Exploring new metrics: Nutritional diversity of cropping systems

Historically, agricultural systems have been assessedon the basis of a narrow range of criteria, such as profitability or yields. Yet, these metrics do not reflect the diversity of nutrients provided by the system that is critical for human health. In this study we take a step to demonstrate how ecological tools can play a role in addressing nutritional diversity as an overlooked ecosystem service of agricultural systems.Data on edible plant species diversity, food security and diet diversity were collected for 170 farms in three rural settings in sub-Saharan Africa. Nutritional FD metrics were calculated based on farm species composition and species nutritional composition.Iron and vitamin A deficiency were determined from blood samples of 90 adult women.Nutritional FD metrics summarized the diversity of nutrients provided by the farm and showed variabilitybetween farms and villages. Regression of nutritional FD against species richness and expected FD enabled identification of key species that add nutrient diversity to the system and assessed the degree of redundancy for nutrient traits. Nutritional FD analysis demonstrated that depending on the original composition of species on farm or village, adding or removing individual species can have radically different outcomes for nutritional diversity.While correlations between nutritional FD, food andnutrition indicators were not significant at householdlevel, associations between these variables were observed at village level.This study provides novel metrics to address nutritionaldiversity in farming systems and examples of how these metrics can help guide agricultural interventions towards adequate nutrient diversity. New hypotheses on the link between agrodiversity, food security and human nutrition are generated and strategies for future research are suggested calling for integration of agriculture, ecology, nutrition, and socio-economics.

ISBN:978-92-5-107288-2

Publication year:2012