Nitrification Inhibition by N-Serve and ATC in Soils of Varying Texture1
- T. F. Guthrie and
- A. A. Bomke2
Although numerous laboratory studies have demonstrated the effectiveness of certain nitrification inhibitors, many field studies have failed to show any significant crop response to inhibitor treatments. Most field studies to date have only evaluated N-serve [2-chloro-6-(trichloromethyl)pyridine], which cannot be conveniently applied with solid fertilizers due to its volatility. ATC (4-amino-1,2,4-triazole) is a nonvolatile, water-soluble nitrification inhibitor which can be easily coated onto solid fertilizers without volatilization loss. The objective of this research was to compare the effect of N-serve and ATC on silage corn (Zea mays L.) production and nitrification rates in two soils (silt and loamy sand). Urea was coated with the inhibitors at a rate of 1% of active ingredient per weight of N and applied as a band or broadcast in the spring of 1977 and 1978. The NH4-N/NO3-N ratio in the soil was calculated for each sampling date as an indicator of inhibitor effectiveness. Neither inhibitor significantly affected nitrification when applied as a broadcast treatment to either soil. In the silt, both inhibitors were equally effective in delaying nitrification when banded, but in the loamy sand ATC had a five times higher NH4/NO3 ratio than N-Serve 3 weeks following application. The effectiveness of N-Serve persisted much longer in the silt (86 days) than in the loamy sand (23 days). This suggested that volatilization of N-Serve severely limited its effectiveness in the loamy sand. There was no significant improvement in crop yields or N content due to inhibitor treatment in either soil.
ATC is recommended for further field evaluation in conjunction with band-applied solid fertilizers, particularly in coarse-textured soils.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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