THE LIME CONTROVERSY.

Southland Times, Issue 17660, 18 February 1916, Page 2

THE LIME CONTROVERSY.

To the Editor. Sir, —In your issue -of 14th February you give notes of a lecture, delivered at Limehills. by Mr Freeman. It is evident that the use of lime in pasturage is only under consideration ignoring altogether the mucli larger need for lime in cropping. We arc asked to look only at the fact that burnt lime, contains a larger proportion of lime (calcium oxide) than- carbonate of lime does. But the figures given represent pure burnt lime, the farmer has to deal with the commercial article; the limestone, from which it has been made, will contain say So per cent, carbonate of lime, therefore 40c\vt of burnt lime will only give ,\oy z cwt. lime. And if it was required to give an equivalent amount of lime as carbonate, using the 85 per cent carbonate, then 63 94 cwt would be necessary. Is is very unusual in Southland to add 40 cwt of burnt lime per acre, from 8 to lOcwt is more likely, so that whilst the ratio would remain the same, the money value does not pan out so much per acre as it is made to look. There are other points of view. To distribute burnt lime, is by no means a pleasant task, if at all windy. Its caustic nature makes it very awkward to exposed parts, hands, face, eyes, and animals also under these conditions run risks of injury. The paddock after treatment with burnt lime will for some time he unapproachable for stock, soil bacteria will be killed, and growth interfered with. These effects will be more or less apparent according to the amount of burnt lime added. The good effect of burnt lime is not evident until it has been converted into carbonate. To do this it must absorb carbonic acid. This it takes from the soil. When one remembers that nearly all the organic fnatter of the plant is derived from the decomposition of carbonic acid, it will be understood how valuable it is in the soil, for this, and other purposes. Burnt lime takes carbonic acid from the soil—carbonate of lime adds carbonic acid, and is tbifs more valuable. Again, stock after the addition of carbonate of lime may graze in the paddock, without fear of injury. When the advantages of carbonate are fully understood It will be found that it is by far the cheaper of the two forms of lime to use. When we consider the use of lime in cropping no one will advise that burnt lime be mixed with artificial manures or drilled at the same time as seed. Carbonate of lime can be, and is thus used, with the best results. It is now 13 years since I first began to write on such a use, and during that period, much change of opinion lias taken place. Your paper carried these letters far and wide, and brought me a good deal of correspondence. Today carbonate of lime is being used in all countries in an increasing quantity, and during the last few years exhaustive experiments have been carried out to decide the best degree of fineness. I have the satisfaction of knowing that I was the means of starting a new industry in New f Zealand, because now there are plants in both Island for the grinding of carbonate, and what I value more is that •whilst at one time the Agricultural Department of New Zealand opposed its use, they now recommend it. and further, the Government is erecting a plant to grind carbonate. Carbonate of lime in the form of chalk and marl, has been used by farmers from time immemorial. The only novelty which I have proposed is that it should be mixed with the manure used and drilled at the same time as seed. As far as I know lam the first to propose this method. I have done so far the following reasons: Ist. Economy; it moans only one visit to the field. Had he used burnt lime the farmer would have made a special distribution, which meant time and cost of distribution. There is also less lime required, because instead of being spread all over the field it is confined to the part ’.where manure and seed are placed. 2nd, Efficiency: Two cwt of carbonate of lime mixed with or drilled at same time as manure, makes the manure basic, encouraging growth of useful bacteria near the rootlets of the plant, destroying noxious products which would interfere ;wlth healthy growth, and is on the spot •where the'plant requires its aid. it would take-too much of your valuable space to" indicate all that might be said. But any farmer can easily put it to the proof. Let him do’'as I have suggested, drill carbonate manure and seed together then leave a row here and there without carbonate. He will thus bo able to see for himself its efficacy. If. he can detect ,no advantage, then his soil is well supplied with lime, but my experience is that the most'of soils require and benefit from the application of carbonate, and I have been told over and over again by farmers who have used the carbonate as I have advised, that where the carbonate had run out, the drills showed it quite distinctly.—l am. etc., GEO. D. MACINDOE. February 17.