804 EXPERIMENT STATION RECORD. 



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 growth of other liinds of plants, the rela- 

 tion between soil conditions and the quality of crops, such as the 

 stajDle of cotton, the effect of sodium salts applied to the soil upon the 

 organic and inorganic constituents of plants, the role of phosphorus 

 and of potassium in plant nutrition, and the role of lime in the soil. 



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

 determination, relations to soil fertility, rate of formation under dif- 

 ferent 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, relation 

 of microscopic life of the soil to fertility in general, nitrifying and 

 other biological properties of the soi*l, determination of the number, 

 character, and biochemic functions of bacteria within the zone of 

 tillage, to ascei"tain the part these organisms play singly and col- 

 lectively 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 and character of these inves- 

 tigations give much encouragement for a better understanding of the 

 complex factors which go to make up soil fertility and adaptation. 



Closely 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 Avhich 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 prin- 

 ciples 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 frorn the ordinary feeding and 

 digestion experiments to which 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 behavior 

 of the constituents of the nitrogen-free extract in digestion and their 

 relation to nutrition, the influence of certain feeding stuffs in depress- 

 ing the digestibility of rations, and the nature and cause of this effect, 

 the process of digestion as influenced by certain factors, and the effect 

 of treatment or preparation of the feed on the digestibility of its con- 

 stituents. Among the fundamental studies in animal nutrition are 

 the influence of age and individuality on metabolism in cattle, an 



