Assessment and Mapping of Soil pH and Available Phosphorus Status in Wuchale District, North Shewa Zone, Oromia

The lack of site specific fertilizer recommendation to replenish declining soil fertility has been the major challenge to boost crop production in Ethiopia. Therefore, an investigation was conducted on soil pH and Av. P status assessment and mapping at wuchale district. About One hundred sixty one (161) geo–referenced soil samples were collected by using grid survey method. For both soil parameter analysis standard laboratory analysis were followed. In order to predict values for not sampled locations the Ordinary Kriging interpolation was used by ArcGIS10.3 software. The pH of the soil samples ranged from 4.84 to 6.67 and about 98.13% of all agricultural soils were acidic in reaction. The district has three categories of soil pH but the majority of the area falls in moderately acidic, strongly acidic and neutral soil pH which account area share of 51.55%, 46.58% and 1.87% respectively. Available P ranged from 2 to 64.79 ppm. The available phosphorus level is categorized as low, medium and high which is 26.70%, 52.80% and 20.50% respectively. The dominating class is medium i.e. (5 to 15ppm). Appropriate rate of lime needs to be applied or cultivating acid tolerant crops is recommended for both strongly acidic and moderately acidic soils of the study district to obtain optimum crop yields. The areas which are low in available soil phosphorus level need to be improved by adding organic manures (FYM/Compost) and inorganic fertilizers to boost the agricultural productivity of the study areas.