Authors of a scientific study spanning over 150 years are alarmed by findings that the use of fertilizers has halved the number of pollinating insects and reduced the number of meadow flowers by five times. A team from the University of Sussex and the Rothamsted Research Center conducted research based on British data, but the trends they highlighted are evident worldwide. The authors of the longest-running ecological experiment focused on the extensive use of nitrogen, potassium, and phosphorus fertilizers in agricultural pastures, specifically examining the damage inflicted on the ecosystems of the Park Grass meadow plots in Hertfordshire. This site has been a hub for ecological observations and experiments since 1856.
What did the scientists discover? According to a report published in the journal npj Biodiversity, bees have suffered the most from this human-induced intervention. In areas where chemicals were not used, the population of these industrious insects was nine times greater than in heavily fertilized meadows. Lead author Dr. Nicholas Balfour noted, “As the amount of fertilizer increases, the number of pollinators decreases; this direct relationship has, to our knowledge, never been demonstrated before.” Such biodiversity losses are attributed to fertilizers creating conditions that allow fast-growing forage grasses to dominate, thereby displacing flowers. Consequently, the variety of colors in meadow flora diminishes. It is well-known that a diversity of colors is linked to a greater variety of pollinators, as insects even show preferences for certain colors, as reported by The Guardian.
The average fertilizer application on British pastures is about 100 kg per hectare. The highest amount used in the experiment reached 144 kg per hectare, which corresponded with the most significant loss of pollinators: their numbers dropped by 50 percent or more. This effect was most pronounced in areas treated with nitrogen fertilizers, which are used more extensively. Researchers found that plots treated with a mixture of fertilizers without nitrogen maintained a relatively high number of pollinators and flowers. According to the study, only one to two percent of pastures in the UK provide high-quality habitats for many species. In the 1930s, the British lost 97 percent of meadows with wildflowers. Now, the situation is steadily worsening due to the rampant use of chemicals.
This research aims to draw attention to the paradox faced by farmers: to foster more species of flowering plants and pollinators, the land must be less fertile, which leads to lower yields. “While reduced yields are generally not seen as a good thing, lower intensity pasture production can unlock many benefits of multifunctional landscapes,” Dr. Balfour noted. Among these benefits are an increase in pollinator populations, improved soil health and air quality, and enhanced environmental resilience to extreme weather events.