TOP-DRESSING PASTURES

New Zealand Herald, Volume LX, Issue 18396, 11 May 1923, Page 10

TOP-DRESSING PASTURES

A GOOD INVESTMENT.

INTERESTING EXPERIMENTS

By T. H. PATTERSON. H.D.A. The addition of fertilising materials to

the soil to increase its productiveness is a very old practice. If we go back to the dawn of /agricultural history we find records of lime having boen applied to the soil. Pliny, particularly, mentions Us use, while the old custom of chalking and marling, which still survives in England to-day, •' dates back to the early Britons,' who used lime to promote and maintain soil fertility. Animal droppings : and vegetable matter have been more or less regarded as the natural means of returning fertility to the soil. The Chin- / ese and Egyptians have used animal man- '/ ures from early dates in history. It is recorded, however, that Hercules made no use of the cleanings of the Augean stables . One could scarcely believe that of this national hero, ' nor of his countrymen. They did not apr predate, apparently, the value of animal excreta. It was only in the first decade of the last century that phosphate of lime in bones was shown to be beneficial as a fertiliser. "' It was not until 1841, when Sir John Lawes treated mineral rock phosphates with sulphuric acid, that . the application / of artificial fertilisers to the soil really, began. Lawes used this product, known afterwards as superphosphate, in experiments at Rothamsted, England. A year - later he ■ patented his process for the manufacture of super, and this marks really the birth of the fertiliser industry, which in less, than a century has grown to enormous world-wide proportions. i Interesting as the historical aspect of manuring may be to the student of agriculture, let us come nearer home and consider j the position in New Zealand to-day as-a business proposition. . -.' Need For Manuring. [' When wo consider methods of farming in the Dominion we can readily grasp the need, for the use of manures. • fake the meat export trade, and we see that the amount of bone phosphate sent out of New Zealand annually is about 25,000 tons. This estimate is based on the assumption that there is about 10 per cent, to 12 per cent, of bone phosphate in; the ...' meat exported. - \ : Again,- we export wool, cheese, butter, dried milk, casein, seeds, grain, and other farm products, so that we are continually - draining our soils. As our farming practice develops, and more intensive methods are adopted', our farm exports will grow with a consequent decrease and more . rapid depletion of soil fertility. Let us examine how' these deficiencies are made up. *<> Phosphates the Chief Need. From data supplied by the customs' returns, Mr. A. "G. Elliott, of the Department of Agriculture, Auckland, has compiled figures covering importations of manures for the year ended March 31, 1923. : Rock phosphates and so-called guanos, which are really rock phosphates, headed the list with 59,414 tons, of which 39,547 tons, or about 60 per cent., came to Auckland. \ New Zealand imported 19,125 tons of basic slag, and of that amount ; 13,120 tons were landed at Auckland, which is , nearly 70 per cent. Of the 2958 tons ot bonedust imported, 2638 tons ' came; to Auckland.;,. In this province alone 55,305 tons of phosphates were imported ; out of a total of 81,497 tons for the year to which I have referred. Allow 'for the rock phosphates made into superphosphate, some of which would be sold outside the province, 'the greater part of the imported material would be used in North and South Auckland. ■ Our: share, therefore, ••... approaches nearly ::■ 70 : ; per cent. Farming .practice thus indicates that the need for phosphates in this part of New , Zealand is , greater than further South. It ■ is known .that the results of "soil analysis, as well a field experiments conducted by the Department of Agricuture, have long ago pointed to the increasing deficiency 'in phosphates in the ':■■ soils as we go north. Farm practice merely veri- .:■ fies this.;. ■■■: ■ ■ v Of the remaining importations which New Zealand received last year,- 4804 tons .of potash manures (of which ": Auckland landed 2896) cam e in, while 808 tons of nitrogen were received, and 673 tons of it were unloaded at Auckland. • ' If our /arming practice is- sound, and we havo reason to think it is, then the ■ above figures point unmistakably to the fact that phosphates are our chief need, and every effort should bo made by farmers to regularly supply available phosphates to the soil in reasonable amounts. Our pastures and crops are alive, and need continuous feeding. Under natural conditions they get no artificial feeding, but they' only produce natural yields, which aro far below what we expect them to produce, and what they do produce by cultivation and manuring. More" Lime ' Should be Used.: In addition to phosphates, lime has been proved to bo an outstanding deficiency in our soils, and when made up good results aro achieved. Most of tho lime- added to the soil is produced from local sources. Nature has been bounteous in this connection. Excellent deposits C of high-grade limestone and . shell are found well-dis-tributed throughout the Dominion. The time must come when greater use will be made, of the limestone resources, w.ih resulting benefit to our soils, and must tend toward the cheapening of this essential soil amendment, which to-day i 3 too dear by reason of freight charges for farmers to use it in adequate quantities. The Most Profitable Phosphate Manure. This.-always presents a problem to farmers, vendors of manures, and agricultural advisers. J. fee] certain that thousands of pounds sterling could be saved Annually if farmers used the right typo of fertiliser in the right quantity. It should be suited to; their soil and crop needs, and tho climatic conditions obtaining. , Experiments during the last few vears by the Department of Agriculture 'have shown that accepted practice has not in all cases been economical. These experiments, conducted on sound lines, with cost as the, chief aim, have been very illuminating. Take our main crop, namely grass pasture.< It is estimated that about it rvv,, acres are now sown in grass in the Dominion. Probably six millions to seven millions of this acreage is in this province. - The maintenance of this pasture in profitable condition requires the major portion of the phosphatic manures .used in the province. With a realisation of the importance of applying the riglit kind of manure, the experiments conducted by the Department of Agriculture have been designed and carried on. At Te Jvnmi. about two miles from Te Kuiti. tests havp been made, covering two years, on this'class of light fern country, which represents thousands of acres sown in grass in the King Country, Waikato, and adjoining districts. The * manures were applied at the rate of 3cwt. per acre, and the crop cut and weighed each season as hay. In drawing deductions it must be remembered that the experiments are notcomplete, but the progress results give rome interesting data. .CI spent on superphosphate: Cash return as hay, £4 5s 4d: gain, £3 5s 4d. £1 spent- on super and lime: Cash return as hay, £2 17s 3d: gain, £1 17s 3d. £1 i spent on Nauru rock phosphate: Cash return 33 hav, £1 17s 9d; train. 17s 9d. £1 spent on basic slag: Cash return as hav, £1 13s 9d; gain, 13? 9d. £1 spent on Nauru rock phosphate and lime: Cash return as h,ay, 15s 8d: loss. 4s 4d. It will be seen that from the weight of hay produced, superphosphate stands cut prominently after two years' trials. -. The yield of hay from the areas dressed with super and lime, judged by weight alone, is not so good, but from the greater amount of clover present the quality of the hay was better, while :=:-'->:;:-■;-■/-. ■■ ~,,:. ...... -r ■ .. •■;■ ;• ■■-. .- >,

