StarFire 3000 globes currently sell for $one arm and a leg, while 6000s sell for $one arm and two legs. If you’re shopping between the two and don’t need SF3, one of the most important improvements of the 6000 is the faster pull-in time. We have one of each on our farm and the repetitive days of fall tillage allowed me to do some real-world comparisons between each.
Data Collection
I collected this data across 6 days in early November (3 days with each globe) in mostly clear skies and flat open fields. Each morning I would keep an eye on the GPS accuracy graph in the StarFire > Diagnostics > Data Logs page, then take a screenshot once it reached 100%.
In each case, the tractor had been operated the day before and was put in a shed overnight. Both are using SF1 and running on a 2600 display.
Data Extraction
These screens are 640 x 480 pixels, and as it turns out the x-axis of this data log graph is 300 pixels wide. I ran these through a batch process in Photoshop to add y-axis labels at the 10% marks and to adjust the pixel density to 1 pixel per inch. Then I set the zero point of the ruler to the time the receiver turned on. Once this is done, I can drag a guide to a step on the graph and the tooltip will tell me how many inches (pixels) that is from the start point. Record these values in a spreadsheet, divide my 5 (pixels per minute), and you have data that should be accurate to about a minute after adjusting for the thickness of the line.
This is the part where someone will probably ruin my Photoshop fun and tell me there’s a way to export this data to a CSV in some kind of diagnostics function.
Throughout all of the frequent rains we experienced this summer, my catchphrase was “what a time to be a fungus”. If there was ever a year we should see a fungicide response it should be this one and it penciled out favorably in most of our cases.
Corn Fungicide
We sprayed all our corn acres with Trivapro plus 1 pint / acre of Brandt’s B-Mo micronutrient product. Most of our acreage was applied via airplane through Brandt while several of our larger fields were custom hired with a ground sprayer.
Brandt Aerial Spray
Cost
$ / gallon
oz / acre
$ / acre
Trivapro
$ 197.72
13.7
$ 21.16
B-Mo
$ 35.86
16
$ 4.48
Masterlock
$ 64.32
5
$ 2.52
Plane Application
$ 9.00
Total
$ 37.16
Response
If you’ve read my article on the corn plot, you may recall that we weren’t able to see a measurable response from the check strip across the plot and the applicator didn’t leave check strips in any other fields that we’re aware of. Not requesting more check strips in other fields was a regretful oversight on our part but we’re at least comforted by having a record corn crop that came from some combination of unisolated causes.
Custom Hire Hagie
Cost
$ / gallon
oz / acre
$ / acre
Trivapro
$ 139
13.7
$ 14.87
B-Mo
$ 35.86
16
$ 4.48
Hagie Application
$ 7.50
Total
$ 26.85
Response
The same summer rains that increased the need for a fungicide also made the ground muddy and hard to drive a sprayer across, so our ground application near brown silk was less timely than it could have been. We were still able to measure a 9.2 bu/acre average response.
Planting Date
Spray Date
Variety
Method
Response
April 2
July 15
Nutech 74B6AM
Ground
+ 9.0
April 6
July 15
Wyffels 7956
Ground
+ 8.4
April 7
July 19
Wyffels 7888
Ground
+ 5.8
April 7
July 19
Wyffels 7696
Ground
+ 13.4
Average
+ 9.2
Profitability
✅ This response is profitable at a corn price higher than $2.92
Soybean Fungicide
This was actually our first year spraying a bean fungicide which we did entirely ourselves with a pull-type sprayer. None of our beans were super tall this year and we followed our herbicide tracks so the plant damage appeared to be minimal.
For chemicals, we applied Cover XL (generic Quilt) and Lambda (generic Warrior) plus added some Brandt micronutrients in half of the loads. This was applied at what we considered R3, although the period at which you can find some 1/4″ pods while more are being added seems wide and ambiguous.
Reduced Data Set
While we sprayed every field with a fungicide and tracked everything in our monitor, not all the data was usable or fair. In several cases, the check strip would be too close to the edge of the field (or even along the edge) which would include some of the headland in the comparison. We angle cut our beans, and even though overlap control is enabled and somewhat helpful, we do still get this sawtooth pattern of low yields.
Most of the data I allowed for use was in the middle of the field and included a check strip which could be measured from both sides to account for a potential gradient change across the field.
