Agronomy Update – Sept 23

A wet and wild morning in PEI.  I hope everyone is staying safe and dry.

As of 9 am, I’m seeing anywhere from 35 to 75 mm of rain in the last 24 hours, and it appears that we’ll have a pretty full day of rain ahead of us today, so over 100 mm in several areas is likely.  Thankfully the accumulation is spread over 2 days rather than all at once, and the forecast ahead of us looks relatively dry and warm so fields should dry out sufficiently by the weekend or early next week.

With this amount of rainfall, growers should be keeping a close eye on their fields later today and tomorrow to look for areas of standing water.  We should all be learning from the lessons of Dorian last year, where huge rainfall resulted in standing water in fields for too long, compromising tubers and resulting in water soak, pink rot, Pythium leak, and other storage issues.  Keep an eye on low spots or any parts of fields that have water in the furrows for too long and mark them with flags.  DIG THESE AREAS LAST…if at all.  Any potatoes at higher risk of storage rot need to go on the front of the pile, not the middle or back of the bin.  The extra effort during harvest will be worth it if you can avoid breakdowns in storage.

I mentioned pink rot before…we’ve seen a bit more pink rot the last couple of years with wet conditions at harvest.  If this is something that you’re concerned about in your fields, a post-harvest application of phosphorous acid (Phostrol, Confine) has shown to be quite effective at limiting the spread of pink rot in storage.

Frost Damage

Unfortunately, we’ve had another early frost again this year.  Many fields that were still green despite the dry summer were significantly defoliated by frost events on Saturday night/Sunday morning and on Sunday night/Monday morning.  Some fields that in the morning looked to have escaped the worst of the damage were pretty black by the evening.  I know that this is very disheartening for affected growers.  2020 has been a year without a lot of positives!

Again, we must look to the lessons learned over the last couple of years.  Fields that are defoliated by frost don’t have an opportunity to move sugars and other nutrients down into the tubers because in frost damage, the cells are destroyed when frozen water in the cells thaws out again.  This prevents the plants from being able to move those sugars down to the tuber and turn them into starch.  It also usually has a negative impact on specific gravity; however, the dry conditions throughout the summer will likely mean that gravity scores are a bit higher than average.

So, if a field is effectively dead and has been stopped in it’s maturation process prematurely, that will likely require adjustments to the harvest schedule.  Don’t expect heavy frosted fields to add much yield beyond what is there right now. Because they were prematurely halted in maturity, expect skin set to be affected as well.  For some varieties this means making extra efforts to handle those tubers as gently as possible during harvest and loading into storage to prevent bruising and secondary infections like Fusarium.

Research Update

Morgan and I (and our various research partners) have started fall sampling.  We’ve got 10 fields worth of potato yield strips done already, and we’ve made a good dent in fall soil sampling for Living Labs fields.  We have lots more to get done however, so we’ll be back at it as soon as the fields dry out enough to get rolling again next week.

For anyone that we have a field trial with that we need to harvest potato samples or do soil sampling in the next 6 weeks:  please make sure to give Morgan or I a call before you head to the field.  We understand if plans change on the fly and a field needs to get dug sooner than expected.  We will do our best to adjust our schedule to ensure that we don’t lose any data.  In some cases we’ve put two years into some of these trials…let’s make sure we don’t lose the data so close to the finish line!

We are also finalizing set-up of some trials on post-potato cover crops as well as lining up fields for our Early Dying survey later in October. Hopefully we get the right kind of weather for harvest that also enables us to get these trials established and data collected.

Thank you to everyone who participates in trials or surveys with us…we couldn’t do our work without your help.  Particularly in this frustrating, challenging growing season, I am very appreciative for your time and efforts.

Stay safe and dry!