Statistical analysis

Crop yield as well as root-knot nematode abundances and damage were analyzed separately for each year because a mixed population of root-knot nematodes was present in 2018. Root-knot nematode soil abundances were analyzed separately by season (preplant, midseason, and harvest). These variables were subject to one-way ANOVA.

All other variables, including trophic group abundances, abundances of individual nematode genera other than root-knot nematodes, and N1 diversity indices were combined between years individually by season. These variables were subject to a modified two-way (year by nematicide treatment) ANOVA where nematicide and nematicide by year interactions were treated as fixed effects of interest and year was treated as a random effect not of scientific interest. For all variables, if nematicide main effects were significant (P < 0.05), means were separated using Fisher’s LSD (P < 0.05).