Improving Applied Nitrogen-Use Efficiency
In the lab or in the field: new technology proven to combat common forms of N loss
Posted on April 16, 2012
Topics: Industry Insight
Many considerations go into managing nitrogen-(N) use efficiency, including minimizing the risk of loss due to leaching, denitrification or volatilization. Nitrogen sourcing paired with strategic application methods and timing, as well as the appropriate use of fertilizer efficiency products, can contribute to minimizing the risk of nitrogen loss prior to plant uptake.
Today’s producers have nutrient-use efficiency advantages previous generations could not imagine. Still, with sound farming practices, modern crop production tools and decades of research, N-use efficiency for crops is a challenging and complex process. In any given year, as much as 50 percent of applied N fertilizer may be lost through volatilization, leaching and surface runoff.1 This presents wasted input cost to growers and contributes to environmental problems, such as dead zones in the Gulf of Mexico.
Managing N loss
One technology has proven to be effective in improving N-use efficiency of urea and urea-ammonium nitrate (UAN) solutions. Known by the trade name NutriSphere-N® Nitrogen Fertilizer Manager, it stabilizes applied N fertilizer (liquid or dry) regardless of application timing, offering growers both flexibility and the most advanced protection against three types of loss — leaching, denitrification and volatilization.
NutriSphere-N helps keep more N in its ammonium (NH4) form, resulting in less leaching, less volatilization and more available N to aid development and growth.
Nitrates also may be lost through denitrification — a process where nitrates are reduced to gaseous nitrous oxide (N20) or elemental N (N2) and lost to the atmosphere through volatilization, which usually occurs in soils under extended periods of waterlogged conditions.
University research proves NutriSphere-N effective nitrification and urease inhibitor
Hundreds of university, third-party and on-farm studies conducted over the past seven years across the United States, as well as the Philippines, the United Kingdom and other countries have demonstrated the positive effects of NutriSphere-N in reducing N volatilization, denitrification and leaching, including the following.
University of Missouri
In spring 2010, David Dunn, at the University of Missouri-Delta Research Center, conducted an ammonia volatilization experiment to test urea’s response to four different N fertilizer additives on corn, including NutriSphere-N. Treatments were applied on May 21, and then volatilization data was collected on June 24, June 26 and June 29. Cumulative volatilization data showed NutriSphere-N and Agrotain to be statistically equal. Research findings proved NutriSphere-N effectiveness increased while Agrotain protection showed decrease over the course of the trial, suggesting NutriSphere-N has a longevity advantage over other products (see Table 1).
University of Kentucky
An incubation study, directed by Mark S. Coyne, Ph.D., crop and soil science professor at the University of Kentucky, tested the effects of NutriSphere-N on urease activity in soil by measuring nitrification in four replicated samples. After only seven minutes of incubation, NutriSphere-N proved to significantly inhibit urease activity (see Chart 1).
Incubation studies by Coyne also showed an inhibiting effect with NutriSphere-N on nitrification. The greatest increase in nitrification was on day 1 for both treatments (see Chart 2); thereafter, nitrification was inhibited by NutriSphere-N.
Arkansas field trials back N-use efficiency
Rice field trials in Arkansas, conducted by Ronnie Helms, Ph.D., show an increased yield response to NutriSphere-N. Urea was applied seven days pre-flood in a variety of rates — 50, 100, 150 and 200 pounds per acre — both with and without NutriSphere-N.
“Even before harvest, visual differences of plots applied with NutriSphere-N and urea were quite apparent — there was a distinct growth and color improvement,” says Helms.
Harvest proved, regardless of application rate, that all plots treated with urea plus NutriSphere-N out-yielded urea-only plots. The most evident yield advantage was applying 100 pounds of urea (N) per acre with NutriSphere-N, with an 11 bushel-per-acre advantage. The urea treated with NutriSphere-N applied at a rate of 100 pounds per acre also achieved essentially the same yield as the 150 pound-per-acre rate of urea alone. Utilizing this data, growers under these conditions could achieve high yields by using 50 pounds per acre less N (see Chart 3).
Nitrogen: A crop’s best friend
Despite its efficiency challenges and threats of leaching, denitrification and volatilization, N is still a crop’s best friend. Nitrogen is a major component of amino acids, the foundation of all proteins. A healthy supply of N stimulates crop growth and development, as well as promotes the uptake of other essential nutrients. In short, N-dependent crops need adequate N uptake in order for other growth processes to function.
Using modern agricultural tools and understanding keys to proper N fertilization as part of a complete nutrient management program can prove beneficial — beginning with healthier crops and leading to the potential for increased yields and profits.
NutriSphere-N stabilizes applied nitrogen fertilizer — liquid or dry — regardless of application timing, offering growers both flexibility and the most advanced protection against three types of loss — leaching, denitrification and volatilization.
For more information about NutriSphere-N, call 1-888-446-GROW or visit www.sfp.com
1Fageria, N.K., Baligar, V.C. 2005. Enhancing nitrogen use efficiency in crop plants. Advances in Agronomy. 88:97-185.
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