Table 4.

Means and their standard errors (±SE) of the number of phylotypes per field, and the Shannon–Weaver indices based on the relative abundance of phylotypes per field, for the cultivation systems and regions in 2004 and 2005

Diversity indices	Cultivation system	Survey 2004		Survey 2005
		Zeeland	Flevoland	Flevoland
Nr of phylotypes	Conventional	2.4 ± 0.9	1.4 ± 0.5	2.8 ± 1.0
	Organic	2.6 ± 0.5	2.6 ± 2.1	2.7 ± 0.7
Shannon index	Conventional	0.70 ± 0.31	0.25 ± 0.35	0.89 ± 0.30
	Organic	0.66 ± 0.22	0.66 ± 0.69	0.88 ± 0.20