Response of bulk chemical composition, lignin and carbohydrate signature to grassland conversion in a ley-arable cropping system
2009
Rumpel, Cornélia | Chabbi, Abad | Institut d'écologie et des sciences de l'environnement de Paris (iEES) ; Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS) | Unité Expérimentale Fourrages et Environnement de Lusignan (UEFE) ; Institut National de la Recherche Agronomique (INRA)
National audience
显示更多 [+] 显示较少 [-]英语. Grassland conversion is a common practice in ley-arable cropping systems. The effects of such a disturbance on soil organic matter status and its consequences for biogeochemical cycles in terms of soil organic matter (SOM) dynamics remain poorly understood. We investigated changes occurring in soil organic carbon and nitrogen content, bulk chemical composition and in lignin as well as carbohydrate signature during 2 years after grassland conversion into arable land. Our results showed a rapid SOM decrease in the first few months after the conversion. The bulk chemical composition as seen by solid-state C-13 NMR spectroscopy was similar under grassland and arable land, whereas different landuse had an impact on the contribution of plant litter compounds to SOM. SOM of arable soil had higher lignin contents and lower contents of non-cellulosic neutral carbohydrates than grassland soil. After grassland conversion, the most prominent change was an increase of the SOM's content of non-cellulosic carbohydrate above the contents recorded for grassland or arable land. Principal component analysis indicated that SOM chemical characteristics of converted grassland even after 2 years are similar to those of initial grassland. We conclude that the chemical composition of SOM is less susceptible to rapid change and that re-installation of grassland within some years will safeguard the initial SOM status in ley-arable rotations.
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