Performance of tropical legumes grown as understory of a eucalypt plantation in a seasonally dry area of the Brazilian Cerrado

Abstract

Nine tropical legumes were grown outside the canopy and in the understory of an 8-year-old Eucalyptus grandis stand in order to assess their seasonal production and forage quality for 4 evaluation periods. Incident photosynthetically active radiation in the understory was 18% of that outside the canopy. In the understory, production of Lablab purpureus, Centrosema schiedeanum, Clitoria ternatea, Pueraria phaseoloides, Alysicarpus vaginalis, Aeschynomene villosa, Estilosantes Campo Grande (Stylosanthes capitata + S. macrocephala), Calopogonium mucunoides and Arachis pintoi was <1 kg/ha/d for most samples. Even considering this low production, the large area available for animal production in forest plantations might justify the interest in legumes because of their high nutritive value. Lablab purpureus produced the greatest amount of dry matter in the understory in the establishment phase (12.1 kg/ha/d), but did not persist. It could be a suitable candidate for a cover legume species mixture to provide early growth. Centrosema schiedeanum developed rapidly and showed a high capacity for ground cover (>70%) and persistence, and had high nitrogen concentration, thus demonstrating good potential for protecting soils and promoting nutrient cycling in forest plantations. Another species with potential is A. pintoi, which established slowly but towards the end of the experiment showed moderate to high understory ground cover. ResumenCon el fin de determinar la producción estacional y la calidad de forraje durante 4 períodos de evaluación, en condiciones de sequía estacional del Cerrado brasileño se cultivaron 9 leguminosas tropicales bajo y fuera del dosel de una plantación de Eucalyptus grandis de 8 años de edad. Bajo el dosel, la radiación fotosintéticamente activa incidente estaba reducida al 18% de la radiación fuera del dosel. La producción de materia seca (MS) de Lablab purpureus, Centrosema schiedeanum, Clitoria ternatea, Pueraria phaseoloides, Alysicarpus vaginalis, Aeschynomene villosa, Estilosantes Campo Grande (Stylosanthes capitata + S. macrocephala), Calopogonium mucunoides y Arachis pintoi fue <1 kg/ha por día para la mayoría de las muestras bajo el dosel. Incluso teniendo en cuenta esta baja producción, la gran superficie de plantaciones forestales disponible para la producción animal podría justificar el interés en leguminosas forrajeras debido a su alto valor nutritivo. En la fase de establecimiento, L. purpureus produjo la mayor cantidad de MS bajo el dosel (12.1 kg/ha por día), pero no fue persistente. Esta especie podría ser un candidato para una mezcla de especies de leguminosas de cobertura, para proporcionar una cobertura y producción tempranas. Centrosema schiedeanum presentó un desarrollo rápido y mostró una alta cobertura del suelo (>70%) y de persistencia con alta concentración de nitrógeno, indicando un buen potencial para proteger el suelo y promover el reciclaje de nutrientes en plantaciones forestales. Arachis pintoi es otra especie con alto potencial de cultivo bajo dosel; aunque...

Influence of low light intensity on growth and biomass allocation, leaf photosynthesis and canopy radiation interception and use in two forage species of Centrosema (DC.) Benth.

“…In turn, soil water deficits and grazing may demand more fixed C into root growth. Therefore, when selecting herbage species for silvopastures, the potential beneficial effects of complementarity in species mixtures to ameliorate contrasting effects of stressing factors (Nicodemo et al., ) should also be further assessed in subsequent studies. In the case of the Centrosema genotypes tested in this study, with contrasting acclimation strategies to shade and seasonal drought (Guenni et al., ), they may be combined with medium shade‐tolerant C 4 grasses like Brachiaria decumbens (Gómez et al., ) and Panicum maximum (Paciullo et al., ) to improve herbage quality and persistence of understory pastures in silvopastoral systems.…”

“…Conversely, the strong plasticity for light capturing and consistent higher forage and N yields of C. macrocarpum CIAT 5713 under full‐light environments may make this genotype more suitable for less shaded (>50% sunlight) silvopastures. Given the potential of these accessions/cultivars, further experiments testing the genetic variability within these two Centrosema species may result in the selection of genotypes with higher plasticity to shade (Nicodemo et al., ).…”

“…The incorporation of tropical forage legumes, as an understorey cover in the grazing component of silvopastures, not only contributes to controlling soil erosion and weed invasion, but enhances forage quality, with the concomitant additional benefits such as improved soil fertility through N‐fixation and the build‐up of a high‐quality pool of organic matter (Humphreys, ). However, in addition to the influence of tree species and plantation management, the success of companion understorey forage legumes in silvopastures will depend mostly on the species′ capacity to persist, maintain high nutritive value and tolerate grazing under restricted radiation and modified light quality beneath tree canopies (Almeida et al., ; Araújo, Silva, Rocha, & Ortêncio, ; Nicodemo et al., ; Paciullo et al., ; Soares et al., ). In forage legumes, this capacity may be further limited because N‐fixers typically require elevated light levels to maintain the carbon costs associated with the plant–bacteria symbiosis (Lambers, Chapin, & Pons, ).…”

“…In Venezuela, they occupy a wide range of habitat conditions: from tree‐less savannahs to savannah‐forest ecotones and low‐ and high‐altitude tropical forest boundaries (Guenni et al., ), yet unlike other forage legumes, these plants appear to tolerate some degree of shade (Cook et al., ; Humphreys, ). Indeed, the genus Centrosema appears to be a good source for cover crops in tree plantations, as well as companion legumes for cultivated or native grasses in silvopastoral systems with a wide variation of shading provided by the tree cover (Humphreys, ; Nicodemo et al., ; Stür, ). Overall, the incorporation of Centrosema in Venezuelan agricultural and grazing lands has proved to be beneficial as cover crops in oil palm plantations (Barrios, Fariñas, Díaz, & Barreto, ), and as forage resources in semi‐arid environments (≤600 mm/year; Faría‐Mármol, Chirinos, Faría, & González, ) and seasonal well‐drained savannahs on acid soils (Grof, Flores, Mendoza, & Pizarro, ; Rodríguez, Flores, & Shultze‐Kraft, ).…”

Using multiple traits to assess the potential of introduced and native vines to proliferate in a tropical region

“…Our approach leverages the diversity of functional types present in vines, as well as the proliferation of alien and native vines alike. Vine diversity is manifested in their diverse climbing mechanisms and host preferences (Gentry, ; Hegarty & Caballé, ), life history strategies and patterns of biomass allocation (Gallagher & Leishman, ; Hairiah & van Noordwijk, ; Kolawole & Kang, ; Lambert & Arnason, ), and horticultural and economic value (Bovell‐Benjamin, ; Nicodemo et al., ; Ortiz‐Ceballos, Aguirre‐Rivera, Osorio‐Arce, & Peña‐Valdivia, ). Additionally, in numerous regions around the globe, including the island of Puerto Rico, a variety of vine species are smothering plant canopies, forest edges, and infrastructure alike over vast areas (Figure ; Delgado, ; Kirkham, ; Taylor & Kumar, ).…”