April 16, 2014

Agronomist Notes

Hello Reader

The only snow left to melt is on south facing slopes and along windbreaks like shelterbelts, buildings, and seeding equipment (we’re parked on a windswept hill, unlike last year). Producers in the west side of my territory will likely start up first provided no major snow storms occur. The ground is actually firming up and soil sampling has started. I’ll be out the end of this week to finish up the fall sampling I missed when Old Man Winter shut me down in mid-October.

There is word of a possible shortage in NH3 and urea this spring after a major malfunction at the Agrium nitrogen plant east of Calgary. They won’t be back up to full production until the end of May. The supply shortfall is unknown so it’s a waiting game.

In this week’s newsletter, we’ll look at mitigating the sprayer rut dilemma using another approach. Next, we’ll look at the options for controlling volunteer canola ahead of seeding canola and also how down force maps on vacuum planters with FieldView technology are shedding new light on soil structure. We’ll finish with technical grain market news.

Photo: The snow is melting and the water is running. Spring is really here! S. Larocque

Agronomy

Solving the sprayer rut dilemma – Revisited

Sprayer ruts are a serious issue in both random and controlled traffic systems. In random traffic systems they destroy soil structure and can leave subsurface compaction layers for decades. In a CTF system, the ditch-like tramlines increase the risk of erosion, which is also damaging.

Russell Zwar of South Australia responded to an article from Beyond Agronomy News and brought forward a very important issue with tire sizes and self-propelled sprayer axle widths. This is his comment:

“I am currently shopping for a self-propelled sprayer and have found that virtually all sprayers are 120-inch wheel track centers with narrow 380 mm tyres. As soon as you put wider tyres on, the minimum wheel track is about 126 inches with 520 mm tyres. Case Patriot, Miller Nitro, smaller Deere’s are all 120-inch minimum centres on 380 mm tyres only. Big Deere and Rogators can do 120-inch minimum centres with 480 mm tyres. (But the Deere 4940 weighs nearly 17 tonne empty so it’s not a great option). So, if I want to run a sprayer on 120-inch centres in CTF with 520 mm tyres I have zero options. Most Dealers don’t even realize this. I would go to 126 inches but my tractors won’t go wider.“

Example: Area covered
320 mm tire, 100-ft boom = don’t bother
380 mm tire, 100-ft boom = 2.5%
450 mm tire, 100-ft boom = 3.0%
380 mm tire, 120-ft boom = 2.1%
520 mm tire, 120-ft boom = 2.8%
620 mm tire, 120-ft boom = 3.4%

I asked my CTF gurus from Downunder to weigh in on this discussion and here's what they had to say:

Andrew Newall, NewAg Consulting, Horsham, VIC.-

“With machinery getting heavier and heavier especially JD 4940’s (German tanks) I see no other alternative but to go to wider tyres. 480 mm on JD 49 series booms is still way too narrow and causes serious rutting. There is a compromise with bigger sprayers and heavier booms and that is wider tyres.

“Clients have been running 520 mm tyres on Case Patriots on a CTF system that includes wide and narrow row crops and we are seeing no repercussions from doing this even though in the “pure’ sense we are not on a 120 inch wheel track.
What many forget to account for is that the wheel track from the header is usually a minimum of 800mm or 900 mm in Case IH headers (Combines) so 520 mm wide wheel tracks are still inside the combine track.

“I realize the other issue is running over more crop but this is just a engineering problem, for any guys who are 12 inch row spacing and concerned, we move the tynes around the spray tracks wider so that we don’t run over as much crop or alternatively nudge the boom so that we line up exactly 2 rows per tyre and run them over rather than running on 2 and half rows which usually happens.”

Tim Neale, Precision Agriculture, Toowoomba, QLD.-

“Keep tyre sizes as is and rotate wheel tracks throughout the season so they rut a bit less (which means you fix twice as many in the off season).
"Put a wheel track fixer on the planter/spreader (weird, I know, but some are trying this).
"Talk to manufacturers (yea right!).
"Go to 4m CTF system (with limited tractor options).”

Sprayer ruts are an issue for everyone because we’re typically spraying during our wettest time of year. If you look at the example above, moving to one set of wide tires (520-540 mm) doesn’t increase your footprint by more than a percent over narrow tires and you reduce the risk of rutting significantly. With 4 to 5 spray passes per year or more it really makes sense to reduce your impact and run wider tires. If you have any comments I’d love to hear them. Thanks to Russell, Andrew and Tim for the input. SL

Previous article on solving the sprayer rut dilemma here.

