The role of soil in the contribution of food and feed

Abstract

Soils play a critical role in the production of food and feed for a growing global population. Here, we review global patterns in soil characteristics, agricultural production and the fate of embedded soil nutrients. Nitrogen- and organic-rich soils supported the highest crop yields, yet the efficiency of nutrient utilization was concentrated in regions with lower crop productivity and lower rates of chemical fertilizer inputs. Globally, soil resources were concentrated in animal feed, resulting in large inefficiencies in nutrient utilization and losses from the food system. Intercontinental transport of soil-derived nutrients displaced millions of tonnes of nitrogen and phosphorus annually, much of which was ultimately concentrated in urban waste streams. Approximately 40% of the global agricultural land area was in small farms providing 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 use 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 enhanced resilience in the face of global change. This article is part of the theme issue 'The role of soils in delivering Nature's Contributions to People'.

Keywords: biogeochemistry; global food and feed; nature's contribution to people; nitrogen; phosphorus; soils.

Figure 1.

Global map of (a) soil order according to USDA taxonomy [34]; and proportion (%) of land under (b) pastures and (c) cropping in year 2000 [35,36]. (Online version in colour.)

Figure 2.

Global map of (a) soil N concentration in 0–5 cm depth (cg/kg; [42,43]), (b) production of food calories (kCalories; 1997–2003; [41]), and (c) production of feed calories (kCalories; 1997–2003; [41]).

Figure 3.

Mean (+s.e.) of global nitrogen and phosphorus content (MMT) in food and feed from 2014 to 2018: (a) maize, (b) soy, (c) rice, (d) wheat). Data are from FAOSTAT-3 [37].

Figure 4.

Mean annual intercontinental N export and imports of (a) total soy, (b) total maize, (c) soy cake, and (d) maize meal over a 5-yr period from 2014 to 2018. Soy cake and maize meal are primarily used for livestock feed. Colours distinguish region and width of arrow indicates size of export; arrow direction symbolizes export direction. Data from the Food and Agriculture Organization [17]. Only exports greater than a minimum threshold of 0.75% of the sum of all region exports are included in figure. (Online version in colour.)

Figure 5.

Mean annual intercontinental N export and imports of (a) wheat, (b) rice, (c) green maize and (d) beef over a 5-yr period from 2014 to 2018. These are all dominant food products. Colours distinguish region and width of arrow indicates size of export; arrow direction symbolizes export direction. Data from the Food and Agriculture Organization [17]. Only exports greater than a minimum threshold of 0.75% of the sum of all region exports are included in figure. (Online version in colour.)