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Titolo:
C and N fluxes of decomposing C-13 and N-15 Brassica napus L.: effects of residue composition and N content
Autore:
Trinsoutrot, I; Recous, S; Mary, B; Nicolardota, B;
Indirizzi:
INRA, Unite Agron Chalons Reims, Ctr Rech Agron, F-51686 Reims 2, France INRA Reims France 2 alons Reims, Ctr Rech Agron, F-51686 Reims 2, France INRA, Unite Agron Laon Peronne, F-02007 Laon, France INRA Laon France F-02007 Unite Agron Laon Peronne, F-02007 Laon, France
Titolo Testata:
SOIL BIOLOGY & BIOCHEMISTRY
fascicolo: 11-12, volume: 32, anno: 2000,
pagine: 1717 - 1730
SICI:
0038-0717(200010)32:11-12<1717:CANFOD>2.0.ZU;2-6
Fonte:
ISI
Lingua:
ENG
Soggetto:
SOIL MICROBIAL BIOMASS; PLANT RESIDUES; WHEAT-STRAW; FIELD CONDITIONS; PARTICLE-SIZE; NITROGEN; MINERALIZATION; CROP; IMMOBILIZATION; MODEL;
Keywords:
Brassica napus L; labeled plant residues; cross fluxes; N mineralization; N immobilization;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
56
Recensione:
Indirizzi per estratti:
Indirizzo: Nicolardota, B INRA, Unite Agron Chalons Reims, Ctr Rech Agron, 2 Esplanade Roland Garros,BP 224, F-51686 Reims 2, France INRA 2 Esplanade Roland Garros,BP 224 Reims France 2 rance
Citazione:
I. Trinsoutrot et al., "C and N fluxes of decomposing C-13 and N-15 Brassica napus L.: effects of residue composition and N content", SOIL BIOL B, 32(11-12), 2000, pp. 1717-1730

Abstract

The interactions occurring between biochemical composition and N content of crop residues while decomposing in soil, and the associated N dynamics were assessed by studying the kinetics of C and N biotransformations of different tissues of Brassica napus L. (roots, stems and pod walls). These residues were obtained by growing a rapeseed crop under low and high N nutrition, in a labeling growth chamber with enriched (CO2)-C-13 atmosphere and a N-15 nutritive solution. The resulting crop residues in which the C-to-N ratio varied between 22 and 135 were homogeneously labeled with C-13 and N-15. Paired labeled residues ((CN)-C-13-N-15 labeled residues with unlabeled soil inorganic N; (CN)-C-13-N-14 residues with N-15 labeled soil inorganic N) were used to determine net and gross fluxes of immobilization and mineralization. Decomposition was studied during laboratory incubations at 15 degrees C, the initial soil N availability being non-limiting with regard to the rate of C decomposition. The rate of C-13 mineralization from the residues was influenced by the biochemical composition of the tissues and particularly by their soluble C content. The N content of the tissues did not significantly affect the kinetics or the amount of C mineralized, except in the very short-term Decomposition was rapid and after 168 days of incubation at 15 degrees C, 82% of the C from the stems and pod walls and 69% from the roots at both low and high N contents had disappeared from the soil coarse fraction. Residue decomposition first resulted in net immobilization of soil mineral N for all the residues. The intensity and duration of this immobilization depended on the tissues and the N content of the residues. Compared to the control, the residues with low N content, still induced net N immobilization after 168 days (-22 to -14 mg N g(-1) of added C) whereas the high N residues induced little net immobilization or mineralization, at -3 to + 4 mg N g(-1) of added C at the same date. The NCSOIL model was used as a tool to calculate, by fitting simulation against the data, the gross N mineralization and immobilization fluxes and also to determine the total N fluxesinvolved over the 168 days of decomposition. Depending on the tissues and their N content, gross cumulative immobilization ranged from 71 to 113 mg Ng(-1) of added C and gross mineralization Varied from 66 to 123 mg N g(-1)of added C. The differences in net mineralization, observed during decomposition of the tissues with low and high N contents, were well explained by the differences between gross mineralization fluxes which were themselves attributable to the different quantities of N mineralized from the residues,The use of modeling to calculate the total gross N fluxes demonstrates that the total amount of N involved in the decomposition of crop residues is much higher than the resulting net fluxes quantified either by N balance or by N-15 tracing. (C) 2000 Elsevier Science Ltd. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 27/11/20 alle ore 13:16:03