New York Agricultural Experiment Station. 145 



One-half the combined yield of Rows 3 and 7 equals 993 pounds 

 which makes the yield of the sprayed rows at the rate of 194 bushels 

 and 37 pounds of marketable tubers per acre ; while the yield of the 

 unsprayed row was only 640 pounds or at the rate of 118 bushels 

 and 2^ pounds per acre. Hence, the increase in yield was at the rate 

 of 76 bushels per acre. 



We wished to obtain the yield of Row 4 for comparison with that 

 of Row 3 ; also the yield of Row 6 for comparison with Row 7. In 

 this way it could have been determined how anuch Rows 4 and 6 

 suffered because of their proximity to the blighted Row 5. But Mr. 

 Welch misunderstood our instructions and took the yield of Rows 

 I and 9 instead. It is interesting to note that had these rows been 

 selected to represent the sprayed portion of the field the increase in 

 yield would have been 81 5^ bushels per acre. 



The total expense of spraying- these 3>4 acres five times was 

 $13.43, the items being as follows: — • 



94 lbs. copper sulphate, at 6%c $6 11 



2 bushels lime 32 



18 hours labor, man and team 6 00 



Repairs on outfit 40 



Interest on investment ($10, at 6% ) 60 



Total $13 43 



The cost of spraying per acre for each application was yj cents. 



As the increase in yield was at the rate of 76 bushels per acre, 

 the total gain due to spraying 3>4 acres must have been 266 bushels 

 of potatoes worth $133. Deducting the expense of spraying, $13.43, 

 there is left $119.57 which is the net profit on 3>^ acres. This is at 

 the rate of $34.16 per acre. 



The soil in the field was a gravelly clay loam. The variety of 

 potato was Carman No. 3. 



