Organic vegetable cropping systems yields and practices in Senegal

Yields in organic farming are controversial and are considered to be lower than in conventional agriculture. In Africa, organic farming practices are very diverse and yields are highly uncertain. Analyses of yields and crop management practices are described on three vegetable crops in Senegal. The results are then compared with the usual yields of conventional agriculture. Two types of data are used, all of which coming from farmers' fields: (i) monitoring of fields cultivated according to organic vs. conventional farming methods; (ii) results from the actions of the non-governmental organization ENDA-PRONAT following specifications copied from organic farming requirements. Comparative monitoring of cabbage and tomato fields in the rainy season showed organic/conventional farming yield ratios of 74 and 40% respectively. These values confirm the general trend of literature. They are explained by a lower nitrogen fertilization and lack of effective measures to protect crops against diseases and pests. The onion yields of organic farmers' fields are very variable: on average, from 19.4 t/ha to 11.0 t/ha depending on the years in the Niayes area, 21.0 t/ha in the Groundnut Basin and only 8.6 t/ha in the Senegal River Valley. According to scientific literature, yields of onion crops in Senegal also vary in large proportions, from 10.7 to 32 t/ha. In some cases, yields in organic farming are higher than those in conventional farming. This observation, already noticed in the academic literature, shows that organic farming is a pathway for agriculture development not to be discarded in Africa.