Agronomist Notes

Hello Reader

I’ve toured across all the wheat, barley, canola, peas and faba bean acres for the first round and covered the RoundUp Ready canola twice. Crop establishment is the best I’ve seen it since the mid 2000’s; nice, even germination with most fields hitting target plant densities. The only thing we’re battling now is cool, wet weather while trying to spray within the optimal window. 

I’m off to Farm Progress Show in Regina on Wednesday and Thursday this week with the Clean Seed Capital team! The CX-6 Smart Seeder debut is here! Email or text me if you'd like to get together for a chat.

This week we’ll take a look at this year's crop vintage according to growing degree days and rainfall. Next, I’ll update you on the importance of watching overnight temperatures during spray season. Next, it’s top dress nitrogen season so we’ll go through the process of planning your top dress nitrogen program. Last, we’ll review the visual symptom of the top six herbicide groups to help you with your post-hebicide checks. We’ll finish with technical grain market news.

Have a great week.

 

Pictured above: A sneak peak at the CX-6 Smart Seeder inside the showroom of Farm Progress Show in Regina, SK.

Crop Staging

(Calgary to Drumheller to Three Hills)
Seeded    May 1-7              May 8-15           May 16-22
Wheat      1st node             5-leaf 2 tiller       4-leaf 1 tiller
Canola     6-leaf                  4-leaf                 3-leaf
Barley      1st node             5-leaf 2 tiller       4-leaf 1 tiller
Peas        11th node           9th node            7th node

Steve's tips and tricks of the week

Follow me on Twitter for in-season updates @BeyondAgronomy

• It’s time to begin post-herbicide checks to make sure herbicides performed well. If not, you have an opportunity to correct the problem with a re-spray.
• Watch for cold (5C or less) overnight temperatures during spraying. Spraying in the evening followed by cold overnight temperatures can stress wheat and barley and reduce herbicide efficacy.
• Early seeded wheat is nearing the start of stem elongation so prepare to top dress nitrogen by the end of the week.
• Stripe rust is now in Washington State and Southern Idaho. With the potential for southerly winds we may see stripe rust show up early this year.
• Early leaf diseases are showing up in wheat and barley. If you plan on adding a fungicide with the herbicide, save the application timing to late tillering if possible. The leaves you’re protecting at 2-3 leaf stages die off at canopy closure and contribute little to yield.

Agronomy

Growing Degree Days: A look at this year's vintage

The late start and cooler weather this spring has given the impression that crop maturity is behind, but by how much?  Crop maturity is directly affected by the number of growing degree days we receive each year. Growing degree days is simply the calculation of the highest daily temperature plus the lowest daily temperature divided by two and subtracting five (Ex: 200C + 100C ÷ 2 - 5 = 10 GGD). Five is subtracted because it is assumed that plant growth does not occur at less than five degrees Celsius. We are currently at 406 GDDs; here is the historical log:

Growing Degree Days from May 1st to June 16th

2014: 323 (Rain 87 mm) 
2013: 406 (Rain 124.5 mm)  Record yields
2012: 365 (Rain 155.8 mm)
2011: 350 (Rain 75.1 mm)    Record yields
2010: 269 (Rain 108.6 mm)
2009: 316 (Rain 40.3 mm)
2008: 352 (Rain 139.5 mm)  Record yields
2007: 394 (Rain 125.4 mm)
2006: 449 (Rain 88 mm)
2005: 376 (Rain 59.2 mm)
2004: 320 (Rain 55 mm)

10-year average: 360 GDD’s (Rain 100 mm)

Growing degree days this season are 10% below the ten year average but with 13% more rain fall. We’re positioned similarly to 2011, which was a cool, wet year with record wheat and canola yields. The 14-day trend is calling for temperatures in the low 20’s with overnights in the low teens and single digits. We’ll need some serious heat in July-August to avoid fall frosts. Based on the weather data, I’m very optimistic on yield potential but slightly concerned about frost on the other end of the growing season. Time will tell! SL

Watch overnight temps to avoid crop injury

One of the little things we do to assist our clients during herbicide season is help them spray inside the optimal window whenever possible. We have to keep a close eye on overnight temperatures, daytime temperatures, humidity, wind and cloud. We do it for two reasons, 1) to get the most out of our herbicide efficacy, and 2) to avoid creating unnecessary stress on the crop.

