44 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



A laboratory to develop work on the chemistry of crops was estab- 

 lished during the year. There is need for work concerning the in- 

 fluence of environment on the chemical composition of crops, 

 including certain features of fertilization, such as the relation of 

 composition of crop to the time of fertilizer application. Past work 

 on the composition of agricultural crops has been directed chiefly 

 toward what may be termed the quantity viewpoint. The new work 

 is directed more toward the subject of quality. The chemist is now 

 seeking to learn whether or not there is danger of producing quantity 

 at the expense of nutritive quality. For instance, it is known that 

 the application of a certain fertilizer, say, sodium nitrate, at a 

 definite time, as one month after sowing, to a crop like corn will 

 increase the yield quantitatively. However, practically nothing is 

 known about quality relations; that is, whether the proteins, vita- 

 mins, or mineral components of the corn so fertilized are superior 

 or inferior for animal and human nutrition. The economic value of 

 improvements in quality resulting from this research may exert a 

 marked influence upon future agricultural practices. 



The physical investigations conducted at the Arlington Experi- 

 ment Farm, Arlington, Va., and elsewhere with and without the 

 cooperation of other agencies are fast providing a scientific basis 

 for highway design, reducing uncertainty to a minimum and assur- 

 ing a greater degree of economy in highway construction expendi- 

 tures. As a result of observations made at the Bates road in Illinois, 

 a design for one of the types of highway surface has been formulated 

 which will reduce the cost by $1,500 a mile without decrease of 

 strength. The department cooperated with the Illinois Department 

 of Public Works and Buildings in this investigation. 



INSECT ENEMIES. 



The fight against insect enemies, which grows year by year, in- 

 volves the use of various methods for eradication and control, 

 and for preventing the introduction of new kinds from other 

 countries. During the past year progress has been made in intro- 

 ducing insect enemies of the corn borer from Europe. During 

 1922 more than a million specimens of one species were liberated in 

 the New England area. Arrangements have been perfected with 

 the Canadian department of agriculture to supply colonies of this 

 parasite for possible establishment in southern Ontario, where the 



