Effect of cover crops on population abundance and diversity of ground beetles in winter wheat-sorghum-fallow cropping system at semiarid plains of New Mexico

Abstract



A two-year field study was conducted to evaluate the influence of different cover crops for the abundance and diversity of ground dwelling predatory beetle in Winter Wheat-Sorghum-Fallow Cropping System at New Mexico State University, Agricultural Science Center (NMSU ASC), Clovis, New Mexico. The eight mixed cover crop treatment included the Fallow, Pea (Pisum sativum L.), Oat (Avena sativa), Canola (Brassica napus), Pea/Oat, Pea/Canola, Pea/Oat/Canola, Pea/Oat/Canola/Barley (Hordeum vulgare)/Vetch (Vicia sativa L.)/Forage Radish (Raphanus sativus L. ssp.). Plastic pitfall traps (710 ml) were deployed in the furrows of the middle two randomly selected rows in each treatment plot and monitored weekly from May to October. A total of 2,096 beetles, representing five families (Silphidae, Tenebrionidae, Carabidae, Scarabaeidae, and Trogidae) and 13 species, were recovered from pitfall traps. Five of the 13 species, Calosoma affine Chandoir, Cicindela punctulata Olivier, Pasimachus sp., Scarites sp., and Calosoma marginale Casey, were predaceous ground beetles. Calosoma affine, C. punctulate, Eusattus sp and Nicrophorus marginatus were the most abundant predatory ground beetles, comprising 68% of the total beetles found in the system. Species abundance and diversity of predatory beetles varied significantly with year and cover crop varieties. More beetles were found in 2019 than in 2020 whereas canola field seems to be most prominent habitats for ground dwelling beetles’ activities amongst the other cover crops.