Conservation agriculture compared to conventional tillage improves the trade-off between ground-dwelling arthropod trophic groups for natural pest regulation in cotton cropping systems

Abstract

Conservation agriculture is an innovative approach based on minimal soil disturbance, soil cover with crop residues, and crop rotation, which increases the biodiversity of soil macrofauna thus contributing to nutrient cycling and soil aggregation. In addition, macrofaunal abundance may play a role at regulating insect pest populations. The study aims to predict the effects of soil management practices (conventional tillage and conservation agriculture) on the abundance of soil macrofauna and herbivore predation in cotton (Gossypium hirsutum L.) based cropping systems.We conducted a field experiment with a randomized complete block comprising twotreatments, Conventional Tillage (CT) and Conservation Agriculture (CA), and six replications in a cotton-maize rotation system from 2020 to 2023. Soil monoliths and pitfall traps were installed in both treatments to collect ground-dwelling arthropods, to analyse the influence of soil management practices on their abundance, their trophic groups, and the rate of pest predation by generalist predators. Pest predation rates were assessed using artificial caterpillars made from plasticine. The results showed significant positive effects of soil management practices on herbivory rate, herbivore abundance, predator abundance, omnivore-predator abundance and pest predation rate. The average herbivory rate was 9.8 % in the conservation agriculture plots and 11.6 % in the conventional tillage plots. Overall, the predation rate was 58.9 % in the conservation agriculture plots and 21.8 % in the conventional tillage plots. The abundance of predators and of omnivore-predators were significantly higher in conservation agriculture than in conventional tillage. These findings suggest that conservation agriculture practices improve soil macrofauna and pest regulation, with potential benefits on soil quality and sustainability in cotton cropping systems.