Evolution of floristic composition and species diversity of weed community after 10-years of different cropping systems and soil tillage in Mediterranean environment

This is the pre-print version of the manuscript "Floristic composition and species diversity of weed community after 10 years of different cropping systems and soil tillage in Mediterranean environment", published as final paper in Weed Research, Volume 58, Issue 4, Pages 273-283. 

https://doi.org/10.1111/wre.12301

https://onlinelibrary.wiley.com/doi/epdf/10.1111/wre.12301

Summary

Sustainable cropping systems based on low inputs are gaining attention, even if may determine a change on weed community composition. This study, conducted from 2011 to 2014, evaluates the changes of weed species under different cropping systems [conventional (CONV) and organic (ORG)] and soil tillage [inversion tillage (IT) and non-inversion tillage (NoIT)] in a wheat-tomato-chickpea rotation under Mediterranean environment after 12-years of cultivation. Treatments were replicated three times according to a randomized complete block design. The ORG was managed according to EU regulations. The IT consisted in moldboard plowing to a depth of 30 cm, while the NoIT consisted in subsoiling to a depth of 20 cm. ORG-NoIT showed the highest weed biomass (134.6, 128.3 and 195.4 g m^-2 of DM in wheat, tomato and chickpea, respectively) and density (66.2, 77.3 and 76.1 plant m^-2 of DM in wheat, tomato and chickpea, respectively), as well as community richness and Shannon Index. ORG always increases weed biodiversity, even if annual dicots were high in ORG-IT, while perennial broadleaved species in ORG-NoIT. CONV increased the relative frequency of annual (CONV-IT) and perennial (CONV-NoIT) grasses. The negative correlation between perennial weeds and crop yield (r²=0.2363, p<0.0001) suggests that perennial weeds was partly responsible for the crop yield reduction. Combining organic practices with non-inversion tillage could lead to the establishment of perennial dicots difficult to manage, which requires the adoption of new management practices.