Selecting a Nitrogen Stabilizer - United Suppliers, Inc.
Selecting a Nitrogen Stabilizer How is Nitrogen Lost? Substantial amounts of nitrogen fertilizer are lost from farm fields each growing season. The three main ways nitrogen is lost are: Loss Mechanism Volatilization
Reaction Urea in dry fertilizer and liquid UAN converts to ammonia gas and enters the atmosphere
Leaching
Nitrate (NO3) nitrogen, which is highly mobile in soil water, moves below the root zone during rainfall events Anaerobic soil microorganisms convert NO3 to gases NO2, NO, and N2, which are lost to the atmosphere
Denitrification
When it Occurs When fertilizer is unincorporated or in slits that don’t close properly; favored by moisture, heat, high soil pH, and crop residue Heavy rainfall in soils that drain rapidly Saturated soil where oxygen is limited
How much N is lost Up to 20% in moist soils under warm conditions
Nitrate can move down 8 inches per inch of rainfall in well-drained soils Up to 10% of nitrate per day in warm, waterlogged soils
How do Nitrogen Stabilizers Work? All nitrogen stabilizers work by blocking one of two reactions: Reaction Volatilization
Where it Occurs Soil Surface
Nitrification
Throughout Soil
What Happens Conversion of solid or liquid urea (-NH2) to ammonia (NH3) gas by urease enzymes in soil and residue. Conversion of ammonium (NH4) by soil bacteria to nitrate (NO3), which is vulnerable to leaching and denitrification.
Nitrogen is stabilized against volatilization in one of two ways. Some nitrogen stabilizers bind directly to urease and block its activity with an active ingredient called NBPT (N-(n-butyl) thiophosphoric triamide). Agrotain® and Limus® are two key brands which use NBPT, along with many generic products. Other stabilizers attract nickel (positively-charged), which is part of urease, reducing enzyme concentration in the application zone. This is how NutriSphere-N® reduces volatilization. Nitrification converts NH, which is attracted to soil particles, to NO3, which readily leaches and is vulnerable to denitrifying microorganisms. In moderate soil temperatures, nitrification occurs within two weeks of fertilizer application. In modern corn hybrids, up to half of nitrogen uptake occurs after-tassel; significant amounts of sidedressed or pre-plant nitrogen may be lost from the root zone before uptake occurs. All nitrification inhibitors reduce the availability of copper and/or iron, which activate enzymes responsible for nitrification. Nitrapyrin (N-Serve® and Instinct®), DCD (dicyandiamide), and NutriSphere-N are three common nitrification inhibitors
Which nitrogen stabilizer is best for your situation? All nitrogen stabilizers are capable of reducing nitrogen loss. To select the best stabilizer for your application, ask yourself the following questions:
Am I targeting the right reaction? o Use NBPT products and Nutri-Sphere to block volatilization. o Use Nitrapyrin (N-Serve or Instinct) , DCD (Agrotain Plus or Guardian®), or NutriSphere-N to block nitrification and associated N losses through leaching and denitrification Which reaction is more important for your nitrogen application? o If you incorporate or inject nitrogen fertilizer, you may only wish to block nitrification o If you are applying urea or UAN to the soil surface, a urease inhibitor to control volatilization may be more important Is there enough active ingredient in your product? o This is typically not an issue with polymer-, Nitrapyrin-,or NBPT-containing products, but can be an issue with DCD. Published research on treating nitrogen with DCD suggests 13 lbs/ac or more DCD should be used. Many DCD products, particularly liquid formulations, do not supply nearly enough DCD to match published rates. Is the product convenient to use? o Dry products may be bulky or dusty to use; liquid products may require drying agents to avoid urea handling issues Is the product rate per-acre or per-ton of fertilizer? o Per-acre products, N-Serve and Instinct, are more expensive when lower nitrogen volumes are applied. Per-ton products are more expensive at high nitrogen rates. Be sure to always check the label for proper treatment rates of each formulation you use.
Conclusion. The best nitrogen stabilizer program will reflect your location and production practices, as well as the form of your nitrogen fertilizer and rate applied. If you’re applying nitrogen in areas where it will be prone to loss through any of the three reactions, stabilization programs should always include a nitrogen stabilizer. A good nitrogen stabilizer will provide enough active ingredient to block nitrogen loss, while being efficient to handle at the farm or the plant. Work with your retail agronomist to identify products that meet these criteria and deliver the greatest value per acre.
