THE TEMPERATURE AND MOISTURE-CONTENT OF STORED GRAIN IN 2 SAUDI-ARABIAN PROVINCES

The temperature and moisture content of bulk wheat, maize, and wheat b ran stored in bins or general stores (in sacks), in the Riyadh and Dam mam provinces, Saudi Arabia, were surveyed periodically during 1987 an d 1988. The temperature of experimental and control bins of wheat and maize increased in direct proportion to the length of the period of st orage. This was true for all heights inside the bins on the same date of observation, for each height on all dates and in both provinces and years. In the Riyadh province, temperature of the headspace air in al l bins showed a trend to increase with increasing period of storage. I n the same storage plant, temperature at any particular height inside a bin varied according to the type of grain and the year. Individual v ariation between bins was also recorded.Storage in bins increased the temperature of the stored grain above that of the environment in both provinces and years. The temperature of stores in both provinces fluct uated in parallel with that of the environment. The moisture content o f grain was significantly affected by height inside bins of experiment al and control wheat, year, period of storage and province. The moistu re content of maize was always higher than of control wheat. In genera l, interactions between province (Riyadh and Dammam), year (1987 and 1 988), period of storage (six periods each year), type of commodity sto red (wheat in experimental and control bins, maize in a control bin an d in general stores, and wheat bran in general stores), storage site ( inside bins or in general stores), height inside bin (7 heights inside each bin) and identity of the bin were significant sources of variati on in temperature and moisture content of stored commodities. To predi ct pest infestation, storage conditions should be accurately assessed with respect.to these factors.