EFFECTS OF TRANSPLANTING DEPTH OF PLUG SEEDLINGS ON THE ESTABLISHMENTAND THE GROWTH OF CABBAGE

To study the effects of transplanting depth on yield and uniformity of head size, cabbage seedlings were raised in plug trays and transplant ed directly into the field at depths of -2 cm, -1 cm, 0 cm (exposed ro otball plots), +1 cm, +2 cm (soil-coverd rootball plots). At fixed int ervals during the experiment, shoot growth, leaf area, rooting capacit y, soil moisture content, and shoot water potential were measured; at harvest, the fresh weights of the heads, and uniformity of head size w ere recorded. 1. Cabbages in the soil-covered rootball plots were abou t 1.5 times heavier and more uniform than were those from the exposed rootball plots. 2. Cabbages in the soil-covered rootball plots had bet ter survival rate, larger leaf area and more roots, and grew faster th an did cabbages from exposed rootball plots. 3. After transplantation, the moisture content in the exposed rootballs decreased more rapidly than it did in the soil-covered ones. In each plot, the initial moistu re contents of the rootballs were higher but eventually became lower t han of the ambient soil. 4. The decline of the shoot water potential i n plants from the soil-coverd rootball plots was slower than that of s hoots in the exposed rootball plots. We conclude from these observatio ns that transplanting rootballs at 1 similar to 2 cm depths resulted i n a better stand and a higher yield of more uniform-sized cabbages tha n planting at shallower depths. The benefits of soil-covering are attr ibuted to: 1) better soil moisture retention within the rootball, 2) i mproved rooting, and 3) a favorable shoot water potential.