Investigating the effects of crop type, fertility managemen and crop protection on the activity of beneficial invertebrates in an extensive farm management comparison trial

Published source details Eyre M.D., Sanderson R.A., Shotton P.N. & Leifert C. (2009) Investigating the effects of crop type, fertility managemen and crop protection on the activity of beneficial invertebrates in an extensive farm management comparison trial. Annals of Applied Biology, 155, 267-276.
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This study is summarised as evidence for the following.

	Action	Category
	Convert to organic farming Action Link
	Use organic rather than mineral fertilizers Action Link
	Reduce fertilizer, pesticide or herbicide use generally Action Link

Convert to organic farming

A randomised, replicated, controlled study in 2005-2006 in Northumberland, UK (Eyre et al. 2009) found that the response of natural enemies to organic farming varied between invertebrate families and crop types. In general, ground beetles (Carabidae) and spiders of the Lycosidae family were more abundant in organically fertilized (averaging 341-671 beetles and 11-37 spiders) than conventionally fertilized plots (285-429 beetles and 3-18 spiders), but not for all tested crop types. Rove beetles (Staphylinidae), money spiders (Linyphiidae) and parasitoid wasps (Braconidae) were typically less abundant in organic (61-125, 53-298 and 13-16 individuals, respectively) than conventionally fertilized plots (114-280, 85-413 and 18-23 individuals). Other natural enemies showed an inconsistent or no response to fertilization regime. Natural enemy abundance showed few or inconsistent differences between organic versus conventional crop protection (pest and weed control). Plots of 48 x 12 m were given organic (mechanical control and mineral applications) or conventional crop protection (synthetic herbicide and pesticide), then further divided into organic (compost or none) and conventional (inorganic) fertilization treatments. Each treatment was replicated 64 times with one of five crop types grown in each plot. Invertebrates were sampled using five pitfall traps (8.5 cm diameter) and three one-minute suction samples per plot.
Use organic rather than mineral fertilizers

A replicated, controlled, randomized study of arable fields over two years in England (Eyre et al. 2009) found that wolf spider (Lycosidae), ground beetle (Carabidae) and true bug (Hemiptera) abundance tended to be higher in plots with organic fertilizers. In contrast, rove beetles (Staphylinidae), money spiders (Linyphiidae), hoverflies (Syrphidae) and parasitoid wasps (Braconidae) tended to be more abundant in plots with conventional fertilizer applications. Effects depended on year and crop type (grass/clover Trifolium spp., cereals, vegetables). There was no effect of treatments on net-winged flies (Neuroptera) and parasitic wasps (Proctotrupoidea). A field was divided into four blocks (122 x 122 m), each with 32 plots (24 x 12 m). Treatments were conventional or organic (no) pesticide applications, and conventional (inorganic) or organic (none or compost) fertilizers. Invertebrates were sampled using five monthly samples from five pitfall traps/plot from May-September and three 1 minute suction samples/plot in the first week of July, August and September 2005 and 2006.
Reduce fertilizer, pesticide or herbicide use generally

A replicated, controlled, randomized study of arable fields over two years in England (Eyre et al. 2009) found that crop protection measures (normal or no pesticide applications) had less impact on insect and spider (Araneae) abundance than type of fertilizer. Wolf spider (Lycosidae), ground beetle (Carabidae), ladybird (Coccinellidae) and true bug (Hemiptera) abundance tended to be higher in plots with organic (compost) compared to inorganic fertilizers and those with no pesticides. In contrast, rove beetles (Staphylinidae), money spiders (Linyphiidae), hoverflies (Syrphidae) and parasitoid wasps (Braconidae) tended to be more abundant in plots with conventional fertilizer and/or pesticide applications. Ground beetles were more abundant in no pesticide vegetable plots in both years, but more abundant in conventionally sprayed bean plots in one year. Effects depended on crop type (grass/clover Trifolium spp., cereals, vegetables) and year. There was no effect of treatments on net-winged flies (Neuroptera) and Proctotrupoidea (parasitoids). In both years the organic fertilizer and conventional pesticide combination had the greatest effect on invertebrates; the organic fertilizers and no pesticide combination also had a significant effect. A field was divided into four blocks (122 x 122 m), each with 32 plots (24 x 12 m). Treatments were: conventional or organic (no) pesticide applications, and conventional (inorganic) or organic (none or compost) fertilizers. Invertebrates were sampled using five monthly samples from five pitfall traps/plot from May-September and three 1-minute suction samples/plot in the first week of July, August and September 2005 and 2006.