ON THE LAND

Kaipara and Waitemata Echo, 6 July 1916, Page 3

ON THE LAND

SOFT LIMESTONE ON THE

GUM LANDS

By B. C. Aston, F.1.C., Chemist for

th 6 Department

(From Journal of Agriculture)

Since August, 1913, when I reported on several samples of soft, easilyweathered marly limestone from Redvale, the principle of using local soft limestone deposits has been given a trial on the gumlands of that area of country lying behind the North Shore of Aucidand City.

The soil in general is poor and difficult to work. In the virgin state it cariies a scanty growth of low nianuku and other native shrubs. The chief native grass is danthonia semiannularis, while a creeping fern, gleichenia diuarpa, is everywhere common. The country has been virell turned over by gum diggers, and even by settlers, who, by exploiting the fossil Kauri>gum of their holdings have in some cases made sufficient to fence them.

After personally maxing a few visits to the district in company with Mr R. Rowan, Fields Inspector, and examining the Redvale limestone deposits, which contain from 65 per cent to 81 per cent of carbonate of lime, it was decided to carry out experiments with large dressings of th« raw stone as dra»vn from the quarry. The deposit appealed easy to work, the hill from which the limestone- outcropped beiug close to the main road, and drays bacKed into the face could easily be loaded from above by means merely of pick and shovel. Some pioneer woric has been done by Mr G. Lepper, who, having dressed his garden with a large quantity of the raw limestone, has demonstrated the value of it by the improved condition of his soil, which before the lime was applied was most difficult to work. The quarry from which the stone is drawn is on private property, and 6d per ton royalty is charged by the owner.

In order to prove conclusively to farmers that the rough stone could be utilised without any treatrrent, a series of experiments was laid down at Albany, within distance of Auckland, where the Department had some plots under Mr Eowan's supervision, the idea being that the limestone should be applied to the land just as it was taicen from the quarry, and that the lumps should be allowed to disintegrate in the soil in the course of the usual farm operations, greatly assisted, of course, by the weathering influences operating in the soil. The principle has the drawbacK that the amount of labour required to carry it out is large, but against this there are numerous advantages, a few of which may be stated.

Tho greatest initial effect is better secured by using oue large dressing than several small one* in different years. It is liice the application of power in moving a weight. One man might use the whole of his strength in attempting to move it without accomplishing anything, whereas ten men oaight easily do the wont in a very short time. So it is with lime. It should be quite possible, theoretically, to repeatedly pepper on to the land which requires it litne in a quantity so small that no appreciable initial effect is pro Jvepd. Under the method adopted in the present case the grinding of the limestone costs nothing, and is done by natural agencies working in the soil assisted by the usual ploughing, harrowing, and rolling Avhich the land receives; whereas when lime stone it> bought already ground a comparatively.,high price has to be paid for the materials, labour, and fuel u.sed in drying, grinding, and bagging the product.

~; The^e potes. of course, only apply where the lucal conditions favour the method^of liming recqrnmended. In fill easps where timing- is permissible it should, however, be rembered tfyat a iargp amount of carbonate pi lim9 in the sp]l inprea.se the availubility of the phosphates, and enable a soil containing a small amount of phosphate to compete with soils richer in phosphate, and so save $ie farmer's manure bill.