Studies on physical properties of soils in relation to fruit tree growth

Abstract

1. A study was made with the same method of previous suudy, of various oxygen concentrations . in the soil atmosphere affecting the growth of pear, persimmon and apple seedlings. 2. Normal top growth was made in the about 7% oxygen level and practically'there was no difference from check plots about 15-20% oxygen level. When the oxygen level decreased below 5%, the leaf color somewhat turned yellowish or dwarfish but not so remarkable as peach seedlings. 3. Below 5% oxygen, root development was also checked. Under the oxygen concentration 1% or more, the root development was made by these three kinds of trees used in contrast with the death -of fibrous roots of peach seedlings in such low oxygen level in previous study. Although furher experiments must be done with an-other method of experiment before the relative difference among the pear, persimmon and apple seedlings for lethal low oxygen level can be found with certainty, there would be not so much difference between them practically.