Trend analysis of growing season characteristics and agro-climatic risks in the 'Trois Rivieres' forest reserve agro-ecosystems in North Benin

摘要

Few studies regarding the assessment of the growing season's trends and the associated agro-climatic risks are focused on agro-ecosystems around forest reserve although adaptive extensive agriculture poses severe threats due to climate variability and change. This study aims at analyzing the evolution of agro-climatic characteristics to identify the associated risks. It firstly consisted in analyzing the temperatures within the period from 1960 to 2016 in the forest reserve of "Trois Rivieres." Secondly, the characteristics of the growing season and their distribution were analyzed. Statistic-based tests were further performed to identify major trends and breaks as well as the associated agro-climatic risks. Thus, the period from 2000 to 2016 generally presents wet conditions (increasing trends of Standardized Precipitation Index and rainy days) similar to the period of 1960 to 1975; which are separated by a relatively dry period (increasing trends of dry spells) from 1975 to 2000. Those facts reveals an apparent return to wet conditions after the 2000s which is coupled with the acceleration of warming resulting in the increase of minimum temperatures by 1.5 degrees C and the maximum by 1 degrees C. We also noticed a great variability of the dry spells within the growing season which has accentuated especially the risk of sowing failure (false start) by 56 to 74% and the yields failure risks by 52%. Our findings showed the degree to which farmers are affected by the realities of climate variability and change in "Trois Rivieres" forest agro-ecosystems. That led farmers, mostly poor, to resort to extensive agriculture which unfortunately is the main cause of deforestation.