Biodiversity and Soil Property Variation Under Coffee-Enset-Based Agro forestry System And Land Affected By Gullies Along The Topo-Sequence In Southern Ethiopia

Abstract

With the objectives of investigating and quantifying farmer's attitude and gully development in relation with biodiversity and soil property variation along topo-sequence in coffee-Enset based agoforestry system, two land units: Land with agro-forestry system (LWAGS) and Land with Gully Erosion (LWGE) under three slope categories (Upper, Middle and Lower slope) were selected in Southern Ethiopia. A household survey was conducted, supplemented with focus group discussions (FGDs), key informant interview and field observations. Concerning the soil, a total of 48 composite soil samples (4 replication _ 2 land units _ 3 slope categories _ 2 soil depth layers: 0– 15 cm and 15–30 cm) were collected to analyze soil physic-chemical characteristics. In addition, 48 undisturbed core samples were also collected to determine soil bulk density (g cm-3). To determine species richness and evenness Shannon-Wiener's index and Simpson’s index were used. Simple counts of naked eye soil macro-fauna (NMF) was also collected just to infer about the biological properties of the soil. The results showed that farmer's attitude was the major contributor for the expansion and developments of gully erosion in the study area. Tree cutting from the agro-forestry system was the main pressing causes of gully development in the agro-forestry system. Concerning the soil, the study revealed that Higher values of SMC (%), Pt (%), Ve (%), SOC (%), EC (µs), pH and naked eye macro-fauna were observed on land units with Coffee-Enset based agroforestry system. However, soil bulk density was higher on land units with gully erosion. SMC (%), Bd (g cm-3), Pt (%) and Ve (%) were significantly varied with slope percent (P<0.001), Land Units (P = 0.001, P<0.001) and Soil Depth (P<0.001), respectively.
KEY WORDS: Coffee-Enset based agroforestry; Farmer's Attitude; Gully Erosion; Soil Macro-fauna; Biodiversity.