Evaluating predatory arthropod population in ecologically intensified organic cropping systems

Ecological intensification is an integrated approach to improving production and maintaining environmental sustainability. It addresses food security and environmental issues, including organic agriculture. This study investigates how soil arthropods in field crops react to ecologically intensified organic cropping systems, focusing on Carabidae. The carabids in eco-intensive organic systems are compared with standard organic systems. Two organic farming treatments (standard and ecologically intensified) and two crop rotation treatments focus on major regional cereal crops, corn and soybean, along with small grain crops. We hypothesized that there would be differences between the systems. The study employs a pitfall trap experiment to monitor arthropod populations, aiming to investigate and compare the abundance and diversity of Carabidae in these organic cropping systems. The experiment covers a 15-week sampling period, involving setting and collecting pitfall traps weekly, followed by taxonomic identification and quantifying the captured arthropods.

We found significant differences in species richness among crop-system treatments(p=0.01), with the eco-intensive system showing higher species richness than the standard system. Similarly, the GLMM showed significant effect of system and crop type on Carabidae genus and species. Genera like Harpalus, Pterostichus, Anisodactylus, Poecilus and Bembidion are the abundant genus. Meanwhile, Harpalus pensylvanicus, Pterostichus melanarius, Poecilus chalcites and Anisodactylus sanctaecrusis are abundant species. Among them Harpalus pensylvanicus has the highest difference in their abundance in standard soybean and eco-intensive soybean compared to other species in any treatment which makes it a key species.