Climatic Conditions and Agricultural Production in Lower Zio Valley (Southern Togo)

This study was carried out in the lower Zio valley, an area located between a latitude of 6.13o and 6.20°N and a longitude of 1.04° and 1.32°E. This zone has increasingly undergone significant climate change in recent decades. The main consequence of this climatic phenomenon is the decline in the standard of living of rural communities whose main economic activity is agriculture. This research aims not only at investigating the variations that characterize the climate but also at analyzing the impact on agricultural production at the scale of the research site. The data of certain climatic parameters such as Rainfall, temperature and evapotranspiration from the period 1981-2020 were used in order to achieve the objective of the study. The Standardized Precipitation Indices (SPI), the Martonne aridity indices, the Lamb index and the Pettit test are the statistical treatments used to describe the hydro-climatic manifestations of the research area. The results from the various statistical processing of climate data show that the lower Zio valley is undergoing more or less significant climate changes with an upward trend in cumulative rainfall. The standardized index made it possible to highlight the rainfall variations characterized by the alternation of surplus and deficit years. Indeed, the years of increased rainfall are for example: 1999 with 30.27% water surplus; 2010 with 27.2% and 2017 with 22.99%. On the other hand, some of the deficit years are 1983 with 34.70% of deficits; 1992 with -36.98% and 2000 with -34.70%. In addition, the low temperature differences are 1.05°C in Lomé and 0.59°C in Tabligbo. In the end, all these climatic phenomena disrupt the normal course of crop development cycles and provoke lower agricultural yields.