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Your search keyword '"Grego, S."' showing total 17 results
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17 results on '"Grego, S."'

1. Assessment of soil nitrogen and phosphorous availability under elevated CO2 and N-fertilization in a short rotation poplar plantation

Author

Lagomarsino, A., Moscatelli, M.C., Hoosbeek, M.R., de Angelis, P., Grego, S., Lagomarsino, A., Moscatelli, M.C., Hoosbeek, M.R., de Angelis, P., and Grego, S.

Abstract

Photosynthetic stimulation by elevated [CO2] is largely regulated by nitrogen and phosphorus availability in the soil. During a 6 year Free Air CO2 Enrichment (FACE) experiment with poplar trees in two short rotations, inorganic forms of soil nitrogen, extractable phosphorus, microbial and total nitrogen were assessed. Moreover, in situ and potential nitrogen mineralization, as well as enzymatic activities, were determined as measures of nutrient cycling. The aim of this study was to evaluate the effects of elevated [CO2] and fertilization on: (1) N mineralization and immobilization processes; (2) soil nutrient availability; and (3) soil enzyme activity, as an indication of microbial and plant nutrient acquisition activity. Independent of any treatment, total soil N increased by 23% in the plantation after 6 years due to afforestation. Nitrification was the main process influencing inorganic N availability in soil, while ammonification being null or even negative. Ammonium was mostly affected by microbial immobilization and positively related to total N and microbial biomass N. Elevated [CO2] negatively influenced nitrification under unfertilised treatment by 44% and consequently nitrate availability by 30% on average. Microbial N immobilization was stimulated by [CO2] enrichment and probably enhanced the transformation of large amounts of N into organic forms less accessible to plants. The significant enhancement of enzyme activities under elevated [CO2] reflected an increase in nutrient acquisition activity in the soil, as well as an increase of fungal population. Nitrogen fertilization did not influence N availability and cycling, but acted as a negative feed-back on phosphorus availability under elevated CO2.

Published
2008

2. Net carbon storage in a popular plantation (POPFACE) after three years of free-air CO2 enrichment

Author

Gielen, B., Calfapietra, C., Lukac, M., Wittig, V.E., de Angelis, P., Janssens, I.A., Moscatelli, M.C., Grego, S., Cotrufo, M.F., Godbold, D., Hoosbeek, M.R., Long, S., Miglietta, F., Polle, A., Bernacchi, C., Davey, P.A., Ceulemans, R., Scarascia-Mugnozza, G., Gielen, B., Calfapietra, C., Lukac, M., Wittig, V.E., de Angelis, P., Janssens, I.A., Moscatelli, M.C., Grego, S., Cotrufo, M.F., Godbold, D., Hoosbeek, M.R., Long, S., Miglietta, F., Polle, A., Bernacchi, C., Davey, P.A., Ceulemans, R., and Scarascia-Mugnozza, G.

Abstract

A high-density plantation of three genotypes of Populus was exposed to an elevated concentration of carbon dioxide ([CO2]; 550 µmol mol¿1) from planting through canopy closure using a free-air CO2 enrichment (FACE) technique. The FACE treatment stimulated gross primary productivity by 22 and 11% in the second and third years, respectively. Partitioning of extra carbon (C) among C pools of different turnover rates is of critical interest; thus, we calculated net ecosystem productivity (NEP) to determine whether elevated atmospheric [CO2] will enhance net plantation C storage capacity. Free-air CO2 enrichment increased net primary productivity (NPP) of all genotypes by 21% in the second year and by 26% in the third year, mainly because of an increase in the size of C pools with relatively slow turnover rates (i.e., wood). In all genotypes in the FACE treatment, more new soil C was added to the total soil C pool compared with the control treatment. However, more old soil C loss was observed in the FACE treatment compared with the control treatment, possibly due to a priming effect from newly incorporated root litter. FACE did not significantly increase NEP, probably as a result of this priming effect.

Published
2005

7. P-state-to-P-state transitions in optically prepared atomic collisions:III. A complete analysis of Li+ + Na(3p)¿Li(2p) + Na+ differential scattering

Author

Dowek, D., Reiser, I., Grego, S., Andersen, Nils Overgaard, Dubois, A., Houver, J.C., Nielsen, S.E., Richter, C., Salgado, J., Svensson, Anders, Thomsen, J.W., Dowek, D., Reiser, I., Grego, S., Andersen, Nils Overgaard, Dubois, A., Houver, J.C., Nielsen, S.E., Richter, C., Salgado, J., Svensson, Anders, and Thomsen, J.W.

Abstract

Udgivelsesdato: 24 April

Published
2002

13. P-state-to-P-state transitions in optically prepared atomic collisions:III. A complete analysis of Li+ + Na(3p)¿Li(2p) + Na+ differential scattering

Author

Dowek, D., Reiser, I., Grego, S., Andersen, Nils Overgaard, Dubois, A., Houver, J.C., Nielsen, S.E., Richter, C., Salgado, J., Svensson, Anders, Thomsen, J.W., Dowek, D., Reiser, I., Grego, S., Andersen, Nils Overgaard, Dubois, A., Houver, J.C., Nielsen, S.E., Richter, C., Salgado, J., Svensson, Anders, and Thomsen, J.W.

Abstract

Udgivelsesdato: 24 April

Published
2002

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