Managing Nitrogen Demand in Leafy Greens with N-Sure
Written by Dr. Zack Ogles, Manager of Agronomy
Maintaining adequate nitrogen in leafy green production is critical whether in South Florida or in the Salinas Valley of California. While nitrogen is essential to plant growth and development, it is also subject to losses that can affect crop yield and negatively impact the environment. Nitrogen can be lost through several pathways including leaching, losses through ammonia volatilization, and through denitrification. These loss pathways ultimately cost the grower yield, quality, and their nitrogen fertilizer investment. One way to reduce nitrogen loss is to add a slow-release nitrogen source such as N-Sure® to your fertility program.
N-Sure is a high analysis 28-0-0 liquid that contains 72% slowly available nitrogen in the triazone form. N-Sure can be used both as a foliar nitrogen source or as a slowly available source when applied to the soil. The triazone form of nitrogen found in N-Sure allows the product to be used in different ways, all the while working to prevent nitrogen losses.
How to use N-Sure on leafy greens
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Foliar applications
Because N-Sure is readily adsorbed through the leaves of various crops, it makes an excellent foliar fertilizer. Research conducted at Michigan State University showed that an application of triazone nitrogen resulted in a 31% increase in nitrogen adsorption when compared to nitrate, urea, or ammonium nitrogen. With lettuce or other leafy vegetables, a 4 quart application of N-Sure has been shown to improve growth and quality when made just prior to maximum growth.
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Foliar Nitrogen Absorption
Source mgN Triazone 9.60 Nitrate 7.40 Urea 7.31 Ammonium 6.75 Source: Dr. Widders, Michigan State University
Safety as a foliar
N-Sure is extremely safe as a foliar fertilizer, significantly reducing the chance of burning. When compared to other quickly available nitrogen sources N-Sure is much safer, allowing higher application rates without the risk of phytotoxicity associated with nitrogen sources such as nitrate, urea, and ammonium. In addition, N-Sure blends readily with many liquid fertilizers and pesticide products allowing for dual purpose applications.
Soil application
Using N-Sure in a soil application can help provide slowly available nitrogen to the crop over the course of several weeks. This application can also reduce nitrogen losses as the triazone form of nitrogen is less subject to leaching than nitrate. This effectively allows more of the nitrogen to be taken up by the plant maximizing the growers’ return on fertilizer investment, in addition to protecting the environment.
Nitrogen Leaching Losses
| N Source | N Leached by Pore Volume (%) – 1X | N Leached by Pore Volume (%) – 2X | N Leached by Pore Volume (%) – 3X | N Leached by Pore Volume (%) – 4X |
| Nitrate | 68 | 98 | 100 | 100 |
| Urea | 43 | 83 | 90 | 92 |
| N-Sure | 25 | 50 | 60 | 63 |
Note: Applied at rate of 5 g N m–2. N-SURE (28-0-0) contained 72% reacted N and 28% unreacted urea. Data supplied by Dr. D.C. Bowman, Department of Crop Science, North Carolina State University.
Blended with quick release nitrogen
Blending N-Sure nitrogen with a quick release nitrogen can bring additional value to the grower. When blended with UAN 32%, a grower can provide a quick boost of nitrogen while also providing a fourth, slow-release form of nitrogen that supplies long term nutrition. Research has shown that replacing 20-30% of the total nitrogen in a blend with N-Sure can result in higher yields and less nitrogen loss. A study was conducted with the University of California comparing UAN 32% alone with 75% UAN 32 and 25% N-Sure blend on head lettuce. The N-Sure/UAN 32 blend resulted in a 9.8% yield increase.
1Trial completed by Richard Smith, Monterey County Farm Advisor, University of California
Conclusion
When evaluating your nitrogen management strategy, consider the addition of a slow-release nitrogen source such as N-Sure. Its versatility allows for easy and safe application both to the soil and to the foliage. N-Sure is compatible with many commonly used fertilizers and pesticides making N-Sure a convenient blend partner. The characteristics of the triazone nitrogen contained in N-Sure help reduce nitrogen losses ensuring more of your nitrogen investment goes into the plant and not lost to the environment.
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