~ COMPOST AND MANURE ~

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 For a good compost heap, the layers of refuse should 150-200 mm thick and trodden down moderately firmly. If the material is dry, add water before applying the activator. Tough material, such as cabbage stumps, should be chopped into small pieces and then mixed with grass mowings or similar material to help to build up heat. Healthy soft growth, nut not woody material can be included. Woody material should be burnt, and the ashes collected to be stored dry for use as fertiliser. Do not burn any soft material unless it harbours soil-borne diseases, as this wastes potential compost.

If a proprietary activator is used, apply it as recommended by the manufacturer. If unprocessed animal or bird manure is used, sprinkle a layer 20- 30 mm thick on top of every 150 mm thickness of compacted compost material. If dried and pulverised sheep or poultry manure, dried blood or fishmeal is used, add it to the heap at the rate of about 90 g per 2 sq. m of each new 150 mm layer. If the garden soil is known to be acid, as well as using an activator sprinkle ground limestone, at the rate of 120 g per 2 sq. m over every alternate layer of compost material.

Build up the heap gradually, as vegetable waste becomes available. Water it weekly during hot, dry weather; during periods of intermittent rain keep the top of the heap slightly concave to catch rainwater. During prolonged wet weather cover with polythene. When the heap reaches a height of, say, 1,2-2 m, put a 150 mm layer of soil on the top to help keep in the heat.

When very soft materials are used, such as lawn mowings and cabbage leaves, provide a ventilation shaft by driving a post 75-100 mm thick into the ground in the centre of the bin or pit. Pile the vegetable waste around it layer by layer and activate in the normal way. When the heap reaches the required height pull out the post, leaving an airshaft through the middle. Alternatively, for larger heaps, use a double roll of wire netting about 300 mm in diameter in place of the post and leave it in the heap.

Some gardeners believe that the compost heap should be turned at the end of three months; but the heap rots satisfactorily without attention. It will probably be ready for use after six months, though it need not be used for several years if it is covered with polythene sheeting.

When the compost is ready for use, it should look like light, crumbly peat. It should be dark brown or black, free from any objectionable odour and show no traces of the original materials. About 85 per cent of it should pass through a 20 mm sifting screen.

When it is properly made, compost can be as valuable as manure, because as well as containing plant foods it is alive with millions of microorganisms. It will also contain most of the small quantities of lesser-known minerals, known as trace elements, which all plants require.

Two other methods are sometimes used, particularly in small gardens. The first is as follows:

Make a bottomless box to contain a heap 1,2 x 1,2 m, and 1 m high. Such a heap will provide 2 sq. m 3 of good compost, weighing a ton. Bolt or screw three sides of the box together, and make up the front by slipping loose boards into position as the box is filled. Where possible, make a reserve bin.

Cut all the vegetable waste into lengths of several centimetres and put it into the box with one-third or one-quarter of the same volume of manure. Incorporate a little soil at the same time. If animal manure is not available, use blood and bone or dried blood at 1-2 per cent of the dry vegetable waste.

When the box is full, make three holes vertically through the mass with an iron bar to improve the supply of air. During wet weather cover the top to keep out excessive rain. After six weeks remove the material and stack it on a convenient site where it can ripen for another six weeks. About 4 tons of compost annually can be made in one of these 1 ton boxes.

The second method is to make the bins with old boards (old railway sleepers are excellent, because they are thick and help to retain heat), wire netting or bales of straw.

Make the bins 2 x 2 m with open ends for ease of access, and intersperse the 150 mm layers of waste with fish-meal, dried sheep manure or poultry manure at 90 g per 2 sq. m. Add any available animal urine and excreta. Once a week in summer, water the heap well. When it is a metre high, plunge a long-timed digging fork into it in several places and move this backwards and forwards to provide aeration.

At the end of the six months the heap will be ready. The top 250 mm and the side may not be fully decomposed, so skim them off and put them in the reserve bin for further rotting.

If the garden soil is acid, use lime as well as fishmeal or sheep manure activator, at 180 g per cubic metre.

HOW TO USE COMPOST

Apply compost at the rate of at least a large bucketful to the square metre each year. Mix it thoroughly with the topsoil to a depth of 150-250 mm with the digging fork or rotary cultivator, or apply it as a top-dressing or mulch on the surface of the cultivated ground.

