Findings from the Field Trial on Corn from Auburn University, AL
The following content are quoted from the Facebook post of Steve Li, Ph.D.
Extension Specialist, Associate Professor
Department of Crop, Soil and Environmental Sciences. Auburn University
I am posting findings of an interesting field trial we did last summer on R1-R2 stage corn with T30, T40, T50 and P100 pro. Not trying to stir the pot about which one is better. But data is data, you see what I see from the field samples. Overall, newer models did better in dye deposition for some reason, which is not consistent with previous data generated from 22 and 23 summers. P100 pro flew faster than other three drones and still achieved good results was impressive.
This gave me the confidence with newer drones that can flew much faster than what we have now. T50 had solid performance overall, not much complaints from me. We still need better atomizers, hydraulic flatfan nozzles beat these atomizers in droplet size uniformity and cover consistency by a very far margin. See pictures for more details.
Fluorescent dye deposition at high, ear, and low leaf. High and low leaf means the 2nd leaf above or below ear leave on the same plant. P100 pro and T50 were almost neck to neck. T50 did a little better at low position than P100 pro but this difference may not be statistically different. T40 flew with same setting as T50 with very similar rotary atomizer. Big difference between T40 and T50 were not expected before the trial. The potential explanation is the age of T40 and wear on the motors of rotary atomizers may led to lower RPM than expected, slightly bigger droplet size (VMD) and fewer droplet hits. I haven’t had time to run stats yet. P100 pro was flown at 45 fps top speed vs T50 at 32.8 fps, significantly faster by 38%. Both sprayed 30 ft swath.
CV means coefficient of variation, similar term than you find in swath testing report. It measures variation in data collected. Higher CV means higher variation. After 20k samples analyzed, we typically see CV in the range of 40-80% from spray drone applications. This is generally higher than ground rig at 10-15 GPA which is totally expected. No treatment has crazy abnormally high CV, but T50 did well in terms of spray uniformity for some reason. It has literally the same atomizers as T40 and fly at same speed at height, not sure why. P100 pro was flown at 38% faster speed which may resulted in higher CV. But at the same time, rotary atomizers on P100 pro may be flooded at the top speed which lead to higher CV. This is another possibility. I look forward to seeing new and improved atomizers on P150 and future drones.
WSP data usually has lower quality than dye data, as you can tell from the stand error bars. Way more mean variation. P100 pro did well. T30 with flat fan nozzles had least amount of variation which is ideal
For contact pesticide, we want more droplet hits. Higher number can directly lead to efficacy. We will prove this linkage in 2025 field trials. T30 with flat fan nozzles had least amount of variation which is ideal. I wish the crazy error bars from rotary atomizers will go lower in future.
For some reason, T30 produced way bigger droplets even though I haven’t used the same settings many times in the past. VMD 500 on ear leaf is not ideal for sure
Because T30 nozzles produced biggest droplets, it also had least amount of driftable fines which means more wind tolerant. But this also led to lowest dye deposition throughout the canopy. The data here shows the importance of proper droplet size selection.
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