Home Ag Colleges Optical Spot Spray Technology 

Optical Spot Spray Technology 

By Brianna Gratton

Precision and digital agriculture technologies are rapidly entering the market, but farmers have little to no third-party, independent data illustrating their effectiveness and economic benefits for use of optical spot spray technology in conventional, dryland farming in Western Canada. 

The WEEDit was pioneered in Australia, is commercially available in Canada and is reported to reduce pre-seed herbicide use by up to 85 per cent by identifying and targeting weeds rather than spraying the entire surface. The Olds College Smart Ag team’s research aims to answer fundamental questions about spot spraying technology such as its performance in western Canadian conditions and its impact on chemical use and crop yield. 

This research will also help identify the need for bias mode and whether or not stubble type and travel speed during spraying has an impact on effectiveness of the technology. 

The overall goal of this project is to assess the practicality as well as the economic benefit of spot spray technology for broad-acre, dryland farming in western Canada. In addition, it seeks to compare chemical use and efficiency between “bias” and “spot” modes.

The WEEDit system that we will be using contain sensors placed at 1 metre intervals, these scan the ground ahead of the boom, identify the presence of plants, and trigger the nozzle in line with the plant. The system identifies weeds based on their green coloration, so WEEDit is suited for spraying pre-seed, pre-harvest or post-harvest. Early adopters of the technology in Canada have focused on using the WEEDit technology for pre-seed burn-off.

The sprayer we will be using is a 24-foot WEEDit mounted on a three-point hitch. The methodology of this project includes field-scale strip trials across all zones of the fields to establish the sensitivity of the WEEDit imagery to accurately detect and target small weeds typically present at pre-seed burn-off.

In addition, we will also systematically evaluate the effect of field condition, spraying mode and field velocity on weed pressure and crop yield. All trials will be conducted over the next two growing seasons using naturally occurring weeds on two different stubble types including canola and a cereal. 

To evaluate weed pressure, populations will be monitored before and after spraying to assess efficacy of treatments and how well the system covers weeds of different types and sizes. The strips using treatments of sport spray, 30 per cent bias and full spray at two different travel speeds will be compared to show how these may effect overall savings and efficacy in field. 

Once season is complete and all data including yield has been collected, a full report will be available.