THE ADAMS ACT. 75 



The large number of soil investigations is a noteworthy feature of 

 the list of projects. Aside from studies of the fertilizer requirements 

 of soils and of laboratory methods and the composition of certain 

 crops as indicative of these requirements, the work includes the 

 nature and extent of the influence exerted upon crops by the previous 

 gi'owth of other kinds of plants, the relation between soil conditions 

 and the quality of crops, such as the staple of cotton, the effect of 

 sodium salts applied to the soil upon the organic and inorganic con- 

 stituents of plants, the role of phosphorus and of ])otassium in plant 

 nutrition, and the role of lime in the soil. 



There are also several projects dealing with humus, its nature and 

 determination, relations to soil fertility, rate of formation under 

 different conditions, behavior and conservation in the soil, and effect 

 of various factors on the humus content. To these are added studies 

 in soil bacteriology as related to humus formation and change, rela- 

 tion of microscopic life of the soil to fertilit}'- in general, nitrif3'ing 

 and other biological properties of the soil, determination of the 

 number, character, and biochemic functions of bacteria within the 

 zone of tillage, to ascertain the part these organisms play singly and 

 collectively in the setting free of plant food, and the bacteriological 

 conditions in irrigated and unirrigated soil in the arid region, with 

 special reference to the formation of nitrates and to the decomposi- 

 tion of barnyard manure. The number anel character of these in- 

 vestigations give much encouragement for a better understanding 

 of the complex factors which go to make up soil fertility and 

 adaptation. 



Closelv related to these studies are various chemical investigations 

 on plants and their products, such as the nonsugars in sugar cane, 

 their nature and amount and the conditions which affect their forma- 

 tion, with special reference to sugar manufacture ; the gluten content 

 of wheat, cause of its deterioration and methods of correcting, the 

 milling qualities of wheat as related to this and other factors; and the 

 factors affecting the lupulin, volatile oils, and other active principles 

 of hops. An investigation of the various sugars and coloring matters 

 in cacti is also in progress, and the rationale of the ripening of the 

 date is to be taken up. 



Animal nutrition does not claim a large number of investigations, 

 but these are of quite a different type from the ordinary feeding 

 and digestion experiments to v>'hich the work has in the past been 

 quite largely confined. Digestion experiments have been undertaken 

 with reference to some particular point, rather than the determination 

 of digestion coefficients for themselves. Among these are the be- 

 havior of the constituents of the nitrogen-free extract in digestion 

 and their relation to nutrition, the influence of certain feeding stuffs 



