Diversity of weed communities in soybean [Glycine max (L.)] crop growing under direct sowing depending on cover crops and different herbicide doses

Abstract

Despite being harmful for agricultural production, weeds are an essential component of biodiversity in agricultural landscapes. A field study was conducted during the period 2007–2009 on grey-brown podzolic soil (sandy), designated as PWsp, with the granulometric composition of silt and classified Class 2 in agricultural land suitability. The study evaluated the structure of weed communities based on selected indicators of diversity of a soybean crop grown under no-tillage with mulch from winter rye, winter oilseed rape, and white mustard as well as using herbicide rates reduced by 25% and 50% in relation to the standard rate (2 L ha−1). The studied factors were as follows: (i) mulch plant species and mulch management method; (ii) rates of the foliar herbicide Basagran 600 SL (a.i. bentazon; 600 g L−1). The results of this study confirm that no-tillage with mulch significantly changes the diversity of weed flora in a soybean crop. Among the mulches used, the mowed rye and winter oilseed rape in particular increased the values of the general diversity (H'), species richness (d), and evenness (J') indices relative to the control treatment. On the other hand, the study found a strong decrease in the value of the dominance index (c). Reduced herbicide rates modified only the species richness index, in the case of which the 75% rate resulted in its significantly higher values compared to the full rate.

Keywords

• biodiversity
• direct sowing
• diversity indices
• Glycine max
• herbicide doses
• mulch