Swathing Canola

Every year there are tough decisions that need to be made when swathing canola. Swathing too early will cause yield loss. The yield loss will vary depending on the conditions at the time of swathing. In hot, dry conditions with the canola being too green, I have observed 50% yield loss. Under normal fall conditions, swathing at 10% color change will give a 10% yield loss. With these statements in mind, knowing the weather and knowing the staging of the canola are essential to making the right decision when it comes to cutting time with canola. To determine the proper swathing time, a producer must know the stage of the canola. To do this, a producer starts by finding the main stem on a plant. The main stem will generally be the longest stem and have the most mature pods. The per cent color change of the seed on the main stem is what needs to be looked at. 50 to 60% of the seeds on the main stem should have totally changed color at swathing time. Start by checking the lowest pods. Seed color change is what a producer is looking for. The seeds must be totally changed to a dark purple. Move up the stem and check the pods in middle of the main stem. Most of these seeds should have changed color. Looking at the top pods, the seed should be firm when rolled in between your fingers. The side branches need to be checked on canola plant. When looking at the side branches, the seed should be firm. If they are not, they will shrink when they are in the swath. This will result in a yield loss. Once this is done, look for other plants. Variability from plant to plant must be considered looking at swathing times. Plants that are diseased will be mature when the other plants are not ready to swath. Sclerotinia and root rot are the most likely diseases to cause premature ripening. Generally, swathing to save these plants is a bad idea because of the potential losses on the rest of the crop. Also, the plants that have disease issues generally have smaller seed and add less to the yield of the field than a healthy plant that was swathed at the right time. Finally, when looking at the right time to swath, consider the weather. If the temperature is goes above 25 degrees Celsius, a producer needs to stop swathing. The plant loses too much moisture too fast when temperatures are above 25. Also, with these temperatures, the plant will lock green into the seed and cause a reduction in grade. If frost is in the forecast, swathing can help maintain quality. The crop needs to be swathed at least two days before the frost to reduce the damage of the low temperatures. Swathing canola at the right time can make a producer money and allow him to grow more bushels. If you are not sure on the timing, give your local agronomist a call


By Dave Cubbon, P Ag