Community structure of soil nematodes associated with the rhizosphere of solanum lycopersicum in a major production area in Argentina: a case study among agroecosystem types

Abstract

The objective of this work was to describe the status of the assemblages of soil nematodes associated with tomato crops, in a major tomato production area in Argentina, by studying ecological indices of nematode food web and determining which indices describe alterations in horticultural soils. Three agroecosystem types were compared: agroecological, conventional with organic amendments, and conventional with methyl bromide (MeBr) application. A pristine site without anthropogenic intervention was also studied. Abundance, frequency, diversity indices, maturity indices, trophic groups, colonizer-persister values (cp), and guilds of nematodes were analyzed and compared statistically between the sampling sites. The most abundant genera in the agroecosystems were Rhabditis, Helicotylenchus, and Filenchus belonging to the guilds bacterivorous (Ba1), plant feeders (Pl3), and fungivorous (Fu2). Within agroecosystems, the agroecological site showed the highest values of diversity and maturity, while the lowest values were found in the site treated with MeBr. Trophic groups, cp, guilds, and the indices provided useful information on the state of maturity and enrichment that effectively contrasted and differentiated the practices of horticultural management. This updated report of the nematode fauna constitutes one of the most important for the horticultural region of La Plata considering the scarcity of studies on this subject.