The worms will pull much of it in, greatly enriching the soil as they consume and excrete it. With the use of compost the soil will be improved and it will contain ample humus.

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It is advisable to rest the soil periodically. Ideally, one-seventh of the area used for vegetables and cut flowers should be rested each year, but usually this is possible only in large gardens.

The rested area can be sown with a green-manure or cover crop which can be dug in at the end of the season. The whole area can thus be rested and refurbished every seven years. A more intensive programme of green manuring, consisting of turning under two, three, or more successive cover crops, may be used to condition poor soil or to restore an area in preparation for a lawn or landscaping.

When crops are dug into the land in a fresh condition, the soil organisms begin to break down the green plants. In doing so they tend to exhaust the land of nitrogen, for they have to make use of a good deal of this nutrient to build their own bodies and those of their rapidly increasing progeny. Fresh green manure, therefore, normally causes a temporary reduction of the available nitrogen content of the soil.

Leguminous plants, such as the quick-growing cowpeas, tick beans and annual lupins, are exceptions. But, even with leguminous plants, undigested organic substances may remain to damage the roots of the next crop.

Because green-manure crops do not give such quick results as well-composted vegetable refuse, they are less frequently used in home gardens than by commercial growers.

The best result with green manure are obtained if:

1. The land is properly drained so that sufficient air is present.

2. The soil is adequately limed.

3. An activator is applied at the time the green crops is turned under in order to provide additional nitrogen with which the organisms can start work.

4. The soil is warm.

It is rarely possible to set aside considerable areas of a garden for lengthy periods for the growing of cover crops to turn under. Ordinarily, the gardener’s green manures must grow quickly and be able to be incorporated with the soil in a few weeks or, at most, a few months from the time of sowing.

The general procedure is to prepare the beds and then add 1 part of superphosphate to 4 parts of seed (parts by volume), mixing thoroughly. Alternatively, add 30 g of superphosphate per 2 sq. m of soil. Broadcast the seeds or sow in drills in moist soil. Turn in leguminous crops when they begin to flower, as the storage of nitrogen is greatest at this time. Other crops can be dug in when about 450-600 mm high.

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The qualities of manure vary according to the food eaten by the animals. Those fed on rich food produce a richer dung, but breeding animals and those with young, utilise more of the nutrients in their bodies.

Old manure, which has been stacked for several months, is safer to use for most purposes than fresh manure, and the nutrients are more readily available. Although farm manure is brought mainly for its humus-forming properties, it supplies a considerable amount of plant nutrients. One ton of cattle manure will give about 4,5 kg nitrogen, 0,6 kg phosphorus, and 3,6 kg potash, much of which is accessible to plants soon after application.

Make allowances for these nutrients when working out fertiliser plans. Pig manure provides slightly less than cattle manure and good horse manure about 75 per cent more.

Farm manure also usually contains quite large amounts of magnesium and calcium and all the trace elements. A good dressing of farm manure will remain active for at least three years, and probably longer. But after buying it, do not leave it in loose heaps; make a solid, compact pile, well trampled down but raised in the centre. This will reduce losses; but even with the best storage, one-third by bulk will be lost in the first three months because organisms convert some of the dry manure into gases that escape.

Manure is most beneficial when mixed in the topsoil. To give a good dressing, cover the ground with a 50-75 mm layer or about 5-7 kg per 2 sq. m,

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Poultry and pigeon manure's are at least four times as rich in nitrogen, two or three times as rich in phosphorus and about as rich in potash as cattle manure, but they provide little humus. They tend to make clay soil more sticky and acid. Poultry manure can be used fresh, but is better used after storage. It is easier to handle when mixed with half its bulk of fine, dry soil and sand, and can be used for top-dressing growing crops. Always keep it under cover to avoid loss of nutrients in the rain. Use at the rate of 1-1,5 kg per 2 sq. m, but do not place it close to the roots of growing plants since it is likely to damage them.

If poultry droppings are dried and pulverised a high-grade fertiliser will be obtained. Apply this at the rate of 120-240 g per 2 sq. m well in advance of sowing, or as a top-dressing

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