Survival and Its Factor of Containerized and Bare-root Sugi Cuttings Subjected to Different Watering Regimes after Summer Planting

Abstract

We investigated early performance of three kinds of sugi cuttings (1-year- and current-year-old containerized, and current-year-old bare-root) subjected to different watering regimes (everyday watering (EW), every 8 days watering (8W), and non-watering (NW)) after summer planting in green house. We also compared plant part mass between dead and survived cuttings after current growing season. In EW treatment, all containerized cuttings survived, while a half of bare-root cuttings died. In 8W, 33％ of 1-year-old and 42％ of current-year-old containerized cutting survived, but all bare-root cuttings died within three months after planting. NW killed all cuttings within 1.5 month. Cuttings planted in the field for a reference showed better tree vigor in cultivated soil than in uncultivated, and the highest survival in 1-year-old containerized cuttings, followed by current-year-old containerized, and bare-root cuttings. These results demonstrated experimentally that containerized cuttings have a certain advantage in establishing under severe drought condition than bare-root cuttings. Survived cuttings had greater root mass than dead cuttings; the difference in root mass was greater than in branch mass. Among current-year-old cuttings, containerized cuttings survived under less watering regime (8W) with a range of root mass which was equivalent to that of bare-root cuttings dead under more watering regime (EW). We concluded these results that a certain level of root growth of each stock type raised the survival of cuttings, and that the soil medium of containerized cuttings has a role of supporting their survival with smaller amount of roots and/or under severe drought.