Improving Nitrogen Fertilizers Efficiency in Soil by Using Nitrification Inhibitor (DMPP)

Document Type : Original Article

Author

Water Studies Center, King Faisal University P.O.Box 420 - Al-Hassa 31982, Saudi Arabia

Abstract

In the present study, the nitrification inhibitor, DMPP (3,4-dimethyl pyrazole phosphate) was used for inhibiting the nitrogen transformation and reduced the nitrate leaching in two types of soil, i.e. sandy loam and sandy clay loam. Soil columns (5 cm diameter and 24 cm length) were packed with soil at bulk density of 1.5 g/cm3. Nitrogen fertilizers (urea and ammonium sulphate) were applied at rate of 150 mg N/column. The soil columns were leached with 150 ml water/5 days and the leachate was collected. The experiment was lasted 40 days. At the end of experimental period the soil was pushed out the columns and sectioned at 5 cm pieces, then extracted for N-NO3- and N-NH4+ .The results showed that DMPP with urea or ammonium sulphate significantly reduced NO3- -N leaching. The cumulative leaching losses of soil nitrate under treatment of urea or ammonium sulphate with 1.0% DMPP, from columns of sandy loam soil were 34.7 and 40.6% and from column of sandy clay loam soil, were 51.7 and 43.4% lower than those of soil columns tested with urea or ammonium sulphate application only within the 40 days observation, respectively. The results also showed that nitrification rate (NR), was reduced as a result of DMPP application. The nitrification rate was reduced from 53.96 (with urea only) to 36.46% (with urea treated with DMPP) and from 65.92 (with ammonium sulphate only) to 27.92% (with ammonium sulphate treated with DMPP) in case of sandy loam soil. The corresponding values in case of sandy clay loam soil were from 60.70 to 43.76 % and from 67.46 to 36.59%, respectively. Also, the inhibition percentage of nitrate was 32.43 and 57.64% with urea and ammonium sulphate treated with DMPP, respectively in case of sandy loam soil. The corresponding values were 27.91 and 45.77%, respectively in case of sandy clay loam soil. It is proposed that DMPP could be used as an effective nitrification inhibitor to control nitrification process, decline N leaching, and increase the utilization efficiency of applied nitrogen fertilizers besides saving the fertilizers and labor costs.                                                                   

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