July 10, 2012

Agronomists Notes

Hello Reader,

The last week brought heat, hail storms, tornados and heavy showers to many parts of my territory. Some farms were hit twice with major storms. Crops are progressing rapidly and the rush is on to keep up with fungicide spraying.

Stripe rust was just discovered in our area on Sunday so I hope you have your fungicide plans finalized because wheat is just starting to head out, leaving it very susceptible to yield loss. Canola insect counts have been minimal with sweep nets turning up very little in the way of lygus bugs or cabbage seedpod weevils. Diamondback moth larvae counts have been low as well thankfully. Next up is wheat midge scouting prior to flowering as the heat wave will increase emergence rates.

This week we’ll look at the results of a water infiltration test inside our CTF system. Next, we’ll look at some great VR work with potassium to show that canola responds even in high potassium soils. Last, I’ll give you the low down on stripe rust and wheat midge as we come into the high risk time of year for both. We’ll finish with technical grain market news.

Have a great week.

Pictured above: Rainbow in behind the hail storm that hit 80,000 acres last week.

Crop Staging

(Calgary to Drumheller to Three Hills)

Seeded    Apr 24-30               May 1-7                  May 8-15
Wheat      flowering                heads emerged        boot stage
Canola     60% bloom             30% bloom              10% bloom
Barley      heads emerged      heads emerging      heads emerging
Peas        50% bloom             20% bloom              10% bloom

Steve's tips and tricks for the week

Follow me on Twitter for in-season updates @BeyondAgronomy

Look for patchy head emergence to pin point air drill issues or residue issues.
The conditions for disease (host-pathogen-environment) have all lined up and disease risk is high.
Stripe rust has arrived in our area, funghave been more frequent in our area. Fungicide in wheat is a must.
Start sweeping early flowering canola for cabbage seedpod weevils.
Start scouting in the late evenings for wheat midge in wheat that has not flowered yet.

CTF tour Wednesday, July 11th at 1pm

Join CTF Alberta to look at the first year of a precision planter project at Durango Farms (Craig Shaw) and the second year of controlled traffic farming near Lacombe, Alberta.

3.7 miles east on Hwy 12 from the intersection of 2A and Hwy 12 in Lacombe to just east of RR 262, south to elevators Google map

1:00 PM – 1:30 Sign in

1:30 – 1:45 Introductions and CTFA project (Peter)

1:45 – 2:45 Precision planter concepts

2:45 – 4:00 CropCam UAV Demo by JZAerial (remote control plane for crop scouting)

Cropwalk and commentary led by Craig, Jay Bruggencate and Peter Gamache

4:00 – 4:30 Wrap-up discussion

Demonstration (weather permitting) of a UAV
Precision planter project
Plant spacing
Row widths
Controlled Traffic Farming
Soil pit
Project update

Three Soil & Water CEUs pending.

CTF improves speed and volume of water infiltration

CTF improves speed and volume of water infiltration
We hosted a field day at the farm last week with CTF Alberta to look at the ins and outs of our third year in controlled traffic farming. As I’ve mentioned before, CTF is known to improve water infiltration and water use efficiency by storing moisture at deeper depths and allowing plants to access that deep moisture later in the growing season. We wanted to test the theory with a white latex paint experiment which required four aluminum rings pushed 2 inches into the soil. Diluted white latex paint was poured inside each one.

One ring was placed on the tram line, one on the wing, one under the castor wheel tracks and one in between the castors and the tram lines. Latex paint was poured into the cylinders, 2.5 inches of moisture equivalent, and allowed to sit overnight. The next morning, a small 2x3 ft soil pit was dug up in front of the rings. The photos you see here shows the results.

Observations

Soil is a cracking clay vertisol which swells and contracts.
Stored soil moisture was sitting at 75% field capacity down to three feet.
Each ring except the tram line infiltrated in less than an hour.
The tram line ring never did infiltrate. This tram line had two passes with the sprayer and one pass with the air drill in 2012.
White paint made it all the way down the 3-foot depth in less than 24 hours except for the tram which didn’t move.
The water/paint seemed to follow root channels to depth with some lateral movement.

