Important tips for proper pulse crop salvage

Source: Saskatchewan Agriculture and Food

Pulse crops are growing in popularity among Saskatchewan producers. That paid off in spades this year, with some very high-quality crops. Processors report that over 90 per cent of lentils, peas and chickpeas in the province should be in the top two grades.

However, according to Ray McVicar, Provincial Special Crops Specialist with Saskatchewan Agriculture and Food (SAF), farmers need to follow proper storage techniques now that their pulse crops are in the bin, or they could be in for some unpleasant surprises.

“Pulse crops advanced rapidly throughout most of the Prairies in 2006,” McVicar noted. Because pulses (other than beans and soybeans) are often planted first, this year’s early spring conditions in areas other than north-eastern Saskatchewan saw early-seeded crops take advantage of warm soils and good rainfall in June.

Many pea and lentil crops matured quickly in the heat of July, and some were ready to be harvested in early August. In fact, drought conditions in south-western Saskatchewan resulted in a very early harvest in that region. According to McVicar, a lot of pulse crops were put into storage at high temperature, which makes them more prone to bleaching and oxidization.

“Monitoring stored grain during and after harvest is an important part of a grower’s day-to-day activities,” McVicar said. “The safe storage of pulse crops is important every year, and the key to avoiding mould and other storage problems is the use of aeration to cool and dry the seed.”

McVicar stated that testing with a moisture meter is something that farmers should carry out several times after the crop is binned. “Now that we’ve had some wet weather, producers should monitor their stored crops immediately to prevent any losses due to spoilage,” he said. “The risk of spoilage becomes greater if the crop was harvested following the wet weather. This risk is greatly reduced if foreign material is removed.”

Because of their large size, stored chickpeas and peas need time for the moisture to equalize throughout the seed. Chickpeas harvested at high temperatures will most likely sweat in the bin. This occurs as the moisture migrates within the bin.

For prolonged safe storage, pulse crops should be cooled to less than 15 degrees Celsius and dried to less than 14 per cent moisture. Seed that is cooled to 10 degrees Celsius will store well for long periods.

The Saskatchewan Pulse Growers Pulse Production Manual, found online at http://www.saskpulse.com/media/pdfs/ppm-field-pea.pdf, contains a table outlining the number of weeks for safe storage of peas at specified moisture content and temperature. For example, peas stored at 14 per cent moisture and 10 degrees Celsius can be safely stored for about 95 weeks. Peas stored at 18 per cent moisture and 20 degrees Celsius have a safe storage limit of only seven weeks. Other pulse crops will be similar.

Different moisture content levels must be taken into consideration for red lentils. Red lentils are considered to be dry at 13 per cent moisture content. Red lentil buyers around the world prefer the crop to be at 13 per cent moisture content or lower, and growers should work to achieve that level. This year’s hot, dry summer allowed most lentils to be harvested dry.

Pulse crops at 12 per cent moisture or lower are more prone to chipping and peeling during handling, especially when the temperature has dropped below minus 20 degrees Celsius.

McVicar noted that a bin equipped with an aeration fan can provide both cooling and drying. But while cooling may be completed in one day, drying can take three to four weeks. To dry the crop, the aeration fan must have adequate power to provide air flow through the grain. “The recommended requirement for aeration drying of a pulse crop is about one to two cubic feet of air per minute per bushel, or about 2,000 to 4,000 cubic feet per minute for a 2,000-bushel bin,” said McVicar.

He added that crops that weren’t taken off before the rains may require supplemental heat-drying. “With pulses, air temperatures should not exceed 45 degrees Celsius to preserve germination, and the sample should not be dried more than four to five percentage points per pass through the drier,” McVicar stated. “The product should be allowed to temper in an aeration bin between passes.”

However, McVicar reminds producers that the augers within a grain dryer can increase seed coat peeling and cracking. He suggested that growers who use long-term storage to help their pulse marketing plan can also make good use of a belt conveyor. “Pulse crops often need to be given a rotation in the bin to prevent spoilage, and a conveyor can accomplish this with very little seed damage,” he pointed out. “Growers in the need of a new auger might want to investigate moving to a belt system.”

For more information on storing pulses, contact the Agriculture Knowledge Centre at 1-866-457-2377.

For more information, contact:

Ray McVicar, Provincial Special Crops Specialist
Saskatchewan Agriculture and Food
Phone: (306) 787-4665