the nutritive value of the grasses would be improved where the lime was used with the super. Those are important considerations which would apply as -well to the hay from. the slagged areas. The ground Nauru rock phosphate, when used with lime proved unprofitable. Judged by the alteration of the pasture from a grazing point of view, super and lime brought about the greatest improvement. f Basic 'slag, also effected a marked improvement in the colour of the pasture and the clover content. Slag, it will be seen, is not uniform in giving superior results to all other manures as a top-dressing, though many farmers think otherwise, and are therefore losing money by applying it to land such as that represented by Te Kuiti, where the soil is light and dry because it is naturally well drained. Experiments on stiff chocolate volcanic loam at Pukekohe show different results to those obtained at To Kuiti. It was found that for the expenditure of £1 on basic slag the cash return as hay was £1 Bs, giving a clear gain of Bs. £1 spent on ground Nauru rock phosphates gave a return of £1 12s, that is a gain of 12s, while £1 spent on superphosphate gave £1 6s 6d, giving a gain of 6s 6d. These prices were assessed to the fertilisers mentioned above two years ago, when the experiments were started, . and were the prices ruling at the time. Considering present-day prices for instance with the Pukekohe results, ground Nauru phosphate would represent a gain of 13s on an outlay of £1, while basic slag would return lis 7d and superphosphate 6s Bd. It will "be observed that on the moister heavier soils the less soluble .fertilisers like slag, and rock phosphates gave better returns than the water soluble superphosphate It can be readily seen that whether for hay or for improvement in the pasture, topdressing is a very profitable investment. The past two seasons have been wet, and, therefore proved favourable toward securing the results which have been obtained with the manures applied. The increase in sale of manures by Auckland firms show that during the past season a great deal of top dressing was done, and itmust have proved very remunerative to farmers who used the right types of manures. \ . Manuring young grass and top-dressing pastures with phosphatic manures and lime have an important effect on the nutrition of farm animals. Prevention is better than cure, and veterinarians to-day recognise that this ready method of. improving the feeding quality of pastures is a potent means of controlling . many diseases that affect stock. Milk production in dairy cows, especially high producers, calls for adequate supplies of easily digestible and highly nutritive feed. It is well known that apart from the increased yield of pastures brought about by top-dressing, the quality of the green stuff is important. Stock readily show • their preference for pastures top-dressed with phosphatic manures and lime. , In conclusion, it must be apparent to all that judicious manuring is the most ready means of profitably maintaing the great crop of the New Zealand farmer (more particularly in the North Island), viz., phosphatic manures give the most remunerative results, that the kind of phosphate to be used to get the greatest monetary return will depend on the. class of soil, the type of pasture and the olimatic conditions involved. It will be seen also that the ruling price of the various fertilisers is a consideration of importance, especially where there is. much difference between the prices quoted for the different lines. " . '