Influence of Lime and Phosphorus Fertilizer on the Acid Properties of Soils and Soybean ( Glycine max L.) Crops Grown in Benshangul-Gumuze Regional State Assosa Area

Soil acidity is one of the major soil chemical constraints which limit agricultural productivity in the mid and highlands of Ethiopia. Especially in the western part of the country such as Assosa and Wellega, soil acidity is a well-known problem limiting crop productivity. The study was conducted to evaluate the influence of lime and Phosphorus fertilizer on yield and yield attributes of soybean in acid soil at Assosa north western Ethiopia during June 2012 to March of 2015. The crop was evaluated in terms of pod per plant, seed per pod, grain yield, hundred seed weight and straw yield. But it had neither interaction with lime and Phosphorus fertilizer nor its effect on yield attribute was significant. Even though lime level at 1.5* Exchangeable acidity (5.652 tone) and phosphorus at 46% shows good yield and had consistency across the year, hence it was best to use such combination of Lime and P. Maintaining soil fertility is possible for the area because simultaneous and minimum use of lime and Phosphorus fertilizer give similar seed yield with maximum use of lime and Phosphorus on the study area though much better than the control. Phosphorus fixation, which is responsible for low availability of P, is one of the major problems of crop growth in acidic soils such Nitisols of Assosa area.