In 2019 we evaluated the spray coverage from nine application methods on corn silks. The results showed that a directed application from drop hoses (aka drop pipes, drop legs) suspended in between the rows gave significantly higher deposits. The results led us to wonder if the superior coverage from a directed application translated to improved yield.
Around this time we started considering the Beluga Drop Hose developed by Agrotop (Germany) and distributed by Greenleaf Technologies (USA). In our experience, flexible drop hoses tended to snag in dense foliage, deflecting or swaying during an application. The Beluga was stiffer and their unique low-profile nozzle body had less potential to snag. Further, unlike homemade, inflexible drop pipes or other commercial solutions such as the Y-Drop with 360 Undercover, the Belugas were lightweight and did not need a break-away section to prevent damage.
In 2021 we initiated a multi-year trial with the Beluga drop hose system in Port Rowan, Ontario. We compared efficacy and return-on-investment in corn compared to conventional overhead technology and untreated checks.
Construction and Installation
We ordered 150 cm (60″) drop hoses with two nozzle bodies each so we could customize them. The instructions were in German but after running them through translation software we were confident in how to proceed (download the translated copy here). We started by determining the hose length. Mounting plates (included) were temporarily fixed to the boom using quick ties and the boom was raised above the corn canopy. The Beluga quickly and easily “keys” into the plate allowing it to swing freely and find plumb. The hose had to clear the ground but still be long enough to span the target region in the canopy.
The corn was planted on 76 cm (30″) spacing. We mounted the drop hoses on the boom so they would align with the alleys, thereby moving between the planted rows. We elected to use 110° flat fan nozzles spaced 38 cm (15″) apart to ensure 100% overlap at the target. Using the jig provided, we drilled holes for the two nozzle bodies. Then we blew-out the hoses to clear them of any plastic shavings that could plug nozzles. The hoses were cut to length and the end plug was installed with a hex key. Once we found a rhythm, the assembly went quickly and easily.
Sprayer Settings, Tank Mixes and Plot Design
The sprayer was a self-propelled John Deere R4038 with a rear-mounted 36.5 meter (120″) boom. Treatments were eight corn rows wide. The boom was nozzled from left to right per the following table. Travel speed was between 8.85 – 11.25 km/h (5.5 – 7 mph) and the application volume was 225 L/ha (20 gpa).
| Year | Broadcast (Overhead) | Directed (Beluga) | Unsprayed Check |
| 1 | TeeJet AIC11005’s on 15″ centres | 4 Airmix 110015’s per drop on 30″ centres | Nozzles blocked |
| 2 | TeeJet AIC11005’s on 15″ centres | 4 Spray Max 110015’s per drop on 30″ centres | Nozzles blocked |
The study took place on 11.3 ha (28 acres) spanning two fields. The corn variety was Pioneer P0720AM which has a Gibberella Ear Rot rating of 4. Different tank mixes were applied, depending on the year, as indicated in the table below. Note: The insecticide “Delegate” (50 g/ac) was also included in each tank mix. However, there was very little evidence of Western Bean Cutworm (WBC) in the treatments and unsprayed checks, so the impact of Delegate will not be discussed. Only the cost of fungicides are tracked in this study.
| Tank Mix # | Product | Rate (/ac ) |
| 1 (Year 1 and 2) | Miravis Neo | 405 ml |
| 2 (Year 1) | Headline AMP + Caramba | 303 ml + 400 ml |
| 3 (Year 2) | Veltyma + Proline | 202 ml + 170 ml |
The specifics of each treatment and the number of replicates are captured in the table below. :
| Tank Mix # | Treatment | 2021 Area (ac) / # Replicates | 2022 Area (ac) / # Replicates |
| 1 | Broadcast (Overhead) | 1.05 / 4 | 1.10 / 4 |
| 1 | Directed (Belugas) | 1.05 / 4 | 1.10 / 4 |
| 2 | Broadcast (Overhead) | 1.05 / 4 | n/a |
| 2 | Directed (Belugas) | 1.05 / 4 | n/a |
| 3 | Broadcast (Overhead) | n/a | 1.10 / 4 |
| 3 | Directed (Belugas) | n/a | 1.10 / 4 |
| n/a | Unsprayed Check | 1.05 / 4 | 1.10 / 4 |
Preliminary and Qualitative Results
Leaves
In 2021 and 2022, a qualitative comparison of randomly-selected ear leaves showed less evidence of disease in the fungicide treatments compared with the unsprayed check. There was also less evidence of disease in the Directed application treatments versus the Overhead broadcast application treatments. There was no obvious difference between the fungicides used.
