Fertilizer = Weeds

Research has now shown that the availability of nutrients is an important factor that limits the number of plant species that can live in one place. For example, grasslands that are polluted with nitrogen and phosphorous (usually from agriculture) have fewer species.

This nutrient-diversity relationship depends on the complexity of interactions between competing species and is directly related to the number of limiting factors (such as soil moisture, nitrogen, phosphorous, potassium and water) present in the system.