MANAGEMENT OF GRASS LAND.

Pukekohe & Waiuku Times, Volume 4, Issue 114, 29 November 1915, Page 4

MANAGEMENT OF GRASS LAND.

(From the "New Zealand Dairyman.") The value of good grass land is well known, but it is too frequently the case that it is managed in a way which must in the end impoverish rather than improve it. It is commonly assumed that the droppings of animals feeding on the land are a sufficient return, and the manure is all applied, to til lage. Even meadows on many farms are neglected, and get little or no return for thv plant food removed. In the case ot old established pastures on good land, and where tluy are used for fattening bullocks, the process of exhaustion is very slow, and on the best feeding pastures there is often an improvement apparent, but there is no question that a certain amount of the mineral ingredient* of plant food is removed annually in the form of beef and bone, and to this extent there must be depreciation and loss of fertility. On tse other hand, it is probable that in respect of nitrogen, tncre may be oa good pasture, where there is a good varitty of herbage, with plenty of clovers and leguimnuus plants, an mcriasj in the amount present in the soils. Kain brings down a certain amount of nitric acid and ammonia in solution, and the toots of the grasses rapidly absorb it, and convert h into organi: matter, which by decay sets free the nitrogen again in an available form. The soil has also a Btiong absorbent power for ammonia, and undsr the influence of a miaute organism, awlays present in teriile soils, and which acts most strocißly under th 3 summer sun, this ammonia ia converted into nitric acid, the only torm in which plants generally can take up nitrogen. Nitric acid and its com-

pounds are exceedingly soluble, and tha eoil has no power of retaining them, and they are, therefore, reaaily wash.d out by every shower. Where, however, thj soil is occupied by the roots i>f grars, which are actively feeding under the conditions most favourable to the action of these nitrifying organism?, tha urates produced are at once taken up and fixed as organic ' matter, and become gradually available by the decay of the dead roots or leaves, or, having been passed through the animals, are returned in their excrement. Glovers and leguminous plants generally have a peculiar and most valuable power of absorbing nitrogen from the air; the air consists roughly of fur parts of nitrogen mixed with one part of oxygen. Ibis power of cbver has been long known, and on it depends the great value of clover as a preparation for wheat. So far as the most valuable and expensive ingredient of plant food—nitrogen—is concerned, therefore, a well-balanced herbage on a pasttire field will] accumulate it, and it is very ! largely to this accuulation that the great fertility ct old pasture land, when conveited into tillage, is due. We roust not, however, forget that there are other elements essential to plant life, and that muscle and bone contain certain mineral matters which are thus removed from the soil. . Foruntately the stores of these minerals in fertile soili are immense, but if no return is made there must be an exhaustive process going on. The point, however, to which these remarks are moie particulaily directid h ' the improvement of

FOOR AND MODERATE GRASS*

It is well known that the first year or two freshly-laid-down grass land, if properly laid down, usually pays well but "after wards we have usually a period from say, the third to the sixth or seventh year, during which a deterioration takes place to be followed by an improvement, slow, very Blow at first, but increasing gtadually. This deterioration is chiefly, if not entirely, due to the notion that grass land, once sown down, can be safely lett to take care of itself, and if grazed the droppings of the animals feedi g on it will be sufficient return. No one would think of managing tillage land on this principle, and those who expect to be able to make grass land in this way deserve to lose heavily, as they assuredly will in the ordinary circumstances. 1 bave already pointed cut that we bave the forces of Nature working with us; we have the ever-feeding grass roots taking up the nitric acid as formed, and fixing and storing it, and we bave tbe clovers absorbing nitrogen and converting it into organio matter, available for future years, and we have also the action if the roots in dissolving ths insoluble minerals, and storing them in an available form. What is necessary is, therefore, to assist tbe plants till the accumulation is such that their natural decay provides fur the want of the season.

ESSENTHL ELEMENTS OF PLANT FOODS,

Unless in very exceptional cases, three, or at the most four, of the fourteen essential elements of plant food are all that we need concern ourselves with. The others are present in mcst, end all fertile, soils in quantities vastly in excess of the requirements. The four substances referred to are nitrogen, phosphoric acil, potash and lime. Nitrcgen, as we have seen, is, in the case of grass land especially, being continually supplied from atmospheric sources, and there is this further consideration, that the application of nitrogenous manures favours the growth of the coarsergrowing grasses at the expense of the finer and sweeter, and of the clovers. Nitrogenous manures are, therefore, not necessary, or, in fact, economical, applications to new grass unless we want to mow. Meadowing is by no means deair, able in the early years of grass land, snd we may, therefore, diemiss nitrogenous manures from cotsideration. This is bo far fortunate that nitrogen is the most expensive of this four substances named. Phosphoric acid, as one of the mineral constituents, is derived solely from the soil. It is present in all fertile soils, but as it is frequently not present in suffkiett quantity to provide for the growth of the fullest crop trie land is capable ol producing, it ia veiy often a nicessary ingredient of manures. As the strength of a chaia depends o.i the weakest link, so lh3 produce of a crop depends on—beyond the weather and treat-

ment of the soil mechanically—the amount of that ingredient of plant food present in the relatively smallest quantity. If the soil be deficient in phosphoric acid it must be supplied as manure; there is no other possble source. There are two < other consideratiocs bearing on this point, one that a large amount of phusphoric acid is removed in milk and grass used for dry cows requires, therefore, occasional dressings, and also bones are largely composed of phosphate of lime, and it the land is used, as probably a newlaid pasture will be, for feeding young growing stock which are building up their frames and skeletons, there will be a much greater demand for phosphoric arid than if used as in the case of old feeding pastures for fattening bullocks; the other consideratiDn is that clovers, which are among the most valuable pasture plants, require a large amount of available phosphates and respond more to an application of phosphates than to almost any manure. In the early stages of new-laid grass, then, phosphoric acid in some form is a most valuable and necessary application.

SPECIAL DKESSINUS. The special dressings to be selected will, of course, depend on considerations of price, etc., and the most general ones are bones and basic slag or Thomas phosphate. This last is the cheapest and most economical and possesses a further important advantags in containing a considerable quantity ot lime. On strong land it is invaluable as a dressing for new grass, applied at the rate of . sc*t per acre in the autumn, and I can speak from experience of its value for this purpose on such land, as I have tried it in several places, and always found a most marked improvement in the quality of the herbage. On atrcng land or peaty soils it may be used without hesitation, but on the lighter class ot land, sandy soils, etc., thould advise a simple t.st. Get a ton or half a ton, if you can get a drill in your neighbourhood, and take, say, two double turns with the drill across the field, miss a strip and repeat. You will see by next autumn whether any good is likely to result. Potash, if required, is best applied in the form of kainit at the rate of lewt per acre. The fourth saostance is lime, but its influence on pasture, which is often great, is not so much in the early years as afterwards as a corrective of sourness", coarseness, etc. To sum up, then and speaking generally, the best and cheapest way of making grass is tc give it a topdresisng ia the first year of basic slag, to be repeated in the third year, and again in the sixth or seventh, and it will greatly assist if the cattle feeding on it have a small allowance ot cake: