The document investigates the potential of Hagenia abyssinica for improving soil nutrient cycling in high-altitude areas of Central Ethiopia, emphasizing its role in enhancing soil fertility and providing various ecological benefits. Research conducted from 2004 to 2006 highlights the tree's high foliage nitrogen content and its significant contributions to soil macronutrients like phosphorus and potassium. The study suggests leveraging both indigenous and exotic tree species to mitigate soil nutrient depletion and bolster agricultural productivity.

1. Exploring the potentials of Hagenia abyssinica (Bruce) J.F. Gmel for soil nutrient cycling in Galessa and the surrounding areas, central Ethiopia Kindu Mekonnen 1,2 , Gerhard Glatzel 3 , Monika Sieghardt 3 , Kasahun Bekele 1 , Mehari Alebachew 1 and Demissew Tserte 1 1 Ethiopian Institute of Agricultural Research (EIAR), Box 2003, Holetta, Ethiopia 2 Current address - International Livestock Research Institute (ILRI), Box 5689, Addis Ababa, Ethiopia, Email: [email_address] or [email_address] 3 Institute of Forest Ecology, UNI BOKU, Peter-JordanStrasse 82, A-1190, Vienna, Austria The soil fertility improving potential and ecological importance of H. abyssinica should be further explored and exploited in the high altitude areas, where soil nutrient depletion is a limiting factor for crop and livestock productivity. The foliage mean N content was high as compared to the N content in the flower bud and stem of Hagenia (Table 1). Lignin content in the foliage was 53 mg g -1 . 1. Introduction Abstract 2. Research methodologies 4. Conclusions and recommendations The poster elaborates methodologies for collecting socioeconomic and biophysical information from H. abyssinica. It also demonstrates research results and discussions of the foliage nutrient concentrations, and soil macro and micronutrients under the Hagenia trees. The depletion of soil nutrients in the highlands of central Ethiopia is a potential threat to agricultural productivity and sustainability. The introduction of potential exotic tree and shrub species and the promotion of indigenous ones in the highlands with the participation of different partners is one of the options to increase biomass for soil improvement, and other services and products. Studies have been conducted from 2004 to 2006 at Galessa and the surrounding areas to collect information on the growing niches and benefits of Hagenia abyssinica (Bruce) J.F. Gmel. evaluate the effect of H. abyssinica on soil fertility, and assess the chemical composition and other quality characteristics of the foliage and flower buds of H. abyssinica . PRA and questionnaire survey approaches were used to study the growing niches, histories and benefits of H. abyssinica . A total of 150 farmers from different social categories participated in the questionnaire survey. Foliage and flower bud samples (Figure 1) were collected and analysed for macronutrients, lignin, soluble phenolics and condensed tannin using standard lab methods. Figure 1. Foliage (a) and flower bud (b) of Hagenia. The tree species grow around the homesteads and the nearby forest areas. The farming communities at Galessa and the surrounding areas identified more than 10 service and product benefits of H. abyssinica . Among the benefits, the soil fertilizing and fodder values of H. abyssinica were mentioned substantially (Figure 2). a) Benefits of Hagenia for the communities The total N content at 0-15 cm depth vs 75 cm radial distance was 6.60 mg g -1 as compared to an amount of 5.66 mg g -1 at 0-15 cm depth vs 225 cm radial distance from the base of the trees. In general, the soil under the vicinity of H. abyssinica contained a substantial amount of soil nutrients such as P, K, Ca and Mg. c) Soil nutrient contents b) Foliage nutrient contents 3. Results and discussion S oil samples were collected at 0-15, 15-30 and 30-50 cm depths and 0-75, 75-150 and 150- 225 cm radial distances from the bases of H. abyssinica . The soil samples were analyzed for pH, organic C, total N, available P and exchangeable cations. (a) (b) Figure 2. Soil fertilizing (a) and fodder (b) values of Hagenia. (b) Enrichment of these nutrients under the Hagenia could be associated to the rooting system and efficient nutrient cycling power of the trees. Hagenia constantly sheds high amount of leaves and provides mulch and green manure to the soil within its vicinity (Figure 3). Figure 3. Hagenia with high leaf deposition. (a) The study was conducted from 2004 to 2006 in the upper plateaus of Galessa-Jeldu areas, Dendi and Jeldu districts, central Ethiopia (9 o 02' 47'' to 9o 15' 00’’ N and 38 o 05' 00'' to 38 o 12' 16'' E). The altitude ranges from 2900 to 3200 m.a.s.l. Acknowledgements: We thank HARC forestry and SWM research staffs, EIAR, AFORNET, KEF (Austria), UNI-BOKU and ILRI for all the support. Produced March 2011 Table 1. Mean nutrient composition of the foliage, flower bud and stem in Hagenia. Nutrients Foliage Flower bud Stem N 30.07 27.20 12.94 P 3.71 4.54 1.54 K 21.22 22.04 16.05 Ca 9.69 5.54 8.57 Mg 2.38 2.53 1.68 S 2.03 2.7 1.5 N, P, K, Ca, Mg and S are in mg g -1 dry matter.