A Treatise on Manures

Abstract

IN this substantial little volume of nearly 400 pages the author treats of natural and artificial fertilizers, with a decided leaning towards the latter. The work is intended to be useful to manure manufacturers as well as to farmers and students of agriculture, and must be regarded as a useful addition to our information. The subject is introduced by two chapters upon the soil and the plant, after which all the leading and the suggested fertilizers are reviewed, and analyses are furnished. It is convenient to have at hand a book written up to date in which the newest sources of phosphatic materials, guanos and alkalies, are brought under notice. The chief interest of Dr. Griffiths's book centres in his chapter upon the use of iron sulphate as a manure. It is well known that Dr. Griffiths first pointed out that the iron sulphate, used in small quantities of about half a hundredweight per acre, exerts a beneficial effect on many crops; and this fact is distinctly brought before the reader in the book before us. The value of sulphate of iron lies in the fact that many soils do not contain a sufficiency of iron in a form to be readily taken up by plants, and Dr. Griffiths considers that when added to such soils it tends to increase the amount of chlorophyll in the leaf, and that this is followed by increased vigour in the elaboration of starch, woody fibre, fats, carbohydrates, and albuminoids. The amounts of increase of crop in the cases cited are remarkable, and the greater percentage of iron in the ashes of plants top-dressed with this substance is decided. It would be unjust to Dr. Griffiths to detract from the value of this observation, which, as he tells us, has been the cause of hundreds of letters on the subject from all parts of the world. The results are indeed open to the criticism that they are almost too satisfactory, for an increase of 19,313 pounds per acre of mangel owing to the use of half a hundredweight of sulphate of iron seems almost too good to be true. Nine tons of mangel are worth something like £6 sterling to the farmer as food for stock, a sum which would effectually turn an unprofitable into a profitable crop. The season is still young, and it would be well if agriculturists would put Dr. Griffiths's results to the test of a simple experiment during the coming summer, upon root crops.

A Treatise on Manures.

By A. B. Griffiths. (London: Whittaker and Co., 1889.)