by Lisa McLean

New research to develop innovative nitrogen management strategy

MOST ONTARIO FARMERS are quick to point out agriculture’s environmental track record in conversations about the industry’s carbon footprint. Thanks to improved technologies, the proliferation of the Environmental Farm Plan, and smarter, safer crop protection products, agriculture has a good news story to tell.

But there’s still room for improvement when it comes to fertilizer use particularly relating to how it can affect soil and water quality. This summer, research is underway in Oxford County to assess the effectiveness and efficiency of innovative nitrogen management practices for crop producers as they relate to reducing nitrate levels in drinking water sources.  

The research – the first of its kind in Ontario – is a partnership between the County of Oxford, University of Waterloo, University of Guelph, the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA), Upper Thames River Conservation Authority, Soil Research Group, and local agricultural producers including OCPA’s Oxford County director David Start.  Funding is being provided by the Ministry of Environment through the Clean Water, Special Projects initiative.

“This project will allow us to evaluate new management practices that farmers could implement to maintain crop production and reduce the amount of nitrate that leaches into soil because it doesn’t get used by the crop,” says Don King, research agronomist with the Soil Resource Group.

Research has already come a long way in offering guidance to producers on how low inputs can go without compromising yields. In recent years many producers have found the corn nitrogen calculator to be a valuable tool (available at www.gocorn.net). David Start has taken advantage of those recommendations on the Oxford wellhead land– including under-seeding winter wheat crops with red clover – to reduce his nitrogen application rate on the following corn crop by as much as 70 percent.

“As farmers, we always want to make environmental improvements on the footprint of growing corn,” says Start.   “This project will provide research that will help farmers like myself make informed environmental and economic decisions when applying nitrogen”.

The County of Oxford has purchased land within the capture zone of the Thornton Well Field, which is surrounded by approximately 80 percent agricultural land and produces about half the drinking water for the city of Woodstock. 

The wellhead protection area has a ‘two year time of travel zone,’ meaning that once the water is in the aquifer, or reservoir that stores large amounts of water that feed the surrounding wells, it takes less than two years to travel to the well intake.

Since the mid 1990s nitrate concentrations in a small number of the supply wells have risen beyond acceptable levels, and agricultural fertilizing practices are one suspected source.

Because well water is combined with other water sources before reaching city water faucets the water poses no health risk to residents.  But since levels in certain wells have been steadily on the rise it’s important to address the issue now.
 
“There are a lot of questions to answer about innovative nitrogen management, particularly about how slow release nitrogen in the form of Environmentally Smart Nitrogen (ESN) can reduce nitrate levels in drinking water sources and how it might stack up against nitrogen from organic sources like a red clover cover crop,” says Greg Stewart, developer of the Corn Nitrogen Calculator.

Researchers will be using soil core samples throughout the growing season to examine nitrate amounts in water selected at specific depths. They’ll be looking at samples from fields that have been under-seeded with red clover, those that use newer ESN products, and fields using traditional urea.  The project will also experiment with variable rate zone application, based on the pre-sidedress Nitrogen test and  timing, with water-soluble nitrogen being applied later in the season so it’s less likely to leach
into groundwater.

In addition, the researchers will conduct an economic analysis to determine the costs and benefits of slow release nitrogen use for crop producers.  Currently ESN is priced at a premium to other traditional sources of nitrogen.

Research will be conducted during the 2009 growing season and repeated again in 2010. The County plans to share results of the project on the County of Oxford and Upper Thames River Conservation Authority websites.