Soil Test Based Phosphorous Calibration for Fababean (Vicia faba L.) Production on Nitisols in Central Highlands of Ethiopian

Soil test based phosphorous calibration study was conducted fababean on Nitisols of farmers’ fields in West Shewa, in central highlands of Ethiopia. The experiment was arranged in a complete block design with six levels of phosphorous fertilizer (0, 5, 10, 15, 20 and 25 kg ha-1) with three replications. Results showed that grain yield of fababean were significantly affected by P fertilizer application rate. The application of phosphorous fertilizer at different rates increased grain yield, up to 58% more than the control. Extractable soil P concentrations (Bray II, 0- 20 cm depth) three weeks after planting significantly responded to P fertilizer rate. Correlations of relative yield with Bray-2 soil test phosphorous values showed that the soil test phosphorous levels greater than 12.5 mg kg-1 (critical phosphorous concentration) was found to be sufficient for fababean production. The average phosphorous requirement factor (Pf) calculated from soil test phosphorous values of all treatments for the study area was 7.02