Effects of Nitrogen Source and Nitrification Inhibitor 3, 4- Dimethylpyrazole Phosphate on Nitrogen Use Efficiency of Wheat in Different Soils

Low nitrogen (N) use efficiency is considered to be one of the major problems in wheat production fields all over the world. This experiment was conducted to evaluate the effects of nitrification inhibitor (NI) 3, 4- dimethylpyrazole phosphate (DMPP) on the nitrogen use efficiency of spring wheat (Triticum aestivum L.) cv. Bahar during 2011 at ShahreKord University. A factorial experiment in randomized complete block design was carried out with two factors of type of N fertilizer [1- control with no added N fertilizer, 2- urea, 3- ammonium sulphate nitrate (ASN) and 4- ASN plus DMPP] and soil kind (10 soils with different physical and chemical properties) with three replicates. Soil NH4 and NO3- concentrations in different soils, possibly duo to greater N uptake by the wheat, did not differ significantly among treatments and between sampling in both of 45 and 90 days after cultivation. The results indicated that application of nitrification inhibitor DMPP led to significant increase (P≤0.05) of N agronomic and recovery efficiency of wheat in some of the studied soils compared to ASN and urea. In different soils the agronomic and recovery efficiency of N in wheat above ground increased about 8.4%-27.7% and 13.4%-31.5%, respectively, in the ASN plus DMMP as compared to the urea. The results of this study suggest that the nitrification inhibitor DMPP could improve N use efficiency of wheat.