Abstract
We conducted seried pot experiments with barley using 2 typical volcanic soils to make clear fertilizer effects of the fused magnesium phosphat. Generally speaking, the fertilizer value of phosphorus in the fused magnesium phosphate was as high as that in the superphosphate. But, -10 mesh samples or quenched product not ground but sieved, which showed that highest effect for paddy rice, was less effective than finer one. It seems better to ground the phosphate to a finess of -70 mesh. For barleys on Ogurobara Strongly acidic soil of which magnesium deficiency was found, the fused phosphate gave by far more beneficial effect than the superphosphate did! The alkaline nature and magnisium content of the former were as effective as these of slaked lime and magnesium sulphate for increasing crops and their magnesium content as well as for liming the soil acidity. Silica in the fused phosphate was also effective as that in water-soluble sodium silicate was, for increasing the silica content of the barley on Ogurobara soil.
