Soil arthropod diversity in relation to weed diversity in organic and conventional agroecosystems

Abstract

There are indications that plant diversity can influence soil arthropod abundance and diversity in terrestrial ecosystems. This study was conducted to investigate the relationships between weed and soil arthropod diversity in organic and conventional agroecosystems. The fields involved in this study were: a) two organic and two conventional vineyards, b) two organic and two conventional olive-groves, and c) one organic rotation system with maize (Zea mays L.) and one conventional maize field. Weed sampling was carried out within a randomised complete block design with five replications, where soil arthropods, were sampled in pitfall traps. For both, weeds and soil arthropods, Shannon’s diversity index was calculated in all studied fields. Weed diversity indices were lowest in conventional vineyards, conventional maize and in organic maize. The highest diversity indices for soil arthropods were found in organic vineyards and the lowest in conventional maize. Coleoptera and Isopoda had higher diversity indexes in conventional than in organic maize. In all fields diversity indexes were significantly lower for Isopoda than for Coleoptera. A positive trend was found between diversity indices for weeds and arthropods. Generally, diversity indexes for weeds showed higher values in organic fields than in conventional ones.