English

Abstract

Nowadays, making available proper and balanced fertilizer recommendations is of paramount importance in order to confirm security and increase crop productivity in sustainable way for farmers and other stakeholders. Soil test based phosphorous calibration study was conducted for barley (Hordium vulgare L.) on Nitosols of farmers’ fields in West Shewa, in the central highlands of Ethiopia. The experiment was arranged in a randomized complete block design with six levels of phosphorous fertilizer (0, 10, 20, 30, 40 and 50 kg ha-1) with three replications. Results revealed that yield and yield components of food barley were significantly affected by P fertilizer application. Phosphorous fertilizer application at different rates increased grain yield of food barley by 23 to 46% compared to the control. Available soil test P concentrations analyzed three weeks after planting were affected significantly by P fertilizer application rate. Relative yield and Bray-2 soil test phosphorous value correlation indicated that soil test phosphorous values greater than 13 mg kg-1 was found to be sufficient for food barley production. The average phosphorous requirement factor (Pf) calculated from soil test phosphorous values of all treatments for study area was 10.2. Most sites tested had Bray 2 P values <10 mg kg−1. In the absence of a soil test, a recommendation of 40 kg P ha-1, resulting in the best response overall, could be made for the first year of application. It was also recommend that to prevent a potential loss of barley yield, a maintenance application of at least 5 to 10 kg P ha−1 be applied every year, irrespective of the calculated recommended rate, in order to replace P exported from the field in the form of grain and straw yield. Further field trials are required to determine interactions between P response and the effects of climate, soil properties, and other management practices.   Key words: Food barley, phosphorous calibration, nitisols, phosphorous requirement factor, critical concentration.