1921.] 



Dri Spraying of Charlock. 



1 89 



unfortunately a very unsettled spell of wet weather set in at the 

 time, and the operation was perforce postponed until June 4th. 

 By that time all the plants were practically in flower, but very 

 little seed had been set. The Barley was 6 to 8 in. high. 



As in the previous year, the spraying was carried out at dawn 

 in the hope of finding a good dew on the plants; but the 

 weather was very unpropitious — there was no dew, and, to make 

 matters worse, a moderately strong w r ind was blowing. The 

 leaves, however, were slightly damp from rain, which had 

 fallen during the night, and the experiment could no longer be 

 delayed. 



The plots were examined on June 21st, 17 days after treat- 

 ment. The Charlock was still in full flower, and from a distance 

 two green patches, afterwards discovered to be Plots 1 and 4, 

 stood out clearly in the surrounding blaze of yellow. The follow-' 

 ing notes were made : — 



Plot 1. About 75 per cent, of the Charlock had been destroyed, and tin- 

 remaining- plants were weakly, and much dwarfed. 



„ 2. The leaves of the plants were badly damaged, and about 50 per 

 cent, of the flower heads destroyed. 



„ 3. Plants slightly damaged. 



„ 4. About 85 per cent, of the plants were dead. This was decidedly 



the best plot of the series. 

 „ 5. Untreated. 

 „ 6. > 



_ > These plots showed no improvement on the untreated plots. 

 ,, 8. Untreated. 



„ 9. Here the spray had evidently been badly distributed. On that 

 half of the plot at which the spraying was started, the effect 

 was as great as on Plot 4, but, on the other half, not more 

 than 30 to 40 per cent, of the Charlock had been killed. < »i e 

 may assume, therefore, that the first half of the plot had 

 received at least twice as large a dressing of the spray as the 

 second half — say at the rate of 150 lb. to the acre. 



.. 10. Practically no effect. 



As regards the crop, the Barley on the sulphate of copper and 

 the sulphate of iron plots showed marked yellowing four days 

 after the spraying, but, on the final examination on June 21st. 

 it had quite recovered, and showed no signs of damage. 



On the whole the results of these trials were better than had 

 been anticipated, but it was felt that their value had been seriously 

 depreciated by the unsuitable weather conditions, which pre- 

 vailed at the time of spraying. The season was very backward, 

 especially in the West Riding, and as the f'harloek there was 

 still in full flower, it was decided to rercut the experiment in a 



