Abstract
Using rabbits as testing animals, the study was done in orchard grass and red clover with the view of finding out the influences of different soil moisture upon the yield of digestible nutrient constituents, such as growth, feeding value and ratio of digestion. 1) In growth of plants, the best condition of soil moisture was at 70-90% of the maximum water capacity in orchard grass and at 50-70% in red clover. 2) In the decrease of absorbing plant nutrients owing to soil moisture shortage, phosphoric acid indicated the largest decrease in orchard grass and nitrogen was next but potassium was comparatively small. In red clover, any obvious effect could not be observed in each constituent. On the other hand, in case of excessve soil moisture, nitrogen was rather remarkable in orchard grass and phosphoric acid in red clover. 3) The difference in percentages of feeding constituents in dry matters was comparatively little. But owing to the fact that the percentage of water in green matters became higher as soil moisture increased, the percentage of each nutrient in green matters of the above-mentioned two plants was the highest in the low soil moisture plots, then in the medium soil moisture plots and the lowest in the high soil moisture plots. 4) The difference between digestibilities by feeding rabbits with two plants was little in protein. In other constituents, the values in the medium soil moisture plots were a little lower than in the low soil moisture plots But the difference between the low and the high soil moisture plots was not remarkable. 5) Every digestible nutrient, TDN and nutritive ratio in the above-mentioned two plants were the highest in the low soil moisture plots, then came the high soil moisture plots and the lowest in the medium soil moisture plots. 6) The yields fo each digestible nutrient and TDN in both of the two plants showed the least in the low moisture plots and increased as soil moisture became higher. This tendency, however, showed some difference among the constituents.
