Working to improve the ground

Guidance on ways to ameliorate poor, infertile soil, with reference to chemical and organic cultivation

THERE IS NO soil in the world that is not able to produce some form of healthy food crop if it is properly understood and cared for.

Food growers should always try to grow the most suitable crops available and the best available variety of that crop, while at the same time working towards maintaining or improving the fertility of the soil they cultivate. All soils are dynamic and can be encouraged to grow food if resources are available. We must understand our soil so that so that we can take the next step to do something about it. Possible cure for infertile soil are: Acid soils can be cured with lime.

Some soils are neutral while some are acidic. We can use pH meter to detect the acidity. When using a meter an indication of acidity and alkalinity of soil and other substances is given by its pH value. pH is expressed on a scale of 0 to 14, pH7 is neutral, less than 7 is acidic and more than 7 is alkaline. In practice soils with a pH of between about 6.6 and 7.3 are often described as being ‘neutral’. But we can also observe some of the indications of the soil by eye. If a field, or part of field are too acidic it lacks of earthworms, the presence of Clubroot diseases in Brassica crops, the presence of acid tolerance weeds such as gorse, bracken, foxgloves, sorrel (sourdock), spurrey (sand weed) and Agrotis (Bent) a species of grass.

It is not disputed that fertilising of acid soil is a waste of fertiliser. Acid soil is a ‘jail’ for nitrogen and phosphorus and to get rid of of this acidic condition, we can spread calcium (in form of crushed limestone) on the soil. Alkaline soils can be cured with organic, basic fertilisers Saline soil can be cured with drainage and adequate supply of rainwater and / or irrigation. Gypsum (Calcium Sulphate) may help the recovery of saline soils. Waterlogged soils can be cured with subsoil cultivation or a good drainage system. Soils which are deficient in the major elements can be cured with organic or inorganic fertilisers, and /or leguminous crops, and grazing animals. Soils deficient in minor (trace) elements can be cured either by adding those missing elements, either to the soil or crops, or by correcting other soil properties such as the pH.

Soils with trace elements toxicities can normally be cured by correcting the imbalance in the soil of other, related nutrients. Food matters Food producers can make use of different kinds of plant and vegetable parts to improve their soil by converting them into organic matter, in compost heaps, etc. Besides saving the plants parts from waste it benefited the farm by using the compost.

Basically, organic matter plays a vital role in the physical properties of the soil. The maintenance or improvement of the soil organic matter content is essential for satisfactory long term food production. Humus, which is often found as a thin and dark layer of top soil consists of organic matter that has partially or fully decomposed, improves the properties of all types of soil. So the great bulk of compost, however, is composed of organic substances resistant to decay and similar in nature to soil humus. But in the presence of moisture, warmth and air the organic matter breaks down, it oxidises, and disappears in the form of carbon dioxide and water, leaving a small residue of minerals. This happens more rapidly in sandy soil.

Therefore soil has to be constantly replenished by adding to it any form of organic material such as manure, leaf mould, peat, seaweed, sawdust, crops residues and roots, weeds, grass etc. Making a compost heap is the answer for this. It does enrich and build topsoil. Plant materials such as discarded leaves and grass can be used to make compost. If there is enough space available, it is better to make three separate heaps sited close to each other. The first heap is currently the one being filled, the second heap is full up and busy in the ‘making’ and remains covered over with sacks, carpets etc until the first heap is filled. The third heap is the one currently being used or ‘mined’ for its humus. As the third heap is used up, any undecomposed material in it is returned to the first heap for a second decomposing cycle.

As soon as the first heap is filled, it is covered over and left for a period, the third heap should be emptied completely, and this becomes the new first heap. It is not necessary to turn over the material, nor to add artificial ‘aids’ providing that there is sufficient movement of air in at least some parts of the heap, especially at the base, which can be started off with twigs and small branches. The sides should be either slatted or open to the elements to allow air to enter. The heap is kept moist.

There are occasional layers of highly nitrogenous material such as manure and most important of all the layers are continuously built up to form a flattish horizontal top. The tendency is to put material into the centre of the heap. The centre should be reserved for mushy edible material, while grasses and other green plants are placed around the edges so as to maintain a flat top surface. Considerations There are some precautionary steps to look into. The rhizome of perennial grass weeds, and seeds of both weeds and crops can re-grow after they have been through the heap and then returned to the soil unless the compost has been made very efficiently that is hot enough so as to destroy them. Wood material, this may take a long time to break down, so it should be either cut up or smashed before being added to the heap, or put back into the next heap. Rodents often eat up some plant material from the compost heap, which should then be ratted.

Alain Charles Publishing, University House, 11-13 Lower Grosvenor Place, London, SW1W 0EX, UK
T: +44 20 7834 7676, F: +44 20 7973 0076, W: www.alaincharles.com

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