Studies of Power Farming Systems of Welsh Onion Cultivation (Part 3) —Growth promotion effects and fertilizer amount reduction with drill fertilizing—

摘要

As farming period of Welsh onion in Japan is restricted due to snow coverage, its transplanting and open ditching have to be improved in order to increase both cultivation area and period. A fertilizer-applicator ditcher which enables transplanting and fertilizing simultaneously is effective for such a purpose. Furthermore, the fertilizer-applicator ditcher can improve the fertilizer absorption efficiency since it applies fertilizer directly to the root in the ditch. We investigated growth propertiesand rooting of Welsh onion cultivation using the fertilizer-applicator ditcher.The fertilizer-applicator ditcher consists of a chisel to cut the bottom of the ditch, a fertilizing opener, moldboards, and a shaping board for the bottom surface of the ditch. Fertilizing positions were 5 cm from the center horizontally of the seedlingand 7 cm from the bottom of the ditch vertically. The total root length in 35% decreased fertilizing was longer than that of normal fertilizing in the germination experiment using no root seedlings. Nitrogen content in the territorial part for the drillfertilizing had lower reduction rate after transplanting and maintained higher until the middle growth stage than usual fertilizing. The plant height, branch height, stem diameter and dry matter mass were greater for the drill fertilizing than for the normal fertilizing through the middle growth stage. The drill fertilizing produced greater total mass and thicker stem diameter (before processing) than normal fertilizing. After processing, the drill fertilizing with 17-20%decreased fertilizing by had thicker stem diameter and higher total yields by 7-13% than the normal fertilizing.