MANURES

Wairarapa Times-Age, 21 June 1940, Page 8

MANURES

VALUES IN THE GARDEN. Though the thorough cultivation of the soil by trenching, bastard trenching, and digging, as well as the important operation of draining is most essential without a supply of the suitable mineral matters usually called plant food in a suitable form we could not' expect to get satisfactory crops. The supply of organic matter which is the decayed or decaying remains of plants and animals is of the first importance, for it is on this that the plants depend mostly on their supplies in Nature. This organic matter not only plays an important part chemically, but it has also a most important part to play mechanically, for unless the mechanical condition is correct, though the soil may be rich in plant food, the plants themselves will not be healthy. In the first place, organic matter darkens the S

colour of the soil (the top layer o: black soil is well known), and thi; helps it to absorb sun heat and conse. quently to be warmer. The organic matter binds together loose sand anc gravelly soils, enabling them to retail water and in it soluble plant food. II also helps to open up stiff clay soils enabling excessive water to drain away, to assist in admitting fresh air and preparing a way for the roots of the plants to penetrate the soil. As it consists of the materials required for the building up of plant and animal tissues, these become available to the plants in a form suitable for being absorbed by the roots, and gradually as they are required for growth. One of the chief sources of organic matter is farmyard or stable manure, and this consists of the excreta of farm animals together with straw or other bedding materials. While it contains all the elements. necessary to plant nutrition its composition and the availability of its constituents depend to a large extent on the kind of animal producing it, its age, and the nature of the materials upon which it is fed. Still more depends on the way it is treated after removal from the stable.

If it is left outside exposed to the

rain, and allowed to ferment, much of the valuable materials are given off into the air or washed away into the drains or subsoil, and are consequently lost. It is estimated that 15 per cent of the available nitrogen is lost in this way, and in some cases it is much more. To get the best results from farmyard manure it should be stored under cover, and for this reason it is most desirable to use the stable manure to form a hotbed. You are not only able to use the heat generated by fermentation, but there is no loss through the liquid draining away.

Fowl manure is a very valuable fertiliser. and if the dropping boards are dusted with, gypsum and the material stored away dry, it can be used for applying as a top-dressing to growing crops or for making liquid manure. Compost heap, if properly made, is very valuable for its mechanical effect on the soil, and also for its manurial phosphate occasionally, and covered ter, including the vegetable cleanings from the kitchen, is put in an odd corner, dusted with lime and superphospate occasionally, and covered with clean soil when there is a danger of it smelling, the resultant material is suitable for digging in for both vegetables and flowers, and the rougher portion can be buried while trenching.

Leafmould is also a valuable source of organic matter, but usually too scarce to be used for any purpose but potting, rooting cuttings, and seed sowing. Every leaf should be collected and stored away in a place where it can rot down for a year. Green dressings are a very valuable source of organic matter, and really there should be no vacant ground in late summer or autumn, every foot should be sown down with blue lupin, mustard, or oats. They should be sown pretty thickly to keep down weeds 1 , and. before they flower should be cut and left to wither for a day or so before being dug or trenched in. It is found by experiment that it is not advisable- to dig in green dressings if the- ground is io be cropped immediately. The bacteria which bring about decomposition take nitrates out of the soil during the process, but when it is completed they are returned again to the soil, and are available for the growth of the crops. It is quite correct, however to dig in green dressings in the autumn if the ground is not to be cropped until the spring. Blue lupins are to be preferred to other green dressings for the garden for they root deeply, break up the sub-

soil, bring mineral matters to the surface, and they have the property of collecting a quantity of nitrogen from the air by means of bacteria which live

in nodules in the roots; this nitrogei being available for the crops when th plants decay. Lime is one of the most valuable substances we can use in the garden Though it is not really to any grea extent a plant food, it plays such ai important part in both the chemica and physical composition of the soil It is found in Nature in many forms such as chalk, marl, and limestone rock, but the most useful form foi gardening is the crushed burnt lime which is obtained in a form suitable for scattering evenly over the ground To be effective, lime should be applied frequently to the garden crops, and in small .to moderate doses, for it is quickly washed away down into the subsoil or it absorbs carbon dioxide from the air, returning to the carbonate and less soluable form. Lime has a distinct effect on the physical condition o.f soils. It breaks up stiff clays, rendering them more easy to cultivate, and it also binds together sand and loose gravels, enanbling them to retain water and soluble plant food until the plants are ready to take it up. Lime as a plant food is required by most, plants, but with the exception of I the pod vegetables it is only taken up in very small quantities. Indirectly, however, it is important from the point of view of nutrition, for by interaction with certain insoluble mineral constituents such as potash and aluminium silicates it sets free potash in. a soluble form. It also acts as a base in removing excess acidity produced by the application of superphosphate

and sulphate of ammonia, also by neu tralising the acidity caused by the de composition of excess organic matter such as peat or bush soil. Some base is required in the soi to take up the excess of nitrate: owing to the action of bacteria. Un les: the free nitrates are cleaned up, the} would accumulate until condition: would be unfavourable for the bacteria and they would cease to function Lime is also most important in controlling such weeds as sorrel and certair undesirable grasses, and it is also a fungicide, to some extent destroying the spores of such troubles as club root in turnips and other members ol the cabbage family. It is also most valuable for destroying slugs. In its caustic form when it comes into contact with their soft bodies it dissolves on their outer skin and. they soon die. Even when applied in the liquid form as lime water, which is easily made by mixing a pound of lime in a petrol tinful of water. Mix thoroughly and allow to stand overnight. In the morning the clear liquid can be puored off, and by watering mat. plants such as aubretia and mossy phlox the slugs which hide under these plants will be destroyed. It should be known that burnt lime cannot be left too long in bags, as it absorbs moisture, swells, burst the bags, generates heat, and is a menace to property. Lime should be bought in small quantities and applied in small quantifies, but often.