Fungicide/Insecticide Only
Cost
$ / gallon
oz / acre
$ / acre
Cover XL
$ 59
19.2
$ 8.85
Lambda
$ 35
3.84
$ 1.05
Surfactant
$ 8
4.8
$ 0.30
Sprayer Pass
$ 6.50
Total
$ 16.70
Response
Planting Date
Variety
Response(vs unsprayed check)
April 16
Nutech 39N05E Nutech 35N03E
+ 3.8
April 19
Pioneer P34T21SE Pioneer P38T76E
+ 5.2
April 19
Pioneer P34T21SE Pioneer P38T76E
+ 2.8
Average
+ 3.9
Profitability
✅ This response is profitable at a soybean price higher than $4.28
Fungicide/Insecticide/Micronutrients
Cost
$ / gallon
oz / acre
$ / acre
Cover XL
$ 59
19.2
$ 8.85
Lambda
$ 35
3.84
$ 1.05
Brandt B-Mo
$ 35.86
16
$ 4.48
Brandt Smart Trio
$ 18
~20
$ 2.81
Surfactant
$ 8
4.8
$ 0.30
Sprayer Pass
$ 6.50
Total
$ 23.99
Note: the Smart Trio called for 16oz / acre, but we went slightly over to make jugs come out evenly on sprayer loads
Response
Planting Date
Variety
Response(vs unsprayed check)
April 26
Pioneer P38T76E
+ 3.4
April 27
Pioneer P38T05E
+ 3.8
May 7
Pioneer P38T05E
+ 4.9
May 13
Pioneer P38T05E Stine 39EA02
+ 3.0
May 13
Stine 36EA02
+ 3.1
Average
+ 3.6
Profitability
✅ This response is profitable at a soybean price higher than $6.66
To Micronutrient or Not?
The responses in each of the previous examples were compared to an unsprayed strip. In several fields we had micronutrient and non-micronutrient strips next to each other to calculate a fair response, but due to unreliable data near field edges or poor areas only one of these comparisons was reliably usable.
Planting Date
Variety
Micronutrient Response
April 16
Pioneer P39N05E
+ 0.3
The additional cost of the micronutrients is $7.29 / acre, so a 0.3 bu / acre response would only be profitable above $24.30 soybeans. I won’t dismiss the product on one data point though as I know adding micronutrients to a fungicide pass is popular for many growers, so I’d be curious to try this again next year with more intentionality about where the adjacent strips are placed and hopefully have better data.
This plot location is well drained and pretty consistent in soil type (mostly Herrick, some Virden on the west end of the rows). We planted the plot rows perpendicularly to the direction we apply fertilizer and spray to make any streaking consistent across varieties. Each variety is 16 rows x 500 feet, with 16 rows of a check variety in between each tested variety. We weighed each strip using a 20 lb precision grain cart and took 3 moisture samples per strip using a Dickey-john M3G.
Shrink Formula
I shrank the dry yield to 15% using a shrink factor of 1.176 as per this article from Pioneer. Our Wyffels representative used the following common yield equation formula:
(100-Moisture)*(109.815)*(Weight of wet bushels)/(rows)*(length)*(row spacing)
His dry yield figures came out effectively the same as what I already computed with the 1.176 factor.
Yield Adjustment Formula
While the field doesn’t experience any wild productivity deviations, the inclusion of check strips allows for indexing each variety against the check strip and making more accurate absolute comparisons across the plot. My formula for this first calculates the performance of the variety as a percentage of the average of the adjacent check strips. Then, it multiplies that percentage by the average of the check variety across the entire plot (P1185AM in this case, which averaged 261). Assuming your check variety can act as a measure of general corn suitability, this should give you an actual yield figure close to what that variety would have done if planted solidly across the plot.
This flattens the variance in the field productivity, lowering the high spots and raising the low spots. This animation visualizes this well:
Adjusted Dry Yield Results
Variety
Moisture
Adjusted Dry Yield
Wyffels W7696
19.4%
268
Wyffels W7956
19.8%
268
Stine 9808E-20
20.4%
267
NuTech 74B6AM
18.4%
266
Wyffels W7876
18.6%
265
Wyffels W7888
19.3%
262
Pioneer P1185AM (check)
18.0%
261
Pioneer P1108Q
18.4%
258
Wyffels W7456
19.7%
257
Wyffels W7878
19.0%
255
Stine 9734-G
19.0%
252
Stine 9746-20
18.3%
246
Stine R9734-32
20.2%
244
I have not attempted to calculate a proper least significant difference for this data, but a quick and dirty technique I’ve heard is to calculate the standard deviation and use that as a stand in for the LSD. The standard deviation is 8.0 for both the adjusted dry yields in this table as well as the unadjusted dry yields of all harvested strips.
