Temperature and moisture are the drivers behind effective seed storage. According to Blaine Timlick, program manager for insect control and sanitation for the Canadian Grain Commission, if farmers can manage those issues, their grain will stay in the best condition for the longest time possible. That, combined with regular germination tests throughout the winter, will help ensure that farmers get through to spring 2012 with the viable seed they need.
COOL CROPS A.S.A.P.
Contrary to the last few harvesst, high daytime temps in 2011 hastened dry-down and provided good harvesting conditions. As a result, the crop in the hopper, and eventually the bin, went in warm. The key is to get the temperature down to between 15 C and 20 C quickly, Timlick says. Like grandpa used to say, Keep your grain cool and sweet, he says. But Grandpa s 10-ton wooden storage boxes cooled off quickly. Cooling grain in today s huge tin cans, Timlick says, requires far more planning and energy. Grain is such a good insulator, he says, that getting the temperatures down can be difficult; aeration systems and temperature sensors are a must.
Even with monitoring systems in place, if you take grain off and it s 30 C in the bin and 30 C outside, aeration s not doing much. Noel White, research scientist with Agriculture and Agri-Food s Canada s Cereal Research Centre suggests running fans at night. Farmers without aeration systems must keep a close eye on the temperatures. Turning the grain a couple of times can help cool it off.
INSECT POPULATIONS DENT GEMINATION
High temperatures in the bin create ideal conditions for insect populations, especially the rusty grain beetle. Below 15 C to 20 C, insects don t die, but they don t feed or reproduce either. If the grain is left hot this fall, White predicts that the beetle could reach large numbers by late November. Insects in the stored grain have a huge impact on germination; Timlick says that hungry insects go for the germ portion of the seed first.
Insects often are overlooked as a storage issue, as they rarely show up in sampling, however given the right conditions, like this fall, numbers could increase substantially. Numbers are probably higher this fall, so Canadian farmers should be on guard, Timlick says. The unusually hot 2011 harvest is similar to normal harvests in the American Midwest where insects are always a problem and grain is commonly fumigated eight to 10 times in order to deal with them. He advises Canadian farmers not to worry about insects getting into the bin, but rather to focus on getting the grain temperature down to 15 C as uniformly and quickly as possible.
PREVENT MOISTURE MIGRATION
High temperatures in the bin also lead to problems with moisture, the next challenge that farmers must overcome when storing seed. Moisture takes a toll on stored crops by setting off several processes that lead to the deterioration of the quality of seed. A high level of moisture causes seeds to germinate. In addition, microflora (fungi and bacteria) can grow.
Farmers can minimize moisture by ensuring no leakage in the bin as well as by drying damp grain.
Even if the grain is at a low level of moisture, say 11 per cent, when it s brought in, if it hasn t been cooled adequately, a convection current will develop inside the bin if the ambient temperatures drop. The warm air in the centre of the mass of grain meets the cool air at the surface to create condensation. As a result, farmers can expect the growth of molds and decrease seed germination, especially on the surface of the mass.
It s common to conduct germination tests through accredited labs as close to the seeding date as possible, but testing germination throughout the winter has huge benefits. If something goes wrong in storage, germination rates immediately drop; in this way testing germination can acts as an important signal. White suggests testing once a month so any problem that arises can be remedied immediately. You can then take steps to dry the grain, adjust the temperature, increase aeration, or turn the crop.
Timlick and White stress how easy testing germination can be. Farmers simply have to scoop out a sample preferably from various areas of the bin and throw the grains onto a wet paper towel on top of a plate and see what comes of it. Unfortunately, many farmers don t get around to it because they re busy with other tasks. In addition, obtaining the sample is not easy. Timlick says that while today s bins are fantastic in terms of pest control and moving grain, they aren t designed for easy access. The logistics of crawling into a hopper-bottom bin to get samples is daunting if not impossible. Corrugated steel bins provide easier access; use the advantage and sample more often.