Evaluating precision sprayers for targeted weed management in corn and soybean

Abstract

A targeted application of herbicides in commercial crop fields is desirable for reducing chemical inputs and promoting environmental sustainability. Precision sprayers, equipped with cameras and sensors, detect weeds in real-time and apply herbicides only where needed. The objective of this study was to evaluate spot spray (SS) technology compared to the traditional broadcast application for early-postemergence and late-postemergence (L-POST) herbicides for broadleaf and grass weed control in corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) fields. Two precision sprayers were evaluated separately: Greeneye Technology's sprayer in a corn field near Clay Center, NE, in 2022 and John Deere's sprayer in a soybean field near Mead, NE, in 2023. In 2022, Palmer amaranth (Amaranthus palmeri S. Watson) and giant foxtail (Setaria faberi Herrm.) control was similar between SS (94%–99%) and broadcast (99%) application 21 days after L-POST. In 2023, common lambsquarters (Chenopodium album L.), kochia [Bassia scoparia (L.) A.J. Scott], and waterhemp [Amaranthus tuberculatus (Moq.) J.D. Sauer] control was similar between SS and broadcast 21 days after L-POST. Herbicide savings varied by site years, ranging from 1% to 94%, depending on the level of weed infestation at the time of target herbicide application. Weed infestation during herbicide applications was low in 2022 and high in 2023, influencing the year-to-year variation in herbicide savings. Corn and soybean yield did not differ among broadcast and SS. The results suggest that precision sprayers can provide comparable control to broadcast herbicide applications and would be more rewarding in fields where preemergence herbicide is applied.