On manure poisoning, with suggestions for the prevention of the pollution of wells in agricultural districts / by Eben. Duncan.

  • Duncan, Eben.
Date:
[1885]
Catalogue details

Licence: Public Domain Mark

Credit: On manure poisoning, with suggestions for the prevention of the pollution of wells in agricultural districts / by Eben. Duncan. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    In some modifications potassic chloride is substituted for potassic nitrate, in others sodic nitrate is substituted for amnionic sulphate. Now these substances, as applied to the soil as manures, do not poison the subsoil water as organic manures have been proven to do. We find in the 6th report of the Rivers Pollution Commissioners, published in 1874, a series of analyses of the water coming from the surface drains of farms which for many years had been manured solely by inorganic manures. They say that the practice of manuring lands by substances exclusively inorganic, though still quite exceptional, is probably increasing, and therefore the study of water draining from such land in high cultivation is not entirely devoid of practical interest. It was found, as might be expected, that after such manures were applied to the soil the first rains which fell carried into the drains a considerable amount of those soluble salts, and on plots on which sulphate of magnesia and superposhpliate of lime were largely employed the amount of these substances dissolved in the water was at first too great to permit of its use for washing purposes. Taking the most extreme case—a table showing the composition of drainage water from land in a state of high culti- vation, manured annually from 1844 till 1874 with a mixture of mineral and ammoniacal salts—the total hardness varied from 76 parts per thousand to 14 parts per thousand, and the permanent hardness from 65 to 7 parts per 100,000. The high figures are the results of analyses taken shortly after the manures were applied. A certain portion of the soluble salts enters the growing crops; the remainder, at first absorbed by the soil, is gradually washed out of it. Although ammonia is added in large quantities in every case, yet it is present, but in very minute quantity, in the drainage waters. It is evident, they say, that some of the ammonia introduced into the soil as sulphate or muriate is transformed by oxidation into nitric or nitrous acids, and discharged in the drainage water as nitrates or nitrites, which afford in all these cases false testimony as to the previous con- tamination of the water with animal matters. The objection of too great hardness for washing purposes which applies to the surface water from the drains of an experimental plot heavily manured annually would not apply to the water of a well situated in a field cultivated in the ordinary fashion and only manured periodically at intervals of years. On talking over this question with a practical farmer in the