عنوان مقاله [English]
نویسندگان [English]چکیده [English]
A paper-pot transplanter was designed, developed and evaluated in the field by transplanting sugar beet seedlings grown in paper pots. A ground-driven counter wheel equipped with an infra-red sensor measures the traveled distance and sends the corresponding signals to a micro-controller. A step motor controlled by the micro-controller turns the driving shaft of the paper-pot metering mechanism to transfer the pots from feeding station to seedling drop tube, where they are released and guided down to the soil furrow made by a shoe type furrow opener. Then the seedlings are then fixed in the soil by a pair of covering discs followed by a pair of press wheels. For field evaluation of the transplanter performance, a factorial experiment was conducted with three levels of transplanter forward speed (0.25, 0.375 and 0.5 m/s) and two levels of seedling growing stage (4 and 6 leaves). The field tests were replicated three times. The evaluated parameters included: mean seedling spacing on the row, lateral deviation of the transplanted seedlings from the row axis, miss index, percent of acceptable vs. unacceptable transplanted seedlings, seedling pot feed rate as affected by the action of the operator, percent of damaged seedlings and percent of survived plants 45 days following transplanting. The seedling growing stage was shown to have no significant effect on the transplanter performance. Forward speed exerted significant effects on plant spacing, miss index, and seedling feed rate as affected by the operator, while having no significant effect on the other evaluated parameters. Working speed of the transplanter was about six times faster than that of hand transplanting. The optimum transplanting speed among the tested levels was 0.5 m/s. At this speed, the percent acceptable transplanted seedlings was 85.6%, seedling feed rate was 98 plants/minute and miss index 5%. Close to one hundred percent of the transplanted seedlings that were irrigated weekly up to 45 days following transplanting survived and maintained their good vigor.