Weed species diversity and community composition in organic potato field

Iliana Gerasimova and Totka Mitova

Abstract: Weeds are the component of biological diversity in the agricultural systems (agrobiodiversity) and one of the greatest limiting factors to efficient organic crop production. The goal of the experiment is to define the influence of organic agricultural practices on the dynamics of weed infestation, weed species diversity and community composition in organic potato field included in three- field crop rotation. The results show that all analyzed weed parameters are characterized by high dynamics during potato grown seasons. The biological development of weeds in the cover crop before incorporation to the potato field was strongly limited. According to the data obtained, cover crop for green manure and mechanical soil tillage in the organic potato field were effective practices for controlling the weed infestation. The effect of organic practices on the weed community parameters were assessed by ecological indexes (Shannon index (H′), Shannon-Wiener evenness index (J′), index of dominance (Simpson dominance index, D) and similarity indexes (Sǿrensen similarity index, SSI). Results show that the studied three-field crop rotation included winter wheat, green bean, peas and rye mixture as cover crops and potato is a strategic scheme for achieving good weed control at the end of the rotation. The comparison of similarity of weed communities in a potato field between 2012 and 2013 using Sǿrensen indices shows that the similarity was higher on the base of the qualitative index (35.3%) than of the quantitative ones (20.8%).

Keywords: ecological indexes; green manure; organic potato; weed community

Date published: 2020-06-29