It was amazing to see how deep and how fast the moisture moved downward in this field after three years in CTF. The tram line which has had three equipment passes in 2012 stopped downward movement of moisture completely. It makes you wonder what the effects of pre-burn, seeding and in crop herbicide applications have on water infiltration. Those three passes alone can create compaction layers across 25% of your land base, which means 25% of the water you could store is evaporating or running off each year.

The experiment provided a great visual to actually see where moisture was travelling after a simulated rainfall event. I remember seeing the ground swell between the rows after a four inch rainfall. There was no tram line erosion or water ponding; it all disappeared. This was not the case for neighbouring fields where water sat for days or ran off.

In my opinion, our competitive advantage with CTF will be our ability to store more moisture and generate higher yields from greater moisture use efficiency, especially in the dry years. Our ability to store and retrieve moisture at depth will allow us to weather droughts better and reduce the financial impact of the poor years. The improvement in water infiltration rates will help us out in the excessively wet years as well. This water/paint experiment has given me even more courage to know we’re on the right tracks. SL

Canola shows response to potassium in high potassium soils

The addition of potassium fertilizer has long been debated in our area due to the high background levels of potassium. Research from Alberta Agriculture has shown that a response to potassium fertilizer is unlikely when soil test levels reach 125 ppm or 250 lbs/ac. However, based on the results of variable rate potassium in canola, perhaps we need to revisit this assumption.

Garth Donald from DynaAgra VRT shared the zone soil test info along with some great photos of canola showing a response to potassium fertilizer on a high potassium soil. The photo shown here shows the canola in bloom a week earlier on the left where potassium was applied in this Zone 2 versus the right side where no potassium was added.

The potassium was applied at a rate of 45 lbs/ac actual to Zone 2 where potassium levels show 286 ppm or 572 lbs/ac in the top six inches. The Base Saturation levels which some folks call BS, is below 4% and under the ideal level of 4-6%. Interestingly enough, this Liberty Link canola, L-150 responded to potassium fertilizer on a soil that contained twice the level where research suggests we should see a response.

Potassium’s role in canola production is to help transport nitrogen up through the xylem and throughout the plant. It plays a key role in over 60 enzyme interactions which drive photosynthesis, improve nutrient uptake, increase plant vigour and even maturity. For these reasons I suspect we are seeing a response from the potassium as it drives root growth, vigour and crop maturity. For more on potassium’s role in plants click here

It’s not often we get to see a side by side like this one and even if it doesn’t translate to yield, which it probably will, gaining a week’s maturity inside our 100-110 day growing season is golden. Those of you on high potassium soils may want to initiate your own research and test the theories that have always been held as gospel. SL

Stripe rust identification and control

The presence of stripe rust has increased over the last week in my territory. This is significant because wheat crops have just started into head emergence which leaves a great deal of time for stripe rust to infect leaves and reduce yield. If you haven’t applied fungicide already, do not hesitate at this point.

Identification and yield loss
Stripe rust can be identified as small orange-yellow coloured pustules forming in vertical lines along wheat leaves. This disease can result in yield losses of 10 to 70% in susceptible varieties and total yield loss has been reported when severe epidemics occur. Like other leaf and stem diseases, yield losses are roughly proportional to the plant area infected. Yield losses are generally most severe when the infection occurs prior to heading. Historically stripe rust has not been of economic significance in western Canada but incidences of the disease have been increasing over the past 4 or 5 growing seasons.

Conditions for development
The major source of rust spores in Alberta is carried by south winds from the Pacific North West. Wind direction and a specific range of temperatures are essential for the onset and development of stripe rust. For example, relative low temperatures and moisture favour development. Urediniospores germinate optimally between 5 and 15oC with limits near 0 and 20oC. Disease development is most rapid between 10 and 15oC with intermittent rain.

Monitoring
If you are growing a susceptible variety, it is important to scout every few days starting with the bottom leaves. Know the visual symptoms of stripe rust and monitor fields in the morning when new spores are distinctly yellow.

