Abstract:
Beneficial arthropods provide important ecosystem services in terms of arthropod pest and weed management,
but these services can be adversely affected by farming practices such as tillage. This study investigated the impact
of two tillage operations (zone tillage and moldboard plow) on the activity density of several beneficial, epigeal
arthropod taxa, and postdispersal weed seed and prey removal in sugar beet agroecosystems. In addition, four
omnivorous ground beetle species were selected for a weed-seed choice feeding assay, whereas a single species
was selected for a weed-seed age preference assay. Ground beetles were the most commonly collected taxon (via
pitfall sampling), with only a few dominant species. Tillage operation did not affect ground beetle activity density;
however, spider, centipede, and rove beetle activity densities were higher in the reduced-tillage treatment. Live
prey consumption was similar between tillage practices, with more prey consumed during nocturnal hours. More
weed seeds were consumed in the reduced-tillage treatment, whereas weed-seed preference differed between
the four weed species tested [Setaria pumila (Poir.) Roem. & Schult., Echinochloa crus-galli (L.), Kochia scoparia
(L.), and Chenopodium album (L.)]. In the weed-seed choice feeding assay, significantly more broad-leaf weed
seeds (C. album and K. scoparia) were consumed compared with grassy weed seeds (E. crus-galli and S. pumila).
No preference for seed age was detected for E. crus-galli, but Harpalus pensylvanicus (De Geer) preferred old
C. album seeds over fresh seeds. Zone tillage is compatible with ecosystem services, providing critical habitat
within agricultural ecosystems needed to conserve beneficial, edaphic arthropods.
