A FEW WORDS ABOUT MANURING.

Waikato Times, Volume XIX, Issue 1574, 5 August 1882, Page 6

A FEW WORDS ABOUT MANURING.

By R. W. Emerson Maclvor, F.1.C., F.C.S., &o. Author of " The Chtmhtry of Agiicultun."

A makukk oan be productive of tbe best results only when il is evenly distributed throughout the depth of soil occupied by the roots of the growing crop. Some manures — as common salt, nitrate of ' soda, potash, salts, and superphosphate — '• are so readily solvable in water that they pais into and throughout the body of the soil after a shower far more evenly than can be effected by any method of sowing. Hence top- dressing should usually be the mode of applying these substances. In the case of the expensive nitrate of soda, our fanners should be careful to apply it to the land only when rain can bo relied upon to carry it down to the roots of the plants. The finer its state of division, the more rapidly will a manure be dissolved and distributed through the soil. Certain manures, when applied by hand, may, with great advantage, previously be mixed with dry soil, so as to increase their bulk, and thereby insure their more equable distribution iv the soil. This is particularly desirable in the cases of nitrate of soda, common salt, ammoniacal salts and guanos, potash salts, and, in some instances, also superphosphate. Fertilisers of slight solubility, or those which the soil can readily absorb and hold in spite of heavy rains, can, with advantage, bp applied to the land some time before sowing the crop. To this class belong phoBphati(! guanos, bonedust, farmyard dung, and, to a considerable extent, superphosphate and potash salts. Nitrate of soda must not be applied until the crop is above ground, and, in the case of ammoniacal salts and guanos, as Peruvian, some important considerations must be borne in mind, as their use is regulated by the climate. Until a comparatively recent date, it was believed that the retentive power of good soils for ammonia would prevent its being to any marked extent removed by lams ; but investigations by our leading British j und continental chemists conclusively bhow thut this costly constituent of manures is soon converted i into nitrates after mixing with the soil, and that these nitrates are washed out by showers and earned beyond tho reach of tho roots of the plants. The importance of this hint can be realised when we remember that ammonia, as a constituent of manures, is worth nearly £100 per ton. Jn localities where tho winters are wet these manure 1 ? should be employed when the crop is above ground, and where a dry winter climate exists they may bo applied with great effect in the autumn. On open, sandy, or sandy loam soils, possessing low rontive power for tho constituents of plant food, it is desirable that only such fertilisers as cannot to any great extent bo removed by rnins should be used. In such oases green-crop manuring, or tho application of bulky mauurcs, as farm yaid dung, sea-weed, or compost, is to be recommended. Concerning the amount of manure to be applied per acre, much depends on the kind of manure, the time of manuring, the nature of tho toil, and the character ot the crop. It may, however, bo pointed out that those of our agriculturalists who aio compelled to use fertilisers generally aprjly them in too small quantity to realise their full value. On wheat land it is no uncommon thing for the f armor to sow twice the quantity of seed that is necessary, and only one- third of the manure that should be used if good returns aie to be obtained. Tt often happens that a, lenlly first-class fertiliser is without much effect ou a crop for no other rep son than that the quantity used is quite inadequate to got properly ditsributed in the space occupied by the roots. It is within tho knowledge of the writer that some otherwise shrewd colonial farmers express disbelief in artificial manuies — no matter how good their quality may be— simply because (he application of one hundredweight per acre did not increase the total ptoduceto tho extent they had expected. It must be remembered that no application of manure, however carefully it may be done, is wholly taken up by the crop for which it is employed, and that, for this reason, dros'nsrs Lr^cr than the necessities of the ciop must be used if itis dcsiicil to get the best lcsults. The more soluble or active a niaiime is the quicker its elket on the crop, and the less its influence on succeeding wops. Farmjard manure and bones, which must undergo decomposition in the soil hufuic their constituents are ready for absorption by plant*, and also spanu<rly soluble guanos aie more lasting in their efleets — that is to say, their iuilucncc on the productive power of tlio soil extends over several years. The well-known prejudice existing amongst farmers in favour, of what they term "lasting " manures arises from their failing to sec that the greatly increased crops lesulting from the judicious use of soluble and active manure means n, quick leturn for the money invested. It is surely true that a manure which pays itself and leaves a. profit in one year is much more lcmuuerative than one which takes ycais to accomplish the same result. Anunoniaciil manures and nitiatc of soda give all their effect in the first season, while farmyaul manure and hones will continue to act for many yea«s after the last application. To thoroughly understand the important subject of manuring it is necessary that the fanner should be covcrsant with the main piinciples involved in the growth of crops, and the impoverishment of land, and these the writer w ill attempt tn make clear to the practical mind in a subsequent paper.