Abstract:
An experimental prototype of backpack type rechargeable battery powered
air assisted electrostatic sprayer was developed, maintaining the commercial
competence and affordability of the marginal and small farmer community in
India. The developed prototype was analyzed for charge induction on spray
droplet, deposition characteristics and field performance on brinjal crop at
instructional farm of KCAET, Tavanur.
The developed prototype electrostatic sprayer established good levels of
charge induction on the spray particles at different stages of electrode potentials (1
kV to 12 kV). The maximum Charge to Mass Ratio (CMR) of electrostatically
charged spray was observed to be 1.79 mC kg -1 at a charging electrode potential
of 9 kV at 2 ml s -1 nozzle discharge. The Electric Ducted Fan (EDF) for high
velocity air assistance was capable of carrying the charged spray droplets towards
the distant targets such as orchard trees and longer (up to 5 m) spray throw for
field crops. The high pressure atomization system produced the fine droplet
spectrum having Volume Median Diameter (VMD) of 91.36 μm which aided
better charge induction and the resultant wrap-around effect. The field study
revealed that the electrostatic charged spray enhanced the on-target deposition
nearly about two folds than the conventional spray. Also, the biological efficacy
was observed to be 54.62 per cent superior to the conventional spraying method.
As there were very less moving mechanical components, reduction in overall
noise and vibrations of the spraying system could offer better operator comfort
and reduced system maintenance.
The cost of a commercial electrostatic (ESS ® MBP90TM) spraying system
(Rs. 4.5 lakhs) was approximately 40 times higher than that of the developed
system (Rs. 12000). The annual operating cost of the developed battery operated
electrostatic sprayer was much lesser (Rs. 28302.00) than that of commercial
gasoline engine powered knapsack mist-blower (Rs. 44677.50). Considering the
annual operational hours as 250, the hourly operating costs of the developed
electrostatic sprayer and the commercial knapsack mist-blower were Rs. 114.00and Rs. 178.00, respectively. The developed battery operated electrostatic sprayer
could give an overall annual cost saving (Rs. 16376.00) of 36.65 per cent over the
engine powered knapsack mist-blower. Moreover, the developed sprayer with
reduced pesticide (active ingredient) dose could lessen the annual pesticide
expenses by 40 per cent compared to the conventional high volume spraying. The
environmental advantage was significant as a large quantity of harmful chemicals
could be salvaged from spilling into the soil which eventually reach the ground
water and enter into the biological system ultimately harming humans.
The
overall features and cost effectiveness of the developed prototype could encourage
majority of the Indian famers to upgrade with the air assisted electrostatic
spraying technology leading to their socio-economic welfare.