effects of nitrification inhibitor 3, 4- dimethylpyrazole phosphate on the yield and nitrogen use efficiency of wheat

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 yield and 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. the results indicated that application of nitrification inhibitor dmpp led to significant increase (p≤0.05) of both above ground and grain dry weight as well as n agronomic and recovery efficiency of wheat in some of the studied soils compared to asn and urea. the greatest quantity of above ground and grain dry weight (25.02 and 11.28 g pot-1, respectively) were obtained in asn plus dmpp treatment – 7.1% and 9.2% greater than that obtained with 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 yield and n use efficiency of wheat.