Gypsum.

Horowhenua Chronicle, 15 May 1911, Page 4

Gypsum.

« Gypsum, or sulphate of lime, u landplaster, as the material is variously called, is composed of aiw.it— 32 per cent, lime, • dG per cent. of sulphuric acid, 22 per cent, of water, and in old. times was u.s?d hiraely as a manure for top dres.ii ig i lover, as also for peas and .egim .ions crops. Benjamin Franklin, in Amei -na is said to have sown the material fo as to form the word "plaster" on clover crops by the wayside in order that passers-by might learn by the eyo what has so stimulated; the growth. Its value as a fertiliser probably arises from lilie faculty of rendering potash in a way more avalbable to the plants, and in confirmation of this view it has been shown that when clover is manured with gypsum blic ash of the crop contans a greater proportion of potash.' Itunlocks the natural store of potash. According to an article contributed by Mr Colebatch to the Agr.cultural Journal of South Afnca the following results may no attvbuted to its use:— 1. It is fairly generally credited wibb being able to fix th" aminuoia in the air to the Iwaefit of the p'ants; but in any case the Humilities of ammonia occu -'ng in licM air are so small that ti- : s property lias no practical value. 2. It is said to hasten the process of nitrification in the foil by nr-itra-IVirig the alkalinity of tne mf 'lying solution. ■i It has lieen assume), and j.nsfibl.v correctly, that gyps * a n'.ts 'i.an oxidising agent- in the soil. If ill & be so, it is likely Uiat pur: of tin- benefit to be deriv.-d from its application under certain conditions is due to the oxidation «!' the organic matter in the soil. Until recently it was believed that , gypsum was useful in preventing or lessening the loss of ammonia from manure heaps by producing calcium carbonate and sulphate of ammonia, but according to many recent experiments it is rjairite useless for this purpose. Although from this point of view gypsum is not to bo recommended to be applied direot-l.v to the man lire heap, yet. when .scattered on the floors of the stables, byres, and styes, it may, by absorbing the odours, checking the fermentations, and drying and sweetening the building do good work. .">. On some kinds of soils, such as clays, gypsum, like many other calcium compounds — partiVnlarly lime—will act beneficially on the physical nature and texture by flocculating or granulating the finer particles. For this purpose, however. lime would, be a much better material to use. G. Roberts, in his book on the "Fertility of the Land." has drawn attention to the. value of gypsum for conserving moisture, or securing it from the air, especially when applied on frialile soils: but judicious and seasonable cultivation are. of "inch greater importance for this purpose.—Mark Lane Express.