Nematode community response to intensive tomato production in the tropics

Abstract

Soil biodiversity and food webs are altered by intensive farming practices. To assess the response of nematofauna to intensive tomato production, soil samples were collected from tomato fields and adjacent natural vegetation in Kirinyaga County, Kenya. Nematodes were assigned to different genera before computation of indices and metabolic footprints. In tomato, there was a high abundance of Meloidogyne and Rotylenchus. Population densities of Aporcelaimellus and Aporcelaimus were greater in natural vegetation. Natural vegetation had more cp 5 nematodes while higher proportions of cp 2 and cp 3 groups were observed in tomato. Omnivores and herbivores occurred in greater numbers in natural vegetation and tomato, respectively. Natural vegetation had a higher Maturity Index (MI), MI 2–5 and Structure Index. In the two systems, there were no differences in the Channel and Enrichment Indices but the Basal Index was higher in tomato. Herbivore footprint was greater in tomato while natural vegetation had greater structure and omnivore footprints. Soil food web in tomato was more degraded with high pest pressure while natural vegetation was highly structured. The results suggest that intensive tomato cultivation in Kirinyaga County, alters the nematode community and food web structure.