Effect of Mediterranean climatic condition during aeration and silo wall coating in on-farm grain storage in South Australia

摘要

South Australia has a unique climatic condition than rest of Australia. In the Mediterranean region of Australia,winter crops are harvested in hot and dry conditions with temperature as high as 40 °C and moisture content as low as 7% wb. It is foundthat grain storage at this temperature provides a better environment for insect growth and similarly a farmer gets a lower return value of the stored bulk at the time of selling. Aeration cooling with controlled humidiflcation to lower the grain temperature to less than 20 °C and increase the moisture value to an optimum range of11-12% wb is the foremost approach to preserve the grain quality and provide better value in grain industry. However, the prevailing weather condition restricts the cooling tosummer only as winter is wet every year. During summer, days are hot and dry while nights are cool and humidity reaches a maximum of 85 to 90%.Thus, aeration cooling trials were conducted onal000 tonne white-corrugated grain storage bin during two storage seasons from November to March of 2017-18 and 2018-19, respectively. In addition, temperature and humidity gradient from the white painted silo wall into the grain was compared with a galvanized silo. Temperature increments (2 to 30) at the lower portion (1.5 m above the silo floor) were observed at the start of the aeration due to warm air accumulation (during the day time) from high wind speed towards the fan inlet. Diurnal wall temperature effect on the north side of the white bin was observed up to 0.05 m in to the grain bulk while it was up to 0.25 in the galvanized bin.