaching.

“Farmers are warned to adopt split fertiliser application to mitigate this. Applying fertiliser in stages and timing application during breaks in rainfall will ensure nutrients are effectively utilised by crops and not washed beyond the root zone,” read the advisory.

ARDAS has also advised farmers to take immediate corrective action by constructing drainage systems, ridges and other water diversion channels to allow excess water to flow away from crops.

This should be done early during the winter season when land preparation is ideal.

Farmers can get ahead of leaching by preparing their fields during the dry season when soils are easier to work with. They can also improve soil structure.

Adding organic matter such as compost, manure or crop residues helps the soil retain nutrients and water more effectively, especially in sandy soils that drain quickly.

For drainage, farmers can dig furrows, ridges and diversion channels before the rainy season to help control water flow and prevent waterlogging.

Levelling fields and creating contours or terraces on slopes can slow runoff, giving water more time to soak in without washing away nutrients.

Another important practice is the efficient application of top-dressing fertiliser. Split applications of fertiliser, applying smaller amounts at different growth stages, reduce the risk of nutrients being washed away.