THE IMPROVEMENT OF PASTURES.

Otago Witness, Issue 2892, 11 August 1909, Page 20

THE IMPROVEMENT OF PASTURES.

A PAPER BY MR B. C. ASTON. Before the Agricultural Conference, held at Wellington, Mi B. C. Aston, chief chemist of the Department of Agriculture, read the following paper on the improvement of pastures in New Zealand. — Recapitulatory.— In my first paper*, which I had the pleasure of reading before the Dairy Union Conference at Palmerston North recently, it was pointed out that of the three essential fertiliser ingredients or New Zealand soils these most usually required were potash and phosphoric acid; 'nitrogen, the most expensive ingredient, could usually be dispensed with, or the proportion of it in the soil could be economically increased by growing leguminous crops or by augmenting. the clovers in a pasture. Available poiesh, where deficient, could often be liberated from tha inert silicates of the soil by applications of land plastei (prpsura) or by lime more cheaply and with greater safety than by applying potash salt?. Of nitrogen, potash, and phosphoric acid, it was the application of the last and cheapest which evoked economically the greatest response from the soil of "God's own courJtry."" To supply phosphoric "acid to pasture, basio slag and superphosphate were the fertilisers which should be used. Of the two baaio slag had giver the most definite results in this country owing to the favourable climatic conditions, acidity of the soil, and deficiency of lime in the soil. Slag could not, howevei, always be relied on to profitably improve pasture, for where the rainfall was small and fell on comparatively few days in the year, or when it contained an excess of carbonate of lime, then it was hardly likely that slag would act as beneficially as superphosphate. — Basio Slag. — From a consideration of the factors which determine the success of basic slag on pasture is seen that the soils of New Zealand should usually be particularly susceptible to its influence. The climate 's generally moist, the soil is acid, damp, and deficient in carbonate >of lime and phosphoric acid, but well supplied with nitrogen and potash, and, lastly, the clover plants are usually present in. fair proportion. As showing the -marvellous fruitfulness of clover under favourable conditions the following instance may be narrated. During the droughty summer of 1907-8 immense quantities of white clover seed were observer! lying on the parched hill soil at Titahi Bay, near Wellington. Some of the seed may have been distributed by sheep brought from Mana Island. When the rain cam© many of the seeds germinated, and Eome paddocks were covered with clover fioecilin^3 so thickly that it was a labqur of some Httie cime to count the number even on such a small spot as a square inch. The actual figures taken from different parts of the same field on 12th April, 1908, were as follows: — 2ir x 1 Jin of turf contained 101 clover seedlings 2in r 2in of turf contained 183 clover s-eedlinga lin x 2in of turf contained 70 clover seedlings lin y lin of turf contained 50 clover seedlings Total on 10 sq. in. of tttrf 404 clover seedlings There are 6,272,640 square inches in an acre, and Primrose M'Connell says that there axe 732,000 white clover seeds in a lb. Hence there must have been about 3451b of clover seed per acre grown or deposited on. thi3 particular paddock, and if we add the usual 14- per cent, allowance for non-germinating soed th? above figures would be increased to 393!b per acre. A significant fact in connection with the Titohi Bay hill pasture — on a soil derived from the underlying grauwaoke rock, which haa been subject to severe stress by the movements of th© earth's crust, the interstitial spaces thus favouring excessive drainage and hence parching — was that although the introduced grasses were dry and withered in the drought, the native Danthonia scmiannularis was living and healthy. An obvious condition for the success of any phosphatio fertiliser on pasture ie, of course, that the soil should 'be deficient in available phosphoric acid. Obvious as this must be to all, it is regrettable that the soil is not always analysed before experiments are laid out. No apology ,is necessary for some details of the origin, nature, and use of c substance which lias so frequently effected the phenomenal and permanent improvement of pasture. Basio slag-, also known as basic cinder, Thomas's slag, Thomas's phosphate, or Thomas's rnoal. and in America as odorless phosphate, is the finely-ground furnace slag obtained as a by-product in the ThomasGilchrist basic process of making mild steel. The process, which was introduced in 1879, entails heating the molten pig-iron tc a very high temperature in a pear : shapcd! ves=pl known as a IWsemor converter. The walls of this vessel are lined with lime* or dolomite (maernesian limestone), or a mixtnro of <!-olomite-, lime, and tar. An airb!a c t is blown throug-h the molten macs, \\ hereby the impurities of the iron, consisting of tho elements phosphorus, manganese. silicon, carbon, and sometimes sulphur and vanadium, are oxidiVod or burnt. These o\ ; clps are oit-her basic or acidic, and are <anablc of combining 1 with each other faxoepttner the carbon- oxides, which .-ire 1 volatilised), with the lime and iron oxide which arc thrown into the molten mass, or with the lime and magnesia of the furnace lining, to form a sag which floats on the surface of t.ho molten metal. The basic process of matin? mild steel ■wa« an accompli shWl fact in 1879. but no uc-«u c -« was found for the thousands of tons of wa^tc slaa: until three- or four y<»flrs later, in IP-83, it besran to attract attention as a fertiliser. Comprehensive experiments, both in fv-'-d and laboratory, were then undertaken, notably by Professor Wagner, of Darnvfcadt, with the result that the we of fin-elv-crround basic slag was full* justified on soils rich in organic matter)-, for all crops: on all pasture coils, if not too dry in oharacter : and on clay soils poor in lime. The world's consumption of basic sla<> waa

