Phosphomonoesterases Activity in Phosphorus-fertilized and Mycorrhizae-inoculated Cassava’s Rhizosphere in Two Savanna Agro–ecologies of Nigeria

Abstract

Rhizosphere is a bio–influenced zone of soil where the interaction of microorganism and plant roots occurred tailored by the activity of soil enzymes. The activity of the enzymes depends largely on the physical and chemical characteristics of the soil environment. Experiment was carried out to examine the activity of phosphomonoesterases in the rhizosphere of cassava planted in two sites (Samaru and Minjibir) located in savanna ecologies of Nigeria. Soils from rhizosphere of the cassava were sampled from each treatment in an experiment involving split plot design. The treatments included 3 main plots (phosphorus rates at 0, 17.5 and 35 kg P₂O₅ ha^–1) and 3 sub–plots (mycorrhizal inoculants: Glomygel and Mycodrip; and a Control). The Result of the analysis indicated higher activities of the phosphomonoesterases (acid and alkaline phosphatases) in Samaru site than Minjibir. The former recorded higher acid and alkaline phosphates activities over the latter with a magnitude of 96.84% and 43.65% respectively. This is attributed to the variability in the soil characteristics between the two sites. The main effect of P fertilizer indicated that 0 kg P₂O₅ ha^–1 recorded a significantly (p<0.05) higher phosphomonoesterases activity than application of 17.5 and 35 kg P₂O₅ ha^–1. Inoculation with mycorrhizae also increased the activities of the phosphomonoesterases in both sites which indicate increase mycorrhizal colonization as a result of inoculation. It is concluded therefore, that the activity of phosphomonoesterases in the rhizosphere can be affected by fertilization as well as enhanced by inoculation with the influence of soil characteristics.