Safe storage of pulse crops
Many acres of lentils and dry peas were harvested during the last hot weeks of August. Some of these crops were binned at high temperatures. Proper storage techniques are now essential to maintain the value of the crop, said Ray McVicar, crop development specialist with Saskatchewan Agriculture.
“As autumn proceeds, the air temperature outside the bin decreases and lowers the air and grain temperature next to the wall more quickly than the centre of the bin,” said McVicar. “This differential starts air moving down the bin wall and upward through the centre of the warmer grain. The air moving through the centre becomes warmer and picks up moisture. When this moist air hits the upper surface, condensation occurs. In the spring, the problem is reversed: Condensation occurs on the bottom of the bin.”
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McVicar said this moisture migration can be prevented by cooling grain in the fall and warming it in the spring using an aeration fan.
For prolonged safe storage, pulse crops should be cooled to less than 15 C, and dried to less than 14 percent moisture. Recent information indicates warm pulse grain cooled within 24 hours of being placed in the bin is more stable even if the moisture content is low, said McVicar. Dry seed cooled to 10 C will store well for long periods.
“Cooling may be accomplished in as little time as one day, but drying can take three to four weeks,” he said. “The recommended air requirement for aeration drying of a pulse crop is about one to two cubic feet of air per minute per bushel.”
McVicar said fully perforated floors provide more uniform air distribution than a hopper bottom design. Pulse crops have large seeds compared to cereals, and provide a lower resistance to airflow. This results in easier drying. The presence of fines, chaff and green weed seeds can greatly reduce airflow, however, and cause air movement to be channelled around wet spots.
Cleaning pulses of foreign matter before they are put into bins can greatly improve long-term storage, said McVicar.
Pulse seeds are extremely susceptible to mechanical and thermal injury in supplemental heat grain dryers. The recommended maximum drying temperature for pulse crops is about 45 C.
To reduce seed coat breakage, it is recommended to dry pulse crops by no more than four to five moisture points in one pass, said McVicar. The grain should also be allowed to temper for about eight hours between passes. For chickpeas and beans, the tempering time should be 24 hours.
Pulse handling equipment such as conveyors, bean ladders and hopper bottom bins can greatly reduce seed coat breakage and maintain high grades. Certain precautions should be taken, however.
“For example, hopper bottom bins and bins with installed bean ladders are subject to denting and collapse due to off-centre or non-symmetrical unloading. Monitoring the contents for crusting and spoilage, and ensuring a smooth, uniform flow out of the bin may prevent problems. Reinforcement of the bin wall, especially at the joint between the hopper and the bin, can help to prevent structural damage,” said McVicar.
– Saskatchewan Agriculture
Fall-applied nitrogen fertilizer
When making the decision of fall versus spring nitrogen fertilizer applications, several factors must be considered. Fall fertilization can range from very effective to disastrous depending on soil moisture, the form of nitrogen used and how it is applied.
“There are some general rules for application methods and timing,” said Ross McKenzie, soil fertility specialist with Alberta Agriculture.
Generally, spring banding is the most effective method of application and fall broadcast the least. However, fall banding nitrogen can be effective if there is no extended period of saturated soil conditions in the spring. Fall banding may be more effective when a dry seedbed is a concern.
“The risk of over-winter nitrogen loss is highest in regions with moister climates,” said McKenzie. “There is less risk in regions that tend to be drier. Even in these regions, nitrogen losses can be high during a wet spring. Normally, nitrogen losses through denitrification in the drier regions are relatively small and fall-banded nitrogen is equal to spring-banded nitrogen. In cases where spring banding causes a significant loss of seedbed moisture, fall banding can be superior.”
Before fertilizing this fall consider these agronomic factors:
- If soil is saturated with water for extended periods in the spring, fall fertilizer application is probably not a good option.
- Soil tests to determine the optimum rates of fertilizer are required.
- Apply a conservative rate of nitrogen fertilizer. An application of 75 percent of soil test recommendation is a hedge against both high soil test nitrogen levels, poor spring soil moisture or low crop prices.
- Select a fertilizer formulation that is right for your conditions.
- Avoid the use of products containing nitrates such as 34-0-0 and 28-0-0 on soils that tend to be saturated in the spring.
- Apply nitrogen in late fall after the soil temperature has dropped below 7 C and the nitrification process has slowed.
- Band, don’t broadcast.
“In summary, fall fertilization can improve time management and allow earlier planting,” said McKenzie. “Producers often find that fertilizer prices and payment schedules are more favorable and the availability of product is often better in the fall. Drier soil conditions in the fall can also mean that application equipment is less likely to cause soil compaction.”.
– Alberta Agriculture
