Physico-Chemical Properties and Agricultural Potentials of Soils of Tembaro Woreda, Kembata Tembaro Zone, Southern Ethiopia

Abstract

Physico-chemical properties of soils of a particular area is crucial for determination of its potential and constraints based on which appropriate management interventions could be applied for enhanced and sustained agricultural production and productivity. Therefore, the objectives of this study were to determine physico-chemical properties of the soils of Ambukuna microcachment and to identify its potentials and constraints for crop production.  Five sites representing a soil each were opened and profile in each site was described for its morphological, physical and chemical characteristics according to standard procedures. A total of 20 disturbed soil samples and 16 core ring samples were collected from five representative sites. The samples were analyzed in the laboratory for texture, BD, FC, PWP, Soil pH, EC, OC, TN, av.P, av.K, exchangeable bases and CEC. The results of the study showed that the proportions of soil separates varied among sites. The BD varied from 1.13 in the surface site 1 to 1.26 gcm^-3 in the site 3. Soil pH ranged from 5.4-6.8 in the surface of all sites with further decrease with depth indicating that the soils in the watershed are strongly acidic to slightly acidic.  The OM and TN contents ranged from 2.96-5.95 and 0.26-0.45% in the surface soil and they were in the low, low to medium and high categories, respectively. Available P was below critical values for all sites except for sites 1 and 4. Exchangeable K was above critical value in all sites.  Exchangeable Mg varied from 2.87 in surface soils of site 3 to 3.98 cmolc kg^-1 in the surface soils of site 4. The observation with exchangeable K and Mg implies that there is leaching phenomenon in the study area. Ca ranged from 5. 37 cmolc kg ^-1 in site 5 to 16.80 cmolc kg ^-1 in site 2. The CEC from 19.22 cmolc kg ^-1 soil in surface of  site 5  to 36.43 cmolc kg^-1 soil  in the surface soil site 1 indicating they are in the medium to high ranges. Most of the soil physical and some of the chemical characteristics studied could be ranked as good indicating that the area has high potential for agricultural production.  However, acidic soil reaction observed in the study area should attract attention for its management now and in the future.  P is also found to be the most important limiting nutrient for crop production in the area. Thus, management of P is indispensible for enhanced agricultural production in the area. Maintenance and enhancement of organic matter content of the soil in the watershed is also recommended for improving soil quality and sustainability.

Keywords: Morphological Characteristics, exchangeable bases, total nitrogen