23 Jun Agronomy Update – June 23rd
Good morning everyone,
Most folks woke up this morning to another welcome bit of rainfall overnight. Totals are variable, from as little as 1 mm in Charlottetown to as high as 17 mm in Bedeque. Totals generally higher in Prince County, which is good, as Prince County missed some of the rainfall that came last week.
Emergence appears to be encouraging in most fields. I have heard very few issues with poor emergence or set rot. There are a few reports of replanting on fields that were planted very early and then were impacted by the cold soil temps at the start of May. There were also a few seed lots here and there that were reported as having issues with Fusarium or heavy bruise that needed to be managed carefully. But in general, the growers that I’ve talked to in the last week sound happy with the way the crop is progressing. Good soil temps (currently 18-20 C) and good soil moisture levels provide favourable conditions for fast growth.
Managing Volunteer Potatoes:
After a relatively mild winter with lots of snow cover and not a lot of frost in the ground, there are lots of reports of volunteer potatoes showing up in fields this year. Attached is a photo of vigorous volunteers in an emerging corn field this year.
Significant numbers of volunteers can pose a number of problems:
- Act as reservoirs for PVY, increasing the risk of spread
- Host for late blight infection and future spread
- Weed issue in other cash crops, impacting yields
- Feeds Colorado potato beetles which then may spread to other fields later in the season (or build populations for the future)
Gavin Graham from the NB Dept of Ag produced a good overview of volunteer management options. (Linked on Agronomy Site). A few key points:
- Glyphosate (Round-Up) provides the best control. Even if it doesn’t completely kill tops, it will limit the ability of those plants to produce viable tubers that will grow next year. Particularly useful on Round-Up ready crops like corn and soybean.
- MCPA had little effect.
- Infinity had immediate effect on tops but then re-grew.
- Spraying for volunteers early is essential
Depending on the number of volunteers you see, it might be necessary to look at mechanical or hand removal of volunteers. Just waiting for Colorado potato beetles to chew on those volunteers might not be enough to prevent ongoing issues.
SpudChat this week: Grower Check-In:
The latest episode of SpudChat is now available at https://spudchat.buzzsprout.com/ or wherever you download your podcasts. This week, we have another monthly “Grower Check-In” with Bryan Maynard, Gordon McKenna, and Chris MacAulay. We get an update on how planting went across the Island, how the crop is progressing, and changes to production practices for this year.
SpudChat episodes are about 30 min in length and can be easily downloaded or streamed on your mobile phone so that you can listen when you’re driving…that’s when I listen to podcasts normally. You can also listen directly from the site linked above.
Time to Plant Warm-Season Rotation Crops:
Conditions are ideal now to plant warm-season grasses like sorghum sudangrass and forage pearl millet as well as disease suppressive crops like buckwheat and mustard. Soil temperature and moisture should result in very quick growth and a great ability to out-compete weeds. Don’t leave planting these crops too long, as you may miss the advantages of greater soil moisture for quick emergence as well as the benefit of having these crops growing for the longest possible time before fall frosts. A few reminders:
- Planting depth for sudangrass and pearl millet with the good soil moisture we have right now is about ¾ to 1 inch deep. Similar seeding depths apply for buckwheat and mustard. If planting in drier soil conditions, consider deeper planting depths.
- For the warm season grasses and mustard, ensure that you are applying sufficient nitrogen to spur on quick growth and maximum biomass. Mustards also require additional sulphur (about a 1 to 5 ratio with nitrogen) to build the beneficial glucosinalates that fight soil-borne pests and diseases.
- Buckwheat and mustard can start setting seed in as little as 6 weeks. Keep a close eye on these crops to avoid them becoming a weed issue in future years. Both crops should be mowed or incorporated before they set viable seed if using as a green manure crop.
- Sudangrasses and pearl millet should be mowed at least once during the growing season to maximize the growth of roots. Root mass can double after the first mowing.
- When mowing sudangrass or pearl millet, mow high (leave 6 to 8 inches of stubble) to ensure it will quickly regrow. If you mow lower than that, it may not regrow well or may be terminated completely.
Have a great rest of the week!