The Impact of Future Climate Change on the Production of a Major Food and Cash Crop in Tropical (Sub)Montane Homegardens

Abstract

Tropical agroforestry systems support the wellbeing of many smallholder farmers. These systems provide smallholders with crops for consumption and income through their ecological interactions between their tree, soil, and crop components. These interactions, however, could be vulnerable to changes in climate; yet a reliable understanding of how this could happen is not well documented. The aim of this study is to understand how tree-soil-crop interactions and crop yield could be affected by future climate change. We used a space-for-time climate analogue approach, in conjunction with structural equation modelling, to empirically examine how a warmer and drier climate forecasted for some tropical regions affects tree-soil-crop interactions and banana yield in Mt Kilimanjaro’s homegarden agroforest. Overall, climate change negatively affected ecological interactions in the homegardens by destabilising soil nutrient cycles. Banana yield, however, was mainly directly influenced by the climate. Banana yields could initially benefit from the warmer climate before later declining under water stress. Our findings suggest that under a warmer and drier future climate scenario, homegarden agroforestry may not be a robust long-term farming practice which can protect smallholder’s wellbeing.

Keywords: Tropical agroforestry, Climate impacts, Banana yield, Ecosystem Services, Climate analogue analysis, Structural equation modelling