Cob Size / Quality
In 2021, preliminary samples showed evidence of disease and tapered-ends in both fungicide treatments and the unsprayed checks, but the size and quality of the cobs from fungicide treatments seemed better. We were encouraged, but reserved judgement until the final yield numbers were in.
Quantitative Results
Net Revenue
Each treatment yielded corn with different moisture levels, so we chose not to compare bushels per acre harvested. Instead, we calculated net revenue based on current market values in the Port Rowan area. We normalized the treatment yields by moisture level and calculated their relative drying costs. Then we accounted for the other inputs (see list below) using the following formula:
Net Revenue (CDN) = Seed Yield × Corn Sale Price – Drying Cost – Treatment Cost
| Item | 2021 ($) | 2022 ($) |
| Corn Sale Price (/bu) | 6.00 | 8.00 |
| Custom Spray Cost (/ac) | 12.00 | 12.00 |
| Drying Cost based on Moisture Levels (/bu) | 0.58-0.64 | 0.60-0.69 |
| Tank Mix 1 (/ac) | 16.66 | 18.24 |
| Tank Mix 2 (/ac) | 15.75 | n/a |
| Tank Mix 3 (/ac) | n/a | 28.52 |
We plotted net revenue from each application method in a box and whisker plot (see below). Only the unsprayed check appeared normally distributed. ANOVA did not indicate a statistically-significant difference between application methods and the unsprayed checks at a 95% confidence level. This means we cannot say with confidence that we would see this trend again next year in these fields, or elsewhere. Nevertheless, in this study, the mean net revenue in CAD for each application method indicated the following differences:
| Year | Treatment | Yield (bu/ac) | Moisture (%) | Average ROI ($/ac) |
| 1 | Broadcast vs. Check | -2.3 | +0.6 | -0.49 |
| 1 | Directed vs. Check | +3.5 | +0.6 | +20.93 |
| 1 | Directed vs. Broadcast | +5.7 | +0.01 | +21.42 |
| 2 | Broadcast vs. Check | +9.8 | +0.2 | +52.48 |
| 2 | Directed vs. Check | +14.6 | -0.04 | +89.14 |
| 2 | Directed vs. Broadcast | +4.8 | -0.3 | +36.66 |
| 1 + 2 | Broadcast vs. Check | +3.8 | +0.4 | +26.00 |
| 1 + 2 | Directed vs. Check | +9.0 | +0.3 | +55.04 |
| 1 + 2 | Directed vs. Broadcast | +5.3 | -0.1 | +29.04 |
- Directed (Belugas) vs. Unsprayed check: Profit of $55.04/ac CAD
- Directed (Belugas) vs. Broadcast (Overhead): Profit of $29.04/ac CAD
- Broadcast (Overhead) vs. Unsprayed check: Profit of $26.00/ac CAD
Return on Investment
We can estimate the return on investment for this scenario. In 2021, 48 Beluga drop hoses ($9,600.00 CAD) with 192 nozzles ($1,920.00 CAD) cost $11,520.00 CAD. Compare this to the cost of 72 nozzles ($720.00 CAD) in the Overhead broadcast application method. Based on the mean net revenues in this study, the Beluga drop hose method would pay for itself in 372 acres.
