Effects of different high intensities of plant production on population density of earthworms
1994
Knuesting, E. (Biologische Bundesanstalt fuer Land- und Forstwirtschaft, Braunschweig (Germany). Inst. fuer Pflanzenschutz in Ackerbau und Gruenland) | Bartels, G.
In the project of 'Ahlum' the population of earthworms were investigated in each of four intensities of crop rotation (winter-wheat, winter-barley, sugar beet) when cultivated in different intensive ways. Therefore the method of electric catching according to Thielemann (1986) was used. The efficiency of this method was tested in comparison with the method of formalin before. The results were similar, so that the method of electric catching could be considered as equivalent. On an area of 0.25 qm eight electrodes with a depth of catching of 50 cm were prosecuted for 30 minutes with a voltage of 60 V. This was done in intervalls of four weeks during the vegetation period in eight repetitions of each date, culture and intensity. The repetitons of electric catching had a distance of 5 m in minimum. Altogether nine species of earthworms were caught. The genera of Allolobophora, Lumbricus and Octolasium were found. Except for the 'main species' Allolobophora calliginosa, Allolobophora rosea, Allolobophora longa and Lumbricidae terrestris five 'accompanying species' with less activity abundance were found. In comparison to other arable areas a relatively high number of species was caught. On one hand it corresponded with the high number of repetitions (higher probability, to find rare species) and on the other hand it was correlated with the particular conditions in the area which were similar to grassland before the investigation. The dries had a great influence and showed negative effects especially on the species of endogeic earthworms in 1988. The influence of the crop had no effect on the number of species, but there were significant differences in the activity abundance
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