Softened ditch bottom conditions and fertilizing methods were examined for Welsh onion root growth and primary growth when using drill fertilizing cultivation systems with a fertilizer-applicator ditcher with a chisel. Ditch bottom soil hardness was not different among test block upper layers, but post-ditching values were lower within chisel blocks. The root length density after drill-fertilizing was progressively higher within chisel blocks, but lower than that of the fertilized area. The root length distributions in upper and lower within chisel blocks were occupied 68-87 % of the total area. Drill and broadcast fertilizing showed equal primary growth because of efficient nitrogen absorption. Ditching chisel use benefited the Welsh onion primary growth by guiding roots into softer soil layers.