Performance evaluation of termite-mound clay, concrete and steel silos for the storage of maize grains in the humid tropics

Abstract

Inadequate storage facilities have contributed to severe postharvest losses in maize in many developing countries. This study determined the potential of termite mound clay (TMC), a readily-available material in Nigeria for constructing on-farm storage silos. 3 tonnes of maize at 11.2% moisture content (MC) was loaded into each silo for an 8-month storage period. Performance evaluation was done in comparison to conventional silos constructed from reinforced concrete (RC) and galvanized steel (GS) by monitoring temperature and relative humidity inside the silos. Selected quality parameters including moisture, protein, oil, crude fibre, starch, and ash contents were also measured. Observations revealed that temperature trends were similar in all silos. A consistent increase in relative humidity was also observed but was less pronounced in the GS silo (10.6%) compared to TMC and RC silos at 15.8 and 22.2% respectively. Maize quality in TMC, RC and GS silos were found to be similar although at varying degrees, with increasing trends for MC and crude fiber contents and decreasing trends for protein, oil, starch, and ash contents. The silos have comparable performance till the fourth month of storage after which MC was significantly different (p<0.05) across silos. MC on the eighth month in TMC, RC and GS silos were 16.0, 15.1 and 12.7%, respectively. TMC silo was found adequate for short-term storage (<4 months). Construction of silos using local materials has a high potential for adoption and improved resistance of TMC silo to moisture permeation may allow for its use for longer periods. Key word: Silo, grain storage, postharvest losses, termite mound clay, grain quality.