Agroecology 5 min

Sustainably feeding the world requires efficient nitrogen use

Two researchers, one from Paris Cité University and the other from INRAE, modelled the Earth’s capacity to feed the global human population and found marked variation in the resulting estimates. Several factors can explain the seven-fold differences they observed, including dietary regimes, land use patterns, and nitrogen management, with nitrogen use efficiency emerging as particularly important. Livestock farming has significant impacts on land use, nitrogen loss, and organic fertilizer availability. Indeed, the researchers demonstrated that livestock farming can maximize global feeding capacity, provided that livestock numbers do not outstrip sustainable sources of animal feed, namely grasslands and crop residues.

Published on 28 September 2023

illustration Sustainably feeding the world requires efficient nitrogen use

The ability of agriculture to feed the global human population is shaped by two key factors: the total amount of farmland and the quantity of food produced per hectare, which together determine the so-called “food yield”. At present, agricultural systems occupy nearly 40% of the Earth’s ice-free land area, representing a 10-fold increase over the last 2,000 years. However, it is simply unsustainable to continue expanding the percentage of the Earth dedicated to agriculture. Thus, further increase in the global feeding capacity should be driven by increased food yield, which is shaped by the availability of nutrients, especially nitrogen, and limited by the physiological constraints of crop and livestock species.

Across the globe, nitrogen availability and food production have climbed dramatically since synthetic nitrogen fertilizers first emerged in the early 20th century. Their use has increased per-hectare productivity, leading world population growth to become uncoupled from the quantity of farmed surface area. When combined with nitrogen use inefficiency within agricultural systems, this situation has triggered massive pollution at a global scale, with adverse effects on the climate, water quality, air quality, biodiversity, ecosystem services, and human health.

To explore the effects of organic versus industrial fertilization on the Earth’s feeding capacity, the researchers developed a model that examines the impacts of key factors related to food production and nitrogen pollution.

The results revealed that the current agricultural surface area could feed 8–20 billion people under industrial fertilization regimes or 3–14 billion people under organic fertilization regimes. These estimates are primarily determined by three variables: 1) competition between food and feed production, which is driven by the composition of human diets; 2) allocation of agricultural area to grasslands versus croplands; and 3) nitrogen use efficiency, in the case of organic fertilization. Within this framework, feeding capacity is a planetary characteristic, and spatial heterogeneity arising from regional agricultural specialization (i.e., local surpluses and deficits) is dampened by the effects of global trade.

The researchers’ findings also highlight that livestock farming has an important, two-faceted role to play. Specifically, the Earth’s feeding capacity is maximized when there is no competition between the production of human food and animal feed. Additionally, feeding capacity estimates are inversely correlated with the percentage of animal proteins in human diets, such that improvements in feeding capacity are seen when lesser amounts of animal proteins are consumed (i.e., reductions of 20–43%). However, the solution is not for the world to adopt a vegan diet. Instead, feeding capacity can be maximised via livestock farming systems that utilize grasslands and crop residues. In addition, livestock production significantly helps balance the supply of nitrogen from animals with the demand for nitrogen from crops. Livestock farming yields precious fertilizer that can be applied to croplands, especially as part of organic agricultural practices. Under all circumstances, for a given agricultural surface area, increases in per-hectare productivity furnish benefits that can be reinvested so as to both boost feeding capacity and replace croplands by grasslands, a shift that will, in turn, enhance carbon sequestration and ecosystem services.

A major challenge in the 21st century is improving the Earth’s feeding capacity while also increasing nitrogen use efficiency. To successfully accomplish this task, we must strike a balance among global population growth, shifts in arable land use, and nitrogen dynamics, with a view to reducing pollution and increasing sustainability at a planetary scale. Against this backdrop, increasing nitrogen use efficiency will be essential to reducing food productivity gaps between organic and industrial agricultural systems. Livestock farming can serve as an effective tool in this demanding work, as long as systems prioritize grasslands and crop residues as feed sources.

scientific contacts

Souhil Harchaoui Soil, Agro- and hydro-systems, Spatialisation

Petros Chatzimpiros LIED, Université Paris Cité



Learn more

Society and regional strategies

The effects of land-use changes in the Mediterranean Basin on local food systems

What effects do land-use changes – from urbanization to increased global markets for commodities, intensified farming practices and even the abandonment of farmland – have on food self-sufficiency locally and on the scale of the Mediterranean Basin? The DIVERCROP project has produced a video to present the lessons learned from four years of international research on these questions.

10 January 2022

Data4Food2030: a Horizon Europe project for a fair, inclusive and innovative data economy to support sustainable food systems

Launched for a period of four years in September 2022 with EUR 10 million in funding, the European Data4Food2030 project is designed to improve the data economy for food systems. Its goal is to offer business and data governance models that are a result of a dialogue with stakeholders. It will involve work to define the data economy and map its development, performance and impact. This project, which brings together scientists and stakeholders on the ground from 12 European countries, also aims at offering a robust monitoring system to ensure a fair and sustainable data economy.

28 March 2023


Using intercropping systems for sustainable global agricultural production

PRESS RELEASE - With the increasing food demands of a growing world population, it is essential to increase agricultural production while reducing its environmental footprint. Crop diversification techniques have often been proposed as agroecological solutions to achieve this goal. Among them, intercropping – the growth of several crop species in the same fields - seems to be particularly promising. This practice has always been uncommon in Europe and, although it has traditionally been used in countries of the Global South, it is currently declining due to urbanization and migration of rural populations. In a new study, a group of scientists performed a quantitative assessment of the performance of intercropping systems by analysing the results of 226 agricultural experiments. This international team comprised researchers from INRAE, Wageningen University (Netherlands), China Agricultural University (Beijing, China), and Inner Mongolia Agricultural University (Hohhot, China). Their findings were published on 3 January in PNAS.

05 January 2023