Devising a Mechanized System for Production of Bare-Root Sugar Beet Seedlings in the Open-Air Nursery

Using bare-root seedlings for sugar beet farming has been given special attention due to recent droughts and introducing a mechanized system for production of seedlings in the nursery is important. To determine an appropriate sowing pattern, a split plot experiment based on the complete randomized blocks design was arranged to evaluate the effect of two seed distribution patterns including drilling and broadcasting (main plots) and applying of sand mulch or without sand (sub plots) on emergence indexes and number of applicable seedlings. To determine the most appropriate digging machine for the seedlings, four digging treatments including: undercutting with a blade digger, digging and sifting with a chain digger, undercutting and digging in two passes with the equipment of first two treatments and digging and picking by labour were compared in terms of quantitative losses and labour requirement in one of the subplots of the planting experiment. The results showed that broadcasting pattern along with applying sand mulch, having more uniform horizontal distribution compared to drilling and higher seed emergence than bare bed, can be introduce as the most appropriate system to host the required number of seedlings for an area equal to 10 times of the nursery. Evaluation of digging treatments revealed that employing the chain digger caused a high percentage of quantitative losses. Undercutting the seedlings by a blade digger, having lowest percentage of damaged seedlings and 30% cut in lobour forces compared to the manual digging, is recommended as the most applicable method among the available technologies.