Agronomy Update – March 17th

Hi everyone….Happy St. Patrick’s Day to all those with Irish ancestry (like me) or who choose to celebrate anyway!

We’re still in “meeting season,” although it’s a bit modified this year still due to COVID.  See below for details on two events in the next two weeks that should prove valuable to growers.


Nutrients from Destroyed Potatoes:

Had some discussions recently about growers about the nutrient value of potatoes that went through snowblowers this winter.  Yes…it’s very expensive fertilizer and having to destroy potatoes is heartbreaking.  For those that did spread some potatoes on fields, there is an opportunity to at least make the best use of those nutrients that you can.

100 cwt of potatoes has the following nutrient value:

30 lbs N
15 lbs P2O5
65 lbs K2O
3 lbs S
2.5 lbs Mg

Therefore, if you spread on 300 cwt/ac of potatoes on a field, that would equal 90 lbs N, 45 lbs P2O5 and 195 lbs K2O.  The P and K would be sufficient for a lot of different crops without the need for additional fertilizer, though depending on what you’re growing and your soil tests, you may need starter P to get things rolling at planting (consult with your agronomist).

Now, the nitrogen…all of that 90 lbs won’t be available during this growing season.  Why?  Potatoes are mostly starch (other than water) and that starch is heavily made out of carbon.  This means that potatoes have a high C:N ratio, which affects how quickly N is released.  In listening to an episode of Wheat Pete’s Word a couple of weeks ago, he noted that the N credits would differ depending on the crop you plant.  If planting wheat or barley…you can only expect about 50% of that N to be available to the crop.  If you’re growing a longer season crop like grain corn, you can expect closer to 70% of that N to be available.  Keep this in mind when planning what crops to plant on the fields that you spread potatoes on this winter, as well as your fertility plans….especially with the high costs of fertilizer!


2021 Research Results:  Seed Projects

Full project results from our AIM Seed Management trials are now available on the Agronomy site, but here are a few highlights from some of our trials from last year:

  • We did another year of trials looking at the physiological age of seed across multiple French fry varieties, either doing a “winter warm-up” to add age to seed or refrigerating the seed to keep it younger. Thanks to Steve Watts of Genesis Crop Systems for his help with this trial.The variety that had the most response to the winter warming (adding 191 degree-days in January) was Dakota Russet, with an average yield increase of 38 cwt/ac and average crop value increase of $681/ac across 2 trial sites. The other varieties (Clearwater, Mountain Gem, Payette, Prospect) didn’t show much response.

    Alverstone Russet showed a positive response to keeping the seed cooler (reduction of 399 degree-days), with an average increase in marketable yield of 53 cwt/ac and increased crop value of $411/ac compared with conventional seed storage.  We also saw statistically higher yield for the refrigerated Russet Burbank at one of the two sites, consistent with previous research.  Refrigerating Clearwater seed was more inconsistent.

  • We did a trial at Harrington (thanks to David Main of AAFC) comparing seed piece size (1.5, 2.0, 2.5, and 3.0 oz) on yield and quality for Dakota Russet and Mountain Gem. For both varieties, average number of stems per plant and tuber number increased with seed piece size.The best marketable yields were in the 2.5 oz size category, because at 3.0 oz, we had higher # of smalls and less 10 oz because we didn’t adjust spacing.  This reinforces that as you increase average seed piece size, you may want to look at adjusting spacing proportionally.  For Dakotas, the yield was about 40 cwt/ac lower in the 1.5 oz seed size.
  • Dave Main also did a plot trial looking at using gibberellic acid (GA) on Payette Russet and Dakota Russet in an effort to get them out of the ground faster. We wanted to see if this would have a beneficial impact on emergence and yield.  In this trial, GA improved emergence by a couple of days and increased the tuber number; however, these extra tubers were mostly in the small category so they didn’t increase marketable yield.  For both varieties, GA doesn’t look to be advised on processing fields, but does look to have value at increasing tuber numbers without reducing yields, which would be valuable to a seed grower.


International Potato Tech Expo – March 30/31

Registration is open for the Potato Expo, and you can CLICK HERE to register for free!

Here are topics we have lined up for the conference, happening both of the mornings of the Expo:

  • Irrigation Research & Extension in Alberta – Michele Konshuch, U Lethbridge
  • Understanding Blackleg and Soft Rot – Jay Hao, U Maine
  • Increasing Profits Through Management – Lance Stockbrugger, Saskatchewan farmer
  • Growing in a Post-Pandemic World – John Cranfield, U of Guelph
  • Effect of Crop Diversity in Potato Rotations – Aaron Mills, AAFC Charlottetown
  • Scouting for Wireworms – Christine Noronha, AAFC Charlottetown
  • Soil Health Planning – Kyra Stiles and Tobin Stetson, PEIDAL

Will be great to see everyone back in person at the Expo!  Sign up for free today.
Note:  Unless there is more rapid change to CPHO guidelines, the Expo Conference will be at 75% room capacity…meaning that if you want to go to the conference, be there early to get your seat!  There will be an “overflow” room of ~60 people where the conference will be livestreamed for those that can’t get into the main room.  See you there!


Canadian Spud Congress:  March 22/23

Are you already registered for the Canadian Spud Congress?  If not, visit to register and learn more.

Topics for presentations will include:

  • Markets overview
  • Potato Early Dying
  • A Sustainable Future for Potato Production
  • How Potatoes make great beef and vodka!
  • Nematode Management
  • Future Proofing Your Operation
  • True Potato Seed