ASSESSMENT OF THE SOIL MICROBIAL BIOMASS AND PHYSICOCHEMICAL PROPERTIES OF DIFFERENT LAND USE SYSTEM IN WONDO GENET, SIDAMA REGION, ETHIOPIA

Abstract

Land use change can have both negative and positive effects on soil physico-chemical properties and microbial biomass. The agricultural activity primarily strongly influence the soil physico chemical and microbial futures, it also regulates annual carbon turn over. Studying the soil microbial biomass and physico-chemical properties under different land use types is great practical significant for land use and soil management regarding soil carbon dynamics and climate change mitigation. The objective of this study was, to investigate the impact of land-use change on physical, chemical and microbial biomass properties in Wondo Genet Woreda, Sidama, Ethiopia. Soil samples were collected from three different agroforestry systems, namely Enset, Enset-Coffee and Enset-coffee-avocado land use type and two soil depths (0–15cm and 15-30 cm) and 20 samples were collected in each land use types. Soil organic carbon (SOC) and total nitrogen (tN), soil microbial biomass were determined by titration method, micro-kjeldahl method, and fumigation extraction method, respectively. The study found that microbial biomass carbon, microbial biomass nitrogen and soil pysico-chemical properties were significantly varied among agroforestry systems across the soil depth. The result show that among all agroforestry systems the highest microbial biomass carbon and nitrogen were observed in the Enset-coffee- avocado, Enset-coffee and Enset which accounts for (1601.3±206.31µg/g), (138.03±17.78µg/g), (288.24±39.06µg/g) on the upper parts of the soil, respectively. The microbial biomass ratio observed as the same fashion in all agroforestry. Enset-coffee-avocado (11.6 µg/g ), Enset-coffee (10.64 µg/g) and Enset (9.2 µg/g) in the upper parts of the soil. Soil OC was found to be higher in enset- coffee-avocado (3.43±0.35%) followed by enset-coffee (2.14±0.22%) and Enset (1.81±0.28%) land use types. tN was found to be higher in enset-coffee avocado (0.29±0.03%), followed by enset-coffee (0.18±0.01%) and enset(0.16±0.02% ). The result of the study indicates that the microbial biomass and soil physico-chemical properties highly correlated with the type of vegetation and soil depths. The values of these parameters in enset-coffee- avocado were higher. Thus enset-coffee-avocado based land type has the potential for improving soil quality and properties in the short term in the tropics.