| 1. |
- Broberg, Malin, 1989, et al.
(författare)
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Effects of ozone, drought and heat stress on wheat yield and grain quality
- 2023
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Ingår i: Agriculture, Ecosystems & Environment. - 0167-8809. ; 352:15
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Tidskriftsartikel (refereegranskat)abstract
- Tropospheric ozone (O3) is a gaseous phytotoxic plant stressor known to reduce wheat (Triticum aestivum) crop yields at current concentrations. O3 is predicted to increase in many crop-growing regions, together with higher frequencies of heatwaves and droughts. In this study, wheat crops were exposed to two levels of O3 (ambient and ~70 ppb) in combination with ambient or elevated temperature (+8 ◦C) and two watering regimes (well-watered and 50% reduced water supply) during the grain-filling period. With this experimental setup, we assessed the interactive effects between O3, temperature and water supply on wheat yield and grain quality, and measured leaf gas exchange to explore the underlying mechanisms. Overall, O3, warming and drought all decreased grain yield and average grain mass but increased grain concentration of N and other nutrient elements. Increasing daytime O3 from 25 to 73 ppb resulted in a 25% yield reduction in treatments with ambient temperature and well-watered soil. Drought reduced the impact of O3 on light-saturated photosynthesis, grain mass, total aboveground biomass and grain concentrations of K, Ca, Mg, Mo. In contrast, concentrations of K and Ca increased to a larger extent when O3 stress was combined with elevated temperature. Grain concentrations of N, Ca and Zn were closely and negatively related to grain yield regardless of O3, heat and drought stress, likely explained by the reduction in grain filling period, with starch accumulation reduced to a larger extent than that of these elements. P, K, Mg, Mn, Mo concentrations were weakly related to grain yield, but were clearly altered by environmental stress. The modifying effect of water availability is crucial to include in assessments of O3 impacts on global food production in relation to climate change, considering effects on wheat yield variables and grain nutrient concentrations.
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| 2. |
- Broberg, Malin, 1989, et al.
(författare)
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Fertilizer efficiency in wheat is reduced by ozone pollution
- 2017
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 607-608, s. 876-880
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Tidskriftsartikel (refereegranskat)abstract
- Inefficient use of fertilizers by crops increases the risk of nutrient leaching from agro-ecosystems, resulting in economic loss and environmental contamination. We investigated how ground-level ozone affects the efficiency by which wheat used applied nitrogen (N) fertilizer to produce grain protein (NE P , N efficiency with respect to protein yield) and grain yield (NE Y , N efficiency with respect to grain yield) across a large number of open-top chamber field experiments. Our results show significant negative ozone effects on NE P and NE Y , both for a larger data set obtained from data mining (21 experiments, 70 treatments), and a subset of data for which stomatal ozone flux estimates were available (7 experiments, 22 treatments). For one experiment, we report new data on N content of different above-ground plant fractions as well as grain K and P content. Our analysis of the combined dataset demonstrates that the grain yield return for a certain investment in N fertilizer is reduced by ozone. Results from the experiment with more detailed data further show that translocation of accumulated N from straw and leaves to grains is significantly and negatively affected by ozone, and that ozone decreases fertilizer efficiency also for K and P. As a result of lower N fertilization efficiency, ozone causes a risk of increased N losses from agroecosystems, e.g. through nitrate leaching and nitrous oxide emissions, a hitherto neglected negative effect of ozone. This impact of ozone on the N cycle implies that society is facing a dilemma where it either (i) accepts increased N pollution and counteracts ozone-induced yield reductions by increasing fertilization or (ii) counteracts N pollution under elevated ozone by reducing fertilization, accepting further yield loss adding to the direct effect of ozone on yield.
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| 3. |
- Diedrich, Amy, et al.
(författare)
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An applied research agenda for navigating diverse livelihood challenges in rural coastal communities in the tropics
- 2022
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Ingår i: One Earth. - : Elsevier BV. - 2590-3330 .- 2590-3322. ; 5:11, s. 1205-1215
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Tidskriftsartikel (refereegranskat)abstract
- Rural, tropical coastal communities are experiencing sustained, often increasing food insecurity, poverty, and global change impacts. These challenges have stimulated a rise in projects aiming to enhance and diversify local livelihoods. The ability of these projects to achieve broad-scale benefits is limited by approaches that do not account for feedbacks among sectors and across marine and terrestrial environments. To address these limitations, we present an applied research agenda to support an integrated approach to livelihood project planning and management. This agenda explicitly examines interactions among natural resources, industries, and livelihoods and is based on three foundational activities: (1) a governance review and assessment, (2) strategic partnership formation, and (3) a diagnostic approach supported by science and shared outcomes. We add structure to the established logic in our field by broadening the sectoral and spatial scope of livelihoods projects, so they can better contribute to interrelated UN Sustainable Development Goals.
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| 4. |
- Emberson, Lisa D., et al.
