Question: What can be done to improve the water-holding capacity of sandy soil?
The water-holding capacity of a soil is controlled by the soil texture and the organic matter content. Soils with a high percentage of silt and clay particles usually have a higher water-holding capacity than soils that have a high percentage of sand particles.
- When there is increased organic matter in a soil, the water holding capacity also increases due to the affinity of organic matter for water.
- Soil that has limited water-holding capacity, reaches saturation point much sooner than soil that has a higher water-holding capacity.
Once a soil is saturated with water, all the excess water – and some of the nutrients in the soil solution – are leached downward in the soil profile. Therefore soils that have a low water-holding capacity are more subject to leaching losses of water and nutrients.
To prevent excessive drainage of water and nutrients, sandy soils should be irrigated more frequently, but with less water applied per irrigation.
The water holding capacity of soil can be improved by adding organic material such as compost. Depending on the percentage of sand in the soil as much as 10 tons/ha to 20 tons/ha (1 kg/m²) to 2 kg/m²) should be incorporated into the soil.
It’s always a good practice to add the compost at least 3 to 4 months before planting your crop.
- This article was written by Erika van den Heever and first appeared in Farming SA.