Gero Benckiser
Institute for Applied Microbiology, Justus Leibig University

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Effects of Nitrification Inhibitors on Mineral Nitrogen Dynamics in Agriculture Soils Tindaon, Ferisman; Benckiser, Gero; Ottow, Johannes Carl Gottlieb
AGRIVITA, Journal of Agricultural Science Vol 33, No 3 (2011)
Publisher : Faculty of Agriculture University of Brawijaya in collaboration with PERAGI

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17503/agrivita.v33i3.86

Abstract

Experiments were conducted under laboratory conditions to elucidate the effect of three nitrification inhibitors viz, 3.4dime-thylpyrazo-lephosphate (DMPP), 4-Chlormethylpyrazole (ClMP) and dicyandiamide (DCD) on mineral nitrogen dynamics of (NH4)2SO4 in soil incubated at 25oC in soils. The quantitative determination of ammonium, nitrite and nitrate were carried out spectrophotometrically, while potential denitrify-cation capacity (PDC) was measured gas chromatographically. DMPP, ClMP and DCD were used on recommended rates of 90kg N ha-1 corres-ponding to 0.36µg DMPP; 0.25µg ClMP and 10µg DCD g-1 dry soil. In all treatments, the influence of 1, 10, 50, 100, 250 and 500 times of the recommended-concentrations were examined. Results suggested that DMPP, ClMP and DCD applied at rates generally recommended for agricultural use may not be effective to inhibit nitrification. Thus even at the highest tested NIs-concentrations, nitrate and nitrite formation still occurred. Application of high concentrations of these chemicals up to 180µg DMPP, 125µg ClMP and 2500µg DCD were needed for inhibiting nitrification completely. The three NIs began to inhibit PDC at 10 to 50 times recommended concentration and were more effective in sandy than in loamy or clay soils. ClMP influenced PDC at much lower concentration as DMPP or DCD.   Keywords: nitrification inhibitors, mineral nitrogen dynamics
Side Effects of Nitrification Inhibitors on Non Target Microbial Processes in Soils Tindaon, Ferisman; Benckiser, Gero; Ottow, Carl Gottlieb
JOURNAL OF TROPICAL SOILS Vol. 16 No. 1: January 2011
Publisher : UNIVERSITY OF LAMPUNG

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5400/jts.2011.v16i1.7-16

Abstract

Agricultural chemicals have been used extensively in modern agriculture and toxicological studies suggest a great potential for inducing undesirable effects on non target organisms. A model experiment was conducted in order to determine side effects of three nitrification inhibitors (NIs, 3,4dimethylpyrazolephosphate = DMPP, 4-Chlormethylpyrazole phosphate = ClMPP and dicyandiamide = DCD) on non target microbial processes in soils. Side effects and dose response curve of three NIs were quantified under laboratory conditions using silty clay, loam anda sandy soils. Dehydrogenase, dimethylsulfoxide reductase as well as nitrogenase activity (NA) and potential denitrification capacity were measured as common and specific non target microbial processes. The influence of 5-1000 times the base concentration, dose response curves were examined, and no observable effect level = NOEL, as well as effective dose ED10 and ED50 (10% and 50% inhibition) were calculated. The NOEL for microbial non target processes were about 30–70 times higher than base concentration in all investigated soils. The potential denitrification capacity revealed to be the most sensitive parameter. ClMPP exhibited the strongest influence on the non target microbial processes in the three soils. The NOEL, ED10 and ED50 values were higher in clay than in loamy or sandy soil. The NIs was the most effective in sandy soils.Keywords: microbial non target processes, nitrification inhibitors, soil enzymes