Story Posted: June 02, 2010

Canola Watch 6: Tips for soggy fields

In This Issue: Have a conversation with crop insurance, More broadcast seeding tips, Excess moisture restricts nutrient uptake, speeds N loss, What to do about crusting?, Consider higher spray rates, Take a plant stand count, Questions and contacts.

Issues of the week
June 02, 2010 - Excess rain continues to hold up seeding in parts of Saskatchewan and has drowned some canola in Manitoba. In this week’s Canola Watch, we discuss broadcast seeding tips, nutrient losses due to saturation, and management tips for crusted fields. For growers who still have canola to seed around crop insurance deadlines, we recommend they call their crop insurance rep and discuss the most cost effective course of action.

Crop and weather update
Peace (B.C. and Alberta): The crop is seeded and about 80% is emerged. After general showers the past week, the region is off to a good start.

Alberta: Canola seeding is complete except for a few fields and pockets here and there. Rain and snow the past week have slowed growth, but damage appears minimal. Read the Alberta crop report.

Saskatchewan: With another week of rain, eastern Saskatchewan saw very little progress. Seeding has barely started in the Yorkton, Canora and Foam Lake pocket and is at around 50% complete in many other eastern areas. Western Saskatchewan is further ahead. Read the Saskatchewan crop report.

Manitoba: Canola seeding is near complete, except for pockets in the west north of Highway No.1 with up to 25% left to go. Many fields are saturated after a week of rain. Some areas reported up to 6", and growers are worried about drowned crop. Read the Manitoba crop report.

Quick Hitters
Rainfall accumulation in May was more than 200% of normal in many parts of Saskatchewan and Manitoba. This will be no surprise to many of you. This AAFC map shows May moisture as a percent of normal. Blue is >200%. For more maps, visit AAFC’s weather page.

Mud raises the risk of clubroot spread. Wet weather brings a combination of mud AND time panic to get crops seeded and sprayed. This is a bad combination for clubroot containment. Growers and custom applicators operating in or near known clubroot zones will need to be extra vigilant in cleaning equipment between fields. Click here for tips on cleaning.

In the haste to finish seeding, growers must remember to scout their already-emerged canola fields. Some growers have sprayed for flea beetles, and feeding will pick up again with warmer weather. Cutworms generally do not like wet conditions, but watch for cuttings and bald patches on high land and south-facing hillsides.

Spray weeds early. We had some growers ask this week about waiting for more weeds to emerge before applying their first in-crop herbicide. Don’t wait. If there is an opportunity to spray early, go for it. The way rains keep coming this year, growers who wait may end up waiting a lot longer than hoped. Plus early weed control pays off with higher canola yields.

AAFC research scientist Tom Wolf, speaking in an audio interview on the Alberta Canola Producers Commission website, explains how glyphosate vs. glufosinate (Liberty) "couldn’t be more different." The key difference: Glyphosate works best at water volumes of 3 to 5 gallons per acre but glufosinate needs at least 10 gallons per acre.

Scout to ID wireworms vs. cutworms. If canola plants are dying due to cutworms, growers can spray to control them. But if canola plants are dying due to wireworm damage, which is rare but can happen, growers should save their money as foliar sprays to control wireworms will be ineffective. No in-crop insecticide is registered for wireworms in any crop. "Wireworms are a problem dealt with using seed treatments in a crop with registered options the following year," says Scott Hartley, insect management specialist with Saskatchewan Ministry of Agriculture. Click here to read an Alberta Agriculture wireworm factsheet.

Coming event: The Seager Wheeler Farm near Rosthern, Sask., will hold its seeding trends field day this Friday, June 4. For more information, click here or call 306-232-5959.

Know anyone who’d like to receive Canola Watch? To sign up, go to the Canola Council homepage and scroll down to the bottom right corner where it says "Sign up for email updates" Check the Canola Watch box, fill in the email address and click "Sign Up."

Have a conversation with crop insurance
While the general Saskatchewan crop insurance deadline to have crops seeded is June 20, the actual date for canola differs by rural municipality and by variety. For example, at R.M. 459 around Melfort, the deadline for one canola hybrid is June 7 while the deadline for another is June 9. This information is not available on the SCIC website, so call the toll free customer service line at 1-888-935-0000 or visit the local SCIC office for specifics. SCIC reminds growers that canola not seeded before the deadline does NOT automatically qualify for unseeded acres coverage. Also take note that broadcast-seeded canola is not eligible for insurance until adequate stand establishment has been confirmed.

