PHOSPHO GUANO.

New Zealand Herald, Volume IV, Issue 1035, 9 March 1867, Page 4

PHOSPHO GUANO.

The superiority of phospho guano over Peru- | vian guano, which had been pointed out to be the case by scientific men, has been now fully demonstrated by practical agriculturalists. The introduction of Peruvian guano into use in Great Britain was, it will be remembered, attended with much, difficulty, and it is said that fully seven years elapsed before its value was acknowledged by agriculturalists. This was not the case, however, with phospho guano. In their notice of guano we find the well-known firm of Peter Lawson and Son, of Edinburgh, thus alluding to the introduction of this valuable manure into Great Britain :— The active measures t<ken in introducing- the phoßpho guano to the farmers of Great Britain, supported by the opinions expressed by the leading agricultural chemists of its great superiority to Poruvian guano, caused it at once to be sought after. The result of careful experiments in the field having fully established this suporiority, the consumption has increased year by year.

Independently of its large sale in the United Kingdom the phospho guano took a good j>osition in TTrance, Gormany, Italy, Spain, Bussia, and Sweden; and in the West Indies it is rapidly superceding Peruvian gunae, as a manure for the sugar cane. In Oeyloa it has been pronounced the best manure for the coffee plant. Immediately on. its appearance in Europe Professor Voelcker and Baron Justus Yon Leibig pronounced it to be by far the most valuable fertiliser, whether natural or artificial, which had yet been offered to the public. Leibig gave the following unqualified approval of it as a manure, " I never," he said, " have had in my hands a manure which, in regard to the best proportions and abundance of efficacious soluble component parts, was to be compared to the phospho-guano. The phospho-guano surpasses most certainly by its more correct and constant composition the best sorts of Peruvian guano, and of its superior efficacy there cannot be the slightest doubt." As we said before actual experiment demonstrated the truth of the opinion of scientific men. Wherever it has been used the most satisfactory results have been obtained.

In Victoria and Tasmania it has been used for more than three years, and the best acknowledgment of its merits is to be found in the fact that in the past season the consumption of it was very largely increased with turnips and with English barley. In. the case of English barley, land dressed with the phospho-guano gave 65 bushels per acre, while the portion of same field unmanured gave only 20 bushels per acre. The grain grown on the manured part weighed 21b. per bushel heavier than the other. One of the most important advantages of the phospho-guano over the Peruvian is its uniform composition. Even Peruvian guano of a perfectly genuine character, varies so much, that dificvont samples analysed at home have shown a difference of as much as £3 per ton. In exceptional cases, we believe samples have been analysed not worth more than two-thirds the price of the better quality, and it is quite common to find a variation in value of from £1 to £2 in the ton.

The pliosplio-guano of Maldon Island, on the other hand, we learn from a pamohlet published in Melbourne on the subject, is described by Dr. Anderson as more uniform than Peruvian guano : the only variation he ever found in it being (as compared with its recognised standard) an addition to its most valuable properties, and a consequent diminution of its less valuable constituents. Dr. Andrews on this points out the difference between phospho-guano and Peruvian guano. 1. Peruvian guano contains a large amsnnt of nitrogen, partly as ammonia and partly in the form of uric acid, guanin, &c., coupled with a comparatively small quantity of phosphate], chiefly in the insoluble form. 2. Phospho-guano contains a much larger quantity of phosphates, principally in a soluble form, along with a moderate proportion of nitrogen, entirely in the state of salts of ammonia. 3. Owing to this difference Peruvian guano is suited only to those eaßes in which an abundance of nitrogen is required by the soil. It cannot be advantageously used as a source of phosphate?, because, whenever it is applied in quantity sufficient to apply an abundance of these substances, the quantity of nitrogen becomes exce»?ive, and is liable to produoe injurious effects. 4. In phospho-guano the proportion of phosphates is so adjusted that it can be üßed without risk in very large quantities ; and as the phosphates are by far the most important substances on most soils, it produces a good and profitable result in cases in which Peruvian guano has comparatively little effect. 5. It is to the favourable relation between the phosphates and ammonia which makes it applicable as a manure in so many cases, that the rapid extension of the use of phospho-guano is mainly due ; and lam satisfied that as its valuable properties are better understood it will be still more largely employed. Dr. Vbelcker thus points out the difference between phospho-guano and Peruvian guano :— 1. Phospho-guano contains nearly the whole of its nitrogen in the form of readily available salts of ammonia. Peruvian guano, on the other hand, contains the larger proportion of its nitrogen in the form of uric acid, gnanin, and other nitrogenous substances. 2. Peruvian guano contains uric acid, gnanin, and oxalic acid. Phospho-guano does not contain a trace of any of these matters. 3. Phospho-guano contains • nearly double the amount of phosphate of lime which is found in Peruvian guano. 4. Nearly the whole of the phosphoric acid in phospho-guano occurs in a Btate in which it is easily soluble in water, while only a small portion of the phosphoric acid in Peruvian guano occurs in such a soluble state.

5. Peruvian guano contains, in relation to its phosphatio constituents, an excessive proportion of ammonia and organic matters yielding ammonia on decomposition ; for which, reason it iB calculated to do harm when it is injudiciously used by she farmer. Phospho-guano, on the other hand, contains in addition to a large amount of soluble phosphate, which is alwayß beneficial to vegetation, an amount of ammonia which renders the application of phosphoguano to the land less hazardous, and in many cases more beneficial than that of Peruvian guano. From the feregoing it will ha seen that the radical defect of Peruvian guano is the relative proportions in whi:h ammonia and phosphate of lime exist in it. It has too much ammonia, and hence it is too stimulating) it has too little phosphate of lime, and hence does not add to the fertility of the land, or return to

it those indispensable mineral elements which repeated crops carry off. That its great excess of ammonia induces an overgrowth of soft straw and of shrivelled grain in the cereal crops, and of a superabundance of foliage, and a soft spongy bulb in root crops, is becoming generally acknowledged. In fact, it does not accomplish one of the primary objects o manuring, namely, to improve the soil; but on the coitrary, exhausts it, and by repaatei injudicious use impoverishes it.

The phospho-guano, on the contrary, according to Dr. Yoelcker, being much richer in phosphates, and not containing bo much ammonia as to cause too luxuriant a development of leaves at the expense of the bulb, is much Baperior to Peruvian guano as a manure for turnips, swedes, mangolds, a"d potatoes. Equally emphatic is the opinion of Baron Liebig", who says that the result of his researches proves that no manure has as yet come to his knowledge so rich in soluble phosphates and other efficacious soluble ingredients. During the last few days the Hercules has arrived in port with a quantity of phosphoguano, and we have judged that a few remarks upon the character of a manure which is not generally known by New Zealand agriculturalists would not be out. of place. The following is the analysis of the phosphoguano which forms the cargo of the Hercules :— • Water . . 6.81 Organic matter . 5.69 Phosphate of lime 71.15 Sulphate ditto . .16 Carbonate ditto 16.48 Alkaline salts . .10 Sand ... .11 100.00 Wn. Dixon, F.C.S. Maldon Island, South Pacific. February 9th, 1867.