How has agriculture affected nitrogen cycling? what are some negative consequences of nutrient enrichment?

Fertilizers are added to agriculture, and less than half of the materials in fertilizers are actually utilized by plants. The remaining materials pollute the ground water, attach to soil particles, and pollute the atmosphere. Polluted groundwater can contaminate well water. Soil particles with attached nutrients affect microbes and the plants themselves. Atmospheric pollution results in atmospheric nitrogen decomposition, meaning excess nitrogenous materials are added to ecosystems which thereby alter the natural ecosystem.