AFSC in Alberta has extended its recommended seeding date to June 5 for Argentine canola and June 15 for Polish canola. Clients who seed within the extended dates will be covered for quality loss. For a link to more crop insurance deadlines and details, click your province: Alberta , Saskatchewan , Manitoba.

More broadcast seeding tips
A fleet of floater trucks is moving into eastern Saskatchewan to help with seeding. We had some tips on broadcast seeding in last week’s Canola Watch. Here are a few more:

• If broadcasting seed and fertilizer at the same time, the ideal is to have a floater with separate compartments for each. If not, then apply the mix shortly after loading. Don't let it sit over night. Fertilizer can "burn" canola seed, damaging its viability. If fertilizer prills stay dry while being mixed, there may be little effect. But with higher humidity, fertilizer break down can start very quickly, damaging the seed.
• Light harrowing after seeding is important to incorporate the seed into the soil and improve seed to soil contact. If a floater truck seeds the crop, then it rains right away and the grower can’t harrow, the risk of crop failure is that much higher. That’s because seed on the surface can easily be stranded if the weather turns dry before roots penetrate into the soil. Alternatively, if soils stay saturated for too long broadcast canola may germinate but the seedlings can die because young roots can’t get any oxygen from the soil.
• The exception: In muddy conditions where harrows create furrows and mud smears, harrowing over the broadcast seed may actually be worse that not harrowing.
• Broadcast canola is only eligible for crop insurance once the field has been assessed to have adequate emergence.

Here’s a recap of last week’s tips:

• Increase seeding rates slightly to compensate for non-uniform seed depth.
• Consider lightly cultivating (two to four cm) or harrowing to incorporate the seed into the soil if field conditions allow. However, avoid creating lumps or clods during cultivation or straw piles with harrows or cultivators.
• If broadcasting fertilizer as well as seed, be aware that broadcast phosphorus is only about half as efficient as banded phosphorous. There also can be greater risk of denitrification on saturated soils, reducing N fertilizer efficiency. Adjust fertilizer rates accordingly, keeping in mind a realistic target yield based on the time of year and field conditions.

Excess moisture restricts nutrient uptake, speeds N loss

Canola is quite susceptible to water logging and shows a yield reduction after only three days. The key is that wet soils cause an oxygen deficiency, which reduces root respiration and growth. Root failure reduces nutrient uptake, and plants can die. CCC senior agronomy specialist Derwyn Hammond (click to email Derwyn) provided this photo of his own canola field. His farm near Brandon got close to 4" on Saturday alone.

Wet conditions also increase soil nitrogen losses. "If growers still haven’t seeded and applied any fertilizer, extended wet conditions mean they’ve probably lost whatever nitrogen was in the soil profile," says Murray Hartman, oilseed specialist with Alberta Agriculture. If they did apply nitrogen last fall or early this spring, then half was probably lost through leaching or denitrification in the past two or three weeks of wet weather, he says. "What’s more, losses will not be even throughout the field." Click here for a MAFRI factsheet that explains how excess moisture reduces nitrogen reserves.

So what’s a grower to do? Wait to see how the crop recovers from saturated soils before investing any more in fertilizer. Certainly don’t do anything while soils are still wet. Roots cannot take up nutrient when soils are saturated. Applying nutrient direct to leaves doesn’t help. Most foliar-applied nitrogen is washed off and then goes into the root zone. Uptake through the leaves is minimal.

Even if soils do dry up quickly and the crop recovers nicely, think twice before applying high rates of nitrogen top dress this late in the season. "Excessive nitrogen applied now will stimulate growth, and make the crop even later. That raises the risk of fall frost grade losses," says Hartman.

What to do about crusting?
Wet conditions followed by warm sunny days may cause soil crusting, which stops seedlings from emerging. We don’t have any research to show the best ways to break up crusting and free the crop. If a few plants have emerged, it may be best to leave them be. Two plants per square foot are better than none.

If nothing is coming through, a light harrowing might help — if the crop isn’t germinated. "But even though growers may have had success using a light harrow to break up crusting in cereals, don’t assume it will work in canola," says CCC senior agronomy specialist Derwyn Hammond. "Harrowing too close to emergence can be really harmful to a shallow seeded crop such as canola."

