Nicholas Institute for Environmental Policy Solutions
Nitrogen Management in Agriculture
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Nitrogen Management in Agriculture

Adding nitrogen to croplands is critical to sustain soil fertility and crop production. Unfortunately, nitrogen is leaky,  converting to inorganic forms that can be lost from agricultural fields and cause environmental problems.

The Nicholas Institute’s research focuses on two primary loss pathways. First, nitrate is lost through runoff and leaching that can result in eutrophication (nutrient enrichment) of freshwater systems and estuaries, resulting in problems such as coastal dead zones and massive algal blooms. Second, gaseous emissions from farms include nitrous oxide, a potent greenhouse gas with 298 times more global warming potential than carbon dioxide.

If we can better understand what is controlling these losses and the potential impacts of various management approaches we can design better solutions.

Fertilizer Management and Nitrogen Losses: Meta-analysis Project

Nitrogen fertilizer has enabled modern agriculture to produce sufficient food for a growing population. However, environmental damages from the loss of nitrous oxide, a potent greenhouse gas, and nitrate, a water quality pollutant, increase the need for improved management of agriculture that minimizes losses and improves efficiency. Policies and programs designed to reduce N losses from agriculture must be based on good scientific information to ensure the best possible improvements in water and air quality.

In 2014, the Nicholas Institute began collecting data from published reports on nitrous oxide and nitrate losses from corn-based cropping systems throughout North America with the goal of exploring how these nitrogen losses are influenced by 4R fertilizer nitrogen management (right rate, right source, right timing, and right placement). The specific aim of this project is to determine the impact of 4R nutrient management, as well as climate, soil, and other management practices, on the unintended losses of fertilizer nitrogen as nitrous oxide or nitrate. Funding was provided by the 4R Research Fund through the International Plant Nutrition Institute. A summary of the project is available on the funder site.

Enhanced Efficiency Fertilizers—Examining the Evidence

By adding onto the database compiled for the meta-analysis project, the Nicholas Institute is assessing the effectiveness of certain fertilizer products to increase farm productivity and reduce nitrogen losses to the environment. For example, treating fertilizer with polymer coatings or nitrification and urease inhibitors  can help nitrogen to remain in forms that are less susceptible to leaching or volatilization. The nitrogen from this enhanced fertilizer may also be more available to the crop when it is needed.

The goal of this project is to find all available data on the yield responses of corn and wheat in North America to nine different products that are promoted to increase nitrogen use efficiency. If the products consistently improve crop yield as a function of their nitrogen formulation, there is also potential for reduced nitrous oxide emissions into the air and nitrate losses to ground and surface water. In this way, the project aims to help agricultural producers improve environmental performance and productivity.

Related publication: Fertilizer Management and Environmental Factors Drive N2O and NO3 Losses in Corn: A Meta-Analysis

Environmental, Economic, and Social Impacts of 4R Nutrient Stewardship in Canada

Canadian agricultural researchers are testing the effects of different fertilizer management practices across varied eco-regions, with the goal of reducing losses of nitrogen and phosphorus. The best practices are anticipated to improve farm productivity as well as air and water quality. Using data from ongoing field trials, this project aims to measure and assess the economic, social, and environmental benefits of adopting 4R fertilizer stewardship at farm, regional, and national levels. This “triple-bottom-line” assessment can then advise policy design with respect to fertilizer management in Canada and beyond.