Enhanced invertebrate activity-densities and weed seed predation in an integrated cropping system

Abstract

Crop production with little to no tillage, permanent plant or residue soil cover, and diverse crop rotations are frequently marketed throughout the world as a way to sustainably produce crops. While these management techniques contribute a wide suite of ecosystems services to crop production systems, they typically come at the expense of increased reliance on herbicides for weed control, which is known to negatively impact ecosystems. This two-year study investigated three cropping systems (i.e., integrated, organic transition and no-till) to determine their effects on granivorous invertebrate activity-density, invertebrate weed seed predation and crop yield. A redundancy analysis (RDA) revealed significant effects of cropping system on invertebrate community structure and associated seed predation rates. Specifically, species abundance and seed predation rates in the integrated treatment differed from those found in the organic and no-till systems (F = 6.97, p = 0.002). Secondarily, no-till systems differed from organic systems (F = 3.09, p = 0.006). The analysis indicated that most invertebrate groups, and seed predation rates for all weed species assessed, were more highly associated with the integrated system. Crop yields did not differ significantly between cropping systems (One-way ANOVAs, p>0.05). This work shows that the application of an integrated crop management system results in an increase in beneficial invertebrate activity-densities and increases surface seed predation when compared to no-till and organic systems. These results suggest that integrated cropping systems can reduce herbicide application while effectively controlling weeds and thereby help to reduce the ecosystem impact of agricultural systems.