The photo you see here is a Liberty Link canola field that was sprayed with Liberty (glufosinate-ammonium) and Assure II (quizalofop-p-ethyl). The right side was sprayed during a warm day but shut down at 5pm because the forecast was calling for chances of frost. The overnight got down to 1 degree Celsius. The left side was two days later without cold overnight temperatures. This field was an extreme case where warm temperatures allowed plenty of herbicide to enter the plant only to have cold temperatures shut the plant down early, leaving little time for the canola to metabolize the herbicide. You can easily see the significant difference in plant growth.

Although this is an extreme case, I want to point out how important it is to try and stay inside the optimal spray window when possible and always watch for cold overnight temperatures. I’ve seen the same damage in wheat and barley when warm days are followed by cool evenings. The last thing we want to do in our climate is to reduce maturity and, above all, yield. SL

Photo credit: S. Larocque

Top dress nitrogen timing

Hitting the nail on the head

The time for split applying nitrogen is just around the corner and I thought I would recap wheat development and the optimum timing for nitrogen application. To build yield in wheat it’s very important to understand the growth stages where yield is derived, then work towards a strategy that supplies plant available nitrogen at the right rate, right place, right form at the right time.

Dr. Dave Hooker from University of Guelph provided me with an excellent slide showing the growth stages of wheat where we can build yield. Let’s look at the optimal window to apply nitrogen and look at nitrogen rates to produce high yielding wheat. The best way to view the wheat yield chart is here on our website.

The wheat development timeline chart outlines four key growth stages where yield is built:

1. Tillering GS 20-30: number of heads
2. Stem elongation GS 30-40: number of spikelets per head
3. Flowering GS 60: kernels per head
4. Grain fill GS 60-90: kernel weight

The stage I’ll focus on today is stem elongation, which starts at the end of tillering (GS 30) and ends at the boot stage (GS 40). It is this stage where nitrogen demand is highest and wheat yield can be influenced the most. Stem elongation is a critical growth stage because of the tremendous amount of cell reproduction that occurs. The wheat plant is building new cells as stems grow taller and thicker, leaves grow longer and wider and new spikelets are being produced on each head, which means up to six sets of male and female parts per row. All this requires a tremendous amount of nitrogen, water and carbon dioxide. A deficiency in any one of these at this time equals a loss in yield. We’ll focus on what we can control for now, and that’s nitrogen.

For a video on how to determine GS 30 go here.

On average, spring wheat will move through tillering (GS 20-30) in our area within about 25 days depending on temperatures. Wheat will move from stem elongation to boot stage (GS 30-40) within about 10 to 14 days depending on temperatures. The reason wheat moves so quickly from stem elongation to boot stage is because it occurs just after the summer solstice, when warm temperatures combine with the longest daylight hours. At 52 degrees latitude, we have 18 hours of daylight each day during this critical growth period. That means cell division is happening at a greater pace than other countries and latitudes experience during this growth stage.

To be successful with split applications you have to apply a nitrogen form that is available or becomes immediately available to get it into the plant quickly. The window is only 10 to 14 days long to apply nitrogen, have it move into the soil, convert to plant available nitrate or ammonium and taken up by plant roots. This is why most producers chose liquid UAN, which is 25% nitrate and 25% ammonium and immediately available to plants. The remaining 50% of UAN is urea and takes a few days for bacteria and enzymes to make it plant available. If you apply granular urea, then you’re waiting on 100% of your nitrogen to convert to a plant available form after its been washed into the soil. Not a great strategy for optimal timing inside a very short window.

Now, to determine how much nitrogen to apply as a top dress, I think we’ll run through a little Steve’s quick math. Let’s bump up a 75 bu/ac spring wheat yield target to 100 bu/ac now that conditions are favourable and the crop is off to a good start.

Steve’s quick math
Yield target: 100 bu/ac HRS
100 bu x 2.2 lbs/N/bu targeting 12% protein for optimal yield = 220 N/ac
Soil N + spring applied N + OM mineralization on 4% OM: 35 N/ac + 100 N/ac + 28 N/ac = 163 N/ac
Total N required for 100 bu/ac: 220 N – 163 N/ac applied = 57 N/ac
Stem elongation N app: 57 N/ac x 80% efficiency = 71 lbs/N/ac

In this scenario we would need 57 lbs/N/ac to achieve a 25 bu/ac yield response. Nitrogen use efficiency of top dressed nitrogen may only be 80% when losses are factored in. This means you should actually apply 71 lbs/N/ac to just prior to stem elongation to get the required 57 lbs/N/ac into the plant. In this scenario that’s a cost of $51.78/ac plus application for nitrogen so use whatever budget you’re comfortable with. A 10 bu/ac yield response would cost roughly $20.00/ac in nitrogen, a 5 bu/ac yield response would be $10.00/ac and so on.

