114 



OROBANCHE AS A PARASITE IN BIHAR 



quantity of 0. cernua and the bulk of this had been concejitiated in a strip 

 along the eastern edge of the plot. In April; I'JIG, about 1 oz. of seed of 

 0. cernua was collected from this i)lot and scattered along the northern side of 

 the other plot, for about one-third of the breadth of the jilot, a light beam was 

 then run over the plot. In September, 1916, both plots were planted out with 

 tobacco ; there were 18 rows with 16 plants in each row, making a total of 

 288 plants in each plot. Instead of manuring the whole of one plot, the eastern 

 half of the western plot (A) and the northern half of the eastern plot (B) 

 received sodium nitrate. The nitrate was given in solution in three doses, as 

 in the previous year, and each plant manured received a total of 1 oz. of 

 nitrate. Thus in each manured area 1) lb. of sodium nitrate was distributed 

 among 144 tobacco plants. The scheme of the experiment in 1916-17 is 

 shown in Texb-figure 4. 



Infected wi^Aseed of- 

 0. cefnuiv\AprilJSI6 . 



^ 

 ^ 



I 

 I 



I 



c 



Nitrate 



N Urate 



Text-figure 4. 



The effect of the nitrate upon the tobacco was especially marked in the 

 case of eastern plot (B). This plot in the experiments of the two previous 

 seasons had not received anv nitrate and the tobacco in the manured half 



