SUPER FOR PROFIT

Hawke's Bay Tribune, Volume XXIV, Issue 11, 23 December 1933, Page 11

SUPER FOR PROFIT

BENEFITS OF TOP-DRESSING IMPROVING PASTURE ASSOCIATIONS. ADVICE TO HAWKE’S BAY FARMERS. Closer subdivision and improved methods of grazing are doing much to increase the carrying capacity of pastures but, though these practices in themselves markedly increase the amount of nutritive material produced from each acre, it must be recognised that maximum results are impossible unless the improved scheme of pasture management includes a regular top-dressing with superphosphate. It is well known that in practically every part of Hawke’s Bay the soils are deficient in available phosphates, and that the quantity and quality of pasture grown on those soils is definitely limited by the amount of phosphate present. Each gallon of milk taken from the farm removes a certain amount of ohosphate from the soil, and unless this is replaced tho time must come when the deficiency will be so marked as to make its effect apparent to even a casual observer. On many of our dairy farms this constant drain on the phosphate reserves of the soil has been going on without interruption for upwards of half a century, and where no attempt has been made to replenish those reserves the once high-grade pastures have gradually deteriorated with a corresponding decrease in carrying capacity. The higher grade plants such as clovers and rye grass cannot thrive in soils deficient in phosphate, and as the supplies of that mineral decrease these plants slowly dwindle in both numbers and vigour, and their place in the pasture is taken by lower-grade plants such as the various flat weeds and the coarser, tussocky grasses. To restore the depleted fertility of tho soil and bring the pastures back to their original productive condition regular top dressing is necessary, and the topdressing of at least portion of the pastures each year is essential, where the farmer aims to carry more dairy cows or other stock. CAN BE RECOMMENDED. In most of the higher rainfall areas top-dressing the pastures with superphosphate can be recommended without any qualification, but in certain areas where the response to the fertiliser is not so marked the question of whether it will pay to top-dress will be determined by a number of factors, some of which vary from farm to farm. The main factors, of course, will be the increase in production as a result of the top-dressing and the value of that increase as compared with the cost of bringing it about. With the price of butter fat at its present low level the number of marginal or doubtful districts is increased, but, except in isolated cases, most soils with a rainfall of more than 20 inches per annum should give a profitable response to this fertiliser. Tho subsidy paid by tho Government on superphosphate should induce many farmers who have not previously topdressed to take advantage of this subsidy and try out a practice so frequently recommended to them, and it is safe to say that in the majority of cases the results will be such that pasture top dressing will be carried out regularly. Where official trials have been carried out to determine the actual effect of the fertiliser on the productivity of the pasture some remarkable results have been obtained. Many farmers are familiar with the wonderful way in which clovers and trefoils respond to a dressing of superphosphate on most soils, innumerable instances having occurred where paddocks apparently con taining no clovers or trefoils prior to top dressing have shown as much as 50 per cent of those desirable plants in the first season after the application of the superphosphate. This capacity to bring about a favourable alteration in the proportions of the various components of the pasture is one of the most important attributes of top dressing. INCREASING CLOVERS. Tests have shown that the use of a phosphatic fertiliser is followed by an increase in the proportion of clovers or legumes in the pasture; while top dressing with a nitrogenous fertiliser, such an ammonium sulphate or nitrate of soda, has the effect of increasing the percentage of grasses. This alteration in the botanical composition of the pasture, due to regular applications of artificial fertilisers, is reflected in the chemical composition of the pasture itself. A comprehensive series of analyses of herbage from topdressed and untreated pastures gave a striking confirmation of this. In almost every case the top-dressed pasture showed marked increases in the percentage of protein, lime and phosphorus—al) important nutriments to live stock, protein being the flesh-forming portion of the food, while lime and phosphorus arc essential in bone formation. The experiment demonstrated that, in the main, the increases in these food constituents were due largely to the higher proportion of leguminous herbage in the top-dressed plots, but there was also an actual increase in the food content of grasses like rye grass and cocksfoot. The enrichment of the actual food content of the pasture by top dressing is of considerable practical importance, since it explains why stock is so much better on top-dressed pasture. It explains also why the herbage In a pasture that has been treated with super-

phosphate is so much more palatable to stock. The fact that stock prefer the treated pasture has been demonstrated on practically every farm where topdressing has been practised. In certain instances, also, the use of superphosphate on pastures has been followed by the complete disappearance of certain “deficiency” diseases such as “cripples.” The predisposing cause of such diseases is a deficiency of calcium phosphate in the pasture. On country whore these diseases exist top dressing is essential.