Sugar beet, a sustainability factor of arable crop stems in northern France

Sugar beet growing is facing several challenges at global level: the need to produce enough food to meet the growing world population and satisfy new non-food uses, to reduce environmental impacts and to take into account climate change. Sugar beet yield made significant progress between 1980 and 2010 and the competitiveness of the crop increased. During the same period, a downward trend in the price of sugar beet was observed in France. In terms of the environment, the energy balance of sugar beet is favourable: it produces an energy potential over 16 times higher than the energy used in cultivation and as inputs. The crop's low nitrogen requirements and the reduction of inputs have several effects: N2O emissions are limited by the low input of nitrogen fertilizer and correspond on average to the standard IPCC, mineral N pools after harvesting are the lowest of all the major crops. The preservation of soil quality remains a major concern with greatly underestimated risks of erosion on bare soil in spring and of deep compaction. The reduction of pesticides is also an issue, but some possibilities exist such as row till or spraying and diversification of rotations. In conclusion, sugar beet is a productive crop and has a relatively positive balance sheet in terms of environmental impacts, but it is necessary to pursue both the reduction of production costs and environmental impacts. Improvements can be provided by genetics, good integration into cropping systems and implementation of innovations. But a main difficulty is the reduction of labour on farms, which limits the implementation of new practices likely to increase the crop's sustainability.