1 Evaluation of Wooden Silo during Storage of Maize (Zea mays) in Humid Tropical Climate

The aim of this study was to evaluate the performance of wooden silo for long-term (wet and dry seasons) storage of maize (Zea mays) under tropical climate. A one tonne capacity, 1.4m diameter and 1.1m height hexagonal wooden silo was constructed and erected in Minna. The silo was of Iroko (Melicia excelsa) ribs and exterior grade (redwood) plywood stress-skin panel as sheathing material. It had double-layered wall panels with a small air gap in-between the layers, for adequate heat insulation. A loading door and discharge chute were located on the wall panels and a triangular loading door on the top panels. The silo floor rested on wooden pile foundation. Grain and ambient temperature measurements and silo evaluation were done for 9 months. The ambient temperatures during the dry season were 40C- 70C higher than during the wet season. The minimum and maximum ambient temperatures were 20.90C (31st day of storage, wet season) and 380C (189th day of storage, dry season) respectively. There were no incidences of moisture condensation within the silo. The structure possessed adequate structural integrity except for slight incidences, colour change, delaminating and peelings of sheathing materials