Effect of land use types in Miesa Watershed on soil quality and productivity

Abstract

Improper land use and poor soil management practices became a great challenge to an attempt to attain increase crop production to meet the growing demand for food. Areas which were previously under natural forest are being converted to cropland and grazing lands. The ecological effects of these changes in land use have not been thoroughly investigated and documented in many parts of Ethiopia. This study was undertaken to investigate the effects of land use types on physicochemical and biological properties of soil and hence on soil fertility and soil productivity. In order to investigate soil fertility status, soil samples collected from different land use types (cultivated land, grazing land and natural forest) from the upper 0-20 cm depth were analyzed for soil quality parameters such as soil pH, organic carbon, total nitrogen, available phosphorous and potassium and micro nutrients (Cu, Mn, Zn and Fe) contents as well as for microbial biomass. To investigate the effect of land use type on soil productivity, the study also involved growing maize crop in plastic pot filled with soil samples taken from each land use type and crop performance was assessed based on plant height, leaf number per plant, shoot and root weights and root to shoot ratio. The results obtained showed that soil taken from natural forestland had higher value of soil quality parameters such as: organic matter, total nitrogen and available phosphorus and potassium contents. Other soil quality parameters such as CEC, microbial population and micronutrient contents were also superior for forestland than for the other land use types. Crop growth parameters such as plant height, number of leaves per plant, shoot and root weights were all significantly higher for plan grown in soils taken from forestland than from the other land use types. The results clearly demonstrated that the different land use types had significant effects on soil quality and productivity suggesting that a change from forestland to the other land use types aggravated soil degradation, thereby resulting in soil fertility and productivity decline and hence in reducing crop productivity.

Keywords: Land use types, Soil management practices, Crop production, Soil fertility, Soil productivity, Miesa Watershed