12 MASS. EXPERIMENT STATION BULLETIN 315 



sorting quality of tobacco for 1932 and 1933 was slightly better from mixtures 

 containing Y2 organic nitrogen. 



Method of Applying Fertilizer. This experiment was continued in 1934 with 

 the same methods and equipment as were used in 1932 and 1933. The average 

 yields were as follows: 



Row Application Broadcast Application (Check) 



Pounds Pounds 



per acre per acre 



4/8 Standard amount 1737 Standard amount 2032 



5/8 Standard amount 1759 Standard amount 2022 



6/8 Standard amount 1798 Standard amount 1994 



These figures show a greater advantage of the standard (full) amount broad- 

 cast than has been shown in the preceding four years of this experiment. The 

 experiment should be continued to determine whether the differences obtained 

 represent anything more than a seasonal variation. Such data as have been 

 obtained on sorting quality of the crop grown under the two methods of fertilizer 

 application show no significant difference. 



Toxicity of Aluminum for Tobacco. (\V. S. Eisenmenger.) As reported in 1933, 

 tobacco plants were grown in aluminum citrate solution for two-day intervals 

 and on the alternate two days in a complete nutrient solution. The decided tox- 

 icity begins at about 17 ppm. of aluminum. 



Other plants were grown in solutions containing aluminum citrate and calcium 

 nitrate in relative proportion of 0.006 M of each salt represented as follows in 

 terms of percentage molecular proportions: 



Aluminum Citrate Calcium Nitrate 



100 



95 5 



85 15 



75 25 



50 50 



15 85 



5 95 



100 



The results would indicate that the calcium ion was a decided factor in over- 

 coming the toxic principle of the aluminum. 



Distribution of Nitrogen in Soils Mixed with Different Plant Tissues and 

 Allowed to React for Six Months. (W. S. Eisenmenger and W. J. Moore.) As a 

 sequel to the determination of forms of nitrogen in infusions, an attempt is being 

 made to perform similar determinations on plant tissue under more aerobic condi- 

 tions. One part of chopped plant tissue was mixed with two parts of soil in crocks 

 and allowed to stand in the greenhouse. Water was added to keep the soil approx- 

 imately moist enough to grow plants. At the end of a six-month period the 

 materials are being analyzed for nitrogen, total nitrate, ammonia, amide, alpha 

 amino acid, protein, and humin. The plant tissues used were red clover, alfalfa, 

 red top, timothy, corn, and tobacco. 



The Relationship of Mineral Nutrients to the Nitrogen Content of Tobacco 



Plants. (YY. S. Eisenmenger and H. R. Knudsen.) Tobacco plants were grown 

 in different ratios of elements, according to the triangular system used earlier 

 by Schreiner and others, to determine the approximate ratio at which plants thrive 



