メヒシバ

In order to study the cause of the ecological distribution of the Crab-grass and to investigate the properties of this palant as a feeding plant, experiments were planed to ascertain the effects of increasing amounts of lime given to the soil with and without fertilizer, on the composition of the plant; and the results are as follows: plants can thrive on strong acid soil with little exchangeable calcium content, (pH 4.5, exchange acidity y1 37 exchangeable calcium 1.7m.e./100gm.) when the soil is supplied with adeqate fertilizer. The optimum point is on a pH value of about 6, exchange acidity y1 1, and exchangeable calcium 10m.e./100gm. As the pH value and calcium content of the soil surpass the optimum point, The plant grows less actively, but its normal growth can be seen till on the alkaline soil such as pH 8.06, exchange acidity y1 trace, exchangeable calcium 23m.e./100gm. (Table 1) The percentage of calcium contained in the plant becomes higher with increasing rate of liming. Thus content of calcium in the airial part of the plant ranges from 0.3％ at pH 4.6, exchange acidity y1 37 exchangeable calcium 1 m.e./100gm. to 0.6％ at pH 8.06, exchange acidity y1 trace, exchangeable Ca 23m.e./100gm. and as a whole, it settles at the point of an average 0.5％ (Table 4) On the other hand the amount of phosphorus in the plant is less affected by the addition of CaCO3 than in the case of calcium and nitrogen, and the percentage of phosphorus in the plant is very low when compared with that of calcium which is given in table 4. The average value of the former is 0.02％. The content of crude protein is increased by the application of the fertilizer, and also by the addition of lime, proportional to the increasing amount of the latter. But liming the soil of pH above 8.01, causes decrease in the crude protein content of the plant. From the results obtained through these studies it is considered that this plant does not need much Ca and P elements, so that it could flourish on reclaimed land lacking in Ca and P elements. The Crab-grass seems to have a very remarkable degree of adaptability to the Ca content in the soil, so that it could widly distribute over the strong acid soil and lime-stone regions. These studies will give a suggestion on the use of the Crab-grass as forage plants.