LIME AND ITS FORMS.

King Country Chronicle, Volume VI, Issue 425, 23 December 1911, Page 7

LIME AND ITS FORMS.

Line is found in the ashes of all plants, and must, therefore, be regarded as an essential constituent of their substance, although the lime requirements of different plants vary considerably. It is most prdnounced with clover, lucerne, peas, beans, and vetches, while it is least important with cereals. Thus a crop uf wheat extracts rforn the soil 161b lime per acrs, roots about twice as much, red clover 961b, hay 501b, and lucerne 150bl; b-.it the value of lime as plant food is small compared with its beneficial action in other ways. The chemical action of lime on soils is very striking. It decomposes the dormant mineral plant food, and thus renders available for the plant phosphoric acid and potash which otherwise would remain insert in the soil. It acts on the vegetable organic matter in the soil and converts part of it into nitrogn compounds available for the plant. It is very effective in sweetening sour land, and thus renders more free from disease crops grown on such soil; it is especially improves the quality of herbage. It enables crops to make the best use of superphosphate, dissolved bone, sulphate of ammonia, and other soluble manufactured chemical manures, peventing any excess of acid in such manurres from exercising an injurious effect on the crop. The physical action of lime on soils is no less important than its chemical action. As Mr Hall, director of Rothamstead Experimental Station,remarks in Fertilisers and Manures, it is "difficult to exaggerate the improvement that lime effects in the dryness and workability of strong soils, which in many cases would not be fit for arable cultivation had they not been so treated with lime," and on lighter soils—the sands and gravels —it exerts a good effect by forming a weak cementing agent and increasing the cohesion of the particles. "Heavy" soils become more porous, better aerated, warmer, and less difficult for the roots or the plants to penetrate. The caking to which such soils are liable in dry seasons is prevented to a great extent. The surface of the soil

is rendered more friable, and lends | itself better to tillage. "Light" j soils are rendered more compact, j although in the treatment of light | soils the application of marl or j chalKis preferable to quicklime. i The application of lime in moderate ! quantities to the soil assists the bene- ; ficia processes always going on in fertile soils, due to the activity of bacteria, thus helping the conversion of ammonia and other compounds j containing nitrogen derived from the ; atmosphere. j