NITROGENOUS FERTILIZERS FOR TOBACCO 9 



Table 6. — Mean burn in seconds of tobacco grown with fertilizer 

 IN which the ratio of organic to inorganic nitrogen varied, 1932-1934 



Percentage of Total Nitrogen Darks Seconds 

 as Organic 



12.5 14.4 26.5 



25.0 16.3 24.5 



37.5 17.0 26.5 



50.0 15.2 34.0 



50.0* 15.9 83.5 



♦standard mixture 



This experiment was conducted through a period of good tobacco-growing 

 seasons, and the average yield and quality are high with all treatments. A 

 cover crop of oats was grown each year following the harvest of tobacco and 

 was plowed under the following spring. This annual supply of organic matter 

 may have been an important factor in the outcome of the experiment. In 

 view of previous experiments (4) conducted on the same soil type in an ad- 

 joining field, the differences shown in Table 5 are no considered significant. 

 The important point to be gained from the data is that neither yield nor grade 

 suffered materially by reducing the percentage of organic nitrogen to one 

 fourth that of the standard mixture. However, Table 6 indicates that the 

 fire-holding capacity of the leaf decreased slightly as the percentage of organic 

 nitrogen decreased. This is in line with theory already advanced. 



Method of Applying Fertilizer 



It has long been the custom in the Connecticut Valley to broadcast tobacco 

 fertilizer on partially prepared land and harrow it into the soil with a smooth- 

 ing harrow. This is done in advance of setting the plants, preferably about a 

 week before. Tobacco plants are then set by a machine. Mixed fertilizer is 

 used at the rate of 3,000 to 4,000 pounds per acre. 



The purpose of this experiment was to see whether, by applying the fertilizer 

 in bands near the plants, the rate of application could be reduced without 

 materially reducing yield and quality of the tobacco. Previous experiments 

 conducted at this station with corn (7) had shown an advantage of row appli- 

 cation of fertilizer over broadcasting, but the rates per acre were smaller than 

 are used for tobacco in the Valley. 



The experiment was started in a preliminary way in 1930. In that year 

 and again in 1931 the row applications were made in an open furrow, and 

 were mixed into the soil by means of a heavy log chain which was dragged 

 through the furrow. Experiments with corn and other crops (7) had shown 

 that in general the best placement for fertilizer was in bands on each side of 

 the seed but not in contact with it. The tobacco transplanter regularly used 

 in experimental work, and of the same make as that commonly used by Con- 

 necticut Valley farmers, was so altered that it placed the fertilizer in two 

 parallel bands 3 inches wide and 3 inches apart, about 1.5 inches beneath the 

 surface of the soil.'* Thus the plants were about 1.5 inches from each band of 

 fertilizer. By this method the fertilizer was applied and the plants set in one 



* The construction of the special fertilizer attachment was under the direction of Professor 

 C. I. Gunness, Head of the Department of Agricultural Engineering. A hopper was built, to 

 which were attached hose lines which carried the fertilizer to specially constructed "shoes." 