Trait Response
Two pairs of the varieties in this plot were the same underlying hybrid in different trait packages. We have not seen corn rootworm pressure in our area and wanted to test what response we’re seeing from the additional trait insertions.
Roundup
Double Stack
Triple Stack
Stine Hybrid
9734-G
R9734-32
Wyffels Hybrid
W7876
W7878
Given the absence of pest pressure, we saw a 5-10 bushel drag for each additional trait.
Seed Profitability Analysis
I’ve often seen people use a breakeven seed cost calculation that compares two varieties, usually starting from the perspective of cheaper variety A and asking (at a given market price) how many bushels it would take to pay for variety B. In this case we have 13 varieties (of which there would be 78 different pair combinations) and already know the yield performance difference in this plot. For this reason I prefer to calculate the seed on a cost per bushel basis which accounts for all the factors and can be ranked across the list without pairings.
Simply divide the seed cost per acre by the yield, right? Eh, this could be problematic. While this will technically give you cost per bushel, it hides the fact that all your other fixed costs will go up or down on a per bushel basis as the yield changes. This will tend to make cheaper, lower yielding varieties look artificially profitable. Imagine a thought experiment in which seed variety A costs $0.40 / acre and makes 1 bushel / acre. Seed variety B costs $115/acre and makes 230 bushels/acre. Variety A is technically $0.10 / bushel cheaper, yet in that scenario your other expenses would be hundreds of dollars per bushel.
For this reason, I account for all the other fixed costs and calculate a holistic breakeven bushel price.
((all non-seed expenses per acre) + (this variety's seed cost per acre)) / (this variety's yield)
I used a non-seed expense of $700 which isn’t out of line with the University of Illinois’ 2021 crop budgets and is a nice round number.
Variety
Total Cost per Bushel
Stine 9808E-20
$2.91
NuTech 74B6AM
$3.01
Stine 9734-G
$3.03
Wyffels W7696
$3.04
Wyffels W7956
$3.06
Wyffels W7876
$3.11
Pioneer P1185AM (check)
$3.16
Wyffels W7456
$3.17
Stine 9746-20
$3.19
Wyffels W7888
$3.20
Stine R9734-32
$3.28
Pioneer P1108Q
$3.30
Wyffels W7878
$3.36
If there’s a flaw in my logic here or there’s a better way to rank seed profitability across many varieties, let me know. I’d be happy to adjust methodologies.
Fungicide Response
Ready to be disappointed?
If you’ve seen my article on manually logging a coverage map in John Deere Operations Center, you may recall how this field was partially sprayed with an aerial fungicide. Our goal was to have half of the plot sprayed and measure a fungicide response per variety across each plot row. How neat would that be?
Problem #1: “Half” Turned into “Fifth”
Aerial application map overlaid with plot
Our plot rows are 500′ long and the spray plane swath is 80′. Three swaths would have been a nice 240′, but four swaths were left unsprayed instead, so 320′ unsprayed, 180′ sprayed (in theory). Two factors whittle down that sprayed length even more; the plane bore slightly too far west, and I didn’t want to include the volatile yield map data right at the edge of the plot as the combine is entering/exiting a pass.
After also accounting for the slight angle mismatch of the eastmost swath, the usable sprayed area was about 90′ long.
Problem #2: Planes are Imprecise
Historical weather data shows the wind peaked at 10mph out of the west the day this was sprayed. From watching the mist fall patterns of spray planes, it’s very believable that a decent amount of eastward drift occured- but how far exactly? Even if you could calculate this drift, how sharp of an edge would you expect to see if measuring polygons?
Future Plans
I’d like to revisit this split fungicide treatment in the future and perhaps have it applied with a ground sprayer to have better precision over the application area.
I’d also like to continue to see how seed profitability comparisons fluctuate year to year. We had a very good growing season for corn this year, just a bit wet. It would be interesting to see how premium/cheaper varieties handle more adverse seasons.
