Nitrogen and phosphorus from fertilizers used in large-scale farming are entering ecosystems and affecting human health. The concern grew after a study by two Catalan researchers warned that wheat crops fed with these nutrients could be linked to celiac disease. The researchers urged a shift away from the current agricultural model and a reduction in livestock farming to reduce nutrient pressures on the environment.
A Science series spotlights the work of Josep Peñuelas and Jordi Sardans from CREAF, the Center for Ecological and Forest Resources Research. They describe a nutrient imbalance created by human activity, noting that intensive farming and heavy fertilization carry serious consequences for living systems across land and water.
The scientists point to a global mismatch of nitrogen and phosphorus that affects soils and waterways. Both elements are essential for life, yet their relative amounts shift under human influence, with ripple effects on ecosystems and health. This imbalance is intensified by practices that push excess nutrients into the environment.
The article’s graphic context identifies the field as a site where nutrient inputs are actively shaped by human activity, illustrating how farming practices alter the natural balance between nitrogen and phosphorus.
Both nitrogen and phosphorus influence the growth rates of microorganisms, plants, and animals. Plants rely on carbon dioxide for photosynthesis and on nutrients to build tissues. Among these nutrients, the balance between nitrogen and phosphorus is critical. Proper proportions support healthy growth.
Peñuelas and Sardans note that recent years have seen humans enrich the biosphere with nitrogen through excessive fertilization, altering the relationship between nitrogen and phosphorus. They urge national and international environmental bodies and responsible policymakers to recognize the risks posed by this imbalance to both the biosphere and human health. International agencies should address the issue with coordinated policy actions. (Citation: CREAF)
Alternatives to imbalance
Experts recommend improving the efficiency of nitrogen and phosphorus use and recycling within farming systems. Precision agriculture can minimize the application of excess fertilizer and reduce nutrient runoff. (Citation: CREAF)
Management and enforcement measures are also suggested. Innovative biotechnology could increase plant productivity by improving nutrient capture and making better use of phosphorus sources. (Citation: CREAF)
Policy approaches proposed by Peñuelas and Sardans include promoting phosphorus recycling through regulations and subsidies, and reducing livestock production. These strategies are still in early stages of adoption. (Citation: CREAF)
The field context illustrates how nutrient management intersects with farm economics and environmental policy, highlighting the need for practical, scalable solutions. (Citation: CREAF)
Humans enrich the biosphere with excess nitrogen through emissions from fossil fuel combustion and through practices that plant nitrogen-fixing crops and enrich fertilizers that enter waterways, they explain. (Citation: CREAF)
Other human activities, such as applying phosphorus-rich fertilizers and detergents, also raise soil and water phosphorus levels. Yet the global rise in phosphorus availability still lags behind that of nitrogen. (Citation: CREAF)
These are two intertwined problems. On one side, soil nutrient availability has risen unevenly; on the other, the nitrogen to phosphorus balance has shifted. When a medium contains too many nutrients, eutrophication occurs, leading to algal and phytoplankton blooms and eventual ecosystem stress. (Citation: CREAF)
Some regions have started water purification strategies to lower concentrations of both elements. However, many water treatment methods remove more phosphorus than nitrogen, which can perpetuate imbalances. (Citation: CREAF)
The said stability
Global nutrient imbalances may be even more pronounced locally and regionally because the inputs of nitrogen and phosphorus are not evenly distributed. Phosphorus is less soluble in water and tends to stay near emission sources, often binding to soil minerals and settling in sediments. Nitrogen, by contrast, is highly soluble and more volatile, allowing it to travel farther from its source. (Citation: CREAF)
The growing imbalance affects soil communities and the species composition of inland waters. As the trend continues, ecological stability becomes harder to maintain. (Citation: CREAF)
The human phosphorus crisis
Food safety and agricultural production are among the sectors most affected by this imbalance, which also harms natural ecosystems and people. Nitrogen-based fertilizers originate from the atmosphere and can be produced via the Haber-Bosch process, which has expanded since the 1950s. Phosphorus, however, is largely mined and concentrated in a few countries such as Morocco. (Citation: CREAF)
Phosphorus availability may become economically unaffordable for low-income regions facing food shortages if supplies decline or become restricted due to geopolitical or market pressures. In the medium term, phosphorus-producing nations may manage reserves to profit from mining and agricultural industries. Phosphorus-based fertilizers are increasingly costly for farmers in poorer areas, exacerbating nutrient imbalances where the problem is most acute. CREAF researchers expect this to widen the economic gap between rich and poor countries. (Citation: CREAF)
Phosphorus and nitrogen sick
The nutrient imbalance alters the chemical make-up of crops and can impact the health of people who consume them. Excess phosphorus can accumulate in soils and water bodies where it is used in inorganic and organic fertilizers. (Citation: CREAF)
Food grown in these environments may lead local populations to overconsume phosphorus, potentially affecting health. Nutrient imbalance is also linked with diet-related diseases in both communicable and non-communicable categories, with CREAF noting that over-fertilizing wheat with nitrogen in 2021 could be connected to higher rates of celiac disease. (Citation: CREAF)
When the nitrogen to phosphorus relationship changes, it can trigger shifts in other elements such as carbon, iron, zinc, calcium, and potassium within plant tissues. This leads to a broader view that the elemental composition of organisms, communities, and ecosystems may be altered. (Citation: CREAF)
Reference work: Global nitrogen-phosphorus imbalance (Citation: CREAF)