Agronomist Notes
Hello Reader
The weather continues to be turbulent with localized hail and rain storms rolling through the area. Would you believe we’ve had 4.5 inches of rain at the farm in the last 7 days? I guess we’ll be storing it for next year! Crops continue to mature quickly with pea harvest right around the corner, canola swathing in a few weeks time and the start of malt barley not far away.Some producers are looking at pre-buying fertilizer for year-end tax reasons. Fertilizer bids have been around $480 urea, $680 phosphorus MAP, $550 potash and $410 sulphur. With sagging commodity prices no one seems in a rush to price fertilizer this summer.
This week we’ll discuss the use of infrequent tillage to manage heavy residue fields. Next, we’ll look at some research that could provide us a way to grow alfalfa without losing a year of production to help it establish. We’ll look at options for desiccating field peas and last I’ll give you my annual formula for calculating yield potential. We’ll finish with technical grain market news.
Have a great week.
Pictured above: Our Sadash soft white wheat at milky dough stage this week, near Morrin, AB.
Crop Staging
(Calgary to Drumheller to Three Hills)Seeded May 1-7 May 8-15 May 15-22
Wheat medium dough soft dough milky dough
Canola late pod mid pod early pod
Barley hard dough medium dough soft dough
Peas complete late pod late pod
Steve's tips and tricks of the week
Follow me on Twitter for in-season updates @BeyondAgronomy
- Continue sweeping for lygus bugs in canola and be mindful of nymph stage and seed firmness. Lygus do not start damaging seeds until the 4th instar nor can they pierce firm seeds. Link to lygus
- Bertha aremyworms and diamondabck moths should appear shortly. Only a few hot spots out there but be sure to check.
- Time to stage peas for pre-harvest glyphosate and dessication.
- Look into pre-buying fertilizer during this downturn in the market.
Agronomy
Infrequent tillage to manage heavy residue
One of the biggest issues with poor residue management is the impact on germination, emergence, nutrient uptake and maturity. Heavy, uneven residue may not always cause yield loss but it certainly does delay maturity and skew nutrient cycling across the field. After years of big crops and heavy residue, everyone is talking about how to manage it. Inevitably, the conversation always comes back to tillage.There is very little research on the impacts of a one time tillage pass in no-till soils. The research that is available is from Nebraska where they receive 29 inches of annual rainfall and follow a corn, sorghum and soybean rotation. In this research, a one time pass with moldboard or chisel plow after 5 years of no-till did not impact yield, or soil aggregate stability significantly, but did impact soil biology by reducing VAM (mycorrhyzae). See research <here>
I do caution the over-use of tillage to manage residue as I’m starting to see with those using aggressive vertical tillage units or cultivations. Multiple tillage passes, even shallow, leads to a breakdown in soil aggregate stability. Once you lose aggregate stability, the zero-till system starts to fall apart. Here’s an example. The photo above shows the difference between a soil that is cultivated each year (right) and a soil that has been in zero-till for 8 years and CTF for 5 years (left).
Aggressive vertical tillage or cultivation breaks down soil aggregates into finer particles (see container on right). The fine soil particles move into suspension after rain events and begin to find their way into small pore spaces. Once the pore spaces fill up with soil, you’re left with an impermeable layer that no longer holds moisture, increases surface runoff and creates more standing water. All those low spots and sloughs we complain about seeding around get bigger in size and in number. This is not a road we want to travel back down.
A better example of this is from those who use disks in low lying areas to dry out soils and control weeds. Every time you destroy the soil structure with a disk you may dry it out temporarily, but you actually reduce the capacity of those areas to drain. Yearly tillage destroys the soil aggregates and when moisture returns, the pores begin to clog with fine particles. The low area drains slowly and requires more cultivation to dry out and the cycle continues.
I do believe that a one-time cultivation or vertical tillage every few years can be beneficial if you can maintain 50% or more residue cover. Maintaining residue cover or standing stubble is paramount to reducing evaporation and the risk of soil erosion. As the research showed, a one-time tillage event did not reverse the benefits gained by zero till. Therefore, a shallow cultivation every few years to manage residue when absolutely necessary is not a bad thing. Just remember, all things in moderation. Even if the smell of freshly worked soil makes you itch to till more. SL
Guess what other country is asking the same tillage question? Find out <here> .
Photo credit: Peter Gamache
Planting alfalfa without losing a years production
Intercropping alfalfa with winter wheat
In a perfect world I think most of us would like to include forages into our rotation. Specifically, forage legumes like alfalfa, which increases soil organic matter, relieves compaction from deep taproots and adds nitrogen to the soil. The added interest in alfalfa is also because it’s been fetching roughly $180/tonne with yields of 3-5 tonne/ac on dryland. The reason most of us don’t include alfalfa in the rotation is because you typically have to take a field out of production for a year to get the alfalfa established.Dr. Bob Blackshaw from Ag Canada in Lethbridge looked at underseeding alfalfa to winter wheat from a different angle. By seeding winter wheat and alfalfa at the same time in the fall, they wanted to see how much nitrogen they could add to the soil to improve the following crop. What they didn’t emphasize was the success they achieved at establishing an alfalfa crop without taking a field out of production for a year. Here are a few notes from the study that compared monoculture winter wheat as the check:
Materials and methods
- Winter wheat variety AC Radiant treated with Dividend was planted 1.5 inches deep on 9-inch rows in mid-September with a double disk zero-till drill.
