The Effect of Organic Matter on the Growth of various Water Plants in Culture Solution
Annals of Botany
With Plate XVII. T HE im~ortance of ol"ganic ma~ures in agricultural ope:ations is a well~ recogmzed fact, and a constderable amount of ev1dence has been accumulated by the author in support of the view that such organic manures are of direct importance in the nutrition of the plant, quite apart from their indirect effect in altering and improving tbe physical condition of the soil and in providing fodd for Soil bacteria. It has already been shown that plants of Lemna mittor will 'not grow and
... will 'not grow and flourish normally in solutions containing mineral nutrients only, and that the addition to such nutrient soluti~ns of small quantities of organic substances 'obtained from decom~ posing vegetable matter,l fro'm cultures of nitroge'n-fix'ing organisms, and from nucleic acid and 'its derivatives 2 which 'the author has found can be extracted from raw peat, 3 enable the plants to multiply rapidly and retain their healthy appearance. , It has also been shown 4 tha:t the failure of a pure inorganic solution to support normal growth in these plants is not 'due to an unsuitable balance of nutrient materials, for similar results were obtained with more than one solution in common use among experi'menters with water cultures ; while trials carried out with water of the pond in which the plants were growing showed that in this medium they 'maintained their normal health and vigour, although their rate of multiplication was retarded as compared with that in the artificial nutrient solution, presumably owing to the lack of any large quantities of the essent.ial inorganic materials in the pond water. The organic matter, which this water contained to the amount of nearly five hundred parts per million, enabled the plants to grow healthily throughout.