EFFECT OF FERTILIZER ON FUNGI COMPOSITION IN THE RHIZOSPHERE OF A CASSAVA PLANT CULTIVATED IN AN ULTISOL

ABSTRACT
The study was carried out at an existing field at Green hills cassava farm stead, Ikpoba-okha local government area Edo State Benin City in Nigeria. This study investigated the effect of fertilizer application on the fungi composition in the rhizosphere of a cassava plant cultivated in ultisols. The soil was treated with NPK fertilizer to determine the composition of the fungal community in soil. Samples were collected with a soil auger from field with different dose of fertilizer treatment plot and a control plot and then bulked at top soil and sub soil (0 – 15 cm and 15 – 30 cm). Soil samples were taken to the laboratory for analysis using the various standard laboratory procedures for chemical properties and biological analysis. The fungal communities were analyzed using pour plates culture and microscopy. Data obtained were subjected to analysis of variance (ANOVA) while means separated using Duncan's multiple Range Test (DMRT) at p<0.05. The control plot exhibited higher TN, OC, OM and Av.P content with a value of (1.50g/kg, 20.59 g/kg, 35.49 g/kg and 19.38 mg/kg respectively) suggesting a potential decline in soil fertility with fertilizer application. K levels were low across all treatment plots with values ranging from (0.12 to 0.14 cmol/kg) across the treatments. Fungal counts were highest in the single dose fertilizer treatment (3.48 log10cfu/g), followed by the control plot (3.39 log10cfu/g), double dose fertilizer treatment (2.52 log10cfu/g), and plant leaves (2.41 log10cfu/g). High fungal count in the single dose fertilizer highlights the potential impact of fertilizer application on soil microbial communities.