Predicting N transformations from organic inputs in soil in relation to incubation time and biochemical composition

Pansu Marc Antoine, Thuriès Laurent, Larré-Larrouy Marie-Christine, Bottner P.. 2003. Predicting N transformations from organic inputs in soil in relation to incubation time and biochemical composition. Soil Biology and Biochemistry, 35 (3) : 353-363.

Résumé : Seventeen different added organic materials (AOM) in a sandy soil were incubated under controlled laboratory conditions (28°C, 75% WHC), and examined for C and N mineralisation. The transformation of added organics (TAO) model has been presented in previous work for predicting C mineralisation. The two variables (very labile and stable fractions of AOM) used in TAO have been related to the biochemical characteristics of the AOM. The transformed added organic N fraction (TAONF) was estimated from the remaining CAOM and NAOM linked by the C-to-N ratios. TAONF was split (Pim parameter) into immobilised N (imN) and inorganic N (inorgN). When necessary, an additional N mineralisation of imN was predicted by first order kinetics (constant kremin). The TAO version with the two parameters Pim and kremin allowed us to predict very different dynamics of N mineralisation and N immobilisation from the AOM. In a few cases, another first order kinetic law (constant kv) was used to predict N volatilisation from inorgN. Biochemical characteristics of AOM were used for predicting N transformations. First, at each incubation date, inorgN was approximated to inorgNa = [alpha](N-to-CAOM) + [bêta] by linear regression. The [alpha], [bêta] and - [bêta]/[alpha] (C-to-NAOM threshold for mineralisation/immobilisation) were related to time. The TAO expression (1-Pim)TAONF was then replaced by the proposed approximation inorgNa as a function of incubation time and C-to-NAOM. Secondly, significant relationships were computed between kremin and organic fibre content of AOM. Finally, a TAO approximation was proposed for predicting the simultaneous transformations of C and N, only using biochemical data (plus the kv parameter in a few cases of N volatilisation). For all AOMs, the validity of the approximation and its borderline cases were examined by comparing the two TAO versions.

Mots-clés Agrovoc : sol sableux, modèle de simulation, azote, minéralisation, carbone, immobilisation, amendement organique, biochimie, propriété physicochimique du sol, résidu de récolte

Classification Agris : P33 - Chimie et physique du sol
U10 - Informatique, mathématiques et statistiques
F04 - Fertilisation

Auteurs et affiliations

• Pansu Marc Antoine, IRD (FRA)
• Thuriès Laurent, CIRAD-AMIS-AGRONOMIE (FRA) ORCID: 0000-0002-1365-7891
• Larré-Larrouy Marie-Christine, IRD (FRA)
• Bottner P., CEFE (FRA)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/515317/)

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