Livelihood and climate trade-offs in Kenyan peri-urban vegetable production
This study (PDF) in the Agricultural Systems journal, investigates productivity and economic and climate trade-offs in soil fertility management strategies in smallholder African indigenous vegetable (AIV) production in Kiambu county, Kenya. Tade-offs between livelihood and environmental outcomes due to agricultural intensification in sub-Saharan Africa are uncertain. Yield, economic performance and nitrous oxide (N2O) emissions were measured of African indigenous vegetable (AIV) to investigate the optimal nutrient management strategies. In order to achieve this, an on-farm experiment with four treatments was performed for two seasons. The results indicate that, treatment with diammonium phosphate (DAP) alone resulted at least 14% greater yields, gross margin and returns to labour in absolute terms but had the highest emissions. Productivity-climate trade-offs, expressed as N2OI, were statistically similar for DAP and mixed treatments. However, N2OEI was minimized under mixed management, while maintaining productivity and gross margins. Thus, soil fertility management strategies that mix inorganic and organic source present a pathway to sustainable intensification in AIV production. Furthermore, this study has shown that the inclusion of economic value versus just productivity alone may change conclusions around the selection of which soil management practice is the best fit for purpose when wanting to optimise climate and livelihood trade-offs. Although limited in scope, these data provide a first indication of the importance of taking the trade-off analysis one step further to include economic value. It is therefore concluded that soil fertilisation from a mix of organic and inorganic nitrogen fertilisers is a promising agronomic pathway towards achieving optimal combined economic and environmental outcomes from vegetable production in peri-urban Kenya. Future work in this field should consider the limitations of considering productivity alone when trying to reflect the true nature of the trade-offs faced by farmers. Including economic performance when considering trade-offs should be considered when studying GHG emissions of crop production.