(författare)
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Ozone effects on crops and consideration in crop models
- 2018
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Ingår i: European Journal of Agronomy. - : Elsevier BV. - 1161-0301. ; 100:Special Issue: SI, s. 19-34
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Tidskriftsartikel (refereegranskat)abstract
- © 2018 The Authors We review current knowledge of the processes by which ozone will cause injury and damage to crop plants. We do this both through an understanding of the limitations to ozone uptake (i.e. ozone being transferred from some height in the atmosphere to the leaf boundary layer and subsequent uptake via the stomata) as well as through the internal plant processes that will result in the absorbed ozone dose causing damage and/or injury. We consider these processes across a range of scales by which ozone impacts plants, from cellular metabolism influencing leaf level physiology up to whole canopy and root system processes and feedbacks. We explore how these impacts affect leaf level photosynthesis and senescence (and associated carbon assimilation) as well as whole canopy resource acquisition (e.g. water and nutrients) and ultimately crop growth and yield. We consider these processes from the viewpoint of developing crop growth models capable of incorporating key ozone impact processes within modelling structures that assess crop growth under a variety of different abiotic stresses. These models would provide a dynamic assessment of the impact of ozone within the context of other key variables considered important in determining crop growth and yield. We consider the ability to achieve such modelling through an assessment of the different types of crop model currently available (e.g. empirical, radiation use efficiency, and photosynthesis based crop growth models). Finally, we show how international activities such as the AgMIP (Agricultural Modelling and Improvement Intercomparison Project) could see crop growth modellers collaborate to assess the capabilities of different crop models to simulate the effects of ozone and other stresses. The development of robust crop growth models capable of including ozone effects would substantially improve future national, regional and global risk assessments that aim to assess the role that ozone might play under future climatic conditions in limiting food supply.
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| 5. |
- Harmens, H., et al.
(författare)
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Wheat yield responses to stomatal uptake of ozone: Peak vs rising background ozone conditions
- 2018
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310. ; 173, s. 1-5
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Tidskriftsartikel (refereegranskat)abstract
- Recent decades have seen a changing temporal profile of ground-level ozone (O-3) in Europe. While peaks in O-3 concentrations during summer months have been declining in amplitude, the background concentration has gradually increased as a result of the hemispheric transport of O-3 precursors from other world regions. Ground level O-3 is known to adversely affect O-3-sensitive vegetation, including reducing the yield of O-3-sensitive crops such as common wheat (Triticum aestivum L.). The reduction in wheat yield has been shown to be linearly related to the phytotoxic O-3 dose above a flux threshold of Y (PODY) accumulated over a specific period. In the current study, we tested whether the flux-effect relationships for wheat yield and 1,000-grain weight were affected by the temporal profile of O-3 exposure. A modern wheat cultivar (Skyfall) was exposed to eight different realistic O-3 profiles repeated weekly: four profiles with increasing background O-3 concentrations (ca. 30-60 ppb) including small peaks and four profiles with increasing O-3 peak concentrations (ca. 35-110 ppb). Both wheat yield and 1,000-grain weight declined linearly with increasing PODY. The slope of the flux-effect relationships was not affected significantly by the profile of O-3 exposure. Hence, flux-effect relationships developed for wheat based on exposure to enhanced peak O-3 concentrations are also valid for the changing European O-3 profile with higher background and lower peak concentrations. The current study also shows that the modern wheat cultivar Skyfall is more sensitive to O-3 than European wheat varieties tested for O-3 sensitivity in the 1980s and 1990s.
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| 6. |
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| 7. |
- Mills, Gina, 1959, et al.
(författare)
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Closing the global ozone yield gap: Quantification and cobenefits for multistress tolerance
- 2018
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 24:10, s. 4869-4893
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Tidskriftsartikel (refereegranskat)abstract
- Increasing both crop productivity and the tolerance of crops to abiotic and biotic stresses is a major challenge for global food security in our rapidly changing climate. For the first time, we show how the spatial variation and severity of tropospheric ozone effects on yield compare with effects of other stresses on a global scale, and discuss mitigating actions against the negative effects of ozone. We show that the sensitivity to ozone declines in the order soybean>wheat>maize>rice, with genotypic variation in response being most pronounced for soybean and rice. Based on stomatal uptake, we estimate that ozone (mean of 2010–2012) reduces global yield annually by 12.4%, 7.1%, 4.4% and 6.1% for soybean, wheat, rice and maize, respectively (the “ozone yield gaps”), adding up to 227Tg of lost yield. Our modelling shows that the highest ozone-induced production losses for soybean are in North and South America whilst for wheat they are in India and China, for rice in parts of India, Bangladesh, China and Indonesia, and for maize in China and the United States. Crucially, we also show that the same areas are often also at risk of high losses from pests and diseases, heat stress and to a lesser extent aridity and nutrient stress. In a solution-focussed analysis of these results, we provide a crop ideotype with tolerance of multiple stresses (including ozone) and describe how ozone effects could be included in crop breeding programmes. We also discuss altered crop management approaches that could be applied to reduce ozone impacts in the shorter term. Given the severity of ozone effects on staple food crops in areas of the world that are also challenged by other stresses, we recommend increased attention to the benefits that could be gained from addressing the ozone yield gap.