* This -was fully reported in tnp Otago Witness of June 30. in the Farmers' Union Advocate of .Tulv 3. et seq, and in the August number of The Xew Zealand Faimer. t As showing, the intense solvent power which organic matter has on sl«g phoswha^, an experiment made by Albert may 1m quoted.— One gram of ba«ic si of, and 100 prams of peat v.c-f 1 mixed together vc one litre of w.+cr, ard if vu? found that ai'er Ftandinp- for 14 days 70 pc- crnt of lh? nhosDhoric anhydride has become soluble

in 1906 estimated in round figures eM 2,500,000 tons annually, of which Germany, used 1,300,000 tons and the United Kingdom only 170,000 tons. The average consumption per acre of grass land and tillage land is, in Germany 321b, and in the United Kingdom about 81b. As a possible correlative ofi this fact, a recent writer pointed out thafc the yield of grass in Germany had increased! nearly 20 per cent, since the application of basic slag became general in that country, where, it may be added, about one-half o£ the phosphoric acid used in field manuring 1 is applied in the form contained in basio 6lag. In Great Britain slajr did not bejria to be used to any extent until 1894. It is interesting to note the effect which the advent of the 'basic process — so-called! from the fact of the preponderating use of alkaline or basic materials, lime, magnesia, end iron oxide, in the manufacturer-has hadl on the production of steel. According to Storer, 85 per cent, of the known deposits of iron, in Great Britain are contaminated) with more than one part of phosphorus per thousand. When the ores- are smelted, practically the whole of the phosphorus remains in the pig-iron, and it was a matter of no little difficulty to convert such pig-iron into steel, as the pigs contained from 2 per cent.to 4 per cent, of phosphorus, which, if not removed, would render the resultant steel 1 brittle or "cold short." The basic process has therefore not only enabled low-grade iron ores to be largely utilised in the manufacture of mild steel, but has proved a method of removing a harmful impurity from the iron, and converting such impurity* into ani extremely valuable manurial constituent. Some idea, of the amount of steel produced) by the process may be obtained from tha figures for, slag production quoted, when it is remembered that for every ton of slag made five tons of steel are produced. — Composition. — Basio slag is essentially a mixture of phosphates and silicates of lime, magnesia, manganese, and iron, together with small quantities of other compounds of minor interest. All the main constituents^ varvwithin certain limits, with one exception — lime — • which is always constant within relatively narrow limits. THe followng complete analjses show th« manner in. which the composition- matf

