A Compact Variable Rate Sprayer for Teaching Precision Agriculture

Abstract

A compact variable rate sprayer for use in teaching precision agriculture was developed and field tested. A 3.57-m (11.7-ft) boom-type field sprayer with a 227-L (60-gal) tank was used as the base unit. Off-the-shelf Global Positioning System and variable rate application components were modified as necessary and installed on the base unit. The cost of the completed variable rate sprayer was approximately $9700. For field testing, a 12.8-m (42-ft) wide 91.4-m (300-ft) long test course was laid out and spraying prescriptions were written for field speeds of 2.74 and 5.47 km/h (1.7 and 3.4 mph). With a 2-s delay programmed into the unit, the mean position error was 0.37 m (1.23 ft) at 2.74 km/h (1.7 mph) and 0.77 m (2.51 ft) at 5.47 km/h (3.4 mph). Once the sprayer traveled into a prescribed spray zone, a mean distance of from 0.87 m (2.85 ft) (for low speed, low application rate) to 3.53 m (11.58 ft) (for high speed, high application rate) was traveled before the sprayer output initially reached the prescribed rate. The sprayer output stabilized at the prescribed rate at a mean distance of 9.59 m (31.45 ft) (high speed, high application rate) to 13.61 m (44.64 ft) (low speed, low application rate). The variable rate sprayer will be used in undergraduate and graduate classes and in workshops for agriculture teachers, Extension agents, and producers.