Top producers from around the world are able to manipulate wheat yield by applying significant amounts of nitrogen just prior to stem elongation (GS 30). The 178 bu/ac HRS wheat crop I walked through back in March had 60 kernels per head versus the 30 per head we normally achieve here. The agronomy program included a significant amount of nitrogen applied at stem elongation.

The bottom line: split applications of nitrogen work well. In Western Canada, our challenge is to figure out how to get nitrogen inside the plant efficiently during the tight 10 to 14 day window. SL

Reference: David Hooker, University of Guelph

It's Time to Check Post- Herbicide Efficacies

The most important role of a farmer or crop advisor during spray season is not only to apply the correct herbicides at the right time but to follow up with post herbicide checks. Follow up efficacy checks should be done 10 to 14 days after application. More wild oat or weed escapes can be corrected if only producers and crop advisors checked how well the herbicides worked after application. Calling the chemical representatives at harvest to tell them the herbicide didn't work is futile and besides, herbicide inquiry cut off dates are usually around the 15th of July.

Below is a list of herbicide injury symptoms for the top six herbicide groups I use to help identify herbicide injury and efficacy. If you want to skip that step and head straight for the photos of visual symptoms click here. 


Group 1: ACCase: Axial, Achieve Liquid, Horizon, Puma Advance, Centurion
Symptoms: The first sign of injury on wild oats or green foxtail may appear as intervenal chlorosis or yellow striping on newer leaves. Older leaves may show red or purple. The growing point turns brown and dies. The newest leaf can be easily pulled from the crown where you will see a "pinching" at the base of the leaf. New growth dies first, such that the plant appears to take considerable time to die after application.

Group 2: ALS: Simplicity, Everest, Frontline XL, Refine SG, Odyssey, Varro
Symptoms: In broadleaf weeds the first visible symptom is the termination of plant growth. A few days after application you may see yellowing, reddening and purpling of the leaves. In grassy weeds like wild oats, you may see a yellow striping and purplish discoloration of the leaves. The youngest leaves die first followed by older leaves. Death of grassy weeds may take 1 to 3 weeks to occur.

Group 4: Auxinic: 2,4-D, MCPA, Attain, Buctril M, Curtail M, Frontline XL, Target
Symptoms: Bending and twisting of stems and petioles, stem swelling, especially at the nodes, elongation, leaf cupping and leaf curling. These signs are followed by yellowing at the growing point, growth inhibition and wilting.

Group 6: Photosynthetic Inhibitors: Buctril M, Infinity, Benchmark, Thumper
Symptoms: Rapid yellowing and whitening begins at the leaf edges. Later symptoms include desiccation and a burned-off appearance of the leaves. Symptoms develop rapidly under full sunlight conditions.

Group 9: EPSPS: Glyphosate: Roundup WeatherMax, Touchdown Total, Vantage PlusMax
Symptoms: Gradual wilting and yellowing at the growing point of the plant that advances into browning of above ground growth. Annuals may show signs within 2-4 days and perennials within 7-10 days.

Group 10: Glutamine Synthetase Inhibitor: Liberty 150
Symptoms: Yellowing and wilting usually occur within one to three days after application, followed by necrosis or bleaching-death of plant tissue. Symptoms develop more rapidly under bright sunlight, high humidity and moist soil.

Group 27: HPPD Inhibitors: Infinity, Tundra, Velocity
Symptoms: Small burnt spots on the broadleaf weeds can appear within hours. The pigment and photosynthesis of the plant shuts down resulting in bleaching symptoms with 6 to 14 days.

Reference: How Herbicides Work, Alberta Ag publication

Market News

The charts I use take a short and long term look at whether the market is oversold, neutral or overbought. I use charts as a way to pull the trigger, not to determine the best price. 


Canola Nov 14: The long and short term trends are down.

 

HRS Wheat: Dec 14: The short and long term trends are down. 

 

Corn Dec 13: The short and long term trends are down.

 

Soybeans: Nov 14: The short and the long term trends are down.

 

Canadian $: Sept 14: The short term trend is up and the long term trend is down.