Hairy vetch cover crop affects weed diversity and composition in no-till sunflower

Summary

Vicia villosa Roth, or hairy vetch, is one of the most productive cover crops (CC) in Mediterranean dry areas, with an interesting potential as dead mulch in no-tillage cropping systems. In low-input cropping systems, mechanical termination of hairy vetch could replace a glyphosate application to control weeds. Mechanical termination (e.g. with a roller crimper) of hairy vetch is ineffective until the late growing stages of vetch, leading to delayed sowing and yield reduction in the following crop.
To find the best compromise in timing between effective termination of vetch and reasonable yield of no-till sunflower, an on-farm experiment was carried out in Pisa (Italy) in 2012/13 and 2013/14 to compare three termination techniques (roller crimper with no, half and full dose of glyphosate) and three termination dates (before flowering, beginning of flowering, 70% of flowering of vetch). Data on weed biomass, species density and soil cover were collected at CC termination and during sunflower growth. Weed diversity and composition were analyzed through ANOVA, PERMANOVA and NMDS.