Questions of the week

How do I reduce combine loss when stems are so green? 

Some farmers are straight combining canola with very dry seeds and very green stems. The scenario can present some challenges for combine loss, with seeds sticking to green dockage and going out the back of the combine. What can be done? 

  1. Let the crop cure a little longer. Move on to another field if you can.  Straight cut scenarios.
  1. Cut as high as possible to limit the amount of heavy stem material entering the combine.  
  1. Be careful of cracking those dry canola seeds with higher rotor speeds trying to push the green material through the combine. Make sure not to over-thresh the material. 
  1. In storage, closely monitor canola binned with green dockage

What is the best time to apply herbicide in the fall? 

Look at the weed spectrum in each field. Perennials such as thistles and dandelions are best controlled from mid-September to early October, ideally before a killing frost. The trade-off is that these weeds need time after cutting to accumulate new leaf tissue to absorb herbicides. Winter annuals such as narrow-leaved hawk’s-beard, stork’s-bill, annual sow thistle (common and spiny) and cleavers are best controlled from October until freeze up. Fall weed control – timing and targets.

When choosing herbicides, note that growers have limited options (see table here) on fields planned for canola next year.

Take advantage of warm fall days. For better herbicide efficacy, spray on sunny days with predicted highs above 15°C. Start the spraying day after temperatures reach 10°C. (Lots of good tips in the “Fall” section here.) 

How do I take the guesswork out of seed decisions?  

Review canola performance field by field over the past couple of years. What was your yield target at seeding? What robbed yield? Many common yield robbers can be addressed with seed traits or seed treatments. Here is a four-step process to choose the optimal cultivars:

  • FIRST: Choose traits and seed treatments that control the most important yield robbers in that field (disease, insects, weeds, days to maturity, etc.). 
  • SECOND: Choose traits based on rotation requirements (ex. herbicide tolerance, clubroot and blackleg resistance). This is a good time for stubble testing to identify blackleg races, which helps with blackleg resistance-gene choice
  • THIRD: Select based on yield or traits that offer a price premium. 
  • LAST: Choose traits that are nice to have (harvestability, standability, etc.) 

Select a package of canola cultivars that you want to grow on the farm and plan to test one or two new cultivars next year.

Why submit separate soil samples for different productivity zones in a field? 

With only one composite sample per field, you may be missing some key learnings about soil variability. 

This year, try submitting three samples for at least one field. Collect them from three distinct areas: (1) an area, such as a hilltop, where yield was lower than expected, (2) a low area, and (3) a higher performing area where you’d normally sample. Be consistent. Use GPS coordinates to keep track of where samples are taken. Cross-reference combine yield maps and soil sample data to better understand nutrient factors that contribute to yield.   

With these three samples, you may find clues that could be used to plan low-tech variable rate applications as an introduction to the potential of full VR. For example, hill tops are often sulphur deficient and could benefit from a targeted application this fall. Low areas with salinity are often very high in nutrients (if kochia hasn’t taken it up) because the area does not produce enough crop biomass to use the applied nutrients. Consider turning off nitrogen in areas where crop doesn’t usually grow.