Table 2.

Effects of nitrogen fertilizer treatments on the Shannon–Weiner (S–W) and Simpson (Simpson) indices of genus-level diversity, the nematode Structure Index (SI) and Enrichment Index (EI), and population densities (nematodes/100 cm³) of omnivorous+predacious (O + P), bacterivorous (Bact) and fungivorous (Fung) trophic groups.

Treatment	S–W	Simpson	SI	EI	CI	O + P	Bact	Fung
0N	7.02aa	5.57a	49a	58a	51	9ab	133	146
1N	6.48a	4.90ab	35b	49b	60	11a	226	218
1.5N	5.43b	4.36b	24c	49b	54	5bc	152	126
2N	4.44c	3.51c	14d	50b	58	1c	137	151
ANOVA summary (p-values)b
Treatment	< 0.001	< 0.001	< 0.001	0.004	0.39	0.004	0.18	0.09
Date	0.21	0.57	0.05	0.07	0.002	0.47	0.19	0.04
T × D	0.57	0.80	0.29	0.05	0.18	0.67	0.91	0.70

Notes: Data are means of three sample dates (April, June, September) and six replicate plots per treatment. ^aMeans within a column labeled with the same letter are not significantly different according to Duncan’s means separation calculated at p = 0.05. ^bMixed-model repeated measures analysis of variance.