POTATO SPRAYING AND DUSTING. 



13 



of tubers per acre on all the sulphur plots very materially. On the whole, however, 

 experiments carried out on a large field such as this, are of more practical value than 

 if only a few rows were treated. The variations in yield due to varying conditions 

 of soil and fertility would sometimes seem to confute all accepted theories. Again, 

 the results obtained may be such as to make the most sanguine theorist enthusiastic. 

 But in order to demonstrate fully the capabilities of any spraying material, as well as 

 those of the field on which the treated crop is grown, one must be fully acquainted 

 with the several conditions w^hich might influence the results either beneficially or 



adversely. 



Table IV. 



Yields of Tubers (Firsts and Seconds) at Robbinsville. 





Yield in bushels per acre. 



Averag 



'e of 



Nature of 

 Application. 



Series I. 



Series II. | Series III. Series IV. 



i 



the 4 series. 





Ists. 



2nds. 



Ists. 



2nds. Ists. 2nds. Ists. 



1 1 



2nds. 



i 



1 

 Ists. 2nds. 



1 



Bordeaux and Lead 

 Arsenate . , 



223-06 



8-86 



297-85 



12-90: 317-99 



1 

 1 



10-32 265-62 



25-00 276-13 



14-27 



Gypsum and Zinc 



- 



Arsenite (control) 



241-66 

 222-02 

 259-25 



7-86 

 9-72 



13-88 



217-58 



252-85 

 240-62 



1 



7-66 248-23 



1 



6-64 240-04 

 9-37: 296-20 



10-48 



5-15 



18-14 



20207 

 202-07 

 217-11 



26-03 

 21-87 

 11-33 



-236-64 



12-34 



Sulphur and Zinc 

 Arsenite . . 



263-88 



9-72 



256-94 



9-25 245-71 



14-45 142-69 



17-69 



224-31 12-77 



Electro-Bordo-Lead 



247-68 9-25 234-79 6-80 297-34 14-96 228-12 2500 251-98 



1 ' ill! 



14-00 



41-41 

 50-31 



24-41 

 17 



25-9 



8-9 



Avg. gain in bushels per acre (firsts and seconds) of Bordeaux plots over control 

 Avg. gain in bushels per acre (firsts and seconds) of Bordeaux plots over sulphur 

 Avg. gain in bushels per acre (firsts and seconds) of Bordeaux plots over electro 



Bordo-lead 

 Avg. gain in bushels per acre (firsts and seconds) of Bordo-lead plots over control 

 Avg. gain in bushels per acre (firsts and seconds) of Bordo-lead plots over sulphur 



and zinc arsenite 

 Avg. decrease in bushels per acre (firsts and seconds) of sulphur and zinc arsenite 



plots below control 



It will be observed by a glance at the last column that there is very little difference 

 in the average number of bushels per acre of seconds, the divergence in yields being 

 practically confined to the firsts. 



As regards previous cultivation, the field at Robbinsville had borne a potato crop 

 for three years (1912-13-14). In the autumn of 1912 it had been sown in rye, which 

 was ploughed in the following spring. After the potato crop had been dug, this same 

 operation was repeated in the autumn of 1913 and the spring of 1914. Fertiliser of the 

 formula 4-8-10 was appHed with the seed at the rate of 1,500 lb. per acre. 



