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Titolo:
The fate of nitrogen from winter-frozen rapeseed leaves: mineralization, fluxes to the environment and uptake by rapeseed crop in spring
Autore:
Dejoux, JF; Recous, S; Meynard, JM; Trinsoutrot, I; Leterme, P;
Indirizzi:
INRA, INAPG, Unite Agron, F-78850 Thiverval Grignon, France INRA Thiverval Grignon France F-78850 F-78850 Thiverval Grignon, France INRA, Unite Agron, F-02007 Laon, France INRA Laon France F-02007INRA, Unite Agron, F-02007 Laon, France INRA, Ctr Rech Agron, Unite Agron, F-51686 Reims, France INRA Reims France F-51686 Rech Agron, Unite Agron, F-51686 Reims, France INRA, Unite Rech Sol Agron, F-35042 Rennes, France INRA Rennes France F-35042 Unite Rech Sol Agron, F-35042 Rennes, France
Titolo Testata:
PLANT AND SOIL
fascicolo: 1-2, volume: 218, anno: 2000,
pagine: 257 - 272
SICI:
0032-079X(2000)218:1-2<257:TFONFW>2.0.ZU;2-D
Fonte:
ISI
Lingua:
ENG
Soggetto:
SUBSEQUENT CROPS; GREEN MANURE; OILSEED RAPE; N MINERALIZATION; FIELD CONDITIONS; PLANT MATERIALS; PARTICLE-SIZE; PEA RESIDUES; WHEAT-STRAW; SOIL;
Keywords:
biochemical quality; Brassica napus L.; decomposition; incubation; leaf fall; N recovery;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
57
Recensione:
Indirizzi per estratti:
Indirizzo: Meynard, JM INRA, INAPG, Unite Agron, BP01, F-78850 Thiverval Grignon, France INRA BP01 Thiverval Grignon France F-78850 al Grignon, France
Citazione:
J.F. Dejoux et al., "The fate of nitrogen from winter-frozen rapeseed leaves: mineralization, fluxes to the environment and uptake by rapeseed crop in spring", PLANT SOIL, 218(1-2), 2000, pp. 257-272

Abstract

For environmental purposes, very early sowing of winter rapeseed may reduce winter nitrate leaching thanks to the high N uptake capacities of rapeseed in autumn. However, freezing could lead to high losses of leaf nitrogen, amounting to more than 100 kg N ha(-1) (Dejoux et al., 1999). Here we investigated the agronomic and environmental consequences of the decomposition of fallen leaves, based on field and laboratory studies with N-15 labeled leaves (C:N=9). The potential kinetics of decomposition of leaves were measured by incubation in the laboratory. In the field, all leaves were removed at beginning of winter and replaced by labeled leaves, artificially frozen at -15 degrees C , which were laid on the soil surface. Compared on a thermal time basis, decomposition proceeded as quickly in the field as in the incubations and was complete after 116 normalized days at 15 degrees C. The proportion of N-15 derived from labeled leaves, absorbed again by the rape plants, was 28% at flowering and 24% at harvest. This high N recovery is assumed to result from the synchronization of leaves decomposition and active Nabsorption by rape in spring. Leaf N mineralization did not increase soil N mineral content at flowering or at harvest, but we observed a 40% loss ofN-15. As no leaching was simulated, this loss was supposed to be gaseous. Such a high percentage could be explained by the fact that the decomposing leaves lay on the soil surface, and by climatic conditions conducive to such emissions. For environmental purposes, the quantity and nature of these gaseous N emissions have to be studied for other climatic conditions and types of leaves. As a proportion of N is reabsorbed, N fertilizer application rates could be reduced accordingly.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/11/20 alle ore 06:20:55