Development of a transplanter-based transplanter for vegetable seedlings cultured in a cuttable nursery mat

Abstract

To ease transplantation, which is labor-intensive and strongly influences yield, fully automatic vegetable transplanters have been developed; however, most of them are heavy and expensive. In this study, we developed a low-cost, high-efficiency vegetable transplanter based on a conventional Japanese rice transplanter. A rice transplanter can be used only on flooded fields; therefore, some mechanical components were modified for transplantation on dry fields. To correctly cut the nursery mat one at a time without damaging the seedlings, components of an end-effector and a rotor case were modified. Moreover, to firmly grasp heavier and larger vegetable seedlings than those of rice, a leaf spring-type retainer and a long guide were developed and a cuttable nursery mat (CNM) was introduced as a new solid nursery bed. The prototype could transplant up to 250 cabbage plants min−1 row−1 for planting speed of 1.0 m s−1. CNM seedlings (CNMS) could be better transplanted and cultivated than conventional plug seedlings (PS). In contrast to PS, CNMS were cultured for short time before transplantation because root spread was not required as the CNM itself has an adequate stiffness. This study is the first demonstration of the possible applications of this rice transplanter-based vegetable transplanting system.