This study investigated Welsh onion cultivation systems using a fertilizer-applicator ditcher in the field. The double-drill fertilizer block exhibited better plant and branch growth, plant weight, and nitrogen absorption than other blocks in the first growth stage. Drill-fertilized blocks exhibited decreased growth because the ditch bottom was softened by the chisel and fertilizer opener. Double-drill fertilizer blocks exhibited better growth than the other blocks. That block showed yields increased by 3.2-15.3%, branching length at 3.9-12.7 points, with a rate of L size at 3.9-12.7%. Results show that Welsh onion cultivation systems using a fertilizer-applicator ditcher should be used with a softened ditch bottom and double drill fertilizing.

In this study, we develop a device for reducing the boom vertical displacement. The device consists of a double-acting hydraulic cylinder, accumulators, a valve block, and other necessary components. This device reduces the boom vertical displacement caused by rolling of a vehicle based on an input signal from a single wheel. A right-side-wheel riding test that assumed vehicle rolling was performed. Based on the results of the tests, we determined that the boom vertical oscillation was reduced by approximately 45% in the right-side-wheel riding test. In addition, the boom vertical oscillation was reduced by approximately 37% when the test was performed in the NARO’s rice paddy. However, this device does not reduce the boom vertical displacement caused by the vehicle’s vertical displacement. An additional device would be required to resolve any displacement caused by the vehicle’s vertical displacement.