Interaction of Different Wheat Genotypes and Nitrification Inhibitor 3,4-Dimethylpyrazole Phosphate Using ¹⁵N Isotope Tracing Techniques

ABSTRACT

To investigate the effect of applying ¹⁵N-labeled ammonium sulfate with or without a nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on fertilizer use efficiency and crop productivity of different wheat genotypes, a field trial was conducted at the Nuclear Agricultural Department’s farm of Iran in 2013–2014. The treatments included five wheat genotypes with different 13  C isotope discrimination and three fertilizer treatments, an unfertilized control, ¹⁵N-labeled ammonium sulfate, and ¹⁵N-labeled ammonium sulfate with DMPP in three replications. Soil samples were taken after 2, 4, and 6 weeks after sowing and also at harvest time. Results from ¹⁵N experiment showed that DMPP delayed nitrification of ammonium for 42 days. Genotypes with lower discrimination index had greater uptake of ammonium ions which led to increase crop yield and nitrogen fertilizer use efficiency. The results also suggested that the use of DMPP may not be beneficial in some fast growing wheat genotypes.

KEYWORDS:

• 13C isotope
• ammonium
• fertilizer use efficiency
• nitrate
• nitrification inhibitor
• nitrogen-15

Notes

^1. 2-Chloro 6 trichloromethyl pyridine.

^2. International Maze and Wheat Improvement Center (Turkey).

^3. International Center for Agricultural Research in DRY Areas (Syria).