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THE DECOMPOSITION OF NAPHTHALENE IN THE SOIL AND THE EFFECT UPON ITS INSECTICIDAL ACTION
Author(s) -
TATTERSFIELD F.
Publication year - 1928
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1928.tb07037.x
Subject(s) - soil water , naphthalene , organic matter , environmental chemistry , volatilisation , soil organic matter , agronomy , decomposition , alkali soil , chemistry , biology , ecology , organic chemistry
Summary.1 The insecticidal action of naphthalene and its duration in the soil have been studied. 2 When naphthalene is incorporated thoroughly with soil it shows a fairly potent toxic action on wireworms; uneven distribution lessens its efficiency as, owing to its low vapour pressure and consequent slow spread, it produces only a small zone of toxic action. 3 Naphthalene is slow in toxic action, taking three or four days to kill wireworms, as a consequence of which and of its repellent action to insects, if the chemical be unevenly distributed in the soil insects tend to move away from positions where toxic action would be exerted. 4 The persistence of the toxic action depends upon the soil type. In soils rich in organic matter, toxicity disappears more rapidly than in soils less rich in organic matter. Toxicity persists longer in sterile soils and in sand than in unsterilised soils, and in dry than in moist soils. 5 The rate of disappearance of naphthalene from soil has been determined. It depends very little upon volatilisation but almost entirely upon some factor inherent in the soil, which is more active in soils rich in organic matter than those poor in organic matter, and in unsterilised soils than in sterile soils. 6 Second and third doses of naphthalene added to the soil, when the first has disappeared, are decomposed more rapidly than the first dose. 7 The bacterial numbers of the soil are at first decreased by the addition of naphthalene, but there is a rapid rise during the period when acceleration in the rate of decomposition of the naphthalene is taking place. All the evidence indicates that the loss of naphthalene from the soil is mainly due to bacterial decomposition. 8 Experiments in sealed bottles indicate that the opening of the bottle and mixing of the sample expedite the disappearance of naphthalene from the soil. 9 The toxicity of α‐chlornaphthalene persists for a longer time in soils than naphthalene, and is decomposed at a slower rate. An admixture of naphthalene appears to induce a more rapid disappearance of the toxicity of the chlornaphthalene. α‐Chlornaphthalene is more toxic to plants than naphthalene. 10 Methods of estimating naphthalene are described. They depend on formation of naphthalene picrate. Picric acid can be more readily titrated by alkali in orange and yellow coloured light than in white light. 11 It was noted in several tests that the prolonged aeration of soils which had been heated and allowed to cool gave rise to formaldehyde.