46 



YIELD OF BARLEY. 



X. W. A. Mackenzie. " Studies in Crop Variation. HI. 



An Examination of the Yield of Dressed Grain from 

 Hoos Field." Journal of Agricultural Science, 1924. 

 Vol. XIV., pp. 434-460. 



Records of the barley yields for 70 years have been 

 analysed in the same manner as in the earlier study of 

 the Broadbalk wheat results. Thirteen of the plots supply an 

 unbroken record of manurial treatment. The variation of these 

 is analysed into three portions representing (I) annual variations 

 ascribable to variations in the weather; (II) steady deterioration 

 ascribable to soil exhaustion; (III) slow changes other than steady 

 deterioration. The annual variations are in general similar in 

 comparable plots to those found with wheat, barley being on the 

 whole the more variable. The average yields bring out the 

 striking fact that no gain in yield can be ascribed to dressings 

 of sulphate of potash, although the responses to superphosphate, 

 rape cake and silicates (in the absence of superphosphate) are in 

 all cases excellent. The failure of potash to improve the yield 

 is brought out decisively by a comparison of the rates of deterio- 

 ration, which seem to indicate that plots receiving potash have 

 fallen off more rapidly than parallel plots without potash. The 

 slow changes other than steady deterioration are smaller than 

 on Broadbalk, and do not indicate, as on that field, any single 

 simple explanation. 



EFFECT OF MANURES ON GOUT FLY ATTACK. 



XI. " Mathetes." " Statistical Study of the Effect of 



Manuring on Infestation of Barley by Gout Fly." 

 Annals of Applied Biology, 1924. Vol. XL, pp. 220- 

 235. 



This paper is a statistical analysis of the extensive 

 data on gout fly infestation compiled by the Entomological 

 Department for the years 1922 and 1923. (See Paper XLIX.) 

 A preliminary examination of the agreement of parallel samples 

 showed that in the data from Woburn and from the several 

 experiments with malting barley the infestation was homogeneous 

 over each plot. In two of the malting barley series significant 

 differences appeared in the infestation of different plots; the same 

 effect was even more strongly shown at Woburn. On Hoos 

 field (1922) the individual plots were not homogeneous in infesta- 

 tion, but the differences between plots were so large and so 

 consistently related to manurial treatment as to deserve a more 

 detailed investigation. 



Of ten comparisons possible with superphosphate all indicated 

 that this manure materially decreases gout fly infestation, even 

 in the two cases where, in the absence of nitrogenous manuring, 

 it has little cfl'ect upon the yield. The percentage infested, which 

 in the absence <>1 this manure ranged from '20 to II, is reduced 

 on the average by 5.1; similarly, rape cake reduced the per- 

 centage by 1.2 ; potassium, sodium and magnesium salts by 3.8; 



