THE GREAT IMPORTANCE OF LIME IN AGRICULTURE

Shannon News, 7 December 1926, Page 2

THE GREAT IMPORTANCE OF LIME IN AGRICULTURE

HOW TO RECOGNISE LIME DEFICIENCY. By certain conditions of herbage, the practical farmer should bo able to recognise the existence of limo deficiency. " Almost .infallible sign* are the occurrence in plenty of spuirey, sorrel, corn-marigold, bent grass, bracken, and gorsc. The inability to grow clover crops, lucerne, and barley may also be taken as evidence of lime deficiency. There are. other crops, however, which appear to tolerate some degree of lime deficiency, the two chief being oats and rye. But lime is very necessary to the growth of lucerne, and healthy crops of legumes generally; barley, maize and root crops cannot usually be grown successfully o,ii sour land. 'On the other hand excessive liming may cause economic harm to all crops; and for this reason it is desirable to obtain a fairly accurate idea of the lime reuirement of soils. Thus the question often arises: what percentage of lime or limestone should the soil possess for economic agricultural practice. • This is a difficult question to answer, since Ihere. are other factois in the chemical composition of the soil which effect the value of the lime content. The most important of these is the percentage of magnesia present. Assuming that in the soil there is no excess of magnesia over lime, .75 per cent .of lime in a soil maybe regarded. as ample. liime Essential in Agriculture.

Of all soil constituents, no others are so seriously liable to loss than is lime. As an essential plant food it is removed from the soil by crops, although such loss is ' not a very marked one. But the loss of llmu by actual drainage is very considerable, especially in light soils. The continuous use of sulphate or arhonia is also an important factoiin depleting the lime content or soils and the continuous use .or superphosphate tends to increase soil acidity. , ..'•.•' Lime is essential to economic agriculture, but some crops are more dependent on a plentiful supply of lime than others. Potatoes, for instance, are practically independent ol , lime, and excessive lime tends to produce a poor quality crop. Functions of liinie in Soil. The various functions of lime In the soil may be briefly summarised thus:— (1). Lime supplies the food constituent essential to, plants, and —by way of stock —to animals. Good crops and healthy live stock cannot be long produced on land suffering from, marked lime deficiency. (2). Lime keeps soil in a sweet condition. i (S). Lime acts chemically upon vegetable matter and sets free nitrogen for use of plants. (4). Lime serves to break up insoluble potash and to set free potash in -a form which can be readily used by plants. For this purpose it is essentially useful in clay soils. (F>>. Lime acts on unavailable potash of iron and alumina in the soil, and converts it into phosphates of lime, which are available for plant nutrition. , t (6). Lime .in soil insures the best utilisation of soluble acid manures, such as superphosphates. It also prevents any detrimental effect, from the acid nature of these manures. ' (7). Lime has a beneficial effect on the physical nature of soil, especially in clays, where its use gradually renders the soil more amenable to cultivation. (S). By the use of lime, certain diseases, such as "finger and toe," which flourish in sour soils, are prevented.