Climatic impact on the productivity of sugar beet in Europe, 1961–1995

A recent study showed that drought stress was the major factor causing yield loss of the sugar beet crop in the UK. That study has been extended here by modelling potential and rain-fed yields (1961-1995) for European areas where irrigation of sugar beet is uncommon. The inputs to this study are an improved crop growth model, the European monthly half-degree gridded meteorological data time series, and a map of soil texture and available water capacity in sugar beet growing regions. Model outputs were scaled using a ratio of national mean to experimental plot yields to reflect commercial performance of a hypothetical 1998 variety for all years. The model was run on daily weather data reconstructed from monthly values. Potential yields increased from north to south and from west to east due to increased radiation receipts. Drought losses were greatest in east Ukraine and southern Russia, at over 40% of potential yield (5 t ha-1). Losses were intermediate (15-30% or about 2 t ha-1) in central Ukraine, west Poland, east Germany and England (sandy soils) and lowest in NW Europe and west Ukraine. Increasing continentality decreases the number of rainy days per month during summer and the fraction of diffuse radiation; this reduces the radiation use efficiency by as much as 11%. Model output was also used to examine the efficiency of sugar beet production across Europe; at the extremes, NW European farmers deliver about 80% of the potential rain-fed yield while Polish farmers are only able to deliver 40%. This study demonstrates the importance of breeding for drought stress tolerance in Europe