- Alfalfa variety AC Longview was planted between the winter wheat rows rows at the same time with the double disk drill at a depth of .75 inches and a rate of 5.3 lbs/ac.
- Fall planted alfalfa exhibited good winter-hardiness, provided some weed suppression without reducing winter wheat yield.
- The alfalfa contributed an extra 16-18 lbs/ac of available soil N at the time of seeding the following spring crop.
- Alfalfa densities ranged from 5.4, 7.6 and 9.6 plants/ft2.
- Alfalfa tonnage weighed in July the following year prior to winter wheat harvest ranged from 150 kg/ac to 690 kg/ac and 1 T/ac.
- Fall-planted alfalfa increased the yield of succeeding canola crops.
- Fall inter-cropped alfalfa did not reduce winter wheat yields.
- The predominant weeds were flixweed, kochia and annual sowthistle but weed densities were low.
Last, the most common method to managing alfalfa is to silage the first cut and then cut and bale the second cut to sell it on the dairy market for $180 to $200 a tonne. You could net a tidy $400 to $500 an acre growing alfalfa, which rivals any crop we produce right now. Food for thought. SL
Read the full research report here.
Photo: Winter wheat was winter killed and alfalfa with no competition grew as tall as the winter wheat beside it. Source: OMAFRA
Update on field pea desiccants
With pea harvest rapidly approaching, I thought I would include the top three products to use for desiccating purposes. The product Heat has a new high rate with a recommendation for twice the surfactant, which will really help this product perform. Here are my notes on staging, application timing along with rates and costs per acre.Application timing
Upper pods
• Pods are fleshy green or starting to turn yellow
• Seeds may be immature but still split when squeezed.
Middle pods
• Pods are light green to yellow
• Seeds are full-size and soft, but not juicy
• Seeds will split when squeezed
Bottom pods
• Pods are dry and translucent
• Seeds are detached from pods
Products
Heat
Group 14
Active: saflufenacil
Rate: 29 g/ac Heat + 400 ml/ac Merge
Cost: $12.50
Heat + Glyphosate
Group 14, 9
Active: saflufenacil, glyphosate
Rate: 29 g/ac Heat + 200 ml/ac Merge + glyphosate
Cost: $12.50 ac + glyphosate
Note: Cannot be kept for seed when used with glyphosate.
Reglone Ion
Group 22
Active: diquat
Rate: 0.83 to 1.12 L/ac
Cost $23.00 Litre or $19.00 to $25.00 ac
The best product on the market is still Reglone but the new high rate of Heat with a 2X surfactant rate should be a very close second and $7.00 to $9.00 an acre cheaper. Heat does give you some flexibility where it can be applied throughout the day while Reglone should only be applied in the evenings. At any rate, it’s nice to see more options for desiccants on the market. SL
Calculating yield potential
At this time of year many producers have an idea of what they think crops will yield. The number they come up with may vary by 20% which makes calculating grain storage and off combine movement difficult. To assist you this fall I've included some quick calculations to help you estimate yield. In my experience, the actual number is somewhere in between your own estimate and the calculated amount. Good luck!Wheat: Heads/ft/row × #seeds/head ÷ row width (inches) × 0.48 = bu/ac
Example: 60 heads/ft/row × 26 seeds/head ÷ 12 × 0.48 = 62.4 bu/ac
Barley: Heads/ft/row × #seeds/head ÷ row width (inches) × 0.60 = bu/ac
Example: 72 heads/ft/row × 22 seeds/head ÷ 12 × 0.60 = 79.2 bu/ac
Canola: plants/ft2 × pods/avg/plant × seeds/avg/pod × 10.7 ÷ 86,000 × 44.1 = bu/ac
Example: 8 plants ft2 × 60 pods/plant × 20 seeds/pod × 10.7 ÷ 86,000 × 44.1 = 52.6 bu/ac
Peas: Pods/ft2 × peas/pod × 4840 × 9 ÷ 3600 × 0.036744 = bu/ac
Example: 40 heads/ft2 × 4 peas/pod × 4840 × 9 ÷ 3600 × 0.036744 = 77.1 bu/ac
Oats: heads/ft2 × kernels/head × 10.7 ÷ 129 = bu/ac
Example: 40 heads/ft2 × 35 seeds/head × 10.7 ÷ 129 = 116 bu/ac
Flax: plants/ft2 × bolls/avg/plant × seeds/boll × 10.7 × 0.000023 × 39.368 = bu/ac
Example: 35 plants/ft2 × 15 bolls/plant × 8 seeds/boll × 10.7 × 0.000023 × 39.368 = 40.6 bu/ac
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 term trend is up and the long term trend is down.
Canadian $: Sept 14: The short and long term trends are down.
