High environmental risk and low yield of urban tomato gardens in Benin

Urban agriculture, Life-cycle inventory,Typology,Cropping system data,Treatment frequency index,Nutrient budget; International audience; In sub-Saharan Africa, urban farmers have recently intensified the production of vegetables to cope with the increasing food demand. As a consequence, such an intensification may lead to potential risks for the environment and human health. There is therefore a need for an integrated evaluation of urban agricultural practices. Here, we studied tomato production in Benin cities. We measured performances and the environmental risks. We have monitored 12 cropping systems during 6 months and we calculated the pesticide treatment frequency index (TFI), the nutrient budgets, and the field emissions. Our results show that yields were low and variable, averaging at 9,533 kg.ha−1 and ranging from 0 to 21,163 kg.ha−1. The average TFI for pesticides was 8.9. The maximum TFI of 25 was observed for an insecticide applied weekly at 2.3 times the official rate. We observed an excess of the average nutrient budget of 120 kg N and 84 kg P. ha−1. In conclusion, our study of urban tomato production revealed poor practices and high risks for health and the environment.