Response of sweet potato cultivars to acid soil infertility factors. II. Effects of calcium supply and soluble aluminium on early growth

Abstract

Good growth in acid soils suggests that sweet potato may be tolerant of acid soil infertility factors such as Al toxicity or Ca deficiency. In a conventional solution culture experiment, 4 cultivars responded positively when solution Ca concentration was increased from approximately 4 to 1300 □М. However, a subsequent flowing solution culture (FSC) experiment showed no significant (P > 0.05) differences in growth by most of the 15 cultivars studied when solution Ca concentration was increased from 45 to 400 □М. Hence, it was concluded that sweet potato could be fairly tolerant of low Ca supply. In contrast, soluble Al markedly decreased growth of the 15 sweet potato cultivars studied. The results of the present study indicate that Al rather than low Ca supply would be more important in limiting sweet potato growth in acid soils. Furthermore, tolerance to low Ca and soluble Al appears to be linked in sweet potato. These results highlight the importance of selecting sweet potato cultivars for specific soil conditions such as soil acidity.