Abstract
The hydroponic technique for sweetpotato cultivation was used under field conditions in a wet lowland. A plastic porous tube was placed in a soil ridge for aeration treatment. Water depth between the ridges was kept at 20 mm throughout the growing period in order to imitate the wet soil conditions in tropical and subtropical lowlands. The growth characteristics and yield of sweetpotato grown with the aeration treatment were compared with those grown in a conventional ridge as a control. The dry weight of above-ground parts was 1.8 times greater in the control than in the aeration treatment, while the dry weight of sub-ground parts was 3.1 times greater in the aeration treatment than in the control. The dry weights of stem and leaf, main stem length and leaf area were less in the aeration treatment than in the control. The dry weight of tuberous roots was 4.4 times greater in the aeration treatment than in the control, while the dry weight of roots excluding tuberous roots in the aeration treatment was almost half of that in the control. The edible biomass index was 4 times higher in the aeration treatment than in the control. Plants in the aeration treatment had greater edible parts (tuberous roots) and less non-edible parts (stems, leaves and roots excluding tuberous roots) than those in the control.
