[The effect of biocides on the microflora of soils and their degradation. 3. Interactions between modified populations of micro-organisms and the decomposition of plants for green-manure in comparison to the decomposition of straw (author's transl)].

The possibilities to influence the decomposition of straw and lucerne by fungicidal, bactericida and total acting microbiocides, respectively, were tested comparatively. Total or fungicidal acting substances caused the heaviest inhibition of decomposition at both the organic matters. The efficiency of active ingredients was greater at straw than at lucerne. The reason of the different inhibiting effects is that the lucerne which is easy to decompose and rich in protein can be decomposed alone by the physiologically active bacteria, which are resistant to active ingredients. That means the decomposition of lucerne takes place without the help of fungi. However, the fungi sensible to the active ingredients play a more important role in the straw decomposition. Therefore substances with permanent fungicidal effects are sufficient for the inhibition of straw decomposition. Inhibiting the decomposition of greenmanure presumes permanent acting fungicidal and bactericidal substances. Such substances are not available at present. Systemic fungicides did not influence the decomposition of plants for green-manure due to their limited scope of activity.