Growing a quality organic crop takes skilful management of the farm ecosystem, including soil, rotations, crops and weeds.
Maintaining the quality after harvest is the key to successful marketing, to pleasing customers and to gaining top dollar for top quality.
According to Bruce Roskens, director of Crop Sciences for Grain Millers in Naperville, Illinois, farmers need to “truly understand your crop’s role as a food ingredient.”
Farmer who think of their crop as a food ingredient are more able to appreciate its value and to take “the steps necessary to make quality,” he said.
Grain stores best when it is cool and dry. Then the grain itself is inactive, it won’t sprout and it won’t activate enzymes that lead to spoilage.
Equally important, insects and moulds won’t be as attracted to the grain and they won’t be able to grow, develop, reproduce or spread in cool, dry conditions.
There are five steps to keeping grain cool and dry:
Harvest grain when it has reached the right moisture level. Most cereals can be stored between 13.5 and 14.5 percent moisture. Oilseeds need to be drier, between 9.5 and 10 percent for flax and mustard. Pulses are stored at slightly higher moisture levels, usually 14 to 16 percent. Chemical desiccants are not used in organic production; swathing can be used to speed ripening of both crop and weeds.
The decision to swath balances ripening against weathering, such as frost damage, mildew, bleaching or staining. Crops weather better standing than in the swath, but also fare better in the bin than in the field. If crops are combined with too much moisture, drying is recommended.
Store grain in a clean, dry and sealed bin. Maintaining organic integrity includes careful sanitation of bins and all equipment that comes in contact with the grain, such as augers, trucks, fans and aeration systems. It is important to remove all previous grain, dust, mould, insects and debris before filling the bin.
High-pressure air, brushes, brooms and grain vacuums are commonly used to provide a thorough cleaning.
Bins should completely seal to prevent water and insect access. Vent holes should be covered to keep out birds. All holes, cracks and seams should be sealed with a food safe and strong material before grain is stored in the bin.
Don’t put anything else in the bin. Extraneous items, such as green grain, weed seeds, chaff and field materials, can increase moisture. This results in moulds, deteriorates the grain and can lead to fires and explosions. Extra materials also interfere with grain flow when auguring and with airflow when cooling, heating or drying. Cleaning the grain between combine and bin can greatly reduce these risks and adds another market stream: organic screenings for animal feed.
Temperatures in the bin change as outside temperatures vary and even as sunshine heats one side of the bin. Temperature variation leads to condensation that produces moisture pockets in the grain mass. This leads to biological changes that result in spoilage and further temperature changes.
Temperatures in the bin should be checked every two weeks using probes or sensing cables. If these are not available, a metal rod can be inserted into the grain at the top, near the centre. After 30 minutes, remove the rod and feel if it is warm to the touch at any point. This would be an indication of heating and of potential grain spoilage.
If heating or condensation occurs within the bin, aeration is recommended. It is an alternative is “turning” the grain — emptying the bin and refilling it.
Aeration is improved if the crop is clean. Small weed seeds and dust can fill the spaces between the grains, reducing airflow. Keeping the surface level in the bin also improves airflow.
The Prairies produce some of the highest quality organic crops. To maintain that quality from harvest to sale, it is important that management be ongoing.
Brenda Frick, Ph.D., P.Ag. is an extension agrologist and researcher in organic agriculture. She welcomes your comments at 306-260-0663 or email firstname.lastname@example.org.