Horticultural Science in France

Abstract

M. Georges Truffaut lectured to the Royal Horticultural Society in October of last year, on the experiments on manuring, pest control and microbiology of the soil, which have been carried out under his direction at Versailles. The text of this lecture appears in the Society's Journal (62, Pt. 3, March) and portrays results which are in sufficient accord with the findings of research institutes in Great Britain to warrant thankfulness, and yet are original enough to provide great stimulation. M. Truffaut and his colleagues have shown that only when the nitrogen, phosphoric acid and potash are combined upon a basis of their atomic weights will the soil yield its fullest increase in response to artificial manures. The insistence of the earlier agricultural chemists on the necessity of lime for the growth of most crops is countered vigorously by the workers at Versailles, who find that the presence of calcium ions is often undesirable in garden soil. The most welcome contribution of the lecture to the science of pest control is perhaps the description of a new spray fluid known as ‘Elgetol'. This is a mixture of a synthetic yellow dye with wetting agents. It has a milder action upon the tree than lime sulphur or tar oil winter wash, but it is quite effective against the overwintering eggs of various insect pests. Workers at the Versailles laboratories have established the fact that soil bacteria can obtain their energy exclusively from carbohydrates and organic salts excreted by the root-hairs of plants. “Living green plants are thus the main source of energy for soil micro-organisms.” The lecture also reviewed a wider field of work than the results here mentioned; the sections on calcium metabolism and the control of pests during winter are most informative.