The itchy eyes, runny noses and bright yellow patches on the horizon say it; there are some bumper canola crops around this year. If you’re growing one, you’ll want to ensure you maximise your return at harvest. But crop topping or windrowing at the incorrect time could ruin your profits. To ensure you’re getting the most from your canola crop and how to finish it off, have a read of our tips below.

Crop Topping

What herbicides can I use in canola crop topping?

Currently, there are only three glyphosate options registered for use in canola. These are; Crucial, Weedmaster DST or Roundup Ultra Max. These are registered for use prior to direct heading, or before/under the windrow, with Nufarm’s DST and Crucial products having a withholding period of five days.

When should I apply?

Ideal timing for glyphosate products is to apply to mature standing crops with a minimum of 20% seed colour change to dark brown or black. See image below. Higher label rates can be used when crops or weeds are dense. Just remember – do not apply glyphosate if you intend to keep the seed.

Image 1 – Wait until at least 20% of the canola seed has changed to dark brown or black before applying a pre-harvest application of glyphosate.

What are the benefits of crop topping?

There are two main reasons you would consider crop topping. One is weed control, and the other is to achieve even maturity at harvest.
First, if ryegrass or other weeds are a problem in your paddock, crop topping gives you an opportunity to have an early crack. It allows you to get on top of any early summer weeds or smaller weeds that are germinating, as well as reducing seed set in mature weeds such as ryegrass and wild radish. Crop topping is an excellent tool to be used in the battle against ryegrass, in combination with other harvest weed seed controls.
The other reason for crop topping is to ensure your canola goes off evenly. That way, when it comes to harvest, you aren’t combating a mixture of mature seeds and seeds that are still green or not ready to harvest. Desiccating will have no detrimental effects on the seed or its oil quality if product is applied at the correct time.

Windrowing

What are the benefits of windrowing?

Windrowing allows earlier harvest (8-10 days) because of the canola seed maturing more evenly. This is especially helpful in higher rainfall areas as it also accelerates maturity. It also allows even maturity across the crop in paddocks where soil types are variable.
Another reason to windrow is to alleviate the risk and reduce losses from wind and hail damage. It also gives you more flexibility if you have larger areas sown, as the timing of harvest is not critical and can be done around the clock. Lastly, it also reduces shattering losses during harvest.

When to Windrow

Windrowing normally starts 20-30 days after the end of flowering when most of the seeds have reached 35-45% moisture. We can determine the timing of windrowing by estimating the level of seed colour change. How do you do this? Start by collecting pods from different positions up and down the canopy from both brown and green coloured pods. The optimum time to start windrowing is when 40-60% of seeds have changed colour from green to red, brown or black. But be careful; windrowing too early can result in lower yields and oil contents, and windrowing too late will lead to shattering losses. Canola will mature from the lower pods up, so when the timing is right, the top third of pods will be mostly green seeds that are firm but pliable when rolled between your thumb and forefinger. The middle third will have 80% green seed or green-red and be very firm but pliable, and the other 20% may be red-brown to light brown. The lowest third of the plant will have dark brown to black seeds.

Image 2 – Seed colour changes determine the optimum time for windrow timing.

Direct Heading

Benefits of Direct Heading

First and most obvious, it makes for one less job for you on the farm (no windrowing). However, direct harvesting also has other benefits, such as giving you cleaner samples with lower admixture. It’s also more suitable to rocky areas or where objects in the paddock can be a problem when windrowing, and you can harvest the paddock according to tramlines.
Direct heading also gives you more control at harvest, as you can selectively harvest sections of the crop as it matures, and it will reduce the risk of harvester blockages that can occur with windows.

When to start Direct Heading

When all the pods are dry and rattle when shaken, you can get the header in and start harvesting. Some tops of the plants might contain a few green pods; however, if you were to wait for those last few to ripen the rest of the crop will begin to shatter. It is important also to remember not to start to harvest until the moisture content has fallen to 8%. The best practice is to harvest in the early hours of the day to minimise seed losses.

Ultimately, whether your crop is windrowed or direct harvested will depend on your situation and variables on your farm. All things come into consideration, such as varieties, soil types, seasonal conditions, availability of windrowers, and the size and variability of the crops. If you would like advice on your situation or want us to have a look at your crops timing, don’t hesitate to phone our team.