48 MASS. EXPERIMENT STATION BULLETIN 305 



DEPARTMENT OF PLANT AND ANIMAL CHEMISTRY 

 Edw. B. Holland in Charge 



The Effect of Fertilizer and Cultural Treatment on the Composition of Havana 

 Tobacco. (E. B. Holland and E. Bennett.) During the past five years numerous 

 samples of different grades of cured and sweat leaf from the station plots have 

 been analyzed and the data are being compiled for publication. The results 

 indicate a distinct increase in nitrogenous compounds and decrease in ash of the 

 web from the base of the plant upward, a noticeable effect of different amounts of 

 applied nitrogen, and seasonal influences difticult to explain. The trend in other 

 plant constituents — fat, fiber, and nitrogen-free extract compounds — in the 

 grades is not as apparent. 



Supplementary work on popular brands of smoking tobacco and of cigarettes 

 has also been continued. A study of seasonal influences on the yield and per- 

 centage of the more remunerative grades has shown a distinct correlation for 

 seven years with five cropping systems, but additional seasons will be necessary 

 for confirmation. 



Oil Sprays. (E. B. Holland.) Miscibles were prepared from special lubricat- 

 ing oils of three different manufacturers, with triethanolamine and oleic acid as 

 the emulsifying agent. These oils had a Saybolt viscosity of about 100 but 

 varied appreciabh' in density and percentage of unsulfonated residue. The 

 main objective this season was to determine whether oils of somewhat higher 

 content of unsaturated hydrocarbons would prove toxic to the fruit trees. The 

 miscibles were applied at concentrations of 2 and 3 per cent of lubricating oils 

 by weight and no ill effects were observed, but the infestation of European red 

 mite was too slight to afford much evidence on control. 



The number of emulsifying agents on the market is increasing rapidly and one 

 commercial "base oil" mixed with three parts of spindle oil was tested in 2 and 

 3 per cent concentrations with satisfactory results. The use of such products 

 makes the preparation of a miscible a relatively simple matter for any fruit 

 producer. 



Cooperative Investigations. (E. B. Holland.) An investigation of the causes 

 and prevention of injury to greenhouse cucumber plants from spraying with 

 various copper fungicides followed by hydrocyanic acid gas has been concluded 

 and prepared for publication. The work was conducted by E. F. Guba at the 

 Waltham Field Station. 



A study of the effect of "dark center" on the composition of turnips has been 

 reported. The initial changes are characterized by a substantial loss of sugars 

 with an increase in protein, fiber, and ash. These analyses supplement the work 

 of G. B. Snyder and R. W. Donaldson relative to the control of the disorder. * 



A large amount of analytical work was expended on ice cream stabilizers in 

 connection with problems of the Dairy Department. 



Nitrogen Fixation in the Presence of or as a Result of the Growth of Legumes 

 versus Non-Legumes Under Certain Defined Agronomic Conditions. (F. W. 



Morse.) The comparison of legumes with non-legumes was continued this 

 year with alfalfa and barley. To prevent weeds overtopping alfalfa, the field 

 was repeatedly harrowed up to July 20. On August 5 the field was sown with 

 alfalfa and barley. The latter was at its full height October 10. A severe frost 

 on October 25 stopped all further growth, and three da>s later the plants with 

 nitrogen fertilizers were prostrate while those without it remained erect. 



