ABSTRACT
Why is nitrogen in groundwater a problem? High nitrate levels in water consumed by humans can cause adverse health problems, and groundwater is a major source of water for human consumption. A part of groundwater resurfaces to feed surface water from streams to oceans. High levels of nitrogen can cause excess plant and bacterial growth, which upon death and decay can deplete much of the oxygen in water. This causes fish kills and ‘‘dead zones,’’ such as the area of hypoxia in the Gulf of Mexico. This encyclopedia article discusses agricultural practices, e.g., row crops, grasslands/turf, container horticultural crops, that contribute to nitrogen in groundwater. Some agricultural practices to reduce the contributing factors are also presented.
