THE USES OF LIME.

Press, Volume LVIII, Issue 11010, 6 July 1901, Page 8

THE USES OF LIME.

[From the "North British Agriculturist. , ')

Several years ago, when we had occasion to write a report of the results of" tibe "first" year's wprk on the experimental station on Lori, RosebeeyV borne term at Dalmeny, we i stated some new and important facts winch bad bsen dfflnacefcrated by these experiments ss regards lima. These experiments, wpdch were, and stil are, coodwited on strictly biological line*—the result of a careful study of soil bacteriology—bad proved beyond the possibility of cavil thai- a large dressing of caustic lime was an unprofitable investment, but that a small dressing of 5 to 10 cwt of lime per acre per annum was a very profitable investment, and was, in fact, the first essential in any rational system of manuring. The reason why the large dressing of caustic lime was unprofitable was because it bad a direct tendency to kill off the nitrifying and otiher advantageous soil bacteria. On the other hand, a small dressing of hot lime, if equally distributed over the soil, and particularly if harrowed in, ia rapidly converted into carbonate of lime, a due supply of which in the surface soil is the first essential of success in manuring. As.the merest, tyro in agricultural chemistry knows, every crop removes a greater or less quantity of lime from the soil; and, in view of that fact, one can only wonder at the unwisdom of the plan of removing crops year by year from the same land witonout even applying any lime to reptace the lime removed by these crops. Soil bacteriology has also shown that the presence of carbonate of lime in the surface soil is essential to the proper discharge of*the functions of the nitrifying and other;advantageous soil bacteria, and hence ths necessity of regular small dressings of lime being applied. At Dalmeny, an annual dressing of scwt per acre of lime was applied with marked success. In order to ensure that this small dressing of lime should ba equally distributed over the whole surface, the lime was* applied in the ground form—that is to say? <it was mecliMiicaliy ground to a fine powder at the lime works —and sown' by means of a manure distributor. Recently some striking proof has been brought forward as to the efficacy of this up-to-dats forni of treatment. Thus Dr. novi Professor of Agriculture at the University of Cambridge, writing in the last quarterly volume of ths "Journal of the Board of Agriculture" respecting the Coclde Paris experiments, refers to the grass plots whici had received a dressing of 7cwt supOTpibris phate in 1837 and 1900, and lOcwt of grounc lime in 1897 and again in 1899, says, respecting thisj plot, "Thus is a plot in whieJ the interest, increases each season, and-.this year it merits special notice, as it has produced the greatest aggregate of all." Or the other hand, the Doctor found that wheis the dressing of 7cwfc superphosphate hac been applied, but wi'thaut the lime, the cioj was not'nearly so good, the reason bsing, a< stated, that "t'lie phosphates used alone havi not been able to exert the maximum influ enoe because of the want of lime."

The results of tbe Dalmeny experiments

also showed that ground lime coul d be very efficaciously applied as a cure for finger-and-toe in turnips. In this case, however, as the object was to kill a soil germ, a greatar quantity had to be applied, with the inevii--able result tikat the crc-p was considerably reduced in conseqiunce, to comparison with that obtained off sound uninfected land; but it was sound, and that was the allimportant consideration. On very badly infested land it was found necessary to raise the quantity of lime to 2 tons per acre, of which, one-half was applied at the time of ploughing the land in the autumn, and the other hJ f vrksn the land was being worked in the spring. This treatment, when followed by a liberal dressing—B cwt per acre —o| ka'init, was found to be thoroughly efficacious in curing the pest, provided that no superphosphate or nitrate of soda were used, though sulphate of ammonia and bone flour, or fermented bones, coii.d be used with perfect safety and great advantage. Some striking testimony to the.accuracy of the Dalmeny results in these respects is now forthcoming. Thus; tihie Rev. Dr Gillespie—the Agricultural Minister for Scotland/ as 'he is called —has been testifying to the efficacy of the plan of using ground lime for the eradication of tlie pest, though the Rev. Doctor neglected to warn his hearers—or his readers—of the other essentials* as above noted, of success in this method of .treatment. With a fuU.er know, ledge of the subject, Mr C. J. R. Tipper B.Sc, formerly a distinguished student ai the Aspatria 6ollege, and now organising secretary of the Ttotonical Education Com mittee of Westmoreland, recently delivered a lecture in the subject of finger-and-tw before the Kendal Farmers' Chib; and he I concluded his lecture by emphasising [ these points:—"First, the infectious natun of the disease; second, the use of lime as « disinfectant, and henoe the need cit its beinj thoroughly mixed with tb.3 soil; third, the cfaims of ground quicklime and fresh slakec Kme as answering all the necessary conditions; fourth, that dissolved manures, sucl a3 superphosphate, dissollved bone, bocn compound, turnip manures, and the like should not be used; that slag should forn a chief part of the manure, and that kami, was valuable in addition; fifth, the. necessity of seeing that diseased turnips did no find their way on to the manure heap." Re centlv, also, Mr Duthie, Collynie, whose success and reputation as a farmer are equalled oniy by his success and reputation as a Shorthorn breeder, testified to the unqualified success which had attended his adoption of the Dalmeny plan of eradicating fimrer-and-toe by the application of ground lime and kainit, buttressed with sulphate of ammonia and bone flour, on the farms under his charge. . Still another proof of the efficacy of applying small dressings of ground lime is furnished by Mr John Hughes, F.1.C., district analyst for Herefordshire, in a paper on "Basic-Superphosphate," which he read before the Society of Chemical In-d-ustry. Mr Hughes, in his paper, takes no account of soil bacteriology, and he has examined the question of lime in the soil from a purely chemical point of view. In fact, he seems to be still fettered by the old and absurd idea that "vegetable acids" and carbonic acid are the great soil solvents, the real truth being that bac* terial action is the great soil solvent. The marked of basic slag in certain soila had led him to look narrowly at the chemical composition of the various mineral phosphates used in the preparation of the ground an<J dissolved phosphates. His analyses showed that the French, Algerian, Florida, Tennessee, and Peace River phosphates had a, percentage of lime ranging up to 15.34 per : cent., and of phosphoric acid ranging up t0V9.90 per cent., whereas basic slag showed a percentage of over 22 per cent, of lime, \with, only 8.70 per cent, of phosphoric acid.\ From this he inferred that the greater succeW of basic slag, in comparison with these phosphates in the ground state, was due to the greater amount of lime in the slag, and \he conceived the idea oi adding a proportion of ground lime to superphosphate, and calling the product basic superphosphate. O ! f course, the addition ol the lime to the superphosphate would cause the solvable phosphate in the super to return to a state in which , it was insoluble in water, but as it was soluble in a very weak solution of citric acidi it would be readily available for the use of\p3ants. In this way, therefore, the basic superphosphate would supply both lime and plk>spha£e to the soil, after the manner of the paot which at Coekte Park has "produced the (greatest aggregate of all." Mr Hughes has this principle, and it is undoubtedly on sound lines, so far ac it goes; but tie amount of lim« which he proposes to add 4>o the superphos phate—namely, 15 per cen\t. of lime to 8f per cent, of super —is not yearly sufficient to meet the wants of the soil in respect oj lime, nor is it then, when sjpmbined witr the free acid in the super, in whici: is best suited to stimulate the activity; anc meet the wants of the nitrifying organisms Besides, the principle which he has jusJ patented has been in use at Dalmeny for the fast five years, and a question may arise as to the validity of the patent <vn that account. But, all tha same, Mr Hughes 'deserves "credit for having moved a step in the right direction as regards the need of regular small dressings of lime applied to the surface Soil, as that is more than the majority of agricultural teachers and chemists hay© yet done. ,