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

Good growth in acid soils suggests that sweet potato may be tolerant of aci d soil infertility factors such as Al toxicity or Ca deficiency. In a conve ntional solution culture experiment, 4 cultivars responded positively when solution Ca concentration was increased from approximately 4 to square M Ho wever, a subsequent flowing solution culture (FSC) experiment showed no sig nificant (P > 0.05) differences in growth by most of the 15 cultivars studi ed when solution Ca concentration was increased from 45 to 400 square M Hen ce, it was concluded that sweet potato could be fairly tolerant of low Ca s upply. In contrast, soluble Al markedly decreased growth of the 15 sweet po tato cultivars studied. The results of the present study indicate that Al r ather than low Ca supply would be more important in limiting sweet potato g rowth in acid soils. Furthermore, tolerance to low Ca and soluble Al appear s to be linked in sweet potato. These results highlight the importance of s electing sweet potato cultivars for specific soil conditions such as soil a cidity.