LIME VERSUS SLAG.

Taranaki Daily News, Volume LVI, Issue 83, 2 September 1914, Page 3

LIME VERSUS SLAG.

(To tfe Kditui-.) Sir, In the letter* o;i t-iie above quu>tion appearing in jvar cttanua oxtsc law Etgnaltanes (x. luteteir and H. \V. Lwi*3ice, lilioro are two or tllnree points conceirndiig tjie nee of tilicse two fertilisers walioh seem to be claudbd, (Mid it appears .to anjs t'luit- it i» Juisfc because of due tliat Mr Ui'Waviux' Beemt> *o be opposed ita Mt Inksier. 1 dio not krnlow Mr Inkster, tut I know Blr (Lawrence ao 'one 01 the foremen elianiitste in, >i ew Zealand, amd i ;ulsi> know lihait lie knows too writ t'he vukie of Jime to otswo to ttdlvccalte ita use on &gr«ultura I land under etruiin conditions. It is 'because tliow; conditions 'have not been Stated Iby either oi Wie twio jrwitlemen tihat tile point at issue, viz., tllie tcoriamic value of liime a furtilisur, is elojjjded. . (

I have deeuiled it my diulby da my lectures to the fanners in. tihe educational I district to make the point dead", par- ' ticularly go since I analysed a repTeseniUative piece of swl from Uakuxa. i The soil in question was entirely de- . void of lime, and contained only a trace of potash, bint contained acid phosphates in m/cne tihtin sufficient quaintUtjetf, ano. what that land, and for tihe matter of that, what imost of the land iromid tilie anoiunttun. requires is not phosphoric acid stimulant, but the addition of correetivu allkallies. It rufciy be til (it tlie land Mr. Inkster Js writing of is similarly circumstanced, or at lieast was so twentythree }*ar|j ago, and Itfoe marked prorepuent in tJie carrying capacity of tlh&t land is due- to tihe added alkali in tlie farm (of occasional N top dressings of sowfc> of lime per acre.

In land of Itlhat nature lime will be fcumd to l>a a miut'li more economic ilressing liliaa slag because, as Mr ■LawTenoe expresses it, "that is thj baias of valuation upon wlhioh .It is sold.'' The lime content is also tlhere, buii, it is something in tte nature of a side line, or at leaat of secondary value, and tihe iron content is niolt considered at all and is practicality valueless. If the land doesn't owed tihe phosphoric . acid but does need the lime, or if it doesn't need, the phosphoric acid as miueli as it needs the lime these twfc contents change position andi the lime in the slag become? the ewaavtiaj ingredient, and the phosphoric acid, like tht iron, becomes an incide<ntai one, and for this essential ingredient tlie farmer pays, say, £4 per ton. If, then, Ith.? larmer whose land nasdis lime and mot phosphoric acid uses basic t,!ag for aft l<me content, Hie pays about flO per iton for limje, 'because title slag contains onily 40 per cent. The economic .principle in-v-olved is qulite apparent. How long it woufd "be ibeforc land treated with, lime instead of slag would be crying wut far {ihoiphoj'ie aciid is a question worthy oi tionsidjenation, ami ■upon its showing good) evidence, of' neutralization) fallowing the use of lime it would be a good plaji to supply both . phosphoric acid and lime, ami tiiis, of course, is wtet is doji'i wflien slag is used. 'lllere is a statement in Mr Inkster's letter respecsting the cube of lime that must nab remain unchallenged. Retfenring to the statement'that "too much lime will irendier the fond almtost worthless," Mr Inkster says ''swell a statement is He (lias only to look at the statement in cold print to lii-'tover ite absolute trulth. Too much ■of anything is bad for mtm or beast or land, but w3iat is too much, and i« it possible to give tlie land too miurih lime' Whilst 1 know that it is possible, 1 am quite convinced that tho misitake that wi.i be miaiJe (if any is), will not be the of too "much lime, biut giving to the soil too little potash, and! lrnrnus. Mr liawrence ateo fears tlie depletion of tlw. soil of its plhosplhates. 'the wouldbe successful farmer will (harve to lcaim the valu« of liiuanui and provicUs it in tlie form of green crops, if he cannot ;jt r t it in any other way, and lie will then be able to appreciate tilwj valwe of lin-JB as a rortilismg agent. If, ho-vcveT. the taniiflirt purawt in to© use of any fertiilLser H'hitili comtains anily one su-b----sUnee wJneh is an esstntiail plant food, the depletion of the soil of the other sulistnncfs will eventually rcduc? that land to a conditio® of poverty, so that the statement quio.ted by Mr Inkstw Li neithw miisleading or worthless. It is Mr Inkster wlho is holding out- t'lic wrong fl:i|g. Instead of Hie white (line elear) flag he lvolds, 1 put. out 'the green to warn men to go cautiously. If the farm land is more acid than allk'.ili, lime may be ÜBod 'to advaiitage. If it be M>mawliii.t neutral, tiiien basic may be used, oadli for a-time icinly, but it will saibscquently ery mut for potash, which wH 1 have to be fu'mif'hed in soun iorm of potash s;ilts ami for nitrogen, wdu<ilj will have to be supplied in somi; of the soluble forerm on the market.—i am, lib 1 .,

J. (i. W. BLLTS, Agrt'diltuvnl Instructor Ttvliaical College, September 1, ISII4.