the goal of the proposal is to develop a workflow to map weeds across a soybean field using drone imagery. The weed map then will be converted to a prescription map to be uploaded to a commercial size sprayer to implement site-specific weed control (SSWC). The general idea is to use the weed map to shut nozzles off on the sprayer on locations where there are no weeds in the field. Previous studies carried out at NDSU with similar approach for corn have yielded savings ranging from 35-50%. Given the acreage of soybean grown in North Dakota (around 6.2 million acres) and the cost of herbicides ($15-20/ac), such approach has the potential to save soybean growers several million dollars annually in chemicals. The reduction on chemical usage can positively impact soybean growers’ bottom line, given the current scenario of the high input costs and low crop price. In addition, weed mapping across a field would be beneficial when controlling herbicide resistant weeds, allowing one to use a more expensive tank mix and applying product only were there are weeds, reducing the overall cost per acre.

i) determine the best combination of drone flight height and sensor (RGB or multispectral) to maximize data collection efficiency to map weeds across a soybean field; ii) identify and implement algorithms to separate soybean plants from weeds based on the UAS imagery; iii) create a weed control Rx-map based on the UAS imagery and weed distribution across the field; and iv) field implementation and assessment of the SSWC approach versus the current approach (blanket application) used for weed control.

a) recommendation regarding flight height and type of sensor to be used to map the weeds across a soybean field; b) a workflow to semi-automate the process of data analysis to generate the weed control Rx-map based on drone imagery; c) an assessment of the efficacy of our site-specific weed control approach compared to a blanket chemical application across the field.

The primary impact for North Dakota soybean growers would be opportunities to reduce herbicide input costs and an overall reduction in the amount of herbicide applied to their soybean acreage. The savings potential will further increase if more than one post-emergence application is needed.