Understanding the combined impacts of weeds and climate change on crops

Abstract

Crops worldwide are simultaneously affected by weeds, which reduce yield, and by climate change, which can negatively or positively affect both crop and weed species. While the individual effects of environmental change and of weeds on crop yield have been assessed, the combined effects have not been broadly characterized. To explore the simultaneous impacts of weeds with changes in climate-related environmental conditions on future food production, we conducted a meta-analysis of 171 observations measuring the individual and combined effects of weeds and elevated CO2, drought or warming on 23 crop species. The combined effect of weeds and environmental change tended to be additive. On average, weeds reduced crop yield by 28%, a value that was not significantly different from the simultaneous effect of weeds and environmental change (27%), due to increased variability when acting together. The negative effect of weeds on crop yield was mitigated by elevated CO2 and warming, but added to the negative effect of drought. The impact of weeds with environmental change was also dependent on the photosynthetic pathway of the weed/crop pair and on crop identity. Native and non-native weeds had similarly negative effects on yield, with or without environmental change. Weed impact with environmental change was also independent of whether the crop was infested with a single or multiple weed species. Since weed impacts remain negative under environmental change, our results highlight the need to evaluate the efficacy of different weed management practices under climate change. Understanding that the effects of environmental change and weeds are, on average, additive brings us closer to developing useful forecasts of future crop performance.

Top management challenges and concerns for agronomic crop production in California: Identifying critical issues for extension through needs assessment

“…Weed management will also experience new challenges. For instance, while glyphosate has been projected to lose its efficacy on weeds as CO 2 levels rise, there are also predictions that increased atmospheric CO 2 concentrations will have a positive impact on several weed species, which may contribute to increased risk of crop loss due to weed pressure (Vilá et al., 2021). As a result, both herbicide use and costs are expected to increase as CO 2 levels rise (Koleva & Schneider, 2009).…”

Impact of Climate Change on Dryland Agricultural Systems: A Review of Current Status, Potentials, and Further Work Need

“…They reported that climate change favors the expansion, growth and multiplication of wheat pests. Furthermore, climate change opens new geographic windows for weed infestations (Mao et al, 2021;Vilà et al, 2021), insect biodiversity (Raven & Wagner, 2021) and disease outbreaks (Chaloner et al, 2021) across Fig. 6 Interactive effect of elevated CO 2 , temperature, and drought on soil organic carbon the globe.…”

“…Generally, weeds or plant species show three kinds of reactions to climate change i.e. (i) migration; (ii) acclimation and (iii) adaptation (Vilà et al, 2021). In the future, we will have to adopt sustainable weed management options to minimize the impact of weeds on cropping systems.…”

AgriWeedClim database: A repository of vegetation plot data from Central European arable habitats over 100 years

“…While changes in land‐use type and intensity have substantially affected the biota of arable habitats (Storkey et al, 2012) there is growing evidence that species are increasingly responding to climate change (Parmesan & Yohe, 2003; Chen et al, 2011). As climate change will continue in the coming decades (IPCC, 2022), the resulting impacts on arable habitats and their biota will become more pronounced (Ziska, 2016; Vilá et al, 2021). In addition, arable habitats in Central Europe show high levels of invasion by alien plant species introduced both a long time ago (i.e.…”