Lloyd Holland pilots Angelina Flying Service's AT-502 in Vidalia, Louisiana. Lloyd has over 23,000 hours ag time, in addition to having two ag-pilot brothers, one that also flies for Angelina Flying Service, while the other sprays bananas in West Africa.
Lower spray volumes = increased efficiency, better coverage
by Alan McCracken
McCrackenAlan@aol.com
VIDALIA, LA — Aerial applicators are constantly under pressure to increase efficiency in order to meet the needs of their customers with quality applications in a timely manner. In early summer, I had the pleasure of working with a very modern operation, Angelina’s Flying Service in Vidalia, Louisiana. This operation operates their fleet of three AT-502s like a fighter base with lots of applications being made on cotton, rice and soybeans for Angelina Farms, in addition to providing application services to other farmers in the Delta region.
Mr. Tommy Elliot, the owner, and his pilots are ably assisted by Rusty Crum, who manages the daily operations to keep these planes in the air, logging over 800 flying hours each in a good season.
The purpose of my visit to Angelina Flying Service was to assist with a reduced volume application of the BASF fungicide Headline on soybeans, comparing five gallons per acre application rate with two gallons per acre using a fluorescent tracer DayGlo mixed with the fungicide. Prior to making the treatments, the nozzles were checked for mechanical operation and the flow rate of each nozzle measured as part of the calibration procedure. It is of utmost importance that all of the nozzles delivered the same volume and that the check valves were in good operating condition. In this test, the equipment was in excellent condition. The CP nozzles were adjusted to maximum deflection to obtain better breakup of the spray in combination with the high airspeed of the AT-502.
The addition of the DayGlo florescent tracer created a spectacular sight with the pink spray cloud being clearly visible above the soybeans. The DayGlo allowed us to observe the individual pink droplets on the leaf surface. We collected samples of the droplets using water sensitive cards that were analyzed using the Sylcomp system from Argentina. The analysis of the spray droplets collected showed a significantly higher deposit with the two-gallon rate at the lower level within the soybean crop canopy. In addition, the droplets collected at the lower level were also significantly smaller confirming that smaller droplets give superior penetration of the crop. These results are particularly interesting in that the wind speed was only about three mph for the five-gallon rate and literally zero wind conditions for the two-gallon treatment. Superior crop penetration is always a plus benefit from a good cross wind.
At night we had a party-like event in the soybean field, when an enthusiastic crowd went to the field to observe the spray deposit using a long black-light lamp powered by a generator. Our photographing efforts were hindered with mosquitoes and other insects from the Delta joining us due to attraction of the black-light, not unlike an over crowded night club.
The effect of the application was nothing less than spectacular. Everyone present observed that the two-gallon per acre rate with the smaller spray droplets provided superior penetration within the crop, right down to the lower levels in spite of low wind conditions during the application. Jimmy Elliott was the first to notice that with the two-gallon rate, there was less chemical on the ground and more on the crop. Even though we had adjusted the nozzles for maximum spray breakup using a boom pressure of 40 psi, we observed with the black-light there was still a significant number of larger droplets that were visible on the soil surface, especially so with the higher five-gallon rate.
Tommy Elliot was excited with the results of the tests. Initially, he was very doubtful that lower volumes could penetrate the dense soybean canopy with narrow-row planting. The possibility of using lower volumes with the smaller droplets will enable Tommy to spray more acres per day with this increase in productivity for his aircraft.
This application experience was in-line with other field tests this year in Brazil, Argentina and Mexico, where I provided technical support to custom applicators to apply fungicides at even lower volumes than two-gallons per acre. Aerial applicators in Brazil have very large areas to cover rapidly, generally using smaller ag-aircraft, like the Cessna C-188, or the locally built, 300 hp Ipanema.