P5: Study on soil fertility, nutrient balances and biological N-fixation under contrasting soil pH and cropping systems in southern Ethiopia

Description

The natural resource base of Ethiopia is more than adequate to meet food production need of the people. Ethiopia is a physically unique tropical country because of the high proportion of its landmass over 2000 m altitude, where the climate is more temperate than tropical. The country is endowed with very diverse physiographic and climatic conditions, which have made possible the presence of diverse faunal and floral resources. Agriculture is the foundation of Ethiopian economy that accounts for 80% of employment, 85% of the export revenue, 42% GDP and contributes around 90% of the total export earnings of the country. Paradoxically, Ethiopia is unable to feed its population and hence millions require food assistance ever year). This is because Ethiopia’s agriculture is predominantly subsistence in nature, where the production system is mainly rain fed and traditional, which is characterized by low use of inputs such as improved seeds, fertilizer, pesticides, and other technologies. Furthermore, climate change is anticipated to accelerate the land degradation and food insecurity problems in Ethiopia. Diverse land use, cropping systems and agro-ecologies settings exist in southern Ethiopia. Farming communities exercise these land uses and cropping systems based on their experiences and resource endowments. The most predominant agricultural practices undertaken in southern Ethiopia are cereal, enset and coffee-enset based land uses. Each land use may have different cropping systems within different agro-ecologies. These land uses and cropping systems substantially influence the crop-soil nutrient flows and balances. A soil nutrient balance is a commonly used indicator to assess changes in soil fertility. Maize and common bean are two of the leading crops in their respective category of cereals and pulses in southern Ethiopia. Accordingly, maize, and common bean occupy 33 and 42% of the area devoted to cereals and pulses, respectively. Limited external input resulted in depletion of soil fertility and negatively affected soil health in southern Ethiopia. Legumes are integral components of the crop-livestock farming systems in southern Ethiopia. Legume crops can reverse the downward spiral of soil fertility depletion by fixing atmospheric nitrogen. Furthermore, they provide nutrients to soils through decomposition of their straw, roots, and nodules.

Research objectives are: (i) Characterize the major land uses with closer evaluation of soil fertility status in some districts (Hagereselam, Indibir, Hawassa Zuria and Boricha) of southern Ethiopia, (ii) Assess nutrient flows and balances of different land uses and cropping systems (e.g., cereal, enset and coffee-enset based land uses), (iii) Assess the natural abundance of rhizobia and enzyme activities under contrasting soil pH and land uses/cropping systems, (iv)Evaluate the effect on biological N fixing capacity of some commercial rhizobia under varying abundance of resident rhizobia using 15N with common bean and faba bean.

Involved persons

• Asst. Prof. Dr. Girma Abera Jibat
• Tadele Etefa Geremu

Involved institutions

• School of Plant and Horticulture Sciences, College of Agriculture

Sponsors

Supported by the DAAD program Bilateral SDG Graduate Schools, funded by the Federal Ministry for Economic Cooperation and Development (BMZ)