Controlling volunteer canola ahead of canola

Volunteer RoundUp Ready and LibertyLink canola is a growing concern across the Prairies. With fall wind storms and tighter canola rotations, volunteer canola pressure could be very high this spring. The question is, how do I kill volunteer canola prior to seeding canola? There are three options available to producers in 2014.

Option 1. CleanStart, $7.60/ac
Apply 15 ml/ac of carfentrazone (Gp 14) and ½ L/ac REL glyphosate (Gp 9). It can be applied pre-seed and post-seed just prior to emergence. IMPORTANT: It will not control cotyledon staged canola, only 1 to 3-leaf stage canola. The carfentrazone must come into contact with the growing point, which is next to impossible with a cotyledon stage canola. To improve performance a medium to fine droplet size is ideal with 10 gal/ac of water volume. Also, to improve performance, apply in temperatures above 8 degrees Celsius.

Option 2. Amitrol + ½ L/ac REL glyphosate, $11.00/ac
Apply 1.0 L/ac of Amitrol (Gp 11) with ½ L/ac REL of glyphosate (Gp 9). This product can only be applied as a pre-seed burn down and controls cotyledon to 4-leaf stage canola. Ideally, you would only wait a day to seed after application if targeting annual weeds. Amitrol works slowly, so don’t apply more than ½ L REL glyphosate per acre or it will reduce effectiveness of the Amitrol.

Option 3. Pardner/Brotex 400-500 ml/ac + ½ L/ac REL glyphosate, $10.00/ac
Apply 400-500 ml/ac of Pardner plus glyphosate as a pre-seed application to hit 1 to 3 leaf canola. The bromoxynil in Pardner is a contact herbicide so warmer temperatures will improve efficacy. Also, you need decent coverage so bumping water volumes to 10 gal/ac would be more effective than sticking to 5 gal/ac. SL

Photo: S. Larocque

Hydraulic down force maps shed new light on soil structure

The technology to measure, map and document spatial information is rapidly expanding. In the world of vacuum planters, there is technology by Precision Planting that measures seed spacing, the number of skips, doubles and the amount of down force an opener requires to maintain seeding depth on each row. This information is used to improve vacuum planter performance but has the potential to provide excellent soil quality information if adapted to small grain air hoe and disk drills.

The image you see here was taken recently of a field in Victoria, Australia during bean planting. The image is a hydraulic down force map produced with FieldView on a vacuum planter. The areas in purple and blue required less than 45 kgs of down force to keep the row unit in the ground at the proper depth, which means the soil bulk density was ideal for planting. The areas marked by red required over 180 kgs of down force to keep the row units in the ground, which means the soil bulk density was high, creating less than ideal conditions for planting, water infiltration and crop growth.

The reason this map is valuable is because it created a soil resistance profile that can be used to reclaim the high resistance areas. The big bonus is that is was done passively while the producer planted his beans. This map will be used to ground truth the high resistance areas to determine whether it needs an application of gypsum to loosen the soil chemically, or deep ripped to loosen mechanically or biologically through tillage radishes or deep rooted crops. The economics of reclaiming these areas can be determined by overlaying yield maps with ground force maps to determine the yield difference between the two areas.

Unfortunately, Western Canadian hoe and disk drills do not currently offer the kind of precision technology that vacuum planters do. We may not be able to measure seeds per row yet, but with the right sensors, we could begin to measure new variables like down force pressure to begin mapping our fields outside of the traditional EM38, NDVI or grid soil sampling. The technology is there; it’s now a matter of turning the new-found information into a solution. Fortunately for those with planters, they’re already a step ahead. Big thanks to Andrew Newall of NewAg Consulting for sharing this image with me.

Image source: Andrew Newall, Horsham, Victoria.

Beyond Agronomy Apps

Tank Mix & Rainfastness Guide

This tank mix app, built for Western Canadian farmers, answers the everyday questions about herbicide rainfastness and the proper order to tank mix herbicides.

Apple or Android

Seeding Rate Calculator

An app designed to help you calculate how much seed is needed to produce a desired plant population when calibrating your seeder.

Apple or Android

Air Cart Maximizer

The air cart maximizer quickly calculates the maximum number of acres per fill based the size of each compartment in your air cart and the desired fertilizer and seeding rates. The app indicates which compartments should be dedicated to seed or fertilizer and how much product to deliver out of each to achieve the greatest number of acres per fill every time.

Apple or Android