Abstract
The variable-rate application is an important aspect of precision agriculture. In order to determine the regular patterns of droplet deposition and compare the actual variable-rate spraying effect of the AS350B3e helicopter with the AG-NAV Guía system, spray tests were conducted with different operating parameters and operating methods. In this study, the deposition distribution of droplets in the effective swath area was evaluated for six single-pass applications at four different flight velocities. The effects of adding adjuvant on droplet deposition, drift and droplet size were compared, and the actual variable effect of the forth-back application was verified. The analysis results showed that the position of the effective swath area was affected by natural wind velocity and wind direction, and would shift to the downwind direction area from the helicopter route of a different degree. The effective swath width increased slowly and then decreased sharply with the increase of flight velocity. It was found that flight velocity of 100 km/h was the peak inflection point of effective spray width variation. Moreover, the effect of flight velocity on the distribution uniformity of droplet deposition in the effective swath area was not significant. In the single-pass application of 90 km/h, adding adjuvant could increase droplet size in the effective swath area. The deposition increased by 8.98%, and the total drift decreased by 28.65%, of which the upwind drift decreased by 28.31% and the downwind drift decreased by 29.06%. In the forth-back application of 90 km/h, the error between actual application volume and system setting dose was 12%. The results of this study can provide valuable references for future research and practices on variable-rate aerial applications by manned helicopters. Keywords: manned helicopter, precision agriculture, variable-rate aerial application, spray test, adjuvant, droplet deposition DOI: 10.25165/j.ijabe.20191201.4039 Citation: Yao W X, Lan Y B, Wen S, Zhang H H, Zhang Y L, Wang J, et al. Evaluation of droplet deposition and effect of variable-rate application by a manned helicopter with AG-NAV Guía system. Int J Agric & Biol Eng, 2019; 12(1): 172–178.
Highlights
In the 1990s, an aerial variable-rate application system was first used in the United States and gradually developed[1]
Kirk and Tom[4] installed SATLOC Flow Control/ Monitor (AgJunction, Inc., Hiawatha, USA) system on a Cessna AgHusky aircraft (Cessna, Inc., Wichita, USA), and compared the spray uniformity of variable spraying and conventional constant spraying under different meteorological conditions
The test results showed that spray control errors of the flow control system was less than the conventional constant spray errors
Summary
In the 1990s, an aerial variable-rate application system was first used in the United States and gradually developed[1]. Kirk and Tom[4] installed SATLOC Flow Control/ Monitor (AgJunction, Inc., Hiawatha, USA) system on a Cessna AgHusky aircraft (Cessna, Inc., Wichita, USA), and compared the spray uniformity of variable spraying and conventional constant spraying under different meteorological conditions. The performance of the two systems was evaluated by experimental and theoretical errors He found that experimental error was not significantly affected by the application rate in either system, but increased with the number of spray passes. Thomson et al.[6] conducted a comparative test on the flow control reaction speed and accuracy of SATLOC M3 (AgJunction, Inc., Hiawatha, USA) system and improved the control system . It was proved that the January, 2019 Yao W X, et al Evaluation of droplet deposition and variable-rate application by a manned helicopter with AG-NAV Guía system Vol 12 No. 173
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