RELATION OF STAND TO YIELD IN HOPS. 1 



By W. W. Stockberger, Physiologist, and James Thompson, Scientific Assistant, 

 Office of Drug-Plant, Poisonous-Plant, Physiological, and Fermentation Inves- 

 tigations. 



INTRODUCTION. 



Among many hop growers the impression prevails that the average 

 yield of hops per acre is annually growing less and that the produc- 

 tivity of a large proportion of the hop soils is decreasing. The 

 statistical data on this point, however, are so meager that it seems 

 unwise to draw from this source very definite conclusions regarding 

 the increase or decrease in yield per acre. From the records of the 

 United States Census the average yield per acre of hops can be 

 determined only at 10-year intervals throughout a period of 30 

 years, and since the figures for any given year will vary widely, 

 depending on whether a light or a heavy crop is produced, it is mani- 

 festly unsafe to assume that the averages for the census years neces- 

 sarily represent actual conditions for the intervening years. If 

 records of the average yield were available for each one of the 30 

 years the evidence of the figures might be accepted as a fair indica- 

 tion of the general trend of the yield of this crop. 



The average yield per acre is materially influenced by a number 

 of factors, prominent among which are seasonal conditions, soil type, 

 and cultural methods. In case large areas are under consideration, 

 such as a county or State, extensive changes in acreage or a shifting 

 of the area of production may also materially affect the average 

 yield. When such modifications take place, changes in the average 

 yield reported for the given area have little bearing on the question 

 of diminishing crop yields. Nevertheless, the statistical data on the 

 average yield per acre in the several hop-growing States and in the 

 chief hop-producing counties therein are worthy of careful considera- 

 tion by every grower of hops, but it is of far greater importance that 

 he should be fully informed as to the successive yields of his own 

 fields. 



On certain types of soil not so well adapted to hops as the richer 

 alluvial soils there is ample evidence of a declining yield, due funda- 

 mentally to soil conditions. This decline is most noticeable in hop- 

 yards located on uplands where beneath the shallow surface soil 



i Issued Feb. 8, 1913. 

 [Cir. 112] 25 



