An Italian field trial shows that a sports field composed of 100% Kentucky bluegrass (Poa pratensis) maintains similar quality when mowed autonomously and traditionally. However, robotic mowing did result in less thatch and higher shoot density.

The study was conducted from autumn 2023 to spring 2024 by the University of Padua. Two mowing approaches were compared on Kentucky bluegrass: conventional mowing with a mulching mower (weekly at 39 mm) and autonomous mowing with a robot (daily at 33 mm).

Conventional mowing produced higher turf quality in September, but from November there were no significant differences between the two mowing approaches.

Initially, turfgrass quality was superior to conventional mowing, but the differences became non-significant over time. The NDVI values showed a similar trend, with higher values for conventional mowing only in October. Autonomous mowing led to a thinner thatch layer, higher tiller density, and greater leaf surface area per unit of canopy volume.

There was also little difference between the systems in terms of NDVI values, with the exception of October, when the autonomous mowing plots showed slightly higher NDVI values. This indicates that at least the autonomous mower did not put additional stress on the vegetation.

The researchers note that the turf may need some time to adjust to the robot’s higher mowing frequency.

Less thatch, more sprouts with robot

More obvious were the differences in morphological characteristics. The turf that the autonomous mower cut daily, developed significantly higher shoot density and more leaf area per unit volume. The thatch layer was also significantly thinner in these plots. The researchers claim that this is because the autonomous approach produces fewer grass clippings. These break down faster. In addition, the higher mowing frequency encourages the plant to form new shoots, resulting in a denser sward with finer leaves.

The study mentioned in this article, can be downloaded here.