Review on research and application of variable rate spray in agriculture

Variable rate spray, which has extensive developing prospects, has become an important part of precision agriculture. This paper reviews the research and application of variable spray technology in weed control. According to weed information source, it can be divided into two types: map based and real-time sensor based, machine vision and image processing used as a weed detection means is developing faster and faster. There are mainly three different ways of variable spray: changing the system pressure, direct injection, and PWM (Pulse Width Modulation), but there have been variable nozzles in recent years. Weed detection means and ways of variable spray vary from each other, but all for the purpose of refinement of weed management and herbicide savings.