Nitrogen: Too Much of a Good Thing?

The recent algae bloom that created a drinking water crisis for Toledo should serve as a wake-up call. Farmers need to start following good nitrate application practices, or more regulation could be in store.


publication. Agriculture is responsible for 73% of nitrous oxide emissions, 84% of ammonia emissions and 54% of nitrate emissions.

Despite all that we know about the problems created by crop nutrients that make their way into the environment, about two thirds of the cropland producing eight major field crops did not follow best management practices for nitrogen, according to USDA.

The same source found that most cropland rotations (from 82 to 96%, depending on region) needed improvements in nitrogen management.

The problem that farmers face is that they do not know what the weather will be like in a given year. So they apply the amount of nitrogen that would be necessary for a year with optimum growing weather. The problem is that most years, by definition, aren’t optimum. So farmers over-fertilize and apply too much nitrogen.

While giving farmers the best shot at high yields to maximize income in an optimum weather year, over-fertilization shifts costs to others. USDA estimates that “consumers spend over $800 million each year on bottled water due to nutrient-related taste and odor problems.” The USDA Economic Research Service also estimates that drinking-water utilities spend $4.8 billion a year to remove excess nitrates. ERS estimates that about $1.7 billion of that is spent on nitrates that came from agriculture.

”Most costs are borne by the large utilities, due to the volume of water treated,” says the ERS.

The farming practices for reducing nitrogen are generally well known among producers. Farmers need to watch the rate, timing and method of application. But the practice of these basic principles apparently has a long way to go.

Without significant progress in adopting all three practices, societal pressure will likely force stricter enforcement of existing conservation compliance rules on producers participating in farm programs or subsidized crop/revenue insurance programs. The next step could the introduction of far more onerous rules.

Daryll E. Ray holds the Blasingame Chair of Excellence in Agricultural Policy, Institute of Agriculture, University of Tennessee, and is the Director of UT’s Agricultural Policy Analysis Center (APAC). Harwood D. Schaffer is a research assistant professor at APAC.