| Abstract: | The influence of agrochemical compounds on the decomposition of straw and cellulose in soil Supplementary to earlier investigations the decay of large amounts of straw-material with normal quantities of pesticides and normal amounts of straw-material with large quantities of pesticides was proved in a gasanalytical instrument and in pot-experiments. At the same time the straw-decay was tested in pot-experiments. The soil used in these pots has been untreated or treated for several years with different kinds of plant-Protecting-solutions. Finally there was made a test about the decay cellulose (KOZOVA 1963) with the same and different investigation materials. The results are as follows: 1. The use of plant-protection in wheat does not diminish the decay of straw even if the double quantity of straw treated with a medium-quantity of pesticides is added and normal quantities of straw treated with high quantities of pesticides are added to the soil. 2. Agricultural soils, which are cultivated for many years by using pesticides, do not show less straw-decay. 3. The decay of pure cellulose in the laboratory tested by the method of Kozova (1963) was diminished in soils, which had been treated for many years with herbicides and herbicides added with other plant-protection-means. This restriction seems to depend on unfavorable food-conditions for microorganisms eating cellulose in a soil without weed, since the direct dipping of cellulose in herbicid-liquid is not causing any decay-restriction. 4. On the other hand the direct sprinkling of the cellulose-filter-discs with fungicid-solutions of normal concentration diminished the decay strongly. However the decay was not restricted under field-conditions. This seems to be due to the fact that in the growing plants the fungicides have been transformed to a large extend and only small amounts could reach the soil. |
