title: Traits affecting early season nitrogen uptake in nine legume species.
abstract: Legume crops are known to have low soil N uptake early in their life cycle, which can weaken their ability to compete with other species, such as weeds or other crops in intercropping systems. However, there is limited knowledge on the main traits involved in soil N uptake during early growth and for a range of species. The objective of this research was to identify the main traits explaining the variability among legume species in soil N uptake and to study the effect of the soil mineral N supply on the legume strategy for the use of available N sources during early growth. Nine legume species were grown in rhizotrons with or without N supply. Root expansion, shoot and root biomass, nodule establishment, N2fixation and mineral soil N uptake were measured. A large interspecific variability was observed for all traits affecting soil N uptake. Root lateral expansion and early biomass in relation to seed mass were the major traits influencing soil N uptake regardless of the level of soil N availability. Fenugreek, lentil, alfalfa, and common vetch could be considered weak competitors for soil N due to their low plant biomass and low lateral root expansion. Conversely, peanut, pea, chickpea and soybean had a greater soil N uptake. Faba bean was separated from other species having a higher nodule biomass, a higher N2fixation and a lower seed reserve depletion. Faba bean was able to simultaneously fix N2and take up soil N. This work has identified traits of seed mass, shoot and root biomass, root lateral expansion, N2fixation and seed reserve depletion that allowing classification of legume species regarding their soil N uptake ability during early growth.
authors.affiliation: USC LEVA, INRA, Ecole Supérieure d'Agricultures, Univ. Bretagne Loire, SFR 4207 QUASAV, 55 rue Rabelais, 49007, Angers Cedex, France.
authors.forename: Elana
authors.initials: E
authors.lastname: Dayoub
authors.affiliation: USC LEVA, INRA, Ecole Supérieure d'Agricultures, Univ. Bretagne Loire, SFR 4207 QUASAV, 55 rue Rabelais, 49007, Angers Cedex, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Naudin
authors.affiliation: USC LEVA, INRA, Ecole Supérieure d'Agricultures, Univ. Bretagne Loire, SFR 4207 QUASAV, 55 rue Rabelais, 49007, Angers Cedex, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Piva
authors.affiliation: Department of Plant Sciences, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Shirtliffe
authors.affiliation: USC LEVA, INRA, Ecole Supérieure d'Agricultures, Univ. Bretagne Loire, SFR 4207 QUASAV, 55 rue Rabelais, 49007, Angers Cedex, France.
authors.forename: Joëlle
authors.initials: J
authors.lastname: Fustec
authors.affiliation: USC LEVA, INRA, Ecole Supérieure d'Agricultures, Univ. Bretagne Loire, SFR 4207 QUASAV, 55 rue Rabelais, 49007, Angers Cedex, France.
authors.forename: Guénaëlle
authors.initials: G
authors.lastname: Corre-Hellou
keywords: Agriculture; Plant biology