Impacts of projected precipitation changes on sugar beet yield in Eastern England

Projected increasing temperatures and reduced summer rainfall in the United Kingdom pose a sustainability and food security challenge for the agricultural industry. This study investigates the potential impact of precipitation changes on eastern England sugar beet yield. Precipitation data over eastern England from weather stations (1971-2000) and a range of the 5(th) Phase of the Coupled Model Intercomparison Project (CMIP5) climate models (historical' for 1971-2000; and Representative Concentration Pathways RCP45 and RCP85 for 2021-2050) were examined. A good agreement was found between the observations and the overlapping model grid cell. The study then investigated the impact of likely future rainfall changes on yield by applying controlled watering regimes informed by the CMIP5 projections to 150 sugar beet plants grown in a greenhouse, the use of CMIP5 projections in this way is a first. Watering regimes that represent present day' and future' precipitation characteristics were calculated: 0.46 L of water was applied every other day to each plant in the present day category; 0.39 L was applied every other day to each plant in the future category. This reflects the 16% reduction in future rainfall that was calculated from the climate models. Results from the greenhouse experiment showed a statistically significant (p < 0.01) reduction in soil moisture in the future category, which was related to a statistically significant (p < 0.05) reduction in mean tuber wet mass: a mean of 360 g for present day and 319 g for future. The results for dry mass were less significant (p = 0.11) but indicated a reduction in the future category (95.2 vs 88.2 g). These findings imply a potential yield reduction of 11% by 2050.