Untersuchungen ueber Auswirkungen unterschiedlicher Bewirtschaftungsintensitaet auf die Nematodenzoenose eines Ackerbodens.
1994
Leliveldt B. | Sturhan D.
In a multi-institute project to establish the long-term effect of different usage of pesticides and fertilizers on the ecosystem of agricultural fields, the experimental field at Ahlum, near Braunschweig, was used to study their influence on the soil nematode coenosis. Soil samples (250 g) were taken at depths of 0-15 cm and 15-30 cm from field plots with winter wheat, winter barley and sugar beet, each cultivated with four different intensities. The sampling took place, usually at a two months interval, from April 1987 to October 1989. From the 1248 collected samples the total number of nematodes was established quantitatively and qualitatively. A total of 83 species was found to be present respresenting 61 taxa. On the average, 35 taxa were present per sample of which 11.6 were classified as bacteriophages, 7,4 phytoparasites, 6.9 mycophages, 5.4 pantophages, 2.0 zooparasites, 1.1. zoophages and 0.6 phycophages. In general mycophages were the most abundant species followed by the bacteriophages and the phytoparasites, the remaining groups were detected usually only in small numbers. Total nematodes density and number of taxa found were similar for the two soil horizons studied; 83 % of all nematodes/qm lived in the 0-30 cm layer. The total nematode density varied considerably during the year depending on the crop cultivated. A correlation with increased intensity of cultivation and the occurrence of nematodes could be not established. For several trophic groups effects of the different agricultural practices were observed: increased intensity of cultivation resulted in an increase of the phytoparasites density in winter barley and catch crop, but in a decrease when sugar beet was cultivated.
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