For the 2024 growing season, Dr. Dan Brainard’s lab in the Dept. of Horticulture at Michigan State University is testing the Naio Oz autonomous cultivator in sweet corn and cabbage. The experiments will look at different frequencies of Oz cultivation both with and without pre- and post-emergent herbicides. The results will help to further determine the practicality of robotic cultivators in vegetable production systems, particularly as it pertains to their efficacy in managing weeds in conditions where preemergent herbicides fail to work or are unable to be applied.
The sweet corn trial was planted on 6-4-2024 at the Horticulture Teaching & Research Center on MSU’s campus in East Lansing, MI. The field was prepared with a Great Plains TurboMax and planting was done with a single row Jang seeder mounted to the back of the Oz unit. The sweet corn variety planted was Xanadu, a bicolor sh2 that received high ratings for sweetness, flavor, tip fill, and other marketable characteristics as noted in the Ohio State University’s 2023 SH2 Sweet Corn variety trials. Sweet corn was planted 10” between plants in rows 30” apart. There were issues with seed singulation using the Jang due to seeds getting clogged in the hopper. This was leading to an inordinate amount of doubles, so crop thinning may be necessary.
The PRE herbicide treatments were applied on 6-8-2024. These consisted of Dual Magnum (1.33 pt/acre) & Aatrex (2 pt/acre) applied with a CO2 backpack sprayer. The sweet corn was just beginning to germinate and had not yet emerged. The first Oz cultivation was performed on 6-10-2024. Weed species present were predominantly wild radish, crabgrass, and lambsquarters that had recently emerged. At this point, sweet corn had just started to emerge in some spots but was mostly below ground still. Between-row cultivation was done using 2 cutaway knives (one on each side) plus a single sweep in the middle. Soil was slightly moist which led the Oz to get stuck in some soft spots (despite dual wheels) but also led to satisfactory cultivation results.
In-row cultivation was done using two floating Tilmor medium finger wheels. Initially, other finger weeders were tried, but the length of their fingers was a little too short, leaving a overly-wide gap between wheels which resulted in a trail of crusted soil directly over the crop row. The linkages could not be moved any closer together on the toolbar, so the gap was reduced using the Tilmor wheels which led to better results.
As mentioned, the Oz got stuck from time to time, which the unit responds to by stopping, lifting its toolbar, moving forward before dropping the toolbar again and resuming its mission. This leads to a veering in the row as the Oz gets back on track. There were also a few instances of a “GPS Lost: No RTK Fix” error, which stops the robot in its tracks. After a short period, however, the Oz finds its signal again and automatically resumes its mission.
We will keep you updated on the experiment as it develops. Next steps are future cultivations, application of POST herbicides, and weed counts. A similar trial in cabbage will also be done later in the season. Dr. Brainard is also working with a larger, solar-powered autonomous cultivator, the Naio FarmDroid, in direct-seeded cabbage and other crops this summer.