各類農(nóng)產(chǎn)品貯藏技術(shù)課程介紹(文件)
【正文】 ge temperature in northern Minnesota is about 25 degrees F. Watch forecasts for 20 to 30 degrees F weather and operate aeration fans 24 hours/day in late fall to cool grain for winter storage.Figure 2. Moisture migration in unaerated grain. Figure 3. Measuring exhaustair temperature. Check Stored Grain Frequently n Check stored grain monthly during cold weather and every 2 weeks during warm weather. Look for evidence of mold on the surface and in probe samples. Also, use probes and insect traps to check for insects.n Measure and record temperatures at several locations and watch for spontaneous heating—a sure sign of mold or insect activity.n Permanently installed temperature cables make this job a lot easier (Figure 4). Also, start the fan briefly on cool, dry days and smell the first exhaust air leaving the bin for musty or sour odors.Figure 4. Permanentlyinstalled grain temperature cables. RICE STORAGE演講完畢，謝謝觀看！。t be cleaned. n After the bin and equipment are cleaned, consider spraying the bin with an approved, residualtype insecticide. Make Sure Grain is Dry Enough n Insects and molds are less active in dry grain, so make sure wheat is 14% moisture or less for 9 months storage and 13% moisture or less for more than 9 months storage. n Barley should be about percentage points drier than these values. Insecticide Treatment n If grain will be stored into next summer or if you often have problems with insects, consider applying a grain protectant as the crop is moved into storage. Contact your county extension office for the latest information on approved protectants. Contact potential buyers to see if they will accept treated grain—some will not. Rusty Grain Beetle on Wheat Red Flour Beetle on Wheat Mites on Wheat AspergillusManage Fines n Fines tend to congregate in pockets in storage bins, they restrict airflow, and they are more susceptible to attack by molds and insects. Try to limit the amount of fines in storage by setting bines for minimum grain damage and maximum cleaning, operate grain augers slowly and full of grain to reduce kernel breakage, and consider cleaning grain before storage to remove fines. Either use a grain spreader to fill bins and distribute fines uniformly throughout the grain mass, or don39。 khapra beetle (Trogoderma granarium)。C and above 12 per cent moisture content. n The metabolic activity of insects and mites causes an increase in both the moisture content and temperature of the infested grain. n Arthropods also act as carriers of mould spores and their faecal material can be utilised as a food source by moulds. n Furthermore, moulds can provide food for insects and mites but, in some cases, may also act as pathogens.mouldsBroken kernelsn Another important factor that can affect mould growth is the proportion of broken kernels in a consignment of grain. n Broken kernels, caused by general handling and/or insect damage, are predisposed to mould invasion of the exposed endosperm. n It has been estimated, for example, that increasing the proportion of broken grains by five per cent will reduce the storagelife of that consignment by approximately one order of magnitude。C.n In general, for a given substrate, the rate of mould growth will decrease with decreasing temperature and water availability. mouldsn The intergranular water concentration is described either in terms of the equilibrium relative humidity (RH, %) or water activity (aw). n Typical water activities which are necessary for mould growth range from to .mouldsn The interaction between grain temperature and moisture content also affects the extent of mould colonisation. n The passage of water from the grain into the vapour phase is encouraged by an increase in temperature. n Maize, for example, can
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