Itxi turnips, and their excellence^ created universal surprise. The draining is faoili*ate*3 'bj- tlie porous, lofrer layers of pumice. Pumice is merely 'the solidified ifroth of molten lava, and its lightness is due to entangled air, steam, and other gases. Much potash and some phosphoric acid is usually present. By the activity of ■the earth forces we thus have being built up before our eyee a distinct type of soil ■which will probably exhibit uniformity of Agricultural results over a very wide area. 2t is such extensive types as these which .would well repay research into the best snethod of treatment. Naturally the greater the area the greater the number of {farmers who will be benefited by any iraproYement in the manner of working a given.' type, and it is the description of tpyes of soil, and the delimitation of their boundaries, which constitutes what is called a soil survey —Improvement of Pastures.— The 6tudy of the economic aspect of the native gTasses is indeed worthy of more attention than has hitherto been devoted to it. . We require more knowledge •as to the types of soil which are suited, not only to different species, but to the different varieties of grasses. Of the smaller Danthoniae, D. semiannulans, and D. pilosa; there are many very distinct varieties, quite as distinct, for instance, as drawing's fescue is from its type. Each of these varieties will probably have- a different value to ihe grazier, and some, no doubt, will suit a given soil better than others, but definite experimental evidence is wanting. Many of the native grasses are undoubtedly of great economic value, but the seeds of only three— tho oat trrars <Danthonia semiannulark and D. piloea), ricesrrass (Microlena stipoides), and the iloubtful Chewing's fescu<» — are on the market, and no endeavour is made to discriminate in the varieties of the firstnamecl. I recently distributed a sack of Agropyrum eeabrum seed for experimental purposes. This species, the native blue grass, is so relished by stock that it is rapidly beingr eate-n out, except on rocky faces, "where it may usually be recognised by the light bluish-coloured leaves. At 'Alexandra. Central Otago, this grass forms tall tussocks on the mica schist soil. This tussock habit is evidently an adaptation developed to meet extreme climatic conditions. The red fescue (Festuea rubra), •nother excellent case in point, is a grass which has developed a tussock habit in its struggle for survival, and is usually found assocfaited with the silver tussock (Poa eaesprtosa). Anothe* type of country favouring the tussock habit in grasses is the Ihumus grassland of the subantarctic islands. The dominant grasses at the Auckland, Campbell, Antipodes. and Macquarie Islands are huge Danthonia and Poa socksl In. the Falkland Islands it is a Dactyl is (the genus of -which cocksfoot is a species) -which has ass-amed a tussock form. This fact suggests that on interchange of Campbell Island atjd Falkland Island grass seed might mutually benefit the pasture of both, sinoe- the climatic and edophic (soil) conditions of these islands must be extremely similar. One great value of the tussock habit on virgin permanent pasturo is that it allows- many finer grasses to flourish in the spaces protected from the Kales by tho larger grasses, which derive their nourishment far below those of their tiny relatives. Thus the roots of Danthonia bromoides, at Auckland Island, were traced down to a deDth of sft in the soil, and I was glad to observe at an elevation of several hundred feet ifi the rigorous climate of Port Ross the abundance of such fine grasses as Hieroohloe Brunonis, Poa incrassota, P. .breviglumis, P. _ foliosa, P. antipoda, Dischampsia graoillima, D. antar-ctica, Deveuxia ' setrfolis, ' Agroetis magellanica flourishing under the giant tussocks. Several of these grasses were cent alive to tfie State Farm, where it is hoped that eventually enough seed may be raised to ascertain the values of the different species and varieties. Analyses and practical tesf« of all native grasses might yield most interesting results, but the initial Hifficulty is. of course, that of collecting enough seed to enable a pure- pasture to be raised. That rfc pays to- know eomethina: of the composition of the various varieties of cereals grown is shown by tho following analyses of maize, millet, and sorghum. ffrown at the Moumahaki Experimental Farm. The proposal emanatmcr from a local scientific body to establish a high-level observing station should commend itself to farmers. - Th« study of the alpiae grasses and upland soils oould then "Be carried on continuously. The elucidation of such problems as the prevention of'washing out of .large tracts of hillside . pasture, so prevalent on the Tararuas, might receive 'considerable aid from observations made on the spot.

