Vermiculite will boost soil fertility 

Background
Vermiculite is a naturally occurring mineral that is composed of hydrated magnesium aluminum silicate.

It is a soft, spongy material that is light in weight and has a shiny, silver-gold or bronze colour. It can be used as a soil amendment to improve the structure and water holding capacity of soil.

It is used by farmers growing various crops such as cereals, horticulture, legumes and root crops among others

It improves soil structure and drainage as well as providing insulation for young seedlings. It is also often used in seed germination mixes and as a rooting medium for cuttings.

There are a number of companies processing the mineral mainly for export and they include Quality Vermiculite Solutions Ltd, Namekara Vermiculite and phosphate mining. Available statistics indicates that the current production rate is about 54.9 million tonnes per annum. 

Geologist scientists contend that Uganda has enough amounts of Vermiculite in soils in Mbale District which can be extracted and processed locally for farmers use.

Seeds of Gold caught up with Nathan Wolukawu Wanda, a geologist consultant in the area of mining and mineral exploitation during a meeting for science journalists.

The meeting involving farmers across the country to discuss about embracing biotechnology legal framework in Uganda and he gives details of how vermiculite can be used by farmers to improve their soil nutrients.

Vermiculite use in agriculture
Wolukawu defines the mineral as naturally occurring thereby containing significant amounts of ammonium, potassium, calcium and magnesium capable of boosting plant growth and retaining water in the soil.

He contends that the reserves of high quality vermiculite is found mainly in Namekara in Manafwa District. Raw vermiculite is similar in appearance to mica, containing water molecules within its internal structure and ranges in color from black to various shades of brown to yellow.

Processing
Once it is dug with mixture of soil, it has to be sieved in or to isolate soil from the mineral to get the flakes.

When vermiculite flakes are heated rapidly to a temperature of 900 degrees centigrade or higher, the forces of molecules in water flashes into steam will expand into the particles, which are gold or bronze in colour. This expansion process is called exfoliation and the resulting lightweight material is chemically inert, fire resistant and odorless.

This is left to cool and eventually crashed into particulars which can be applied in the soil during planting. Wolukawu is currently processing vermicular in his village in Manafwa which he uses on his maize farm and he says he has realised tremendous yield improvement.

A few other individual farmers in the same area are also processing vermicular which they are selling to fellow farmers. A 50kg bag is sold at Shs70 000.

Advantages of the mineral
In a US based publication croplife about the use of vermicular in agriculture by Claudia Ringler, it is stated that the mineral has a number of unique properties that make it a useful material in agriculture.

It is particularly effective in improving soil structure and drainage in sandy or loamy soils, which can be prone to compaction and poor drainage.

Vermiculite can help to loosen compacted soil and improve root growth by providing a porous, well-draining environment for plants.

It is also effective in retaining moisture in soil, making it a useful material for watering plants in dry conditions.

However, it is important to note that vermiculite is a sterile material that does not contain any nutrients. It is not a substitute for fertilisers and should be used in conjunction with other soil amendments that provide nutrients to plants.

In heavy clay soils, vermiculite may be less effective at improving soil structure as it may not be able to loosen the soil enough to make a significant difference. In these cases, it may be more effective to use other soil amendments, such as compost or fertiliser to improve soil structure.

It also reduces soil leaching because it has high iron, potassium and magnesium content.

Soil amendment
Vermiculite can be mixed into soil to improve its structure and water-holding capacity. It can help to loosen compacted soil and improve root growth by providing a porous, well-draining environment for plants.

Seed germination 
Farmers often use it in seed germination mixes to provide a sterile, nutrient rich environment for seedlings to grow.

Rooting medium
Vermiculite can be used as a rooting medium for cuttings and as a growing medium for hydroponics.

Mulch
It can be used as a mulch to regulate soil temperature and moisture levels and to suppress weeds.

Potting mix component
Vermiculite can be mixed into potting soil to improve its structure and water holding capacity especially in nursery beds where potting is used to raise seedlings of plants.

Vermiculite is pH neutral, making it suitable for use with a wide range of plant species. Its non-toxicity makes it suitable for use in all types of gardening and farming applications.

Experiment
The expert explained that between 2001 and 2004, selected farmers in Mbale with the help of Canmin Resource Ltd set up experimental farms where they applied the mineral in their farms where they grew cabbages and tomatoes. The result showed double yield. It was proved that once it is applied in soil during planting it holds the soil well for small seeds of vegetables such as tomatoes and cabbages.

Processing
Once it is dug with mixture of soil, it has to be sieved in or to isolate soil from the mineral to get the flakes.

When vermiculite flakes are heated rapidly to a temperature of 900 degrees centigrade or higher, the forces of molecules in water flashes into steam will expand into the particles, which are gold or bronze in colour.