E-Delivery

P U L S E C R O P N E W S F A L L 2 0 1 7 | 29 15°C or less. Although fans can be turned off during rain storms, PAMI suggests there is very li le moisture movement between grain and air at low airflow rates, 0.1-0.2 cubic foot per minute (cfm) per bushel, which is the rate associated with aera on. Producers who must actually dry their grain by 3-4% moisture content require a natural air drying (NAD) system, also referred to as near ambient drying. Ambient air is the air outside the bin which has the capacity to remove moisture from grain. NAD requires an increased fan size in horse power that provides a higher air-flow rate of 1-2 cfm/bushel. For NAD, fans should be run only during the day when the air has the best capacity to dry un l the grain is about 1% above the safe-to-store moisture content. Then, as men oned for aera on only, con nuous night and day air can be used to finish drying the grain down one more moisture content point and cool the grain for safe long-term storage. Later in the fall as air temperatures drop, NAD systems lose their effec veness for drying grain. Cool air can only hold a small amount of moisture and moisture movement from grain to air is very slow at temperatures less than 10⁰C. So, adding supplemental heat to the inlet air of a NAD system increases the air's ability to hold moisture and dry the grain. PAMI suggests limi ng the air temperature increase to 10°C and use a Canadian Standards Associa on cer fied hea ng system (not a homemade system). Supplemental heat can be used when the ambient air temperature is between -5⁰C and 15⁰C. The maximum air temperature a er the heater should be between 5⁰C and 25⁰C. The disadvantage of using supplemental heat is that it increases the possibility of over drying the grain, especially at the bo om of the bin. PAMI suggests running fans with a heater un l the bin is "average" dry, mix the grain, and then cool with aera on. If ar ficial heat grain drying is required, air temperatures should not exceed 45⁰C for pea and len l to prevent seed germina on problems or to prevent quality losses due to hardening or cracking of seed intended for food use. Addi onally, the sample should not be dried more than four to five percentage points per pass through the dryer. For feed pea, dryer temperatures up to 70°C can be applied. To get grain into the safe storage zone, it should be brought down to 15⁰C or lower. Regularly check the temperature of the grain in the bin. Measure temperature by using temperature sensing cables that are permanently installed, by probing the grain with an electronic sensor device or by inser ng a metal rod into the bin and checking it for warmth at various points from the p. If an aera on system is not available to cool the grain, turning grain outside the bin, or coring, is an alterna ve to aera ng it in the bin when the ambient air temperature falls below 15°C. Turn the grain every two to four weeks un l the grain temperature reaches 15°C or less. This procedure involves removing about one-third of the grain from the bin, allowing it to cool overnight, and then pu ng it back in the bin. When moving pulse crops, grain augers operated full and at low speeds reduce seed coat cracking and seed spli ng. Pulse seeds at 12% moisture content and lower are more suscep ble to chipping and peeling when handled. Cool, dry storage condi ons allow the crop to be stored for a lengthy period, but if seed moisture content or temperature rises, storage me lessens. The table above indicates the number of weeks recommended for safe storage of field pea at various grain moisture contents and storage temperatures. Other pulse crops are similar. Table 2: Number of Weeks for Safe Storage of Field Pea at Specified Grain Moisture Content and Storage Temperature. Source: Sokhansanj, 1995. Storage Temperature in Degrees C Moisture Content (%) 12 14 16 18 21 25 31 16 7 4 2 20 55 28 13 7 4 15 100 50 20 12 6 10 200 95 38 20 21 5 370 175 70 39 20 "To get grain into the safe storage zone, it should be brought down to 15⁰C or lower, with regular temperature checks in the bin."

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