Forage production and nitrogen dynamics in silvopastoral systems with Leucaena diversifolia in Urochloa grass-based pastures
No hay miniatura disponible
Fecha
Título de la revista
ISSN de la revista
Título del volumen
Editor
Elsevier BV
Resumen
Descripción
In tropical regions, cattle production often relies on grass monocrops (GMC), which limit productivity and land-use efficiency. Sustainable intensification of pastures is needed to meet rising demand for animal-source foods. Silvopastoral systems (SPS) with nitrogen-fixing legume trees, such as Leucaena diversifolia , offer a potential solution but may increase nitrous oxide (N₂O) emissions due to higher nitrogen (N) inputs. We conducted a one-year study comparing Urochloa GMC versus SPS with L. diversifolia on a fertile Pachic Haplustoll in Valle del Cauca, Colombia. Two grass cultivars were evaluated: Urochloa hybrid cv. Cayman and U. brizantha cv. Toledo. In SPS, tree rows created two zones: grass-only (SPS/GO) and under-tree (SPS/UT). We measured forage biomass, grass N uptake, N₂ fixation by L. diversifolia , and soil N₂O emissions under two conditions: no additional N input (+water) and after urine deposition (+urine). SPS produced 30% more forage dry matter than GMC. Leucaena diversifolia obtained 54% of its N from atmospheric fixation. The grass in SPS absorbed 8 kg N ha⁻¹ more per grazing cycle than GMC. Under no additional N inputs, soil N₂O emissions were higher in SPS/UT, likely due to greater N recycling. With urine addition, emissions were variable, with higher values in SPS/GO, but no statistical difference was found between SPS/UT and GMC, possibly due to inappropriate urine-N overdosing in GMC. Although SPS showed higher N₂O emissions under specific conditions, their greater forage yield and quality, plus potential co-benefits like lower enteric methane emissions and higher carbon capture, indicate a favorable production–environment trade-off.
Palabras clave
greenhouse gas emissions, livestock, nitrous oxide, trees, silvopastoral systems, emisión de gases de efecto invernadero, nitrogen cycle, ciclo del nitrógeno, grazing systems, biomass production, producción de biomasa, sistema silvopascícola-sistemas silvopastorales, Óxido nitroso, sistema de pastoreo, forage production, biological nitrogen fixation, fijación biológica del nitrógeno, Árbol fijador de nitrógeno