Research from the world's longest-running ecological experiment, conducted by the University of Sussex and Rothamsted Research, reveals that high levels of common fertilizers on grassland drastically reduce pollinator numbers and flower diversity. The study found that increased nitrogen, potassium, and phosphorus fertilizers halve pollinator populations and reduce flowers fivefold. Bees were particularly impacted, with chemical-free plots hosting nine times more bees than those treated with the highest fertilizer levels. Fertilizers promote fast-growing grasses that overshadow diverse flower species, essential for various pollinators. Historically, 97% of UK wildflower meadows have vanished since the 1930s, correlating with pollinator decline. While reduced fertility may bolster pollinator diversity, it presents a challenge for farmers due to decreased yields, prompting calls for biodiversity-friendly practices and financial incentives. This landmark study spans nearly 150 years, offering crucial insights into long-term fertilizer impacts on biodiversity.