Effects of yellow mustard amendments on the soil nematode community in a potato field with focus on Globodera rostochiensis

Green manures from the Brassicaceae family are used to control different soil-borne pests, including plant-parasitic nematodes due to their biofumigant compounds released during the breakdown of the plants. We studied the biofumigant and biological soil disinfestation effects of a yellow mustard green manure on the potato cyst nematode Globodera rostochiensis, a quarantine species with high economic importance for potato growers worldwide, in the field. In addition, we recorded the changes in the composition of the free-living nematode community for a better understanding of the overall ecological effect of this biocontrol method. We followed agricultural practices of sowing the green manure in late summer and incorporation in fall (with or without plastic cover) before planting of potato. Hatching and infectivity of G. rostochiensis juveniles were not consistently affected by growing yellow mustard or its amendments, but the population densities of plant-parasitic nematodes in general were reduced. Changes in the abundance of nematode trophic groups were observed for treatments with yellow mustard amendment. In addition, a beneficial effect was observed when covering the plots with plastic, as the abundance of plant-parasitic nematodes decreased. The amended plots exhibited an increase of the enrichment index while the channel index decreased significantly, indicating a soil food web with a decomposition pathway dominated by bacterial-feeder nematodes. (c) 2012 Elsevier B.V. All rights reserved.