TESTING FOR LIME

Nelson Evening Mail, Volume LVI, 9 January 1926, Page 3

TESTING FOR LIME

some simple methods indications 'j ' soc'cve :■; Pi' leUeallv PWI'V 1.11 :.-:.•:" i :; tell, lis obsiTvai ion, » l" the natural herbaijo <A his farm, whet he- -he soil is deih i: nt_ in |;':ne. Tih' on i;i ri'iii i' in excess of sign (it lime l uefieieliey. Inability h. gi ir clover and luct I lie SUei r.-. hilly is ail iitlifr infallible imlii :111■ n of a simi'ar condition. Apart from an actual lia-ini lal analysis i I the soil. :i number , ;' tests have been devised In determine whether the snil contains a sut'fti ieiu-y of lime for agricultural nreds. A somev.iia! rough and ready method is 10 test tin soil by drying a small quantity of it and aokiing to i: a little dilute hydrochloric acid. Effervescence indicate-! the presence of a carbonate. most probably limestone. In neutral or sour soil no such effervescence takes place. Blue litmus paper (i-.htaiuahle from the chemist) may be used to find nut ii Ibe soil is sour. A little of ihe soil should in' taken from m vci-al plat o in should lie tin roitgi Iv mixed on a clean Mirfnn without handling. A small quantity of this mixtui" should be placed in a clean cup and stirred into Paste. A pice ~f I, hi,,uis pap.r should then be pressed i:i;< the paste by means <if a piece of slick, leaving about half the paper m | i,i contact with the soil. After some 15 minutes. the paper should he withdrawn and an examination made of thai par; which has been in the soil. !f the blue 1 o|. m has changed to red. the soil is acid. Il is suggested by si me chemists thai an idea of the 1 I' sourness i: nidi catefl by the depth ■ f Ihe red colour. Two simple tests fi>r soil soiii ness have iccently been devised by I'rol'i ssor ( '1 111ber. of the I'uivcrsity' of Lech. lie suggests using either a scon;,., (5 . J(;l . cent. to 10 per cent.) of pctassinm salicylate in water, or a saturated solution <if potassium thiocvanaie in alcohol. To carry out the test, spadefuls of soils arc taken from several places in the held and thoroughly mixed. Tins mi:, t lire is a ll' 'Wed to dry in 1 he air and a tenspoonful of it is iben placed in ; , small bottle. A small quantity (ahm.l a tablcspoonlul) of eitln y of ihe shove solutions is then added, and the bottle is shaken vigorously and afterwards al lowed to settle. The appearance 1 ■:' a red coloration in the liquid above ihe soil is an indication of sourness. Neutral soils ami those containing plenty of lime give brownish and yellow colorations. Professor Comber' prefers the thiocynnate. tost. which works very well when the soil sourness is due to nil excess of mineral acid, while. in such soils, the mineral acid would dispel the colour given the salicylate test. Far the farmer's own use. however, the salicylate test is generally quite satisfactory. The agricultural r< lieges in England are now issuing packets of potassium salicylate to Farmers with in slructions lew to carry out Ihe test. Willi Hie noles given above every farm er should he able lo decide whether or not his soil is suffering Frcin lime deficiency.