Nature's contribution to people: the role of soil in the provision of food and feed at a global scale

Whendee Silver, Andrew Jones and Whendee Silver, Environmental Science, Policy, and Management, UC Berkeley, Berkeley, CA, Tibisay Perez, Instituto Venezolano de Investigaciones Científicas (IVIC), Tibisay Perez, Department of Environmental Science, Policy and Management, University of California, Berkeley, Berkeley, CA, Allegra Mayer, Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, CA

Background/Question/Methods
Soils play a critical role in the production of food and feed for a growing global population. The globalization of markets for agricultural products has led to the transport of soil nutrients from the site of origin to regions that differ greatly in geology, climate, biota, and soil characteristics. In this paper we explore global patterns in food and feed production in relation to soil properties and use recent data on global food production to determine regional patterns in the production of a subset of important agricultural products (corn, wheat, rice, soybean, and beef). We use these data to identify patterns in the transport of food, feed, and associate nitrogen and phosphorus via international trade. Finally, we discuss emerging challenges to soil systems in feeding a growing global population and review proposed solutions for the future.
Results/Conclusions
Global crop yields were highest in soils rich in nitrogen and organic matter, yet the efficiency of nutrient utilization, measured as the proportion of calories converted to food for human consumption, was concentrated in regions with lower crop productivity and lower rates of chemical fertilizer inputs. At a global scale, soil resources have increasingly been concentrated in the production of feed for animals, resulting in large inefficiencies in nutrient utilization and losses from the food system. The intercontinental transport of soil-derived nutrients via international trade displaced millions of metric tonnes of nitrogen and phosphorus annually, much of which was ultimately concentrated in urban waste streams. Local, small scale agriculture accounted for approximately 40% of the global agricultural land area and provided over 50% of the world’s food and feed needs but yield gaps and economic constraints limit the ability to intensify production on these lands. To better utilize and protect soil resources in the global food system, policies and actions should encourage shifts to more nutrient-efficient diets, strategic intensification and technological improvement, restoration and maintenance of soil fertility and stability, and enhancing resilience in the face of global change.