ANNUAL REPORT, 1932 11 



for tobacco was started in 1032. The organic nitrogen was supplied by cotton- 

 seed meal, and the inorganic nitrogen by a mixture of equal parts of sodium 

 nitrate and ammonium sulfate. The fractions of organic nitrogen were 1/8, 2/8, 

 3/8 and 4/8 of the whole. Comparison was made with the standard mixture. The 

 highest yield (1954 pounds) was obtained with 1/8 organic 'nitrogen and 7/8 in- 

 organic, followed by 4/8, 3/8 and 2/8 organic. All mixtures yielded more than 

 the standard mixture. Since organic nitrogen is generally assumed to have an 

 especially favorable influence on quality of tobacco, it will be necessary to await 

 the sorting records for these treatments before they can be properly evaluated. 

 The experiment on different total amounts of nitrogen was discontinued in 1932. 



Method of applying fertilizer. Prof. C. I. Gunness of the Agricultural Engineer- 

 ing Department modified the transplanting machine used in these experiments so 

 that fertilizer could be placed by the machine at the time of setting tobacco. The 

 fertilizer was placed in bands 3 inches wide at each side of the plant and 1 inch from 

 it. The standard broadcast application of 3500 pounds per acre was compared 

 with machine application of 4/8, 5/8 and 6/8 of the standard amount of fertilizer. 

 The average yields of tobacco (pounds per acre) were as follows: 



Machine Broadcast 



Application (Check) 



4/8 Standard application 1846 Standard application 1822 



5/8 Standard application 1732 Standard application 1855 



6/8 Standard application 1861 Standard application 1881 



Comparable experiments were conducted on several private farms of the 

 vicinity. Results obtained thus far from these experiments are similar to those 

 obtained on the station plots. On account of the possible residual effect of fer- 

 tilizers used in previous years, it will be necessary to continue this experiment 

 several years on the same field. 



Distribution of Nitrogen in the Tobacco Plant. (W. S. Eisenmenger.) 

 Tobacco plants were grown in nutrient solutions for about one month. They were 

 then divided into four groups of fifty plants each. Two groups received the same 

 complete nutrient solution — one growing in normal light, the other growing in 

 complete darkness. From the other two groups nitrogen was withheld — one in 

 the light, the other in darkness. The plants were continued thus for eleven days. 

 At the end of this period all were harvested and divided into roots, stems, mid 

 vein and residual leaf portion. They were kept frozen until they were analyzed 

 for total and water soluble nitrogen, a - amino acids, ammonia, amides, protein, 

 peptid, humin, and nitrate nitrogen. The results indicated that much of the ni- 

 trate is reduced in the aerial portion of the plant, at or near the mid vein. Dark- 

 ness increased the nitrate and a-amino acid in the plants and decreased the leaf 

 weight. Withholding nitrogen lowered the dry weight of roots and stem. 



The results of this investigation have been accepted for publication in the 

 Journal of Agricultural Research. 



Toxicity of Aluminum for Tobacco. (W. S. Eisenmenger.) Tobacco 

 plants were grown in nutrient solutions for slightly less than two months. The 

 solutions were renewed every second day. For two days they grew in a complete 

 nutrient solution (Knop's), and on the succeeding two days the solution was the 

 same except that phosphates were withheld and aluminum citrate was added in 

 varying concentrations — 0, 2, 5, 15, 30, 50, 70, 85, 95, 98, and 100 per cent of .006 

 Mol. Definite toxicity effects were indicated in the dry weights of top and roots. 



Similar toxicity effects are being determined for the seedling stage of soy beans, 



