Precision weed control using a smart sprayer in dormant bermudagrass turf

Abstract

Precision herbicide application can substantially reduce herbicide input, thereby cutting chemical costs and minimizing adverse environmental impacts. A smart sprayer prototype was designed and developed for precision herbicide application in turf. This is the first study evaluating the performances of a precision sprayer for weed control in turf in field conditions. The objectives of this research were to 1) evaluate and compare the performances of the traditional broadcast application and a newly developed precision spraying technology for control of weeds in dormant bermudagrass turf, and 2) investigate the influence of weed coverage on the spray volume requirement when using the precision spraying technology developed here. DenseNet, GoogLeNet, and ResNet were evaluated for discriminating the grid cells containing weeds (spray) with the grid cells containing bermudagrass turf exclusively (nonspray). All three neural networks had an F1 score above 0.989 in the validation datasets. ResNet outperformed DenseNet and GoogLeNet with the highest F1 scores (≥0.992) in the testing datasets. Applying herbicide only to turf areas infested with weeds saved a significant amount of the herbicide, while achieving the same level of weed control compared to the broadcast application. The developed precision spraying technology performed well and effectively reduced the amount of herbicide input applied to the dormant bermudagrass turf, compared to the broadcast herbicide application. Overall, the smart sprayer prototype developed in this research can be used for precision weed control in dormant turf, although its design needs to be further optimized.