($11,520.00 – $720.00) ÷ $29.04/ac = 372 ac
The Drop Hose Experience
We felt it was important to describe the utility and user-experience. While this study focusses on the Port Rowan trials, several other operators have adopted the Beluga system and reported on their experience. We will include their comments as well.
Port Rowan, Ontario (2 seasons):
- Installing and uninstalling the drops took roughly 60 seconds apiece, including moving the ladder.
- Deflection was minimal, even when they were dragged perpendicular to the rows through headlands.
- Initially, it was a little unnerving not being able to see the spray but the operator quickly got used to it (see video below).
- There was no issue folding the boom or driving between fields with the drops installed. They did note that the lugs on the front tires did contact the drops on tight turns, but adjustments were made.
- The drop hoses rinsed as easily as any nozzle. There were initial concerns that using 015’s nozzles to maintain the target 20 gpa might cause plugging issues, but none occurred.
- The drops were resilient. The operator bent the hoses by lowering the boom and then dragged them along the ground. They returned to plumb and appeared undamaged.
- The mounting bracket permits the drop to be “keyed in” from either side, however this may have led to drop hoses detaching in shorter corn stands. Rather than the current slot positions of “9:30 and 2:30”, “11:00 and 1:00” would likely prevent detachment.
- Once removed, the drops stored compactly and easily on a utility shelf, repacked in their original box.
Morrisburg, Ontario (1 season):
- When using a front mounted boom (New Holland Guardian) the Beluga’s appeared to bend backwards, dragging through the corn. The operator used a NutraBoss Y-Drop mount to stiffen the top few inches of the Belugas (image below). Further, cutting the excess hose from beneath the bottom nozzle body (to a final length of 48″) reduced drag.
- The New Holland Guardian boom folding system was not compatible with the Beluga mounts, and compromises had to be made.
- The rear boom section of the New Holland Guardian is 12″ lower than the front (9 feet off ground rather than 10). The Belugas were not adjusted to account for this since corn tended to bend lower after passing under the belly of the sprayer. The result was that the nozzles remained aligned with the target region.
- Opinions differ as to which portion of the corn stalk should receive direct spray. In Port Rowan, we spanned the silking region. However, this operator positioned the nozzle bodies 20″ apart (Spray Max 015’s) and aligned them to the top 1/3 of the stalk, ensuring the top leaf was thoroughly covered. The operator noticed spray occasionally escaping through the top of the canopy.
- When scouting for disease, the operator reported an obvious improvement in favour of overhead broadcast versus unsprayed check, and an equally obvious improvement in favour of directed (Beluga) versus overhead.
- The operator reported a bushel/ac advantage using the Belugas and noted 35% less fines in their corn dryer, implying far less WBC damage versus the overhead condition.
Conclusions
We elected to separate the mycotoxin results from this analysis of utility and ROI. There are many factors that influence ear mould pathogens, and we did not see any clear correlations between the fungicides or application method used and the level of Deoxynivalenol (DON aka vomitoxin) or zearalenone detected. When that report is ready a link will appear here.
We did see an increase in mean net revenue both in year one and year two in corn sprayed using directed application versus a conventional overhead broadcast. Further, we saw an average increase in mean net revenue when fungicides were applied versus the unsprayed checks.
Right now this technology might make more sense for a home farm operation where the drops can be cut to a size that aligns the nozzles for a specific boom height and corn variety. Additionally, fewer acres means it’s less punitive to use a minimum volume of 20 gpa. Alternately, a custom operator would have to adjust boom height (if not already maxed) or swap drop hoses to configurations that align correctly with the client’s crop. And, it would have to be a minimum of 20 gpa because going any less would require <015 nozzles (think plugs and misty spray). Both of those requirements mean additional time and cost to a client. The value proposition becomes the added cost for an efficacious application versus the potential losses should conventional application methods fail to control devastating diseases such as Tar Spot. Time will tell as this technology finds its niche.
Thanks to Petker Farm Ltd. for participating in the study. Thanks to Corteva and Syngenta for contributing the pesticides used.