In situ metal silos grains storage performance: Maize and pearl millet for improved food security in an arid environment

Grains are commonly stored for improved food security. Among the grains storage facilities are metal silos. However, there is limited data on the performance of maize and pearl millet grains when stored in metal silos in real life (in situ) operations. To fill this gap, this study evaluated maize and pearl millet grains qualitative (nutritional) and quantitative (weight) losses during a 6-month storage period in metal silos in a semi-arid environment. Ash, protein, fat and carbohydrates & fiber contents were evaluated to indicate qualitative losses and moisture content was evaluated to indicate quantitative apparent weight loss of the stored grains. Percentage changes were calculated for moisture, ash, fat, protein and carbohydrates & fiber contents of the grains. In Katima Mulilo silo 1 based on % changes, fat contributed 5.76%, ash contributed 9.89% and carbohydrates & fiber contributed 1.61 % to the nutritional loss. There was no statistically significant protein loss in stored grains in all the studied silos. Pearl millet grains that were stored in Okongo silo had a % change of 30.38%, suggesting an apparent weight loss. The cause of ash, fat and carbohydrates & fiber loss of grains could be attributed to increased pest infestation at 6-month storage while moisture loss in pearl millet grains stored in Okongo silo could be attributed to increased temperature during the 6-month storage period. Maintenance of grains at appropriate relative humidity and temperature levels can mitigate grain weight loss.