Which of the following technologies are integral components of Variable Rate Application (VRA) systems in precision agriculture?
Options:
(A) Differential Global Positioning System (DGPS)
(B) Electronic control unit (ECU) with actuator valves
(C) GIS-based prescription maps
(D) Standard mechanical ground-wheel driven star wheel without electronic controls
Answer Key:
A, B, C
Step-by-Step Solution & Explanation
A modern VRA system integrates:
1. GNSS/DGPS to identify real-time field coordinates.
2. GIS prescription maps defining target application rates per zone.
3. Electronic Control Unit (ECU) and PWM/servo actuator valves to dynamically vary fertilizer/chemical dosage.
Option D describes a fixed mechanical rate system, not a precision VRA system.