USE OF LIME

Wairarapa Times-Age, 23 June 1939, Page 3

USE OF LIME

LIBERATION OF PLANT FOODS. We Tully realise that lime in some form or other has uses in garden man • agement for which no adequate substitute can be found. It serves no useful purpose to saddle lime with the credit of being able to achieve more than it can do. The kind, and quantity of lime to be used, should be considered in relationship, to the individual cases concerned, and the season of application must not be treated as a matter of indifference.

The statement has been made so frequently that lime is a plant food, many people have formed the opinion that the application of lime is equivalent to a dressing of manure. It is quite true that the ash of most plants reveals a percentage of lime, but it does not follow that repeated dressings are responsible for that analytical result. The bones of our bodies contain lime, but we do not sprinkle lime over our food. Lime is the liberator of other plant foods in the soil. Many soils, particularly heavy clays, contain ample potash but it is in an inert form. A dressing of freshly burned lime applied to heavy, roughly dug clay in autumn, will liberate potash, and render it available, to plants and crops during the ensuing season of growth. One pound to each square yard is sufficient for one such dressing.

In addition to the chemical action, the lime will have an important physical effect on the closely compressed clods of earth. During the winter, the clods will become loosened so that they will crumble down easily in spring. Of equal value is the capability of fresh burned lime to correct acidity of soils which have become soured by prolonged manuring and burying of decaying vegetable matter. Its action on the acids of rank rotting vegetation is to liberate ammonia, encouring the formation of nitrates. This will be beneficial to those dark, soured soils of old gardens. It must be remembered that if one repeatedly dresses such soil with lime, the nitrates will eventually be exhausted and the soil impoverished. Itwill then be necessary to recommence manuring to replenish the food supplies. Then there are the loose, dry, sandy soils, which contain too little clay, and are lacking in humus. It would do more harm than good to apply caustic lime to such soils. There is. little either of potash or nitrogen to be liberated here, and the caustic properties would be devoted to burning up the vegetable matter of which there is already too little. The carbonate of lime can be used in this case with greater safety and effect. It is strange, but true, that whereas lime pulverises stubborn clay, its action on sands is to hold the tiny particles together. It is common knowledge that lime is combined with sand to make a plastic and.adhesive mortar. This binding action in sandy soils is of great benefit, because it facilitates retention of moisture and

checks evaporation. Let it be remembered. that after liming light soils, the need for manures and humus forming material will be as great as before. The benefits will, however, be greater when the lime deficiencies are rectified.