Threshold
Spraying should be done when stripe rust reaches 1% of flag leaf area and before it reaches 5% of flag leaf area. Once this infection level is reached, stripe rust becomes very difficult to control. The period of infection to the release of spores is as little as 8 days, which can result in multiple generations per growing season.

Growth stage
Apply fungicide at flag leaf or prior to watery ripe stage. Fungicide treatments made past the watery ripe stage rarely provide an economical benefit.

Fungicide Options

Caramba: 283 ml/ac, $13.50/ac

Folicur 432: 118 ml/ac + 0.125% v/v Agral 90, $10.50/ac

Folicur EW: 200 ml/ac, $10.85/ac

Headline: 160 ml/ac, $11.50/ac

Prosaro: 320 ml/ac, $15.50/ac

Quilt: 400 ml/ac, $11.80/ac

Twinline: 200 ml/ac $9.00/ac

The most effective fungicides on the market for control of stripe rust are Folicur EW, Prosaro, Quilt, Headline and Twinline.

Stripe Rust Tolerance Ratings
(Scroll down to page 5 for hard red spring varieties and look for the stripe rust column for ratings.)

Photo: Daryl Chubb

Wheat Midge Identification, Damage & Control

With wheat beginning to head out, now is the time to prepare for Wheat Midge scouting. We’re nearing the threshold growing degree day number where they begin to emerge. These small bugs are about half the size of a mosquito and bright orange. They lay eggs in the wheat head and the larvae will then feed on the wheat kernels.

Damage Potential
One midge per 4-5 wheat heads can decrease yield around 15%. They can also reduce the grade of your wheat. If there is more than one midge per 8-10 wheat heads there is a risk of a reduced grade. The Canadian Grain Commission limits midge damage in No. 1 CWRS wheat to 2% and 8% in No.2. In durum the tolerances are similar.

Scouting
Adults appear in late June and early July. Wheat fields should be scouted regularly between heading and flowering. Scout in the evenings, from about 8-10 pm, when the temperature is around 15 degrees Celsius and there is no or very light winds. Also, scout four or five places in the field for a more accurate count.

Threshold
One adult midge per four or five wheat heads is usually enough to warrant control measures.

Control
Cygon™, Lagon™, Lorsban 4E™, Nufos™ and Pyrinex™ are all registered for use on wheat midge in wheat. Check the label for any other restrictions regarding the chemicals. For example Cygon™ and Lagon™ do not control the eggs, just the adults. Also, application in the evenings are most effective. Check the label for application timing.

Cost: Lorsban: $8.40 acre + $7.50 ac/aerial application = $15.90/acre

Considerations for Control
Late evening or early morning are the best times to control the adults, as the females are most active in cool night time temperatures (but above 15 degrees Celsius or 59 degrees Fahrenheit) and when the wind is less than 10 km/hr (6 mph). Also, good coverage is critical for control if your chemical controls eggs as well; make sure the water volume is adequate. Optimal control happens when 70% of the crop is in the heading to flower stage. If 30-60% of the crop is flowering then it needs to be sprayed immediately to have good control on the wheat midge. If 80% of the crop is flowering then control is not recommended as the window has passed and the midge damage has already started. Spraying therefore should be done early to protect the main stem and first tiller, as this is where most of the yield potential of the crop is.

Wheat Midge Forecast Maps
Midge emergence can be modeled using accumulated temperature calculations called Growing Degree Day (GDD). Data provided by Agriculture & AgriFood Canada (AAFC), Saskatoon suggest using a base temperature of 5°C for predicting midge emergence patterns using accumulated GDDs. Thresholds for combined emergence of male and female midge are:
10% emergence     693 (±39) GDD
50% emergence     784 (±38) GDD
90% emergence     874 (±41) GDD

As of July 10th in the Calgary corridor we are at 607 GDD.
Wheat Midge Information
Alberta Midge Forecast map
Prairie Midge Emergence maps

Photo source: Saskatchewan Agriculture