10 MASS. EXPERIMENT STATION BULLETIN 305 



Field Experiments with Tobacco. (A. B. Beaumont and M. E. Snell.) 



Cropping Systems. Results for the period 1924-1932 were summarized in the 

 last annual report and have since been published in Bulletin 297. 



In 1933 changes were made in the plan of the experiment which involved the 

 lengthening of the tobacco rotation and the substitution of new cover crops 

 for some which had been tried several years. As no lime had been applied to 

 the field since the beginning of the experiment, and the reaction of the soil had 

 been reduced to a fairly low point (about pH 5.0), all plots except five of the 

 check plots were given an application of limestone at the rate of 1 ton per acre 

 in the spring of 1933. (It should be understood that the differential treatments 

 listed were supplementary to fertilizer which was applied to all plots alike.) 

 Yields from the various treatments were: 



Pounds per Acre 



Check plots without lime 1894 



Check plots with lime 1809 



Manure supplement 2017 



Manure and red top cover crop 1747 



Oats cover crop 1 742 



Barley cover crop 1557 



Spring wheat cover crop (sown in the fall) 1545 



Clover cover crop 1 766 



Form Of Nitrogen. In the experiment with fertilizers having one half of 

 the nitrogen from cottonseed meal and the other half from different carriers, 

 the highest yield was obtained from the mixture containing calcium c\anamid, 

 closely followed by the standard mixture (containing a mixture of different 

 nitrogenous materials), urea, nitrate of soda, and ammonium sulfate. 



Quantity of Organic Nitrogen. In the experiment with different proportions 

 of organic and inorganic nitrogen, the highest yield was obtained from the mixture 

 containing 3/8 organic nitrogen and 5/8 inorganic nitrogen, while that containing 

 ]/i organic nitrogen gave the lowest yield. Tobacco grown in this experimeht 

 in 1932 showed little difference in grade index when sorted. 



Method of Applying Fertilizer to Tobacco. This experiment was continued in 

 1933 with the same methods and equipment that were used the previous year. 

 The average yields were as follows: 



Machine Application Broadcast Application {Check) 



Pounds Pounds 



per Acre per .'\cre 



4/8 Standard application 1782 Standard application 1900 



5/8 Standard application 1778 Standard application 1801 



6/8 Standard application 1885 Standard application 1852 



The experiment was repeated on one of the nearby private farms used in 1932. 

 The highest yield was obtained with the 6/8 standard application alongside 

 the row. 



Four \ears' results from this experiment indicate that the amount of fertilizer 

 may be reduced 1/4 to 3/8 without reducing yield or impairing grading quality 

 of tobacco, if the fertilizer is applied near the row instead of broadcast. In 

 addition, the operations of broadcasting and harrowing in fertilizer are saved. 



