PHOSPHATE MOBILIZATION BY ADDITION OF THREE ANIMAL MANURE SOURCES IN THE SOILS OF KARU, NASARAWA STATE

Abstract

One mechanism by which plants can mobilize organic and inorganic forms of phosphorus (P) in soils is by exudation of molecular weight organic acids. Screen house trial was carried out in 2021 to study the effects of additions of three levels of animal manures (poultry manure, goat manure and cow dung at 0, 10 and 20 t ha -1 on the mobilization of phosphate in soils from Karu, in Nasarawa State. The experimental design used during the screen house trial was Completely Randomized Design (CRD) with three replications and maize was planted as a test crop. Some agronomic, soil Olsen P, and inorganic P data were taken. All data collected were subjected to Analysis of Variance (ANOVA),significantly different means were separated using the Least Significant Difference at 5% level of probability. The results obtained indicated that Olsen – P and NH4 – P significantly increased by treating with the three organic manures. Al phosphate (Al – P), Fe phosphate (Fe – P), occluded phosphate (Occl – P) and calcium phosphate (Ca – P) were also mobilized and released in various degree irrespective of the organic manure source. The relative fractions of inorganic P was in the order Occl – P > Fe – P > Al – P > Ca – P. The effects of organic manure sources on maize plant height at 4 and 6 weeks after planting was also significant. These three organic manures therefore have the potentials to increase the availability of available P. The practical implication of these processes is that organic residues could be used as a strategic tool to reduce the rates of fertilizer P required for optimum crop growth on P-fixing soils of Nigeria.