VALUE OF LIMING

New Zealand Herald, Volume LXX, Issue 21579, 25 August 1933, Page 17

VALUE OF LIMING

EFFECT ON HERBAGE IMPROVING MINERAL CONTEN ENGLISH EXPERIMENTS [nY OUR AGRICULTURAL CORRESPONDENT] LONDON, July 21 That limo deficiency in stock feeds has much to nnswer for in relation to somo of the diseases which afflict the animals of tho farm is now generally recognised. It has heen established, for example, that milk fever in dairy herds is duo to a shortage of lime in the animal's ration. Such deficiency can, in a way, he corrected by adding mineral salts to the ration, or by the provision of mineral licks. But tliero is no question that if the minerals can ho supplied in nature's way as a constituent of the herbage eaten by tho animal it is much better. In general opinion, the usefulness of applications of limo to pasture is duo almost solely to tho neutralisation of soil acidity which it effects. But an experiment carried out last year at the Harper-Adams Agricultural College proves that limo is not merely an antacid, but that applications of it can 1)0 depended upon to give a full calcium content to grass, so providing the animal with a natural diet containing tho minerals necessary for its health. Of tlirec grass fields, one was given 8 dressing of farmyard manure, a second was heavily limed, while the third was left to gr.ow as it would. Each was cut at regular intervals, and tho herbage dried, weighed and analysed.. Analysis brought out a vitally important difference, for while the lime content of the dry matter from the herbage of the manured plot was but 0.73 per cent, it was 1.7 per cent in the case of the untreated plot, and reached 3.02 per cent in the dried herbage of tho lirned area. Comparing the manured plot with that which was untreated, the dry matter of the herbage wa3 heavier by 88 per cent in the former case than in the latter. But this weight of dry matter contained only 43 per cent as much lime as that in the smaller weight of herbage from the untreated plot. Since neither plot was given lime, the conclusion is that if a heavy dressing of fertiliser is applied to a pasture, bringing about an increase in the weight of grass produced, then in proportion as the crop is heavy, it will also be deficient in calcium unless calcium is supplied in the form of lime. This seems to provide an explanation of a matter that has often puzzled stockowners —i.e., of fields that grow heavy crops of grass which look well, but on which cattle and sheep do not thrive well.

Experience shows that the best praotice in liming is the fairly frequent application of small doses, about lOcwt. to the acre every two or three years. This is generally sufficient to ensure not only freedom from acidity, but also a calcium supply for the herbage. After acidity has been corrected, the calcium still remains available in the soil as plant food.