What should you do about nitrogen in rivers and groundwater?
(contributed by John Rogers; email: jrogers@email.unc.edu)
One of North Carolina's leading environmental problems is that high nitrogen concentrations in rivers and groundwater are hazards to human health and are also promoting such rapid growth of undesirable plant life that normal ecosystems are distorted. The nitrogen comes from industrial discharge, human and animal waste, fertilizer runoff, and aerosols generated by burning coal and oil. Government and private organizations spend many millions of dollars a year in an attempt to determine the relative importance of these sources, but the number of variables is so large that all conclusions are highly contentious.
Without waiting for full understanding of the problem and the development of expensive solutions, individuals can start now to make at least small contributions. Perhaps the best way to reduce the nitrogen output from your home is to make sure that you do not use more fertilizer on your lawn and garden than it needs. Because the nitrogen part of fertilizer is so soluble, much of it washes out of the soil before it has a chance to be absorbed by plants. Therefore, we suggest that you use only fertilizers that have most of the nitrogen surrounded by a "timed-release" coating, which will allow the nitrogen to be released into the soil slowly enough that most of it will be absorbed and not enter the runoff.