抄録
Lodging is one of the most serious injuries of the. grain production of wheat and barley. Though a lot of experiments concerned with this phenomenon have been reported, most of them have dealt with strength of culms, and few of them with. environmental factors causing lodging. This series of studies was made to make clear the effects of environment, especially wind and rain, on lodging of wheat and barley plants. A mobile wind tunnel which was able to be moved in fields (Fig. 1) was constructed for this purpose. Preliminary tests were made to determine the way of treatment with this wind tunnel. Eight varieties of wheat and barley were used for these tests, and the measurements of wind velocity in the wind tunnel were simultaneously made. Plants grown in pots were carried into the wind tunnel with wind velocities of 9 and 13 m/sec for 10 and 20 min. Inclined angles of culms during and after the treatments were measured to determine the lodging resistance of varieties. Results obtained are as follows: 1. Distribution curves of wind velocities in the wind tunnel were obtained (Fig. 2 and 3), and favorable place in the wind tunnel for the test were made clear. 2. Inclined angle during wind treatment varied with varieties (Fig. 4), and the variation of lodging resistance in field agreed with this tendency. 3. Lodging resistance was in best accord with the ratio of recovered angle after treatment to inclined angle during treatment (Table 2). 4. Stiffness of culms did not always agree with lodging resistance (Table 2).
