ISSN:
1573-2932
Keywords:
NISOTOP model
;
PAHs
;
plant nitrogen
;
soil nitrogen
;
15
Source:
Springer Online Journal Archives 1860-2000
Topics:
Energy, Environment Protection, Nuclear Power Engineering
Notes:
Abstract An isotopic model (NISOTOP) has been developed to investigate the effect of the addition to soil of xenobiotics on urea hydrolysis, N mineralization and immobilization, nitrification and plant uptake of nitrogen in a soil-plant system, after addition of 15N enriched compounds. Therationale of the model follows from the errors in %15N abundance (15N D) and N concentration (CN) determinations which cause high variability coefficients in the calculation of the amount of nitrogen present in the different compounds derived from the added 15N enriched urea. The extent of these errors, besides depending on CN and 15N D errors, will also depend on natural 15N and 15N of the added compound, and therefore on the experimental conditions. The model is described by 18 first-order differential equations and is numerically solved by Euler's method with a time increment of 0.01 day. As an illustration, the model is applied to the effect of phenanthrene, chrysene and benzo(a)pyrene to a soil-plant system, following the addition of 15N-urea. These compounds have been chosen as examples of molecules having 3, 4 and 5 fused aromatic rings and are hereafter collectively referred to as PAHs. PAHs at the rate of 2 mg kg-1 soiland 15N-urea at the rate of 166.7 mg N kg-1 soil were added to wheat pots. At harvesting (after 14 days from plantation) the dry matter yield, the total N content and the N concentration of the wheat seedlings were not statistically affected by addition of the PAHs (P = 0.05). The efficiency of N uptake, that is the percentage of fertilizer taken up by the plants at harvesting in the absence of PAHs was 47.3%, while it was 11.7, 15.2 and 14.8% in the presence of phenanthrene, chrysene and benzo(a)pyrene,respectively. The computation of the first-order rate constants of the N transformations showed that N mineralization, nitrification and N-uptake were affected by the addition of phenanthrene, chrysene and benzo(a)pyrene, whilst benzo(a)pyrene inhibited urea hydrolysis more than phenanthrene and chrysene.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1005214310900
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