June 11, 2013

Agronomist Notes

Hello Reader

We’re full swing into wheat and canola herbicide spraying with the usual challenges of showers, wind, wind, showers followed by some hail and sunshine. I would rate most canola stands as above average with wheat and barley stands average to below. Cereal stands struggled to achieve optimal plant densities and will require some tillering to fill the gap. The 14-day forecast calls for tempratures hovering around 20C with lows in the single digits so we may fall behind the 5-year norm for crop staging shortly.

Spraying has been a challenge with many falling a little behind due to wet, windy conditions. On the flip side, the decent moisture conditions have inspired some producers to top dress nitrogen this year. Urea prices are still hovering around $600.00 MT with UAN around $450 MT.

In this issue of Beyond Agronomy News, we’ll take a closer look at the right time to apply top dress nitrogen. I’ll give you the details on what we learned on our farm tour last week. Last, I’ll provide you with an update on the vacuum planter canola trials. We’ll finish with technical grain market news.

Pictured above: Wheat on wheat stubble showing inter-row (left) and not so inter-row (right). Messy! Photo: S. Larocque

Crop Staging

(Calgary to Drumheller to Three Hills)

Seeded    May 1-7            May 8-15 May 15-22
Wheat      4-leaf, 2 tiller     3-leaf 1 tiller 2-leaf
Canola     5-leaf                 3-leaf 2-leaf
Barley      4-leaf, 2 tiller 3-leaf 1 tiller 2-leaf
Peas        8th node 6th node 4th node

Steve's tips & tricks of the week

Follow me on Twitter for in-season updates @BeyondAgronomy

Watch for cold (5C or less) overnight temperatures during spraying. Spraying in the evening followed by cold overnight temps 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 to your herbicide application, save the application timing to late-tillering if possible. The little reasearch that is out there suggests a response to fungicide at late tillering is possible. SL.

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. After combining 178 bu/ac HRS wheat with Craige Mackenzie in New Zealand and measuring 60 kernels per head, it was encouraging to know hard red spring wheat has that kind of yield potential. Let’s take another look at how we can manipulate wheat yield with split applications of nitrogen.

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 U of Guelph provided me with an excellent slide showing the growth stages of wheat where we can build yield. We’ll 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:

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

The stage I would like to 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.

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. I understand that’s a cost of $51.78/ac plus application for nitrogen in this scenario 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. In Western Canada, our challenge is to figure out how to get nitrogen inside the plant efficienctly during the tight 10 to 14 day window. SL

Reference: David Hooker, University of Guelph

2013 Beyond Agronomy Client Tour

Observations on disc drills, stripper headers, & top dress N applications

We held another successful client tour last Wednesday. Twenty-one of us jumped aboard a bus and toured what seemed like all of Southern Alberta inside of eight hours. It was worth it. Here are some of the tour highlights:

Stripper headers and disk drills go hand in hand. Don’t attempt stripper heading with hoe-drills. The residue will kill you.
There is only 30 to 40% of the stubble still standing after a pass with a disk drill on stripper stubble.
Lodged straw is a disk drill’s nemesis. One could say the same for a hoe-drill.
Stripper headers have been used to combine peas, canola, flax, lentils, fababeans, wheat and barley.
You can easily travel up to 7.5 mph on a 70 bu/ac wheat crop. Your limiting factor is sieve capacity. Some producers have moved to Case combines which have larger sieve areas compared to John Deere. (I won't comment on that one)
Stripper headers allow you to combine flax much earlier than conventional straight cut headers because it strips the bolls off and leaves the wire-like tough flax straw standing. Knives on conventional headers can’t cut through tough flax straw even if the grain is dry.
Shelbourne stripper headers are roughly half the cost of a draper header.
An excellent crop rotation to manage residue when using disk drills is peas-canola-spring wheat-winter wheat. The lack of residue with peas makes seeding canola shallow easier than in wheat stubble. Canola stubble dries out a little faster than cereal stubble allowing you to seed wheat early when straw can get damp. The temperatures in early fall when seeding winter wheat are warm which makes seeding winter wheat into spring wheat stubble easier. Seeding peas into two years of wheat residue is manageable because you’re seeding deep and placing seed below the residue.
One producer had a top response from streamer bar applied UAN of 30 bu/ac in winter wheat from 30 lb/N/ac. It was showering when he left the field. Right time, right rate, right amount of rain right after.
One producer had wheat yield 103% of check when UAN was split applied with no rain after application. The split app of nitrogen was equal to the total amount of nitrogen applied at seeding.
With streamer bars on the sprayer, you can travel 25 mph with a 120-foot boom while applying 10-15 gal/ac of UAN. That would certainly get the acres covered in a day!
Seeding with disk drills can be very finicky. The straw has to be dry enough for the disks to cut through the residue. Patience is a virtue and the crop always gets planted. SL

