Nitrogen transformations

In addition to a continued increase in the number of use patents in these fields, a new use of xanthates as inhibitors of fertiliser nitrogen transformation in soil has been reported, as well as the use of certain metal xanthates as color developers for image-recording materials (113,114) (see Fertilizers Color photography). For several years, sodium isopropyl xanthate was used as an intermediate in the manufacture of saccharin (see... 

Further variations on this methodology were explored in chemistry directed to the synthesis of antitumor antibiotic CC-1065 61. Intramolecular cycloaddition with concomitant loss of nitrogen transformed 62 into 63. Further manipulation gave 64 which served as a building block in the assembly of 61. 

Shearer, G., Duffy, J., Kohl, D.H. and Commoner, B. 1974 A steady-state model of isotopic fractionation accompanying nitrogen transformations in soil. Soil Science Society of America... 

H. W. Hunt, J. A. E. Stewart, and C. V. Cole, Concepts of sulphur, carbon and nitrogen transformations in soil evaluation of simulating modeling. Bioj eochemis-try 2 163 (1986). 

L. Klemedtsson, P. Berg, M. Clarholm, and J. Schnurer, Microbial nitrogen transformations in the root environment of barley. Soil Biol. Biochein. 79 551 (1987). 

Metals have been shown to negatively affect nitrogen transformation and urea hydrolysis. For example, Antil et al.69 discovered that the microbial biomass in a soil receiving sewer water or industrial wastewater decreased with increasing concentrations of cadmium and nickel. The rate of urea hydrolysis was 1.6 times greater in an uncontaminated soil than in a soil containing 0.026 mg Ni g 1. Ammonium concentrations increased for up to 14 days in a soil containing over... 

Nitrogen transformation Cd2+ 0.040 mg/g soil Indigenous community Soils receiving sewer/ industrial wastewater 69... 

Antil, R.S., Gupta, A.P., and Narwal, R.P., Nitrogen transformation and microbial biomass content in soil contaminated with nickel and cadmium from industrial wastewater irrigation, Urban Water, 3 (4), 299-302, 2001. 

Rostov, O. and Van Cleemput, O., Nitrogen transformations in copper-contaminated soils and effects of lime and compost application on soil resiliency, Biol Fert Soils, 33 (1), 10-16, 2001. 

Antil, R., Mahata, M., and Narwal, R., Urea hydrolysis and nitrogen transformations in soils containing different lead contents, Arch Agron Soil Sci, 52 (1), 69-77, 2006. 

Figure 4.10 Nitrogen transformations in submerged soils on a redox scale (McBride, 1994). Reproduced by permission of Oxford University Press...

Table 7.1 Acid-base changes in nitrogen transformations in ricefields...

De Datta SK. 1995. Nitrogen transformations in wetland rice ecosystems. Fertiliser Research 42 193-203. 

Cookson, W.R., Marschner, P., Abaye, D.A., Clark, I.M., Murphy, D.V., Stockdale, E.A. and Watson, C. 2005a. The influence of season, agricultural management and soil properties on gross nitrogen transformations and bacterial community structure. Australian Journal of Soil Research (in press). 

Jones, R. A., Broder, M. W. Stotzky, G. (1991). Effects of genetically engineered microorganisms on nitrogen transformation and nitrogen-transforming microbial populations in soil. Applied and Environmental Microbiology, 57, 3212-19. 

This method of establishing retention time is valid only if isotopic fractionation effects during nitrogen transformations are unimportant. For example, nitrification results in a 15N enrichment of the residual NH4 + pool... 

Nitrogen transformations such as nitrate assimilation, denitrification, and decomposition (eqs 10-12) contribute to alkalinity by consuming H+. In contrast, both ammonium assimilation and nitrification (eqs 13 and 14) consume alkalinity via the production of H +. 

Harrison J.A. Matson P.A. and Fendorf S. (2005). Effects of a diel oxygen cycle on nitrogen transformations and greenhouse gas emission in a eutrophied, subtropical stream. Aquatic Sciences, 67, 308-315. 

Davidson et al. (1978a) also used first-order kinetics for nitrogen transformations, but they considered that some of the transformation rate coefficients were dependent on several factors including environmental ones The rate for nitrification was empirically adjusted for water suction. Overall, most of the nitrogen models assume first-order kinetics. Some of them also consider the effects of temperature on rate coefficients. 

Mehran, M., and Tanji, K. K. (1974). Computer modeling of nitrogen transformations in soils. J. Environ. Qual. 3, 391-395. 

Abril, G., Riou, S.A., Etcheber, H., Frankigoulle, M., deWitt, R., and Middelburg, J.J. (2000) Transient, tidal time-scale, nitrogen transformations in an estuarine turbidity maximum-fluid mud system (The Gironde, south-west France). Estuar. Coastal Shelf Sci. 50, 703-715. 

Buffam, I., and McGlathery, K.J. (2003) Effect of ultraviolet light on dissolved nitrogen transformations in coastal lagoon water. Limnol. Oceanogr. 48, 723-734. 

Hart, S. C., Nason, G. E., Maryold, D. D. Perry, D. A. (1994). Dynamics of gross nitrogen transformations in an old-growth forest the carbon connection. Ecology, 75, 880-91. 

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