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| 8. |
- Mills, Gina, et al.
(författare)
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Evidence of widespread effects of ozone on crops and (semi-)natural vegetation in Europe (1990 - 2006) in relation to AOT40 - and flux-based risk maps
- 2010
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Ingår i: Global Change Biology. - : Wiley. - 1365-2486 .- 1354-1013. ; 17:1, s. 592-613
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Tidskriftsartikel (refereegranskat)abstract
- Records of effects of ambient ozone pollution on vegetation have been compiled for Europe for the years 1990–2006. Sources include scientific papers, conference proceedings, reports to research funders, records of confirmed ozone injury symptoms and an international biomonitoring experiment coordinated by the ICP Vegetation. The latter involved ozone-sensitive (NC-S) and ozone-resistant (NC-R) biotypes of white clover (Trifolium repens L.) grown according to a common protocol and monitored for ozone injury and biomass differences in 17 European countries, from 1996 to 2006. Effects were separated into visible injury or growth/yield reduction. Of the 644 records of visible injury, 39% were for crops (27 species), 38.1% were for (semi-) natural vegetation (95 species) and 22.9% were for shrubs (49 species). Owing to inconsistencies in reporting effort from year to year it was not possible to determine geographical or temporal trends in the data. Nevertheless, this study has shown effects in ambient air in 18 European countries from Sweden in the north to Greece in the south. These effects data were superimposed on AOT40 (accumulated ozone concentrations over 40 ppb) and POD3gen (modelled accumulated stomatal flux over a threshold of 3 nmol m−2 s−1) maps generated by the EMEP Eulerian model (50 km × 50 km grid) that were parameterized for a generic crop based on wheat and NC-S/NC-R white clover. Many effects were found in areas where the AOT40 (crops) was below the critical level of 3 ppm h. In contrast, the majority of effects were detected in grid squares where POD3gen (crops) were in the mid-high range (>12 mmol m−2). Overall, maps based on POD3gen provided better fit to the effects data than those based on AOT40, with the POD3gen model for clover fitting the clover effects data better than that for a generic crop.
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| 9. |
- Mills, Gina, 1959, et al.
(författare)
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New stomatal flux-based critical levels for ozone effects on vegetation
- 2011
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1873-2844 .- 1352-2310. ; 45:28, s. 5064-5068
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Tidskriftsartikel (refereegranskat)abstract
- The critical levels for ozone effects on vegetation have been reviewed and revised by the LRTAP Convention. Eight new or revised critical levels based on the accumulated stomatal flux of ozone (POD gamma, the Phytotoxic Ozone Dose above a threshold flux of Y nmol m(-2) PLA s(-1), where PLA is the projected leaf area) have been agreed. For each receptor, data were combined from experiments conducted under naturally fluctuating environmental conditions in 2-4 countries, resulting in linear dose response relationships with response variables specific to each receptor (r(2) = 0.49-0.87, p
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| 10. |
- Mills, Gina, 1959, et al.
(författare)
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Ozone pollution will compromise efforts to increase global wheat production
- 2018
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 24:8, s. 3560-3574
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Tidskriftsartikel (refereegranskat)abstract
- Introduction of high-performing crop cultivars and crop/soil water management practices that increase the stomatal uptake of carbon dioxide and photosynthesis will be instrumental in realizing the United Nations Sustainable Development Goal (SDG) of achieving food security. To date, however, global assessments of how to increase crop yield have failed to consider the negative effects of tropospheric ozone, a gaseous pollutant that enters the leaf stomatal pores of plants along with carbon dioxide, and is increasing in concentration globally, particularly in rapidly developing countries. Earlier studies have simply estimated that the largest effects are in the areas with the highest ozone concentrations. Using a modelling method that accounts for the effects of soil moisture deficit and meteorological factors on the stomatal uptake of ozone, we show for the first time that ozone impacts on wheat yield are particularly large in humid rain-fed and irrigated areas of major wheat-producing countries (e.g. United States, France, India, China and Russia). Averaged over 2010-2012, we estimate that ozone reduces wheat yields by a mean 9.9% in the northern hemisphere and 6.2% in the southern hemisphere, corresponding to some 85 Tg (million tonnes) of lost grain. Total production losses in developing countries receiving Official Development Assistance are 50% higher than those in developed countries, potentially reducing the possibility of achieving UN SDG2. Crucially, our analysis shows that ozone could reduce the potential yield benefits of increasing irrigation usage in response to climate change because added irrigation increases the uptake and subsequent negative effects of the pollutant. We show that mitigation of air pollution in a changing climate could play a vital role in achieving the above-mentioned UN SDG, while also contributing to other SDGs related to human health and well-being, ecosystems and climate change.
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