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Nutritional diversity

Map of global diversity of food commodities. Diversity is represented by the Shannon diversity index, H, which represents how many different types of foods are produced in a pixel and how evenly these different types are distributed. The higher the Shannon index, the higher the diversity. Figure from Herrero et al. (2017).

The outputs of agricultural systems are traditionally described in terms of yield per unit area (e.g. tonnes per hectare), where the main goal has been to maximise production. But this gives no indication of nutritional quality of the food produced. Innovative metrics to describe the nutritional quality of food production systems is a new and expanding field of research which aims to leverage the potential of agriculture to improve nutrition.

We are working to evaluate the usefulness of various nutritional diversity metrics for future integration with models of global food supply. This works contributes to answering the question “How will global food supply meet the nutritional needs of a growing population?”

Farming and the geography of nutrient production for human use

Our work by Herrero et al. (2017), published in the first issue of the Lancet Planetary Health, used existing spatially-explicit global datasets to estimate the production levels of 41 major crops, seven livestock, and 14 aquaculture and fish products. From overall production estimates, we estimated the production of vitamin A, vitamin B12, folate, iron, zinc, calcium, calories, and protein. We also estimated the relative contribution of farms of different sizes to the production of different agricultural commodities and associated nutrients, as well as how the diversity of food production based on the number of different products grown per geographic pixel and distribution of products within this pixel (Shannon diversity index [H]) changes with different farm sizes.

We found that, globally, small and medium farms produce 51–77% of nearly all commodities and nutrients examined in this study. However, important regional differences exist. Large farms dominate production in North America, South America, and Australia. In these regions, large farms contribute between 75% and 100% of all cereal, livestock, and fruit production, and the pattern is similar for other commodity groups. By contrast, small farms produce more than 75% of most food commodities in sub-Saharan Africa, southeast Asia, south Asia, and China. Very small farms are important and have local significance in sub-Saharan Africa, southeast Asia, and south Asia, where they contribute to about 30% of most food commodities. The majority of vegetables, roots and tubers, pulses, fruits, fish and livestock products, and cereals are produced in diverse landscapes. Similarly, the majority of global micronutrients and protein are also produced in more diverse agricultural landscapes. By contrast, the majority of sugar and oil crops are produced in less diverse ones, which also account for the majority of global calorie production. The diversity of agricultural and nutrient production diminishes as farm size increases. However, areas of the world with higher agricultural diversity produce more nutrients, irrespective of farm size.

Our results show that farm size and diversity of agricultural production vary substantially across regions and are key structural determinants of food and nutrient production that need to be considered in plans to meet social, economic, and environmental targets. At the global level, both small and large farms have key roles in food and nutrition security. Efforts to maintain production diversity as farm sizes increase seem to be necessary to maintain the production of diverse nutrients and viable, multifunctional, sustainable landscapes.

visual summary by Food Matters.

story map by Food Matters.

Explore the connection between farm size and food and nutrients from selected countries using the app below.

Contact Mario Herrero for more information.