1244. Impact of Soil Health on Crop Yield and Nitrogen Use Efficiency

More than 120 million tons of nitrogen fertilizer are applied annually to support food production for a world population of 8 billion people. However, most of this input is not absorbed by crops and is released into the environment, causing serious environmental problems, including deterioration of air and water quality, ecosystem health, and climate stability. Increasing nitrogen use efficiency (NUE) to improve crop yields while simultaneously curbing nitrogen excess in the environment is essential for global sustainability.

Soil health affects both food production and environmental quality. However, quantifying its impacts remains a major global challenge due to the lack of comprehensive soil health data and the complexity of isolating its effects from other variables. A study published in Nature Food integrated high-resolution global data on soil, climate, and field management practices to systematically evaluate the impact of soil health on agricultural productivity and showed that soil health management is critical to achieving both food security and environmental sustainability.

The study constructed a comprehensive global soil health dataset at 0.5° × 0.5° resolution for the world's croplands. The dataset takes into account traditional factors such as soil pH, nutrient content, and bulk density, as well as soil bacteria, viruses, and fauna. To quantify the contribution of soil health to agricultural productivity, the dataset also incorporates aspects such as agricultural management and climatic conditions.

Globally, soils show consistent patterns in both crop yield and NUE, with higher scores in high-latitude regions such as Northern Europe, Russia, New Zealand, and southern Latin America. Conversely, soil health scores tend to be lower in arid regions at low latitudes, such as the southern United States, North Africa, and India. This pattern indicates that improved soil health may simultaneously improve crop yield and NUE.

The study also sought to elucidate the contributions and functional pathways of soil, climate, and management factors on crop yield and NUE. Among all direct and indirect influencing factors assessed, nitrogen input emerged as the major contributor, with a standard deviation change in yield of 0.56 per standard deviation change in nitrogen input. This finding is consistent with the notion that the Haber-Bosch process for nitrogen fixation contributes to nearly half of the world's crop production. Soil chemical content and pesticide use were positively correlated with crop yield. In contrast, some factors, such as nitrogen input, pesticide use, temperature, and soil chemical components, were negatively correlated with NUE. Conversely, field size expansion and soil physical and biological health were positively correlated with NUE as they improve nutrient utilization by crops. Although climatic factors directly contribute modestly to crop yield and NUE with standard coefficients of 0.07 and –0.2, respectively, they have a significant indirect effect through soil health. Temperature has a negative effect on soil health, except for biological properties. Meanwhile, precipitation has a positive effect on soil physical properties, while it has a negative effect on soil chemical and biological properties. Climate conditions shape soil health by altering moisture levels and soil texture, which are key factors influencing soil virus diversity, and thus affect agricultural yields and NUE.

Globally, crop yields and NUE vary across the world. South America, the United States, Western Europe, and China have high crop yields, exceeding 1,000 kg N ha^-1 yr^-1, whereas Africa, Central Europe, and Australia have yields below 200 kg N ha^-1 yr^-1. NUE shows a different pattern, with high efficiencies (over 60%) in South America, Central United States, Europe, and Africa, but generally below 50% in Asia and Australia. These differences are due to interactions between soil health, climate, and agricultural management across spatial scales. In areas with intensive agricultural management, such as Asia, Western Europe, and parts of South America, the contribution of soil health to crop yield variation is less than 10% in many hotspots, with an average of 6%. However, in North America, Africa, and Central to Northern Europe, where over-fertilization is not common, soil health is important, accounting for more than 30% of the contribution. Notably, the contribution of soil health to NUE variation is larger than that to crop yield, exceeding 50% in regions such as Northern Europe, the southern United States, the Middle East, parts of Latin America, South Africa, and southeastern Australia. However, in regions where over-fertilization is observed, such as China and India, soil health contributes only 7% to NUE.

Agricultural management has always had a large impact on global crop yields, with China accounting for 79%. Also, an average of 60% of NUE variation is driven by agricultural management in China, northern India, Western Europe, and parts of South America. Meanwhile, in other regions, the contribution of management practices generally ranges from 10% to 40%, with an average of 25%. This indicates that soil health, climate, and management interact at various spatial scales, highlighting that regional soil health management is essential for both food production and environmental sustainability.

The study also finds that integrated soil health management, including cover crops, conservation tillage, soil amendments, and biological disease control, can increase crop yields and improve nitrogen fertilizer use efficiency globally. A cost-benefit scenario analysis of the feasibility of soil health management approaches reveals that the upfront costs of implementing a range of technologies, such as cover crops, no-till farming, crop rotation, and organic fertilizer application, are high across all scenarios at a uniform US$155 billion. This uniformity represents a substantial capital input required to implement them. Despite these costs, the benefits of these investments are multifaceted, including increased crop production, improved soil health, enhanced ecosystem services, and a significant contribution to climate change mitigation through carbon sequestration. Especially as we approach 2050, the benefits of integrated soil health management in crop yields and climate change-related benefits are notable for significant growth, with cumulative benefits estimated at up to US$894 billion, highlighting the magnitude of economic and environmental benefits to be derived from long-term, sustainable soil management efforts.

Such practices are not just cost-effective, but also an investment in the very foundations of our food systems and the health of the planet. The Anthropocene represents human impacts on the Earth's geology and ecosystems, with profound implications for soil health. Soil health, the foundation of global food production, is a barometer of the sustainability of human civilization itself. Mounting evidence suggests that protecting soil health is not only beneficial but essential, creating an urgent need to incorporate comprehensive soil health measures into global agricultural policies.

The paper acknowledges that while the study provides valuable insights, there are limitations to interpreting the findings. While the analysis in this study focuses primarily on soil health and climate, it is important to recognize that crop varieties and agricultural practices also play a pivotal role in agricultural productivity. Different crop varieties respond differently to soil conditions, nutrient availability, and climate, which can affect yield and NUE. Future studies will be required to refine soil health datasets and incorporate more detailed data on crop varieties and management practices to provide a more comprehensive and accurate assessment of the factors that drive crop yield and NUE globally.

(Reference)
Xu, J., Ren, C., Zhang, X. et al. Soil health contributes to variations in crop production and nitrogen use efficiency. Nat Food (2025). https://doi.org/10.1038/s43016-025-01155-6

Contributor: IIYAMA Miyuki, Information Program