Water Quality in Relation to Farm Use of Fertilizer

Abstract

In spite of the enormous increase in the use of commercial fertilizers containing N and P in the last 30 years, there is little direct evidence that they contribute generally to significant water quality deterioration. However, there are areas of overuse or unusual circumstances where nitrate in significant concentration may reach underground water. Phosphate use on farms appears to present no pollution problems provided soil erosion is controlled. Much is unknown about the fate of fertilizer N not recovered by crops. Separation of the effects of fertilizers from other sources of nutrients arising from industry, sewage, and soil degradation incident to cultivation is difficult. Fertilizer restriction would produce serious reductions in yield of most crops, particularly vegetables and fruit. More land would be needed for crop production and the erosion hazards increased. Legal restriction on use of fertilizers should be considered only on a watershed basis, and not on a state or national basis.