Effect of mixed manure on selected chemical properties, and phosphorus adsorption characteristics of Vertisols in Haramaya district, eastern Ethiopia

Abstract

Abstract The phosphorus (P) fixing behaviors of Vertisols have been identified as one of the key drivers of crop response to fertilizer application. More than 75% of applied P in tropical soil was found to be inaccessible to crops due to adsorption and precipitation reactions. A pot experiment was carried out to investigate the effect of mixed manure (MM) on P adsorption characteristics and other selected Vertisol properties. The soil was amended with 0, 5, 10, and 15 t ha−1 of MM. Changes in selected soil parameters and P adsorption characteristics were evaluated after a 30‐day incubation period. An analysis of variance was used to analyze the data. The results demonstrated a substantial drop in soil pH and an increase in soil organic carbon, total nitrogen, available P, and cation exchange capacity compared to the control. The overall quantity and efficiency of adsorbed P were drastically reduced as a result of MM rates. Moreover, the interaction effect of MM and added P concentration demonstrated a considerable increase in both the quantity and efficiency of adsorbed P. Both parameters increased with increased rates of added P concentration but decreased with increasing rates of MM. Despite the fact that all treatments fit well to both the Freundlich and Langmuir isotherms, the former was used due to its greater R2 value. When compared with the control, the Freundlich adsorption coefficient and intensity were found substantially lower. As a result, MM treatment boosted P availability by decreasing adsorption and associated Vertisols characteristics.