The benefits of mulching
11 November 2020 | Agriculture
Mulching reduces the frequency of watering gardens or crop fields and therefore reduces the cost of water used in growing crops.
Hanks Saisai, technical advisor for crops and poultry in Agribank’s Agri-Advisory Service Division, sid in countries such as Namibia where water is a scarce resource, it is always advisable for farmers to use water-conserving practices.
One common method to ensure water retention in fields or gardens is mulching.
Simply defined, mulching is the practice of covering the surface of the soil (seedbed) between growing crops or vegetables with a layer of material.
Saisai said mulching has several benefits and it is an efficient way of promoting water retention in the soil after irrigation.
Saisai said a prominent benefit of mulching is that it slows down the amount of soil moisture that is lost to evaporation.
“On very hot days, seedbeds or crop fields that have no cover on the surface of the soil between growing crops tend to suffer water losses due to evaporation, thus lowering the amount of soil moisture available to plant roots.”
When mulch is correctly placed on the surface, evaporation is reduced, thus minimising damage to vegetables due to dry soil as they approach maturity, explained Saisai.
Mulching also reduces the soil compaction caused by watering, rain and trampling when working in the garden. This improves water penetration in fields and gardens and reduces the chances of runoff, consequently preventing soil erosion.
“Mulching with a thickness of about 5 cm to 7.5 cm helps to prevent the germination and emergence of annual weeds by limiting the penetration of sunlight that is needed to stimulate the germination of most seeds,” said Saisai.
Furthermore, mulching insulates the soil to a considerable extent from extreme day and night temperatures, ensuring an ideal environment for soil micro-organisms that are vital in decomposing dead plant and animal materials to provide nutrients to the roots of crops and vegetables.
Saisai said when compost or manure is used as a mulch, it can provide a steady supply of nutrients to the roots.
Mulching also helps to reduce the greening effect of roots and tubers due to protection from prolonged exposure to sunlight.
“If you are in areas with scarce water supply or scorching day temperatures that limit your ability to successfully grow vegetables, it is recommended that you consider introducing mulching as a prudent practice to conserve soil moisture.”
Grass straws, palm leaves and black plastic sheets can be used as mulching materials.