Abstract
Five soils were investigated in pot culture, using a wide range of levels of monocalcium phosphate. The amount of phosphorus required to produce phosphorus toxicity symptoms in subterranean clover (Trifolium subterraneum L.) varied widely between soils, even when all other nutrients were adequately supplied. Soil effects are ascribed largely to differences in capacity to "fix" soluble phosphorus in forms not readily available for plant growth. Wherever the problem is likely to occur in the field, poor nodulation may accentuate the malady.