Ecosystems provide multiple services to society. While most research on ecosystem services has not addressed interactions between ecosystem services, compelling evidence for large-scale and long-term ecosystem service interactions has emerged recently, arguing for redoubled work on ecological mediation of interactions at finer scales. In agroecosystems, ecosystem services such as crop production, wood production, livestock forage production, and soil formation can influence one another both positively (a synergy) and negatively (a trade-off), altering the supply of each service. We investigated 1) the degree to which these services influence one another, and 2) the means by which these influences may occur, over relatively fine scales (0.1 ha; 2 years) in smallholder farms in western Kenya. In 59 0.1 ha plots in fallow fields, we measured tree diameter at breast height, and visually estimated cover and height of large shrubs and forage species. Near infrared spectroscopy was used to predict most indicators of soil formation (soil N, C, cation exchange capacity), while steady infiltration rates were estimated with asymptotic regression of ring infiltrometer data. After cultivation of the fallows, grain yield of maize was sampled in a 9 m2 subplot in the center of each 0.1 ha plot.
Results/Conclusions
Indicators of soil formation were positively associated with wood production, and negatively associated with production of forage for livestock and grazing, while wood production and production of livestock forage were negatively associated with one another. Post-fallow maize yields increased with the values of soil indicators, suggesting that maize yields also exhibit synergy and trade-off with, respectively, wood production and production of livestock forage. The results further suggest that the diversity and functional traits of large woody plants play significant roles in mediating interactions of wood production with production of livestock forage, soil formation, and post-fallow maize yields.
