Assessing Drought Tolerance of five Improved Forage Legumes to Improve Smallholder Dairy Productivity in Uganda
John Kigongo1, Birthe Paul2, Emmanuel Zziwa1, Brigitte L. Maass2, Jolly Mary Kabirizi3
1Makerere University, Uganda
Livestock production is an important component of smallholder farming systems in Uganda. One main constraint to especially dairy production is the lack of sufficient quantity and quality feed on a consistent basis. Therefore, this study aimed to evaluate and identify forage legumes that are adapted to drought. An on-station experiment was established at the NaLIRRI research station in Tororo, an area experiencing prolonged dry seasons. Five improved forages were compared under rainfed and irrigated conditions in a complete randomized block design (five replicates): Canavalia brasiliensis (CIAT 17009), Desmanthus virgatus (ILRI 321), Desmodium uncinatum cv Silver leaf (ILRI 6765), Lablab purpureus (CIAT 22759) and Macroptilium bracteatum cv Burgundy. Herbage biomass was sampled five times at two-monthly intervals, while root biomass was measured once. Biomass estimates were consistently higher on irrigated than non-irrigated plots, especially during the dry season. Lablab (1269.2 kg ha-1), Desmanthus (1257.6 kg ha-1) and Canavalia (1267.9 kg ha-1) were screened as promising forages with the highest herbage biomass on non-irrigated plots and thus potential candidates for dry season feeding. Macroptilium and Desmodium recorded 1011.2 kg ha-1 and 894.43 kg ha-1 of herbage biomass which was significantly lower compared to the other forages. Root biomass was assessed once and was highest for Desmanthus, followed by Desmodium (36%) and Canavalia (26%) while both Macroptilium and Lablab had root biomass of less than 21%. Stable carbon isotope signatures (δ13C) are currently analysed to assess water use efficiency of the forage legumes.
Keywords: Drought resistance, herbage, tropical forage quality
Contact Address: Birthe Paul, International Center for Tropical Agriculture (CIAT), Tropical Forages Program, Nairobi, Kenya, e-mail: b.paulcgiar.org