May 28, 2013

Agronomist Notes

Hello Reader

The heavens opened up last Friday and dumped two inches of rain, more than three in some areas, across my territory. Everything is in good shape now and any seed that was lying in the dust will count. Seeding is about 95% complete with the last of the barley and silage going in. Crops are progressing quickly and we’ll be spraying peas by the end of the week and early wheat and barley the beginning of next week.

In this issue we’ll look at the results of a two-pass inter-row seed and fertilizer system. Next, I’ll show you the technical way of leaf staging to help you time spray applications. I’ll discuss the issues that canola residue brings and finish with a review on three precision drills on the market. We’ll end with technical grain market news.

Have a great week.

Pictured above: Canola cotyledons pop up in the warm sunshine. S. Larocque

Crop Staging

(Calgary to Drumheller to Three Hills)

Seeded    May 1-7        May 8-15        May 15-22
Wheat      early 3-leaf     2-leaf            1-leaf
Canola     2-leaf              1-leaf            cotyledon
Barley      early 3-leaf     2-leaf            1-leaf
Peas        3rd node         2nd node      emerging

Steve's tips of the week

Follow me on Twitter for in-season updates @BeyondAgronomy

Now is the time to look for emergence patterns. Is residue management causing emergence delays? Is seeding depth highly variable? What is causing crop emergence variability?
Monitor volunteer canola in wheat and barley fields. It can get out of control fast with warm temperatures.
Start measuring plant stand densities inside each foot of row across your drill. Some drills have very uneven distribution systems and you may uncover an issue.
Avoid spraying when temperatures are about to drop below 5C at night and begin applying when daytime temps climb above 10C for optimal weed control and crop safety.
Missed a pre-burn herbicide? Apply Express SG + 0.35% v/v non-ionic surfactant to control volunteer canola, wild buckwheat, cleavers, dandelion, flixweed in 1-leaf or emerging cereals. It works very well but it’s not registered!

Two-pass inter-row seeding in high residue

Salford disk drill

Craig Shaw of Lacombe, AB farms high organic matter soils that are known for high yields and heavy residue. Each year, heavy residue skews seed depth, emergence, maturity and yield. Craig is now in his third year of controlled traffic farming and inter-row seeding and has found a way to manage residue and improve emergence using his Salford disk drill in a two-pass system.

Last fall Craig banded nitrogen between the rows using the Salford disk drill and RTK guidance. This spring he used the disk drill to seed in-between the rows where the fertilizer was placed and the residue was managed. You can see in the photo how dark the areas are between the rows. You’ll notice how black and exposed the soil is in between the rows in the photos. Normally, a thick mat of residue covers the soil, the source of many ugly issues come seeding time.

The benefit of the two pass inter-row system is the ability to keep tall standing stubble. As we know, tall stubble reduces wind speed at ground level, reduces moisture loss and keeps the heat that radiates from the soil at night from drifting away. This all leads to better emergence, maturity, yield and efficiency in the spring. The downside like all two-pass systems is the potential to dry out the soil by working it.

I like the way the disk drill creates enough disturbance between the rows to blacken the soil while maintaining tall stubble. Two-pass systems aren’t for everyone but they do serve a purpose. Craig has found an excellent way to incorporate the standing stubble of a one-pass system into the efficiencies and benefits of a two-pass. SL

See more on Salford disk drills here.

Pictured above: Craig Shaw tried a two-pass system with his Salford disk drill as a way to beat heavy residue and win on emergence and yield. Sure looks good to me. Photo source: Craig Shaw

Predict leaf staging & spray timing

What’s a phyllochron?

As we move into in-crop herbicide season it’s important to understand the time it takes to reach each leaf stage to time our herbicide programs properly. The easiest way to determine the length of time it takes to produce a leaf is to measure phyllochrons. A phyllochron is simply the length of time it takes for a leaf to emerge and is driven by temperature and measured in degree days (°C days). Degree days are simply calculated based on adding the daily high and daily low temperatures and dividing them by two. (i.e. 22 C + 8 C ÷ 2 = 15 GDD). Research out of North Dakota suggests the phyllochrons for spring wheat, durum wheat and spring barley are roughly 78 days. Although each cultivar has a slightly different phyllochron, 78 days will get you pretty close.

Let’s work through an example. Your spring wheat is at 3-leaf and you need to spray a herbicide before the wheat reaches 4-leaf, 2 tiller. Under the current weather pattern, how long will it take before you reach 4-leaf, 2 tiller? The current forecast suggests that the average temperature for the next 14 days will be a high of 22°C and with a minimum of 9°C.

Steve’s quick math
Max daily temp 22°C + Min daily temp 9°C ÷ 2 = 15.5 day °C
Phyllochron 78 days °C divided by 15.5°C day = 5 days per leaf emergence

Therefore, you would have 15 days under current temperatures before the crop would reach 4-leaf, 2 tiller. Instead of rushing through spray season in a panic to stay within crop staging limits, this calculation tool will let you know if you have room to breathe without the guesswork. SL

Phyllochron research

Canola residue kills seed placement

Every year I see the same issues with seed placement in canola stubble. Unevenly spread canola residue creates a thick mat across 40-50% of each field and skews seed depth. If you set the drill to seed 1-inch deep, the seeds end up 1-inch below the residue but placed on top of the soil surface. Hello, poor emergence.

