Optimization of the year-round mowing schedule of a robotic lawnmower in a Japanese pear orchard

Abstract

Commercial robotic lawnmowers have recently gained popularity in orchards. However, more widespread adoption of this technology in orchards requires optimization of the weed cutting height and cutting frequency. To determine the optimum weed cutting height, we tested a robotic lawnmower (Automower 430X, Husqvarna, Sweden) in a Japanese pear orchard at Ibaraki University, Ami, Japan. The mower was operated on short (weed height = 175 ± 42 mm (±SD), medium-sized (weed height = 286 ± 87 mm) and tall weeds (weed height = 404 ± 118 mm). To determine the optimum cutting height and frequency, we used a weed growth model and data from photogrammetry, weed mechanical properties, and field performance. Our analysis indicates that the mower should be operated when the height of the weed reaches 20 cm. To maintain weed height at <20 cm, the mower, on average, should be operated 10 h week⁻¹ between April 5 and October 13. We believe that the proposed mowing schedule would significantly help the mower tackle field challenges in the orchard.