State can reduce nitrogen effects

A dairy in Galt in 2013 installed a state-of-the-art anaerobic digester to convert manure from their 1,200 dairy cows into renewable electricity, one way to reduce nitrogen pollution.
A dairy in Galt in 2013 installed a state-of-the-art anaerobic digester to convert manure from their 1,200 dairy cows into renewable electricity, one way to reduce nitrogen pollution. Sacramento Bee file

Nitrogen is one of our greatest resources, and a major environmental challenge in California.

We have been able to pull nitrogen out of thin air and convert it into fertilizer for our crops, helping to feed our state, nation and world. But increasingly, we are learning of its undesirable side effects, including polluted water and air. Without a clear understanding of how much nitrogen is in California, where it’s coming from and where it’s going, it has been difficult to make meaningful headway on the issue.

Released this week, the new California Nitrogen Assessment from the Agricultural Sustainability Institute at UC Davis is the first time we’ve been able to see a complete picture of nitrogen in California. From this science-based starting point, the state has an opportunity to take a proactive, comprehensive approach to maximize the benefits of smart nitrogen management while decreasing the costs of nitrogen pollution.

Farmers and ranchers are the keystone to solutions in agriculture, so success will require collaboration among them and with regulators.

The public also needs a better understanding. Think of nitrogen as a bank balance sheet. What comes into the state must eventually be accounted for somewhere else.

Agriculture accounts for more than half of the nitrogen entering the state, from organic and synthetic fertilizer and from feed for dairy cows and other livestock. Fossil fuel combustion adds another 22 percent. In total, we’re bringing 1.8 million tons of nitrogen into California each year.

Where does it go?

Some becomes food, but on average, about half is released and accumulates in the state’s soil, groundwater and air. Much of the ammonia and nitrogen oxide pollutants emitted into the atmosphere go downwind to affect other states, while some nitrogen ends up in landfills and the Pacific Ocean.

As nitrogen accumulates in the state, so do problems. Particulate matter from manure and fossil fuel emissions can cause respiratory problems. We are also starting to understand the health effects from drinking water with excess nitrate, a form of nitrogen. Yet we need to do a much better job of monitoring the health impacts on poor people living in agricultural regions and ensuring they have safe drinking water.

We’ve seen great improvements in fossil fuel emissions thanks to technological innovation and state policy. And with monitoring efforts already in place for dairies and more being added for crops in multiple regions, we’ll soon know more about how to better manage nitrogen in agriculture.

In the face of many challenges, we are certain about two things: Business as usual won’t get us where we need to be, and we must work together to turn nitrogen waste into resources. We must address the problem as a whole, not in pieces that may ultimately work against each other.

If we can approach it collaboratively, California will demonstrate once again its national and global leadership in food, agriculture and environmental stewardship. Farmers will have continued success, save money by using nitrogen more efficiently, and the state’s people and environment will benefit for decades to come.

Craig McNamara is president of Sierra Orchards, founder of the Center for Land-Based Learning and president of the California State Board of Food and Agriculture. He can be contacted at