Dynamics of nematode community composition in a potato field

The effects of agricultural inputs on the soil nematode community were inve stigated at depths of 0-10 cm and 10-20 cm in a field throughout a potato-g rowing season. Ecological measurements of soil nematode community structure , diversity, and maturity indices were assessed and compared between the ma naged (high input treatment) and unmanaged (zero input treatment) fields. D uring the post-planting, mid-season and post-harvesting periods, the total number of nematodes at the 0-10 cm depth was less in the high input plot th an in the zero input plot. During the post-planting, mid-season and harvest ing periods, the total number of nematodes at the 10-20 cm depth was higher in the high input plot than in the zero input plot. During the post-planti ng and mid-season periods, bacterivores and fungivores were the most abunda nt trophic groups in both plots and at both depths. However, during the har vesting and post-harvesting periods, plant-parasites increased significantl y, and their relative abundance in both plots during the harvesting period averaged 16.7-20.4% and 20.7-25.9% of the nematode community (7.5-10.4% and 7.5-11.4% during the postplanting period), respectively. Cephalobus, Eucep halobus, Rhabditidae, Aphelenchus, Tetylenchus, Tylenchus and Dorylaimus we re found to be dominant genera/families in both plots at both depths. Among the ecological indices tested, ratio of fungivores and bacterivores to pla nt-parasites (WI), Shannon index (H'), maturity index (MI) and plant-parasi te index (PPI) were effective in distinguishing differences in nematode com munity structure between the treatments during the potato-growing season.