TOBACCO INVESTIGATIONS. 6 



development of the disease-producing organisms, and which, at the same 

 time, is mifavorable for the optimum growth of the tobacco? 



7. What corrective fertihzation and cultural methods may best be 

 employed in the latter instance? 



Briefly, the investigation may be divided into three main parts, as 

 follows : — 



1. A study of the meteorological factors as related to the growth of tobacco. 



2. .4 biochemical study of the soils of normal and "sick" fields, including 

 fertilization experiments. 



3. A study of the micro-flora and micro-fauna of normal and "sick" soils, 

 including those forms found to be imrasitic on tobacco. 



Is THE Tobacco Crop actually failing? 



It has been repeatedly stated that the average yield per acre of tobacco 

 in Massachusetts is decreasing gradually, and has been so doing for the 

 past ten or fifteen years. This, if true, would be very alarming, and 

 would indicate a widely distributed, serious situation due to parasites 

 or to improper cultural methods. The following data will show the 

 situation as it really is. Some years ago the United States Department 

 of Agriculture, through its Bureau of Statistics, began reporting various 

 data regarding the principal crops of the United States. Tobacco was 

 included, and the following data have been secured from the annual 

 figures as published in the various Year Books of the Department. 



The average yield of tobacco in Massachusetts from 1870 to 1910 is 

 calculated as 1,580 pounds per acre. At present this would seem a rather 

 high figure, as the acreage devoted to shade-grown Cuban has increased 

 in the past ten years, until in 1918 approximately 1,100 acres were devoted 

 to this crop out of a total acreage of some 9,000. The yield of shade 

 tobacco is much less than field-gro^mi, not averaging over 1,000 pounds 

 per acre, and this low yield of the Massachusetts acreage would of necessity, 

 reduce the average yield, if yield is calculated on total acreage. However, 

 as no other figures are available, the above-mentioned average is taken 

 for the period 1870 to 1910. 



The yield per acre is plotted in Fig. 1, and is self-explanatory. The 

 straight broken line indicates the average yield. The heavy black line 

 represents the seasonal variation. 



It is at once apparent that until the disastrous seasons of 1915 and 1916 

 the yield over a period of fourteen years was, with four exceptions, well 

 above the average, and two of these years, 1902 and 1913, were only 

 slightly below the average. If we average the yields as plotted for the 

 eighteen years we find that, even with the exceedingly low yield of 1915 

 included, the average yield for the period has been 20 pounds above the 

 average yield calculated for the forty-year period of 1870-1910, — namely, 

 1,580 pounds. 



It is only too true that the figures available are based on estimates 

 which are, perhaps, somewhat at variance with the actual facts; but in 



