The Invisible Enrichment

The paradox of enrichment, proposed by Rosenzweig in 1971, predicts that adding resources to a predator-prey system destabilizes it. More food for the prey means more prey, which means more predators, which means predator-prey oscillations that grow until one or both populations crash. The theory is clean and well-established: enrich an ecosystem, and you get boom-bust cycles.

The Green Revolution enriched agricultural ecosystems massively — fertilizer use surged worldwide starting in the 1960s. By the paradox of enrichment, this should have destabilized crop-pest dynamics: more plant biomass should fuel pest population oscillations, increasing the frequency of pest outbreaks and crop failures. Yet global crop yields have been remarkably stable. The paradox predicts instability; the data show stability.

The resolution (arXiv:2510.15811) is that insecticides, routinely co-applied with fertilizers, act as stabilizing agents that counterbalance the enrichment-driven instability. Using modified predator-prey models with empirically grounded parameters for soybean-aphid, wheat-aphid, and cabbage-diamondback moth systems, the analysis shows that fertilizer increases yields but destabilizes dynamics — exactly as the paradox predicts. Insecticides restore stability by suppressing the pest populations that would otherwise oscillate.

The structural insight: the paradox of enrichment has been empirically present in agriculture all along — hidden, not absent. The enrichment effect is real; it’s just been continuously and inadvertently counteracted by a second intervention applied for different reasons. Nobody designed insecticide application to solve the paradox of enrichment. The stability of the Green Revolution rests on a mechanism that was never understood as such.

“Fertilizers Fuel, Insecticides Stabilize: Resolving the Paradox of Enrichment in Agriculture,” arXiv:2510.15811 (2025).