The unfortunate part is that all residue management systems, even the MAV chopper, struggle to spread canola residue evenly out 30 feet or more. If you can picture throwing a feather as hard as you can, you’ll soon realize the issue. A feather with wind behind it will go a short distance and then flutter to the ground. No matter how much wind coming out of the chopper, it’s still too far to carry the canola residue the full width. It will always drop out of the sky, and by my estimates canola residue drops out 10 feet or so past the chopper on average.

In reality we’re just looking for choppers to move canola residue another 5 feet per side on a 30-foot cut. Trying to manage canola residue with a heavy harrow is a lost cause because the residue is too short to move with tynes. The answer has to be at the back at the combine. Perhaps the fins need to be extended out the sides of the combine to carry the velocity out a little further. Whatever the solution, equipment manufacturers need to be made aware of the problem. We have four months until harvest; perhaps we can motivate some people to find solutions quick so we can address this issue before then. SL

Pictured above: A classic example where no wheat is growing in the row because it’s laying on the dry soil surface under the heavy residue. Where the residue decreases the seed is placed at the proper depth and the plant stand is excellent.

Precision drill assessments

SeedMaster, Case 800, John Deere 1870

We are set to host our annual precision drill tour next week and I thought it would be good to refresh our memories on some current precision drills. It’s only when you see these dills in the field that you get a sense for how they perform. Viewed from the tradeshow floor they all seem perfectly designed. Let’s review my notes from last year on the three most common precision drills on the market. The SeedMaster, Case 800 and John Deere Conserva Pak.

SeedMaster: 60-ft, 300 bu on frame + 800 bushel TBH tank

This machine has the largest depth from front to back at 17 feet. This doesn’t make for the best depth control on hilly ground. Other drills are between 7 feet and 14 feet from front to back.
Height from ground to paralinkage was hard to measure because shanks were in up position but I estimate it at 14 inches. The aluminum residue deflectors are built to offset the short height from ground to hinge point, which normally catches residue and balls it up.
Seeding depth is set by packer wheel and so is SeedHawk. Conserva Pak sets seeding depth independently of packer wheel.
300 bu on-frame tank with tow behind 800 bu tank offers excellent seeding efficiency.
Load sensors on tanks are an excellent idea to help calibrate machine and calculate leftover fertilizer and seed.
The frame-mounted tank is a pain to unload because the auger can’t reach underneath.
Aluminum deflectors on shanks help direct residue to the side.
SeedMaster has a bolt-together frame as does SeedHawk. Conserva Pak has welded frames. Bolts and pins can stretch and wear.
Sectional control works well and is a real money saver in odd-ball fields.
Packer to seed opener is 4 inches, which reduces residue flowing back into the furrow before the packer wheel follows.

Case 800: 70-ft, 430 bu TBT tank and 3500 gal TBH NH3 tank

Depth of frame is 7 feet, 6 inches; the shortest frame on the precision market. This gives it decent ground following capabilities, especially in the hills.
The packer wheel is 11 inches from seed tube, which allows a little more residue to flow back into the furrow unlike the dual shank machines, which are typically just 4 inches.
Height from the ground to paralinkage is 20 inches, leaving plenty of room for residue to travel up the shank and fall off without balling up.
This drill has the tow between 430 bu tank with twin 1750 NH3 tanks which gives them roughly 100 acres per fill even with 100 to 110 lbs N/ac.
CNH now has the tow behind 580 bu tank to boost seeding efficiency but the Bourgault, SeedMaster and SeedHawk have much larger tank capacities.
The single shank design makes residue flow very acceptable compared to dual shank machines like SeedMaster, Seedhawk and Conserva Pak.
The Case opener was good when it first came out because it didn’t have hard surfacing on it. It started to wear on some soils so they decided to put hard surfacing on it last year. The hard surfacing collects soil that builds up and plows soil instead of letting it flow around the opener.
The Dutch 2-inch sideband opener worked very well on heavy clay soil. The Dutch 2.5-inch precision paired row opener did not fair well on this drill with several plugging issues at the opener.
Mud scrapers on this machine are insufficient in wet clay soils.

John Deere 1870 Conserva Pak: 56-ft, 430 bu tow behind tank

Handles residue better than the SeedHawk and much the same as a SeedMaster.
Depth of frame is 10.5 feet front to back, similar to the Bourgault.
Packer to seed opener is 4 inches. The short distance allows less residue to flow back into the furrow before packer wheel follows.
Height from paralinkage to ground is 20 inches, which allows residue to flow up and off shank.
Fertilizer shank depth can be set independently of seed shank. Other dual shank machines can only adjust fertilizer shank a couple of inches. This is important when clay soils get wet and you want less iron in the soil.
John Deere has a 550 bushel tank but is still behind in capacity compared to Bourgault, SeedMaster and Seedhawk.
Seed knife and fertilizer knife are very close together, almost one behind the other. This improves residue flow compared to SeedHawk and SeedMaster, which have seed and fertilizer knives a few inches apart and to the side.

What I learned most on our tour last year was that residue issues, seeding depth, packing pressure can all be managed poorly on a pricey precision drill and leave you with a seeding job no better than a regular hoe drill. Spending the time to really fine tune your seeding system is worth it. It’s the ability to make subtle but necessary changes that will improve germination and emergence from a precision hoe drill. SL

Picture: SeedMaster (top) Case 800 (middle) and Conserva Pak (bottom) shanks. Photos: S. Larocque