Einfluss verschiedener Bodenentseuchungsmaßnahmen auf das Unkrautsamenpotenzial sowie auf mikrobielle Aktivitäten im Boden

In autumn soil from the upper layer of a long-term weed nursery was sampled. This soil was fumigated with “Basamid Granulat” (dazomet) or treated with a steamer or remained untreated. During 19 months germinating weed seeds were counted in representative samples. Both sterilizing procedures nearly eliminated the seeds of annual weeds. Another part of the treated soil was incubated under laboratory conditions up to twelve weeks to investigate biomass-related dehydrogenase activity (DHA) and substrate-induced short-term respiration (KZA) as well as carbon mineralization (LZA), alkaline phosphatase (APA) and arylsulfatase (ASA). The steaming strongly reduced APA, ASA, DHA and KZA whereas “Basamid Granulat” mostly acted weaker. The LZA was slightly reduced by “Basamid Granulat” but slightly increased by steaming. Lucerne meal partly modified these effects. In a succeeding trial the disinfected soil was additionally treated with the herbicidal reference compound “Herbogil Liquide D” (dinoterb) after ten weeks. In the not disinfected soil the herbicide caused a dose-related inhibition of the DHA and – depending on sampling time, lucerne meal or dosage – affected the LZA. In the previously fumigated soil herbicidal effects may be modified. Overall the soil disinfection as well as the reference compound impaired the soil biocenosis.