Reaction Urea in dry fertilizer and liquid UAN converts to ammonia gas and enters the atmosphere
Leaching
Nitrate (NO3) nitrogen, which is highly mobile in soil water, moves below the root zone during rainfall events Anaerobic soil microorganisms convert NO3 to gases NO2, NO, and N2, which are lost to the atmosphere
Denitrification
When it Occurs When fertilizer is unincorporated or in slits that don’t close properly; favored by moisture, heat, high soil pH, and crop residue Heavy rainfall in soils that drain rapidly Saturated soil where oxygen is limited
How much N is lost Up to 20% in moist soils under warm conditions
Nitrate can move down 8 inches per inch of rainfall in well-drained soils Up to 10% of nitrate per day in warm, waterlogged soils
How do Nitrogen Stabilizers Work? All nitrogen stabilizers work by blocking one of two reactions: Reaction Volatilization
Where it Occurs Soil Surface
Nitrification
Throughout Soil
What Happens Conversion of solid or liquid urea (-NH2) to ammonia (NH3) gas by urease enzymes in soil and residue. Conversion of ammonium (NH4) by soil bacteria to nitrate (NO3), which is vulnerable to leaching and denitrification.
Nitrogen is stabilized against volatilization in one of two ways. Some nitrogen stabilizers bind directly to urease and block its activity with an active ingredient called NBPT (N-(n-butyl) thiophosphoric triamide). Agrotain® and Limus® are two key brands which use NBPT, along with many generic products. Other stabilizers attract nickel (positively-charged), which is part of urease, reducing enzyme concentration in the application zone. This is how NutriSphere-N® reduces volatilization. Nitrification converts NH, which is attracted to soil particles, to NO3, which readily leaches and is vulnerable to denitrifying microorganisms. In moderate soil temperatures, nitrification occurs within two weeks of fertilizer application. In modern corn hybrids, up to half of nitrogen uptake occurs after-tassel; significant amounts of sidedressed or pre-plant nitrogen may be lost from the root zone before uptake occurs. All nitrification inhibitors reduce the availability of copper and/or iron, which activate enzymes responsible for nitrification. Nitrapyrin (N-Serve® and Instinct®), DCD (dicyandiamide), and NutriSphere-N are three common nitrification inhibitors
Which nitrogen stabilizer is best for your situation? All nitrogen stabilizers are capable of reducing nitrogen loss. To select the best stabilizer for your application, ask yourself the following questions:
Am I targeting the right reaction? o Use NBPT products and Nutri-Sphere to block volatilization. o Use Nitrapyrin (N-Serve or Instinct) , DCD (Agrotain Plus or Guardian®), or NutriSphere-N to block nitrification and associated N losses through leaching and denitrification Which reaction is more important for your nitrogen application? o If you incorporate or inject nitrogen fertilizer, you may only wish to block nitrification o If you are applying urea or UAN to the soil surface, a urease inhibitor to control volatilization may be more important Is there enough active ingredient in your product? o This is typically not an issue with polymer-, Nitrapyrin-,or NBPT-containing products, but can be an issue with DCD. Published research on treating nitrogen with DCD suggests 13 lbs/ac or more DCD should be used. Many DCD products, particularly liquid formulations, do not supply nearly enough DCD to match published rates. Is the product convenient to use? o Dry products may be bulky or dusty to use; liquid products may require drying agents to avoid urea handling issues Is the product rate per-acre or per-ton of fertilizer? o Per-acre products, N-Serve and Instinct, are more expensive when lower nitrogen volumes are applied. Per-ton products are more expensive at high nitrogen rates. Be sure to always check the label for proper treatment rates of each formulation you use.
Conclusion. The best nitrogen stabilizer program will reflect your location and production practices, as well as the form of your nitrogen fertilizer and rate applied. If you’re applying nitrogen in areas where it will be prone to loss through any of the three reactions, stabilization programs should always include a nitrogen stabilizer. A good nitrogen stabilizer will provide enough active ingredient to block nitrogen loss, while being efficient to handle at the farm or the plant. Work with your retail agronomist to identify products that meet these criteria and deliver the greatest value per acre.
