Management practices influence the competitive potential of weed communities and their value to biodiversity in South African vineyards

Abstract

Weeds have negative impacts on crop production but also play a role in sustaining biodiversity in agricultural landscapes. This trade-off raises the question of whether it is possible to promote weed communities with low competitive potential but high value to biodiversity. Here, we explored how weed communities respond to different vineyard management practices in South Africa's Western Cape, aiming to identify whether any specific practices are associated with more beneficial weed communities. Eight weed community characteristics representative of abundance, diversity and functional composition were used as indicators of competitive potential and biodiversity value. We explored how these responded to farm management strategy (organic, low input or conventional) and weed management practices (herbicides, tillage, mowing or combinations of these) using ordination and mixed models. Mown sites were associated with weed communities of high biodiversity value, with higher weed cover in both winter and summer, higher diversity and more native weeds. Mowing also promoted shorter weeds than either tillage or herbicides, considered to be less competitive with grapevines. However, high summer weed cover may be problematic where competition for water is critical, in which case tillage offers a method to limit summer weed cover that did not adversely affect diversity or native weeds. In contrast, herbicide-treated sites had characteristics indicative of a lower biodiversity value and higher potential for competitiveness with few native weeds, lower diversity and relatively tall, small-seeded weeds. Mowing in winter combined with tillage in spring may thus optimise the biodiversity benefits and production costs of Western Cape vineyard weeds.

Autonomous Mowing and Complete Floor Cover for Weed Control in Vineyards

“…Moreover, the combination of constant mowing and low cutting height resulted in an evident effect on therophyte species (i.e., Conyza canadensis and Digitaria sanguinalis) especially in the IR, compared to the UT. In fact, many authors state that mowing selects for short species and for species with a creeping habitus [32,38,49,50] and that management intensity can affect weed populations [50]. These findings may explain the higher weed cover percentage and the lower weed dry biomass in SC-AM plots compared to SC-CM plots.…”

“…Moreover, particular interest is placed on weeds height in vineyards. This trait is linked with competition at both aboveground and underground levels [32,33]. Preventing weeds from growing tall inside vines canopy is another main goal of under-trellis management [23].…”

Comparison between flaming, mowing and tillage weed control in the vineyard: Effects on plant community, diversity and abundance

“…A large-scale investigation in vineyards in France highlighted that different management practices, such as herbicide application and tillage, promoted some characteristics species pools [52]. Another study [53] investigated the influence of alternative management practices in plant communities composition in South African vineyards, proving that mowing was associated with a higher biodiversity value and a higher cover than tillage and herbicide, promoting at the same time shorter plants, that could be less competitive for grapevines [53]. However, tillage offered an increased plant control efficiency, being beneficial in Summer season, when competition for water may become critical [53].…”

Autonomous Mowers Working in Narrow Spaces: A Possible Future Application in Agriculture?

“…The effects of autonomous mowers constant mowing decreased the weed incidence on tall fescue [17] and manila grass [18] lawns compared to conventional rotary mowing. A constant mowing height showed to favor low creeping weeds [2]; however, the low height of these weeds resulted in an overall lower competition with the crops [19]. According to Slaughter et al [7], autonomous weed control technologies contribute to reduce human labor and herbicides applications.…”