Integral Assessment of Productive and Environmental Parameters of a Forage-Based Silvopastoral System
Jacobo Arango1, Mauricio Sotelo1, Jhon Fredy Gutierrez2, Belisario Hincapie1, Eduardo Vazquez3, Nikola Teutscherová4, Xiomara Gaviria5, Isabel Molina6, Rolando Barahona7, Mirjam Pulleman8, Ngonidzashe Chirinda1, Michael Peters1
1International Center for Tropical Agriculture (CIAT), Colombia
To quantify the productivity and environmental benefits of improved forage-based silvopastoral systems, a six hectares field trial was established in 2013 at the headquarters of the International Center for Tropical Agriculture (CIAT) using improved forages developed at CIAT and the International Livestock Research Institute (ILRI). A randomised complete block design with three replications was used with three treatments: T1 grass alone, Brachiaria hybrid cv. Cayman; T2: Grass + herbaceous legume, Canavalia brasiliensis and T3: Grass + herbaceous legume + tree legume Leucaena diversifolia.
In order to measure animal productivity, a group of steers was fattened (from 200 to 450kg) and subgroups of animals were assigned to the three treatments (T1, T2 and T3) in a rotational grazing system (stocking rate: 4 animals per hectare). Animal subgroups were kept in each treatment for comparison purpouses. Live weight gain per animal was recorded monthly and large differences were found between treatments with an average of 240, 744 and 819 kg ha-1 yr-1 for T1, T2 and T3, respectively. Environmental parameters evaluated in the three treatments included soil chemical and physical parameters as well as soil macrofauna, as an indicator of soil health. A positive impact of forage diversification on key soil properties and the abundance and diversity of soil macroinvertebrates was found with best results in T3 compared to the other two treatments. The taxonomic abundance and functional diversity of soil macrofauna were found to correlate positively with forage diversification and the level of inclusion of legumes in a grass-alone system.
Keywords: Climate change, greenhouse gases, soil quality, tropical forages
Contact Address: Jacobo Arango, International Center for Tropical Agriculture (CIAT), A A 6713, Cali, Colombia, e-mail: j.arangocgiar.org