An experiment was conducted at the Teaching and Research Farm of the Faculty of Agriculture and Veterinary Medicine, Imo State, University, Owerri Nigeria to investigate the interaction of crude oil and manure on the agronomic characteristics of maize. The experiment was arranged in Randomized Complete Block Design of a split plot fashion with four main plots represented by the levels of crude oil pollution (0 ml, 100 ml, 200 ml, & 300 ml), while the organic manure (poultry manure, cow dung manure and farm yard manure) and a control (no treatment) plots made up the subplots. The set up was replicated four times. Soil collected from the University’s farm site was used to fill 64 buckets of 30 cm3 capacity each to 2/3 of their volumes. Crude oil was applied to the buckets according to the levels. Organic manure was applied 14 days after pollution at the rate of 2Kg/20Kg of soil, while the maize seeds (Obatampa variety) were planted at 28 days after pollution. Soil samples were collected for physical and chemical analysis before application of crude oil and 28 days after application of crude oil. The germination percentage was determined two weeks after planting. Plant height (cm) and leaf length (cm) were determined at 3 and 6 wks after planting, while cob length (cm), cob diameter (cm), number of seeds per cob and weight (g) of 100 seeds were determined at maturity. Results showed that application of manure significantly influenced the growth and performance of maize plant in the crude oil polluted soil. Poultry manure significantly improved the agronomic characteristics of maize more than the cow dung and farm yard manure in the crude oil polluted soil. This indicated that poultry manure exhibited a higher remedial potential of the crude oil-polluted soil than the other organic manures (cow dung and farm yard manure). The results further showed that application of poultry manure positively interacted with crude oil and it is therefore recommended to be used in the remediation of crude oil degraded soils.
Key words:Crude oil, Zea mays,Interaction, Organic manure, Remediation