Abstract
To study the effects of transplanting depth on yield and uniformity of head size, cabbage seedlings were raised in plug trays and transplanted directly into the field at depths of -2cm, -1cm, 0cm (exposed rootball plots), +1cm, +2cm (soil-coverd rootball plots). At fixed intervals during the experiment, shoot growth, leaf area, rooting capacity, soil moisture content, and shoot water potential were measured ; at harvest, the fresh weights of the heads, and uniformity of head size were recorded. 1. Cabbages in the soil-covered rootball plots were about 1.5 times heavier and more uniform than were those from the exposed rootball plots. 2. Cabbages in the soil-covered rootball plots had better survival rate, larger leaf area and more roots, and grew faster than 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 moisture contents of the rootballs were higher but eventually became lower than of the ambient soil. 4. The decline of the shoot water potential in plants from the soil-coverd rootball plots was slower than that of shoots in the exposed rootball plots. We conclude from these observations that transplanting rootballs at 1∿2cm depths resulted in a better stand and a higher yield of more uniform-sized cabbages than planting at shallower depths. The benefits of soil-covering are attributed to : 1) better soil moisture retention within the rootball, 2) improved rooting, and 3) a favorable shoot water potential.