Ifc will bo seen that the variety of mai?e lowest in dry matter would only give half the amount of nutrient matter per aero of that which gives almo-t the highest amount of dry matlor, although the yicius per acre of green matter a*e ahoo-t I'k-i-tical. Another example of tariatiin of composition in c-ereals is that ai'toid.^l by experimental sample-s of vh <t u•r .w n in farmers' o«n lan da fi_..i ;:^J s ..i pLed by

' th* Department. When itt Sydney some years ago I was informed that we could not grow -rrheat to compare with Australian. It was therefore satisfactory to learn from a milling test made by tho Queensland Official Agricultural Chemist, Mr Brunnich, of the New Zealand samples that one, " Comeback," was well above the average in most points, as the following results show. The figures for the Australian samples are taken from the analyses of 100 samples of good quality (abnormal specimens excluded) during the years 1906-7-8 :—

N.Z. "Comeback 1 * Average of three Samples. Australian Average of 100 Samples.

Appearance of grain (max. 10) 10.0 9.0 Weight per bushel, lb .. 62.8 63 5 Ease of milling (max. 10) ... 8.6 8.6 Percentage of flour . . 71.5 70.3 Colour of flour (max. 15) .. " 15.0 13.8 Strength of flour (ie&x. 20) . 19.3 18.9 Percentage of gluten .. ..j -.» 11.76 13.1 Total, points (max. 100) . - 90.0 83.0 Compared with the Australian varieties, the New Zealand " Comeback " is superior in appearance of grain, colour of flour, and percentage' of flour. Slightly inferior in weight per bushel and percentage of gluten. — Organic Manures. — The great value of farmyard manure on pasture is shown by the Rothamsted experiments. The effect of a 14-ton dressing of dung for eight consecutive years was well marked on the crop 40 years afterwards, the respective yields on the continuously unmanured and the dunged portions, at the end of that period, being as 100 to 113. Well-rotted waste from flax mills was recommended in the previous paper as a substitute for farmyai-d manure which is not usually obtainable. An experiment recently conducted at the Ruakura Experimental Farm, at my request, with flax i waste on potatoes may be quoted. Twenty tons per acre was the dressing applied, which cost 2s 6d per ton for carting and distributing. Without the aid of any artificials, ifc gave an increase over the unmanured plot (which yielded 10 tons) of two and a-half tons of potatoes per acre — an estimated orofit of £7 per acre due to the New Zealand flax (phormiumj refuse. Analysis shows that this waste material contains much more potash than farmyard manure, and hence should be better suited to a potash-loving crop like potatoes. It is highly probable that this material would have a beneficial effect on pasture. A singular aspect of some humus soils may be here mentioned. Usually, of course. if a soil is well supplied with any food ingredient, it is unnecessary and wasteful to add more, and so hopelessly is it at variance with farm practice that ifc would be the result of ignorance rather than of intention. Humus soils, however, frequently respond well to dressings of stable manure, an effect due, possibly, to bacterial causes. Whether top-dre3sing with flax waste would similarly ameliorate humus 3oils can, of course, only be determined by experiment. Consideration of the value of this artificial organic product suggests that inquiry i be made as to the value of a natural product; — the black mould or humus of swamiw. In many parts of New Zealand, clay or sandy soils occur on the same farm with black swamp soils, consisting almost sntirely of organic matter. When the swamps are drained the mould could be f carried on to the dry land, allowed to : sweeten for a l?»v weeks, and mJui^'ioJ jin Pctstf*? and mangolds might then le ; grown, as in the above experiment. i Humus soils vary considerably in ■.uality, i.?id a small experiment should always f e- • cede larger operations of the same kind. — " Dominants " and Antipathies. — ' Another phase in pasture treatment ' which is worth noticing is tho ease with which profound alteration in the botanical composition of the crop may often be affected by quite simple chemical mean?. In many pastures a sure sign of acidity and deiiciency of lime in the soil is an abundance of sorrel. The Rothamsted experiments showed this on die plots continuously manured until 1397 with annnonium sulphate only — a fertiliser which leaves