Effects of Phosphorus and Nitrification Inhibitor of 3,4 Dimethylpyrazole Phosphate (DMPP) on the Quantitative and Qualitative Characteristics of Wheat

For evaluation of the effects of phosphorus (P) and nitrification inhibitor (NI) of 3،4 Dimethylpyrazole Phosphate (DMPP) application on the quantitative and qualitative characteristics of spring wheat (Triticum aestivum L.) cv. Pishtaz during 2010، a factorial experiment in randomized complete blocks design، with two factors of type of nitrogen fertilizer at five levels (1- control، 2 and 3- ammonium sulfate fertilizer (ASF) with and without nitrification inhibitor of DMPP، 4 and 5- ammonium sulphate nitrate fertilizer (ASNF) with and without nitrification inhibitor of DMPP) and four levels of P (0، 30، 60 and 90 mg P/kg soil) with three replicates in soil with low available P (Olsen-P ≤ 5 mg/kg soil)، was carried out at Shahrekord University. The amount of nitrogen application in all treatments was equal to 100 mg/kg soil. The results indicated that application of NI DMPP with ASNF at the levels of 60 and 90 mg P/kg soil led to significant increase (p≤0. 05) of grain total number per pot and thousand-grain weight as well as significant increase in biological and grain yield of wheat at the levels of 30، 60 and 90 mg P/kg soil in comparison to ASNF but without NI. According to the results، application of NI DMPP with ASNF led to significant increase in wheat grain protein and zinc concentrations and decrease in molar ratio of phytic acid to zinc (PA/Zn) of grain. Also the increased application of P led to significant increase (p≤0. 05) of biological yield and grain protein concentration. According to the results، the use of nitrification inhibitor DMPP with ASNF is recommendable to improve quantity and quality of yield in wheat.