Soil test-based phosphorus fertilizer recommendation for malting barley production on Nitisols

Abstract

Malting barley production in the Southeastern highlands of Ethiopia relied on almost a blanket phosphorus (P) fertilizer recommendation regardless of the diverse fertility status of the soil. This study was, therefore, conducted in Lemu–Bilbilo district at 24 fields for two cropping seasons to provide farmers with P fertilizer recommendations based on soil fertility status and to enhance malting barley production. The experiment comprised six levels of P fertilizer (0, 10, 20, 30, 40, and 50 kg P ha−1) arranged in a randomized complete block design with three replications. The critical concentrations for soil P levels were found above 13 mg P kg−1 for Olsen and 16 mg P kg−1 for Bray II, and were sufficient for malting barley production on Nitisol of the study area and other similar agro-ecologies. The mean P-requirement factors were 5.80 and 6.10 mg P kg−1 for Olsen and Bray II, respectively. Results further revealed that P fertilization, at a rate of 30 kg ha−1, gave 10 and 73% more grain yields of malting barley compared to the existing recommendation, 20 kg P ha−1, and treatment with no P fertilizer, respectively. Such information can be used as a guideline for soil-specific P fertilizer recommendations to increase the productivity of malting barley in the study area and other similar agro-ecologies, where soil test studies were not conducted.

Keywords

• critical phosphorus concentration
• malting barley
• nitisol
• phosphorus calibration, phosphorus requirement factors