Mulching is the application of a layer of material over the surface of the ground. It reduces evaporation of moisture from the soil by insulation. If you examine the soil underneath a flat stone, you will find that it is both cooler and damper than the surrounding exposed soil. A layer of mulch acts similarly. Mulching protects the soil from extremes of temperature, protecting it from hot summer sun and trapping warmth in the soil in winter. Mulch should be applied whenever possible, except in early spring when it may prevent the soil from warming up.

Mulching also reduces the number of weeds by preventing germination. Any weeds that manage to grow through mulch can easily be uprooted and added to the mulch.

Mulching around permanent crops such as fruit trees will prevent competition from grass for moisture and nutrients.

Mulching with a thick layer of straw or veld grass provides a surface that protects fruit of various crops, such as tomatoes and strawberries.

Mulching with compost will improve the nutrient level of the soil as it is decomposed by earthworms and other organisms. Even coarse mulches will gradually break down and improve humus levels.

A layer of mulch will protect the soil from compaction by heavy rain by breaking the size of the droplets. Mulching will also reduce or prevent erosion.

Many different materials can be used for mulching and you should learn to identify useful materials in your area. If you are near a grinding mill for example, the maize cobs can be used to mulch permanent crops. Stones can also be used where organic material is scarce. Any organic material, leaves, straw, hay, weeds, crop residues – can be used.

Polythene is sometimes recommended for mulching, but as it is impervious to rain, it can result in moisture problems. Further more, as an inorganic substance, it will not breakdown, so it can cause pollution problems.

Termites will usually consume organic mulch, but will generally not cause any damage to growing plants. If the mulch is not maintained, they may attack living plants. It is advisable also to keep a small gap between the stem of a plant and the mulch.

Mulching is one of the most important routes to successful gardening, whether for pleasure or profit.

• Fewer trips to the borehole or well.
1. The moisture content of your garden is maintained at a high and balanced level, thus ensuring a health soil ecosystem.
2. Less water is wasted through evaporation into the atmosphere. So you also conserve water.
• Less labour in tending the garden /orchard.
1. Weed pests are reduced to a minimum by a mulch, so less time is used in pest control.
2. The need for manure is reduced, as nutrients are recycled back into the soil
• Increased crop yields, better health and profits.
1. Harvest from the garden and orchard will improve, thus attracting income for a market gardening venture.
2. More people can benefit from the produce, so nutrient consumption per head is improved.

 

REMEMBER

1. Successful mulching is subject to proper timing. The early spring months (around August) are not very good for mulching, as it may keep the soil too cool for micro-organisms (decomposers).
2. Plastic is not environmentally friendly. Because it does not decompose easily (non-biodegradable), it is therefore discouraged where better materials are available.
3. ‘Inorganic’ mulches, such as stones or old plastic bags, old bits of carpet, even old tins, still conserve water and keep the soil fertile, however they will NOT improve the texture of the soil and are extra work because they must be lifted whenever you water, or the water will not sink into the ground.

 

HOW TO MULCH

1. Dig/cultivate around the plant/tree/bush.
2. Enrich the soil with manure from livestock.
3. Cover the soil with about 10cm of mulch.

 

 

 

Compiled by:

J. Z. Nyilika

Community Development Officer

Painted Dog Conservation &

Wildlife and Environment Zimbabwe