The nitrogen dilemma: Food or the environment

Excerpt

Nitrogen (N) is the most important essential element for crop production because it is required in large amounts and is nearly always the first nutrient that becomes limiting after an ecosystem is converted to cropland. Cereal grains provide about 50% of the world's calories, and their production has become largely dependent on the use of synthetic N fertilizer. However, fertilizer N not used by plants can degrade the environment and negatively impact both people and ecosystems. In addition, efficient use of N fertilizer generally requires phosphorus (P) fertilizer which is made from rock phosphate derived from mines. Therefore, huge amounts of N and P from outside sources are being added to the environment each successive year leading to additional environmental concerns.