Biological Nitrogen Fixation, Carbon assimilation and plant performance of Lotus tenuis, contribute to define a strategic role in the lowlands in the Salado River Basin (Argentina)

Abstract

Background and AimsForage production constitutes a great challenge for the Salado River Basin (Argentina), the major area devoted to livestock in the country. The successful naturalization of the European legume Lotus tenuis has been a productive and environmental relevance for the region. This study aims to evaluate its strategic contribution, reporting for the first time the B value for this species in these marginal environments for agriculture.MethodsThe 15N natural abundance method was used to evaluate the BNF of L. tenuis at soil plots and non-leguminous weed species in the same plots were utilized as reference plants. The assays included determinations of the 13C isotope, as well. Simultaneously, evaluations were carried out in the greenhouse for the determination of the B value of L. tenuis and the relative reproducibility of the field experiments.ResultsThe results obtained demonstrated that the L. tenuis promotion is accompanied by an increase in forage quality, due to the predominance of this C3 legume species, over C4 species. Moreover, its contribution to N inputs to the system, through the BNF with native rhizobia demonstrated to be about 80%, a highly relevant percentage for these constrained agroecosystems.ConclusionsThis work supports the hypothesis that L. tenuis promotion plays a strategic role in the sustainability of the ecosystem, especially in soil constrained areas. Joined with data previously published, the results obtained contribute to support the criteria that define the naturalized legume playing a strategic role in the sustainability of agriculture marginal soils.