A Revolution That Outgrew Itself

When Fritz Haber discovered the synthesis of ammonia in 1909 and Carl Bosch brought it to industrial scale,
a new era of agriculture began. The so-called “Green Revolution” of the mid-20th century brought a massive
increase in food production thanks to synthetic fertilizers, pesticides, and modern cultivation techniques.
Nitrogen—particularly in the form of ammonium nitrate (NH₄NO₃)—became the main driving force of growth.
But every revolution comes at a cost.
Global Nitrogen Overload: Statistics We Can’t Ignore
• In 2023, more than 120 million tons of nitrogen fertilizers were applied to fields worldwide. By
comparison, natural nitrogen fixation processes (microbial and atmospheric) generate “only” around
60 million tons per year.
• Humanity has doubled the amount of reactive nitrogen entering the biosphere compared to preindustrial
times (Rockström et al., Stockholm Resilience Centre, 2009).
• Around 80% of nitrogen from fertilizers never reaches plants. It is lost through leaching into water,
emission into the atmosphere, or being locked into inert forms in the soil (Galloway et al., 2008).
Soil as the Victim of an “Accelerated Metabolism”
Intensive fertilization has brought short-term benefits: higher yields, faster plant growth, and the ability to
meet food demands. But the long-term costs are becoming more visible:
Degradation of Soil Microbiome
• Excess nitrogen suppresses natural symbiotic relationships between plants and nitrogen-fixing
bacteria (e.g., Rhizobium, Frankia), as plants opt for the “easy way”—fertilizer-derived nitrogen.
• Key organisms such as soil fungi and actinomycetes, crucial for soil structure and regeneration, are
declining.
• Microbial diversity is shrinking, making soils more vulnerable to erosion, drought, and disease.
Acidity and Loss of Balance
• Ammonium-based nitrogen fertilizers acidify the soil (nitrification produces acids).
• Changes in pH destabilize the carbon-nitrogen balance, reducing the soil’s ability to sequester
carbon and retain water.
Global Impacts: Nitrogen as an Invisible Pollutant
Nitrogen has become a global environmental threat, escaping fields and spreading into all parts of the
biosphere.
• Water eutrophication: Nitrogen residues lead to algal blooms, fish die-offs, and the collapse of
aquatic ecosystems.
• Air pollution: The release of nitrogen oxides (NOx) contributes to smog, ozone formation, and acid
rain.
• Climate impact: Nitrous oxide (N₂O), a by-product of fertilizers, is 300 times more potent as a
greenhouse gas than CO₂. Agriculture is the main source of N₂O.
Agriculture at a Crossroads: What Lies Ahead?
If current trends continue:
• We will see further soil fertility loss—the FAO predicts that over 90% of soils are already
degraded in some way.
• Dependence on industrial fertilizers and rising nitrogen costs (linked to fossil fuels) will threaten
food self-sufficiency.
• Vulnerability to extreme weather, pests, and diseases will increase, as soil loses its natural
resilience.
Aquaponics as Part of the Solution: A Closed Nutrient Cycle
One innovative approach that defies the traditional logic of “adding nutrients to soil” is aquaponic farming—a
combination of fish farming and hydroponics:
• Fish produce ammonia, which bacteria convert into nitrates—a natural and recycled form of
nitrogen.
• Plants absorb this nitrogen and clean the water, which returns to the fish—a closed, low-loss
system.
• Aquaponics doesn’t use soil and minimizes external inputs. In environments with limited fertile soil
or water (e.g., urban areas or arid regions), it can be a critical component of future agriculture.
Conclusion: We Need Nitrogen—But Differently
Nitrogen is not our enemy. But the way we’ve used it over the past 80 years has made it a disruptor of
biological balance. The food security of the future depends on our ability to shift from chemistry to biology,
from external inputs to internal regeneration.
Aquaponics, regenerative agriculture, microbiome restoration, and support for symbiotic processes are not
alternatives—they are essential steps if we want to grow food in the year 2100 and beyond.