PASTURE IMPROVEMENT

Hawke's Bay Tribune, Volume XXIII, Issue 275, 3 November 1933, Page 13

PASTURE IMPROVEMENT

ARTLFIOIAL MANURES. A SCOTTISH TESTIMONY. In a short survey of the effect of artificial fertilisers on grass land aud farm crops, Mr. James Grant, B.So. Agr., of Aberdeen, states that the basis of all improvement of pastures is phosphatic manuring. He points out that basis slag has proved to be better and cheaper than superphosphate, but today it is often cheaper to use a finelyground mineral phosphate, although it is not so available and, therefore, not so rapid in its action. Superphosphate gives equally as good results as slag, provided that tho soil contains sufficient lime, .but it is more valuable for meadow land, as tho phosphate it contains is water-soluble, and therefore immediately available. The beneficial effect of phosphates depends on tho stimulus imparted by them to leguminous plants in the pasture. The proportion of these is greatly increased by an application of slag, as is also the proportion of good grasses, so that the nutritive value of the herbage is increased and weeds tend to be smothered out. Potassic manures in general promote the growth, of clovers and all leguminous plants, especially on the lighter classes of soil, as these are more likely to be deficient, in potash. They adso assist pasture plants in dry periods and increase the nutritive value of the herbage. When applied with slag a greater live weight increase is made by the animals grazing on the pasture, but it is doubtful whether that greater increase can be obtained at a profit. In some eases it may, but in the majority of cases potash is not required on land that is grazed. It has been found at Rothamsted, however, that the grasses on the no-potash plots failed to a large extent to develop seed, the heads remaining soft and barren, this being probably due to lack of sufficient carbohydrates. It would, therefore, appear that, hay crops grown for seed would benefit, from an application of potash. Nitrogenous manures result in increased production of leafy herbage, and therefore an increased total yield. The percentage of protein is also increased, while the percentage of fibre is correspondingly decreased. The grasses are apt to become stocky, however, so that the pasture should be kept closely grazed, as the herbage is of much greater feeding value when in the young stage. The grasses respond more to the manure than do the clovers, with the result that excessive nitrogenous manuring usually results in clovers being smothered out. One of the most important effects of nitrogen on grass land is that it extends the grazing season at both ends. A little expenditure on nitrogenous manures may r erefore bring about"® consWer-

able saving in the foodstuffs bill if they are applied at the correct times and in the correct amounts. ROTATIONAL SYSTEM. By following the rotational or sectional system of grazing, Mr. Grant states, the farmer can take full advantage of the effects of artificial fertilisers on grass land. He shows that where this system is followed the basal manuring is phosphatic —preferably in the form of basic slag—applied in autumn, and theu the pasture is given top-dressings of available nitrogen at ! intervals throughout the grazing season. The stock are grazed for a fixed period on one field, after which they are moved on to another, each field being allowed about three weeks to recuperate after the animals are removed before being grazed again. Research at the Rowett Institute has shown the importance of the mineral content of the diet of all farm animals, and has also shown that tho elements most likely to be lacking are phosphorus and calcium. This is, therefore, another reason for applying artificial fertilisers to pastures, slag agaiu being most useful, as frequent applications of it. will return to the soil all the phosphorus, eafciom and other

minerals removed by stock while grazing, and thus prevent depletion. Geneerally speaking, the application of mineral fertilisers will increase the yield, the nutritive value and the mineral content, thus enabling stock to make a bigger live weight increase or produce more milk. Mr. Grant expresses the view that with the increasing knowledge of the value of artificial manures, and with the increasing knowledge of their value there is no doubt but that they will be applied to a greater extent to grass land within the next few years. “Research work on the subject in still incomplete, but great advances have been made and are being made, and it remains only for the farmer to reap the fruits. Many are doing so at the present time, but many are still rather inclined to scoff at artificials and experiments that have beeu carried out with them, and they can quite easily do so, but not if they aim at getting maximum yields and maximum financial returns for their outlay. If these would only obtain a general knowledge of manures and thc : r effects on crops on their own particular type of sot', and app'y that knowledge, then their monetary returns would be far greater than they are at present.”