Effect of weeds on microbial community in vineyards soil

Abstract: Weeds, in particular agrestals, represent a threat for a variety of cultivated plants,because they compete for nutrients, water and sunlight. In addition they may affect the crops byproducing toxic compounds through a mechanism called allelopathy. Their presence leads tohuge economical losses, but on the other hand their control, especially through herbicides, couldnegatively affect the environment. Therefore weed control through different strategies ofprevention, control and eradication by means of sustainable approaches is a priority worldwide.Almost nothing is known on the interaction between weeds and soil microorganisms, for exampleif weeds could play a role in the interaction with beneficial soil microbes and in preserving soilmicrobiological quality. In this study we determine the effect of different weeds on total bacterialand fungal abundance in different soils under controlled conditions. We collected soil samples infour vineyards in northern Italy and three weeds, Poa trivialis, Taraxacum officinale andTrifolium repens, were selected based on their ubiquitous presence in the original soils. Eachweed was planted in each soil type. The total amount of fungi and bacteria during different plantstages development was assessed. Total fungi are poorly affected by the plant introduction, evenif, at the true leaf stage of T. officinale and T. repens, an increase was observed. Total bacteriacommunity at true leaf stage also showed a significant increment with T. officinale and T. repensin some soils. The monocotyledon P. trivialis globally did not affect the bacterial and fungalcommunities. Even if a general trend cannot be inferred, we demonstrate an interaction with thecombination of weed species and soil.