Management Options to Improve Drought Resilience in Sugar Beet

Weather-extreme events are increasingly common due to climate change, with longer periods of drought and periods of strong rainfall. Drought periods are a problem in agriculture with several crops suffering from qualitative and quantitative yield reduction depending on the crop growth stage. Sugar beet (Beta Vulgaris) makes up 20% of sugar production worldwide and is the main source of sugar in temperate regions, with a recent increase in its use for biofuel production. The search for drought-resistant varieties of sugar beet with lower water requirements is expanding, however substantial variability in drought resistance regarding yield and quality has not been found so far. The goal of this study was to develop strategies to improve yield security in sugar beet cultivation under low water availability conditions. Therefore, two field experiments were established at sites representative of Austrian sugar beet production (Oberhausen, Marchfeld; Guntersdorf, Weinviertel) over the course of two years, 2020 and 2021. The experiments involved combining breeding strategies (variety selection) with agronomic approaches (soil management, land cover, irrigation, fertilization) to investigate the sugar beet's response to water stress and assess the performance of different sugar beet varieties, leading to a more climate-resilient sugar beet crop. Direct methods of measuring soil hydraulic properties (e.g. via soil moisture sensors) and plant properties (e.g. stomata density and conductance) with stable isotope analysis for carbon and water were combined. As a result, a significant yield increase was found in irrigated plots. Nitrogen fertilization had a detrimental effect when applied extensively. A yield increase was obtained by soil coverage with wooden chips in both years and sites. Furthermore, the choice of variety also played an essential role, especially regarding the trade-off between drought resistance and yield.