ABSTRACT
Tropical agriculture in West Africa is confronted to several constraints of ongoing climate change. Variations in rainfall with disturbed onset and length of rainy reasons are major challenges in the Savannah Region of northern Togo. The agricultural sector, traditional and modern, is especially vulnerable to such climate irregularities. The spatiotemporal analysis of rainfall variability between 1965 and 2014 and the study of physiological needs of selected plants (millet, sorghum, maize and rice) was examined. It was possible to highlight the inter-annual and spatial variability of precipitation, and to detect plant growth stage during which water deficit occurred according to the growth cycle of the crops. The results show that seasonal rains do not always correspond to water requirements of crops during the vegetative cycle. The ecological requirements of crops are not met and their biological cycles are often disturbed. Crops’ vulnerability is noticed through the delay in growth and the rate of appearance of tillers, the wilting of plants, the early leafy stage of the aged leaves. Correlation between rainfall and agricultural yields showed a positive relationship for all the crops studied. In conclusion, food production and supply of the consumers are undermined by changes in regional rainfall patterns and disturbed rainfall distribution.
