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Phosphorus deficiencies limit production of cereal crops including bread wheat in many acidic soils of Ethiopia. Although, considerable amount of work has been done on response of wheat to the applications of mineral nutrients, in view of precision agriculture, site and crop specific nutrient management are very pertinent. There is, however, a paucity of information, on which to base fertilizer P recommendations. The equilibration period and quantities of fertilizer required to obtain the desired equilibrium concentration was determined. A pot experiment was conducted to evaluate the external and internal P requirements of Damphe and Picaflor varieties. Maximum P adsorption and stable equilibrium P concentration were achieved at eight days incubation period. The Freundlich adsorption model was found capable to describe the adsorption of P and its requirement for the two varieties. The interaction of mineral P, soil type and variety has significantly affected some yield and yield components of both varieties. The external P requirements of 0.24 and 0.2 mg P L−1 for Damphe and 0.3 and 0.22 mg P L−1 for Picaflor in Goha1 and Doyomarufa2 soils were recorded, respectively. The two varieties were found to respond differently to the same soil solution P levels in soils. Evaluation of crop plants for genotype variation in their ability to access soil phosphorus is a means to determine the quantity of fertilizer required. It could be suggested that application of P fertilizers should consider the knowledge of internal and external P requirements of the wheat varieties. [ABSTRACT FROM AUTHOR]