Background Fodder trees and shrubs are among the strategic feed resources that complement the dry season feed supply in the tropics. They are an integral element of the farming system incorporated into different land uses and deliver multiple functions, even though their diversity relies on various anthropogenic, physiographic, and agroecological factors. Objective The study aimed to identify indigenous legume fodder trees and shrubs (ILFTS) and estimate their diversity in terms of land use and agroecological zones in southern Ethiopia's Gamo landscape. Method Respondent households were selected using a stratified multistage sampling procedure. Information about the ILFTS was gathered through key informant interviews conducted in each agro‐ecological zone. A total of 273 households from three agro‐ecological zones were selected and interviewed using a semi‐structured questionnaire to assess ILFTS. The information acquired by the questionnaire survey was complemented with a focus group discussion held with 10 respondents in each agro‐ecological zone. Herbarium samples were collected for each of the species for identification and confirmation of the botanical names. Sixty randomly selected sampling plots of each with a dimension of 20 m × 20 m were created, and inventories of ILFTS species were performed and recorded on species inventory sheets. The Shannon–Wiener diversity index (H) was used to determine the species diversity. Result The study identified 21 ILFTS that have been an integral constituent of the land uses recognised for their multiple functions in all agroecological zones. The mean species richness and diversity indices of the ILFTS differed significantly with land use and agroecological zones, where the lowland area closure exhibited the highest, and the highland homesteads and highland grazing land revealed the least. Conclusion Farmers’ indigenous knowledge and previous experience determined the species richness and diversity of ILFTS in farmlands and homesteads; however, the level of exploitation or protection was the reason for variation in area closure and grazing lands.

The aim of the study was to determine the in-vitro gas production characteristics and methane emission potential of the indigenous legume fodder tree and shrub (ILFTS). The most common 11 ILFTS species were selected and the leaves, fruit and pod samples were collected, oven dried and ground for experimental analysis. The potential leaf biomass yield was estimated by measuring the stem diameter. The contents of dry matter (DM), organic matter (OM), ether extract (EE), crude protein (CP), acid detergent lignin (ADL), Ash, total phenolic (TP) and condensed tannin (CT) were analyzed. The Gross energy (GE), digestible crude protein (DCP), digestible energy (DE), total digestible nutrient (TDN), digestible carbohydrate (DCHO), digestible crude fat (DCF) and metabolizable energy (ME) were estimated. In-vitro gas production technique was used to determine the gas production characteristics and methane emission potential of the ILFTS. Metabolizable energy (ME, MJ /Kg DM), organic matter digestibility (OMD) and short-chain fatty acids (SCFA, µmol) were calculated using the values of proximate analysis and gas volume. The study indicated a wide variation in the nutritional value parameters among the ILFTS species. The potential leaf biomass yield, nutritive quality, gas volume, gas production characteristics and methane emission potential, OMD, ME, and SCFA revealed significant variation with species and agroecological zones. Moreover, GE, TDN, DE, TP and CT showed negative correlation with the gas volume unlike methane which showed positive correlation. In general, the gas volume, gas production characteristics and methane emission of the ILFTS species depends on their chemical and cell wall composition. Thus among the ILFTS species examined Acacia hocki leaf and Acacia tortilis pod in the lowland excelled in their nutritional quality for feeding ruminants however the midland species had comparable qualities.

The study was conducted to investigate the in vitro gas production characteristics and methane (CH4) emission potential of indigenous legume fodder trees and shrubs (ILFTS). The most predominant 11 ILFTS species were selected, and leaves and fruit/pod samples were collected, oven dried, and ground. The potential leaf biomass yield (PBY), dry matter (DM), ether extract, digestible crude protein, carbohydrate (CHO), acid detergent lignin, ash, total phenol, condensed tannin, gross energy, digestible energy, metabolizable energy (ME), gas production characteristics, CH4 emissions, organic matter digestibility (OMD), and short‐chain fatty acids (SCFA) were determined. ANOVA and independent t test were used to examine variation among species in plants nature and between fruits and pods within agroecosystems, respectively. Correlation analysis was used to determine relationships among parameters. The study indicated that only DM and CHO showed substantial variation in nutritional quality parameters among trees, shrubs, and fruit/pods in the lowlands. Fruits/pods and trees displayed significant differences in gas production characteristics in the lowlands, unlike shrubs, which had non‐substantial variations. Moreover, the PBY, CH4 emission, OMD, and ME of ILFTS revealed substantial variation (P < .05) with species and among trees, shrubs, and fruits/pods in both agroecosystems. Besides, CH4 production showed a positive significant correlation with gas volume and (b) substantiating the effect of rate and degree of fiber fermentation on CH4 emission. It was discovered that there was a positive significant correlation between the 6 and 24 h incubation period, (c) which substantiated the need for optimal microbial density and substrate for high rate constant gas production of b (c). In conclusion, ILFTS produce considerable biomass rich in nutrients but vary in the degradability of CHO with plant nature, species, and forage origin. This elicits differences in gas production characteristics and CH4 emission with in vitro fermentation, resulting in differences in the corresponding OMD, ME, and SCFA values.