Dynamics of nematode community composition in a potato field

The effects of agricultural inputs on the soil nematode community were investigated at depths of 0-10 cm and 10-20 cm in a field throughout a potato-growing season. Ecological measurements of soil nematode community structure, diversity, and maturity indices were assessed and compared between the managed (high input treatment) and unmanaged (zero input treatment) fields. During 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 than in the zero input plot. During the post-planting, mid-season and harvesting 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-planting and mid-season periods, bacterivores and fungivores were the most abundant trophic groups in both plots and at both depths. However, during the harvesting and post-harvesting periods, plant-parasites increased significantly, 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 post-planting period), respectively. Cephalobus, Eucephalobus, Rhabditidae, Aphelenchus, Tetylenchus, Tylenchus and Dorylaimus were found to be dominant genera/families in both plots at both depths. Among the ecological indices tested, ratio of fungivores and bacterivores to plant-parasites (WI), Shannon index (H'), maturity index (MI) and plant-parasite index (PPI) were effective in distinguishing differences in nematode community structure between the treatments during the potato-growing season.