Canola vacuum planter trials

This year I have three clients trial the new Case IH 1240 vacuum planter to seed canola. Each client has a 50-acre trial comparing his own drill (Concord, Case 800 precision, New Holland P2060) to the Case planter. I measured the plant stand density, seeding depth and seedling mortality between the Concord drill on 12-inch spacing with 3.5-inch paired row opener with the Case 1240 planter. Here are the details and results of the side-by-side trial:

Variety: Liberty Link L130
Seeding date: May 16th
TKW: 5.8

Concord Results (12-inch spacing)

90-0-0-0 NH3 fall
0-30-0-20 blend with seed
Seeding rate: 5 lbs/acre (391,379 plants/ac)
Plant density achieved: 5 ft2 (217,800 plants/ac)
Seedling mortality: 45%
Seeding depth: 0.75” to 1.25”

Case 1240 Results (15-inch rows)

90-0-0-0 NH3 fall
0-30-0-20 pre-banded spring
Rolled prior to seeding
6-26-6-0 Alpine applied in furrow at 4 gal/ac
Seeding rate: 3.8 lbs/ac (300,000 plants/ac)
Plant density achieved: 6.4 ft/2 (278,784 plants/ac)
Seedling mortality: 7%
Seeding depth: 1 to 1.25 inches

The results clearly show how well canola plants establish when planted with a vacuum planter at a shocking 7% mortality compared with 45% on the Concord. This was achieved with a deeper seeding depth than the Concord. A little Steve’s quick math will tell you the planter improved the emergence by 38%! Mortality rates of 45% are quite common for air-hoe drills on canola.

The second thing I noticed was the uniformity in plant size in the planter trial. As you can see in the bottom photo, plants are evenly matched in root length and leaf size. This may have been from the starter 6-26-6-0 liquid phosphorus which provided even distribution along the entire furrow so each seed had access to starter phosphorus. The 3.5-inch paired row openers on the Concord scatter phosphorus inside the furrow, even at 30 lbs/ac actual, that’s 1 lb of phosphorus per 200 ft2 based on 12-inch row spacing. There is a trial close by with no liquid starter phosphorus that I’ll check to confirm my suspicions.

In the end, the Concord did a “good” job and we achieved the 5 plants ft2 we thought we would, factoring in our normal 45% mortality. The crop has excellent yield potential even though the canola plant stand density is variable. What caught my attention was the ability to achieve just 7% mortality with the Case planter. The planter trial increased canola emergence by 30% from 5 to 6.5 plants ft2 with 24% less seed. On this farm, that would work out to a $51,000 savings in seed cost. Not a bad return on a system we’re trying to figure out.

Note: Vacuum planters are not a plug and play system when matched with direct seeding. It takes some effort to fine tune vacuum planters to manage residue properly, apply nitrogen in a separate pass, fix disk plugging issues (now solved) and somehow find a way to singulate seed which isn’t happening yet. The ones who do try to make this system fit will reap the rewards in the future. SL