Author: Annie Christine Boucher, M. Sc, Project Manager, IQDHO
For several years now, drone technology has been gaining in popularity and has been developing in many areas, i.e., rescue missions, air sampling, detection of health indicators in crowds (such as coughs or fevers). In agriculture, drones are used to improve productivity, either to identify less productive areas into the fields or to take aerial photos, to generate levelling plans, spread beneficial insects, etc., among other things.
The IQDHO, in collaboration with GEOGRID (a geomatics and drone mapping company) and the Centre de géomatique du Québec, carried out a project on the potential use of drones to monitor pests in sod farming.
Sod farms cultivate sod over large areas in the field. These crops, which are not mechanically weeded, require applications of herbicides and other pesticides to control weeds and pests, respectively.
Motorized vehicles access must be limited, except for mowing. The passage of heavy machinery over the crop is known to cause enough soil compaction that adversely affect sod growth and harvesting. In this context, the use of drones could be justified to identify problems and areas where treatments are needed.
This two-year project helped optimize flight parameters for the detection of weeds and the plant pathogen causing turf rust. Visual imagery (pictures taken with natural colours) was determined to be better suited to achieve this than vegetation indices derived from multispectral imagery (image processing method that allows the estimation of certain vegetation parameters). Rust, the main disease found in sod farms, could be identified at 60 m of height at least. However, on pictures, it was not possible to differentiate between rust and drought areas. Regarding weeds, it was found that their spectral similarity with sod species made them difficult to identify. The flying height required to identify broadleaf weeds was below 60 m, and 20 m or less for grasses. However, weed identification proved to be quite a challenge, depending on the height, weed species and crop stage.
In conclusion, the cost associated with pest problems identification on sod farms using drones is relatively high as these devices must fly at a relatively low altitude. However, this technology is constantly evolving, and improvements to the various sensors could possibly make it possible to achieve this objective while reducing the flight time required. In addition, the use of drone technology coupled with robotics could be very interesting to reduce the use of pesticides. More to come…
A copy of the full report (French only) is available for download here.
This project was made possible thanks to financial assistance from the 2013–2018 Prime-Vert program, subcomponent 3.2, from the ministère de l’Agriculture, des Pêcheries et de l’Alimentation (MAPAQ).