マンガン集積土壌における牧草の生育に関する研究 : I. マンガン集積土壌の理化学性と牧草の生育

To attempt to elucidate how to make behave manganese in pasturage soil, which was accumulated into pan or crust in subsoil during the soil had been previously utilized as paddy, and how to effect this accumulated manganese on the growth of foliage crops, this paper deals with the general properties of this soil and the pot trials by the soil.

1) Concentration.; of manganese in the topsoil, the subsoil, and the subsoil with Mn deposit were 4,400 ppm, 10,780 ppm and 27,000 ppm in the total, and 2,340 ppm, 2,780 ppm and 5,080 ppm in the easy reducible, respectively.
2) However, water soluble and exchangeable manganese contents in the soils were rather lower as below 20 ppm and 150 ppm.
This would be due to the fact that the soil pH was near to the neutral.
3) Contents of iron in soils, eluted by water, pH 7, 1 N ammonium acetate, and ammonium acetate containing 0.2 % hydroquinone were very low in these soils.
4) Contents of manganese in grasses and legumes appeared considerably high as 150 to 900 ppm in dry matter. However, these pot trial pasturage crops would not suffer from manganese toxication because of their iron contents.
5) Yields of 2nd cutting of grasses was lower than that of 1st cutting but this was almost non existent in the case of legumes.
6) It could be important to apply phoshorous to the soil with accumulated manganese to improve yields of pasturage crops and to prevent crops from manganese toxication.