Short-time impact of soil amendments with medicago plant materials on soil nematofauna

Soil amendments with plant materials from Medicago species are widely acknowledgedfor a suppressive effect on plant-parasitic nematodes but their impact on beneficial components ofsoil nematofauna is still unknown. A study on potted tomato was carried out to investigate theshort-time effects on the overall nematofauna of dry biomasses from six different Medicago species,i.e., M. sativa, M. heyniana, M. hybrida, M. lupulina, M. murex and M. truncatula, incorporated tonatural soil at 10, 20, or 40 g kg-1soil rates. All amendments resulted in a significant decrease of thetotal nematofauna biomass, whereas total abundance was significantly reduced only by M. heyniana,M. hybrida, and M. lupulina biomasses. Almost all the Medicago amendments significantly reducedthe relative abundance of plant-parasites and root fungal feeders. All amendments significantlyincreased the abundance of bacterivores, whereas fungivores significantly increased only in soilamended with M. heyniana, M. lupulina and M. sativa plant materials. Mesorhabditis and Rhabditiswere the most abundant genera of bacterivores, whereas Aphelenchoides and Aphelenchus prevailedamong the fungivores. Predators were poorly influenced by all the tested Medicago biomasses,whereas the abundance of omnivores was negatively affected by M. heyniana and M. lupulina. Valuesof the Maturity Index and Sum Maturity Index were reduced by treatments with M. heyniana, M.hybrida, M. lupulina and M. sativa plant materials, whereas most of the tested amendments decreasedvalues of the Channel Index while increasing those of the Enrichment Index. Enrichment andbacterivore footprints raised following soil addition with Medicago biomasses, whereas compositeand fungivore footprints were significantly reduced. According to their overall positive effects onsoil nematofauna, amendments with Medicago plant materials or their formulated derivatives couldrepresent an additional tool for a sustainable management of plant-parasitic nematodes.