Effect of Agricultural Practices On Carabid Populations

Controversy exists over the impact of soil cultivation on soil macro-arthropods. Inappropriate sampling methodologies and experimental design have been partly responsible for the contradictory findings. In this study emergence trapping was utilized during 1998 from plots ploughed in winter, spring or left undisturbed in fields of wheat stubble or undersown grass leys. In 1999, emergence from winter-ploughed or undisturbed plots in fields of wheat stubble or undersown grass leys was compared, with and without frost protection. The catch was dominated by adult and larval Coleoptera, of which 68 and 77% were Carabidae in 1998 and 1999 respectively. In 1998 the period of peak emergence of Carabidae, Curculionidae and total Coleoptera were earlier from unploughed compared to ploughed treatments. None of the treatments influenced the time of arthropod emergence in 1999. In 1998 only Curculionidae were affected by ploughing, with more being captured from the winter-ploughed plots. In 1999 the emergence of six carabid species was lower from the ploughed plots, whereas Notiophilus biguttatus (Coleoptera: Carabidae) favoured the ploughed plots. Total Carabidae, other coleopteran adults and larvae and aranean groups were also lower in the ploughed plots. The provision of frost protection had no impact, but temperatures throughout the winter were relatively mil