s.n acid residue in the soil. Sorrel formed 15 per cent, of the v^hole heibrißi?. The only portion of the plot from which sorrel was absent was a strip that was dressed with chalk in 1833 and aprain in 1887. This simple remedy, therefore, may be relied on to banish .sorrel from sour pasture. This experiment si y es an exaggerated, though -^eiy instmotive, example of changes induced by ammonium sulphate. This fertiliser, applied in such a way that the sulphuric acid libeiated is neutralised, is a sure agent to. produce a pure sward of grass, and this fact is taken advantage of in the commercial manufacture of weed killers and lawn dressings designed to kill the broad-leaved and non-gramineaceous plants in bowling or putting greens, where it is desired to produce grass plants only. Both nitrate of soda and sulphate of ammonia act in this way, if continuously used, and kill out piactically all c-Joveis. Tho correct way to proceed, if this is desired, is to apply a mixture of those salts. The alkalinity of the one is rhen neutralised by Ihe acidity of the other, J and the harmful results of either an alkaline or an acid residue are thus avoided. , The elimination of charlock (field mustard) from land by spraying it with bluestone solution an I the hiuh increase in the percentage of clovors on gra«r> land j treated with basic slag are. with the foreI going, but a few of Ihe in^raiico 5 ; \«hich I might be adduced to show tho toleiation ! exhibited by c cne «peeie-5 for compounds inimical io oche'-s o>" the o-zros-iw ptinm- ' lating pfTi-ct of crfain fertiliser incp"<lients ultimately rencl"> in<r a parr.eular family of plants tuuinphant over all orh^r*. The riUtribmSc'i by v;a''r of can'iy matter cA'H" li:i.l worn our a.'.J Tcjiii' mg 'ei.owi.!oi> a:id an acr" i --.on rf uin r ,i! ii>,,f--t r, lv ' übjt js known a^ "wj'dhi. 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in productiveness. Warping is a very Ancient method of soil treatment. - Tlie Egyptian practice of sowing their corn before their muddy flood waters receded from their Nil© lands is supposed to have given origin to the beautiful figure, '"Cast thy bread upon ths waters, and it' shall return to thee after many days.'' I have not come- across any mention of an agricultural community, at any rate within the confines of our own Kmpire, profiting by a "wind warp," such as that afforded by our northern volcanoes. , The sterility of certain products of erup1 tion is no doubt due to unoxidised sulphur and its compounds. Any material brought up from the bowels of the earth will not support plant life for this reason. The tailings heaps from the Thames mines will only support shallow-rooting grasses, and is fatal to trees. As the years go by and tbe atmosphere has time to oxidise these harmful compounds there is no reason why volcanic mud should not grow gcod crops. In bringing 1 this paper to a close I trust that you will pardon the many shortcoming^ which you will doubtless detect. Within, the compass of a paper such a 6 this, dealing with such a vast subject, one can only suggest- ideas and indicate- general principles. It is yours to strive after the perfection of the soil's fertility. Within the borders of this Dominion is to be obtained every essential necessary for successful agriculture. With a plentitude of sunshine, rain, ILnie, and phosphates, much may be accomplished. "When the nitrogen supply runs low in the soil, there- is aoi abundance of water power, coal, and limestone, with which the inert nitrogen, of tho air may be captured. This is indeed a land of promise, a good land, .«. land of brooks of water, .of fountains, andt depths -that spring out of the valleys and hills ; a land of -wheat and barley and vin«6 and fig trees* and pomegranates ; a land of oil olive.and honey ; a land wherein thou shalt cat bread without scarceness; thou shalt not lack anything in it; a land whose stones are iron and out 1 of whose hills thou mayest dig brass. j

Lzoss on ignition Silica iron oxides ■•hoaphoric anhydride Lime (CaO) Uuminia Magnesia . . Manganese oxide Sulphur, etc. Vanadium oxide Julphurio anhydride 7alciura K153. O.BS 10.32 12.50 18.85 46.40 2.15 3.90 4.20 0.80 t» K376. 2.40 14.50 17.46 10.52 43.66 2.40 4.60 3.65 1.23 K842. 18.90 15.81 8.55 44.00 2.60 4.33 4.80 1.01 t 7.39 22.18 14 38 41.53 2.67 6.1* 3.79 0.25 1.29 0.12 0.31

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