NITROGEN AND GRASS

Sun (Auckland), Volume 1, Issue 21, 16 April 1927, Page 18 (Supplement)

NITROGEN AND GRASS

INTERESTING EXPERIMENTS SOME REMARKABLE RESULTS It is certainly only within recent years that science has been applied extensively to agricultural and pastoral problems, but during that time discoveries of such paramount importance to the farmer have been made that he is justified in .looking forward to the possibility dr doubling his output and largely increasing his profit in the near future. Experiments designed to estimate the nutritive value of pasture grasses conducted recently at Cambridge University, resulted in the important discovery that short grass contained immensely more nourishment than long grass, and, in fact, rivalled concentrates in food value. Since then the results of extensive experiments conducted in Britain, and also in Germany. have been published, which give some conception of the immense scope for greater production by the use of artificial fertilisers —more esspecially nitrogen. SCIENCE IN FARMING

The British campaign for the greater use of science in farming was begun by Dr. (now Sir) William Somerville at his famous experimental farm of Cockle Park. His "manuring of mutton" demonstrations are known to every farmer in Britain as well as, probably, to many in the Dominions, as is, also, the triumphant success of his ideas when put to practical test on “Poverty Bottom" farm, in Sussex. The then established theory was—phosphates (originally basic slag) stimulate white clover; the clover introduces nitrogen from the air; nitrogen. in its turn, stimulates the growth of nutritious grasses. It is to be observed that in the end nitrogen “did the trick."’ ADDITION OF NITROGEN Why then. not apply nitrogen directly? “Oh." said Sir William Somerville, “we have proved that if you apply nitrogen (sulphate of ammonia) you ruin the soil; you get a growth .'f matted bottom grasses.” Since the Cambridge experiments, however, experimenters are beginning to learn that, provided the pasture is grazed close enough—never allowed to get away—the result is entirely different By adding nitrogen as well as phosphates no mat forms, and we get a continuous supply of rich grass and Practical graziers are agreed that pasture improves by close grazing, the scientific reason being that each plant receives a maximum of sunlight and air—none are smothered. The nourishment which these plants draw from sources apart from the soil is converted by the grazing animals into meat. wool. etc., and the residue which is returned to the land as manure and from the decay of plant, root, and foliage, is much greater than that >hicb the plant extracts from the soil.

The higher grass grows, excluding thu sunlight from its lower leaves and stems —the nearer it approaches the flowering stage—the less its feeding value, as proved by analysis and feeding tests. It follows that animals fed on short grass return more valuable manure to the land than those grazed on rank pasture. In the August number of the Journal of the British Minister of Agriculture there appeared an article by a practical member of the Ministry’s staff who visited Hohenheim, in Germany, where, for a number of years, Dr. Warm bold has been experimenting with the manuring of grasses. He has found that, provided adequate amounts of phosphates and potash are also given quite unheard of amounts of nitrogen can be applied profitably. But a regular system of grazing is a necesssary accompaniment, involving rotational grazing and spelling. The figures given in the Journal article •ire remarkable. Shortly, it is possible to maintain two or more beasts an acre without concentrates. IMPORTANCE OF SUBDIVISIONS In practical application of the principle it is. essential to have the land well subdivided into small paddocks w'ith either temporary or permanent fencing to facilitate the practice of the rotational system—the alternate grazing resting and manuring—which the method requires. Again, means have to be taken to prevent he land becoming foul from accumulated droppings. Another practical consideration is this: The growth of grass is not regular; it is more luxuriant in the early pajrt of the season, and to combat this it is necessary either to carry more stock during this period, which would mean disposing of some or being overstocked later, or using a part of the spring growth for hay or ensilage. This grass —according to the result of the experiments—must be cut when short. . . Not the least of the benefits claimed is that the grazing season is lengthened by a month at both ends. Stock prices are, of course, correlated with the supply of natural “feed," hence the farmer who can provide abundant grass for stock before and after other graziers have thei:*' llush of growth is in an exceptional position to buy stock at the best figures. ABUNDANT OPPORTUNITY It may well be that the German system will require modification in detail in order to meet New Zealand conditions, but the main fact now established, viz., that heavy nitrogenous manuring is not necessarily injurious —and, in fact, is highly beneficial when properly done —to grass and clovers has been established beyond question. Here in New Zealand we have abundant opportunity of using our wonderful water power for cheaply extracting nitrogen from the air, which placed on the market at a reasonable price, would make an immense and immediate improvement in our primary production. At the present time much is being said regarding deteriorated and unprofitable grazing lands and the ever-increasing cost of cultivating arable lands. This is, therefore, an opportune time for the development of new methods of grazing and manuring, which may well make much of this "useless” land highly re-

productive. With the possibility of immensely increased output through the application of this and other findings of science to agriculture and grazing, the future looks a little less dark than some have prophesied.