Respuesta de pasturas fertilizadas con N o en mezcla con leguminosas, a la huella hidrica, desempeño animal, y caracteristicas de forraje

Authors: Jaramillo, David

Submitted to: Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/24/2021
Publication Date: 4/21/2021
Citation: Jaramillo, D.M. 2021. Respuesta de pasturas fertilizadas con N o en mezcla con leguminosas, a la huella hidrica, desempeño animal, y caracteristicas de forraje. Symposium Proceedings. 2021.

Interpretive Summary: Replacing N fertilizer with forage legumes may increase sustainability of grazing systems. The objectives were to evaluate herbage and animal responses and to quantify the water footprint associated with beef production in N-fertilized grass or grass-legume systems during 4 years under continuous stocking. The three year-round forage systems were: 1) Grass+N which included N-fertilized bahiagrass (Paspalum notatum Flüggé) during summer, and it was overseeded with N-fertilized cereal rye (Secale cereale L.) and oat (Avena sativa L.) during winter; 2) Grass+Clover included bahiagrass without N fertilizer during summer, and it was overseeded with rye, oat, and a mixture of clovers (Trifolium spp.) during winter; and 3) Grass+Clover+RP included rhizoma peanut (Arachis glabrata Benth.)-bahiagrass mixture during summer, and it was overseeded with a similar rye-oat-clover mixture as for Grass+Clover. Clover inclusion improved uniformity of herbage distribution throughout the winter. Including rhizoma peanut increased warm-season cattle average daily gain (ADG) by nearly 80%, with ADG in Grass+Clover+RP of 0.61 kg d-1 compared with 0.35 kg d-1 on Grass+N and Grass+Clover. Beef water footprint during summer was less in Grass+Clover+RP than Grass+Clover (14 and 24 m3 kg-1 bodyweight, respectively). Gain per area (GPA) was similar across all treatments through the year, indicating similar productivity in grass-legume and N-fertilized grass systems, and N-fertilizer inputs were reduced from 224 to 34 kg N ha-1 yr-1 in Grass+Clover+RP. Inclusion of rhizoma peanut and clovers contributes to developing sustainable grazing systems with reduced levels of off-farm inputs.

Technical Abstract: Replacing N fertilizer with forage legumes may increase sustainability of grazing systems. The objectives were to evaluate herbage and animal responses and to quantify the water footprint associated with beef production in N-fertilized grass or grass-legume systems during 4 years under continuous stocking. The three year-round forage systems were: 1) Grass+N which included N-fertilized bahiagrass (Paspalum notatum Flüggé) during summer, and it was overseeded with N-fertilized cereal rye (Secale cereale L.) and oat (Avena sativa L.) during winter; 2) Grass+Clover included bahiagrass without N fertilizer during summer, and it was overseeded with rye, oat, and a mixture of clovers (Trifolium spp.) during winter; and 3) Grass+Clover+RP included rhizoma peanut (Arachis glabrata Benth.)-bahiagrass mixture during summer, and it was overseeded with a similar rye-oat-clover mixture as for Grass+Clover. Clover inclusion improved uniformity of herbage distribution throughout the winter. Including rhizoma peanut increased warm-season cattle average daily gain (ADG) by nearly 80%, with ADG in Grass+Clover+RP of 0.61 kg d-1 compared with 0.35 kg d-1 on Grass+N and Grass+Clover. Beef water footprint during summer was less in Grass+Clover+RP than Grass+Clover (14 and 24 m3 kg-1 bodyweight, respectively). Gain per area (GPA) was similar across all treatments through the year, indicating similar productivity in grass-legume and N-fertilized grass systems, and N-fertilizer inputs were reduced from 224 to 34 kg N ha-1 yr-1 in Grass+Clover+RP. Inclusion of rhizoma peanut and clovers contributes to developing sustainable grazing systems with reduced levels of off-farm inputs.