2019 ASHS Annual Conference

As labor costs increase, Vidalia onion (Allium cepa) growers are looking for ways to automate labor intensive processes such as transplanting and harvest. Plant Tape technology is an automated planting machine, which uses transplants that are grown in a biodegradable tape. Vidalia onion transplants are typically produced in field beds, pulled and replanted as bare-root plants. There is often a time period between when the onion transplants are planted in the ground and when growth resumes. Therefore, many growers do apply nitrogen fertilizer prior to planting. Because PlantTape-grown plants are produced in a transplant cell it was anticipated that growth would resume quickly after planting. Therefore, the role of preplant nitrogen was evaluated. Two varieties, Plethora and Vidora were planted by hand and using the Plant Tape technology on 14 Nov. 2017. Plants received either 16.8 or 33.6 kgˑha^-1 applied at planting or 17 days after planting, with all other fertilization managed the same. Trials were a split-split plot design with planting method and variety being main plots and fertilizer treatments being sub plots. Total yields were not affected by fertilizer treatment. However, total yields were significantly lower in both varieties grown using the Plant Tape technology. Cull rates were significantly higher in plants grown using Plant Tape technology as well. Much of the reduction in yield was due to lower germination percentages and plant populations in the Plant-Tape grown plants as well as increased cull rates. Our data did not allow us to determine if supplemental nitrogen is required for Plant Tape-grown plants compared to bare-root grown plants.