The Effect of Avocado Tree (Persea americana Mill.) on Selected Soil Properties and Under storey Plants in Southern Ethiopia

Abstract

Avocado tree plays an important role in influencing soil properties and under storey plants. Thus, evaluating its influence becomes valuable for identifying sustainable land management practices. With the objectives of assessing the effect of avocado tree on selected soil properties and understorey plants, thirty (30) model farmers were selected from three Woredas using simple random sampling technique for semi-structured interview. In addition, a total of 72 composite and undisturbed soil samples were collected using RCBD design to analyze chemical, physical and biological properties of the soil. Understorey plants were counted within 2m2 at each treatment for determination of richness (S) and Shannon diversity index (H'). Root distribution was counted within 0.2m2 area. The result of the study indicated that all farmers in the study area have witnessed the negative impacts of avocado tree on soil and understorey plants. However, the soil analysis didn't support the farmer's apprehension. SOC, TN, Pt and sand decreased while bulk density, silt and clay fractions increased along treatments and soil depths. Species richness and diversity of plants increased along the treatments. Higher root density was observed at the top soil surface and becomes less in number along treatments. SOC played a vital role in influencing soil properties in the area. Management differences (land use, shading and spacing), micro-climate variability and hydrology might be the contributing factors for the influence of avocado tree on the soil and understorey plant. Thus, adjusting the spacing between avocado trees, land use and implementing site-specific management practices may reduce the problem. Key Words: Model Farmers; Persea Americana; Soil Properties; Under storey Plant.