Using a roller may be worse than harrowing when soils are wet below the crust, says Murray Hartman, oilseed specialist with Alberta Agriculture. Instead of cracking up the soil surface, a roller could turn the whole topsoil zone to concrete.

Again, there is very little research on how to manage crusting. It’s trial and error. If you have techniques that have worked for you, we’d like to hear about them. Please click to email Canola Watch editor Jay Whetter.

Consider higher spray rates
Weed growth will resume quickly when conditions get warm and the rains stop. Then it will be at least a day or two after that before fields are dry enough to drive on and before crop stressed by frost or excess moisture recover enough to allow good tolerance of herbicide. That means bigger weeds to content with. In that case, growers will want to use higher spray rates — but stay within label limits — to ensure optimal control of these larger weeds.

When it comes to weed control, don’t delay when the opportunity presents itself. "Moisture tends to bring more moisture. That means spray windows this year are going to be smaller," says Jim Bessel, CCC senior agronomy specialist (click to email Jim).

Take a plant stand count

While scouting for disease and insects, take time to assess the stand. If the stand is spotty and thin, be more conservative with thresholds when protecting the crop from insects, diseases and weed competition. Also, recording the average number of plants per square foot will help growers improve seeding methods for 2011.

Stands of less than 4 or 5 plants per square foot (roughly 40 to 50 per square metre) generally cannot reach their full yield potential. Stands of 10 plants per square foot (100 per square metre) are ideal in that they give a cushion for plant death due to frost, diseases or insects. The photo shows a hoop equivalent to one quarter of a square metre. There are 23 plants inside the hoop, which works out to 92 plants per square metre. For a more accurate measurement, take several counts and average them.

A key part of stand assessment is to identify why the ideal plant population was not achieved. Was it directly related to the seeding operation? Or did insects, disease or environmental factors (frost, wind or flooding) reduce the stand after emergence? Clint Jurke, CCC agronomy specialist (click to email Clint), reminds growers that with heavy rains moving soil around, cover over the seed may be deeper than expected. Growers should lower their expectations for emergence as a result, he says.

Questions and contacts
If you have general questions about Canola Watch, direct them to Jay Whetter, whetterj@canolacouncil.org or 807-468-4006.

If you have questions on regional issues, contact one of the following Canola Council of Canada regional agronomists or provincial oilseed specialists:

• Derwyn Hammond, senior agronomy specialist, Manitoba, hammondd@canolacouncil.org, 204-729-9011
• Jim Bessel, senior agronomy specialist, Central Saskatchewan, besselj@canolacouncil.org, 306-373-6771
• Tiffany Martinka, agronomy specialist, Eastern Saskatchewan, martinkat@canolacouncil.org, 306-231-3663
• Clint Jurke, agronomy specialist, Western Saskatchewan, jurkec@canolacouncil.org, 306-821-2935
• Troy Prosofsky, agronomy specialist, Southern Alberta, prosofskyt@canolacouncil.org, 403-332-1412
• Doug Moisey, senior agronomy specialist, North East and East Central Alberta, moiseyd@canolacouncil.org, 780-645-9205
• John Mayko, senior agronomy specialist, West Central Alberta, maykoj@canolacouncil.org, 780-764-2593
• Erin Brock, agronomy specialist, Peace Region, brocke@canolacouncil.org,
  780-568-3326
• Murray Hartman, Alberta Agriculture and Rural Development, murray.hartman@gov.ab.ca, 403-782-8024
• Kerry Clark, B.C. Ministry of Agriculture and Lands, Kerry.Clark@gov.bc.ca, 250-784-2559
• Venkata Vakulabharanam, Saskatchewan Ministry of Agriculture, Venkata.Vakulabharanam@gov.sk.ca, (306)787-4668
• Ingrid Kristjanson, Manitoba Agriculture, Food and Rural Initiatives, ingrid.kristjanson@gov.mb.ca, 204-746-7504

This report is supported by each of the provincial canola grower associations. For more information on some of their activities, check out the following links:

• The Alberta Canola Producers Commission (ACPC) has a free e-newsletter called Alberta Canola Connections. Visit canola.ab.ca and click the sign-up icon on the right site of the homepage.
• In Manitoba, sign up for the Manitoba Canola Growers Association newsletter at Canola Growers E-update by visiting www.mcgacanola.org.

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