140 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



ress include studies of all problems bearing on this point, such as the 

 economic use of fertilizers, the retention of the proper quantity of 

 moisture by the soil and its use by the growing crop, rotative cropping, 

 green manuring, especially with leguminous plants, the action of bac- 

 teria in relation to soil fertility, etc. The dillerent types of soils are 

 studied in regard to the reduction of fertility by cultivation, and many 

 interesting and valuable facts are being brought out. To give an 

 instance of this kind, the Nebraska station found that the cultivated 

 loess soils of the State contained as much phosphoric acid, potash, and 

 lime in the surface as in the subsoil, but that the content of nitrogen, 

 humus, and unhumified organic matter decreases rapidly from the 

 surface downward. This indicates that the maintenance of fertility 

 in so far as chemical composition is concerned is essentially a matter 

 of keeping up the supply of total organic matter. 



The extent to which some of the experiment stations are extending 

 their work throughout their States is illustrated by one station, 

 which has two regular substations, and the management of twenty- 

 five county and as3dum farms used for experiment and demonstration 

 purposes, had the past year 1,600 centers where its pedigreed barley 

 was being growTi for breeding and increase, and over 20,000 boys 

 growing corn and barley for prizes. Among the prizes are scholar- 

 ships covering all the expenses of a week's attendance on a young 

 people's corn and grain course at the college, 20 boys receiving such 

 prizes and attending the course last year. 



More attention is being given from year to year to crop production 

 under dr}^-farming conditions, which is essentially a matter of moist- 

 ure conservation. The stations have done valuable work along this 

 line, and in many States this is given recognition by the establish- 

 ment and maintenance of dry-farming experiment stations at the 

 expense of the State, but under the general direction of the central 

 station receiving the Federal funds. In many instances the work of 

 these dry-farming stations is carried on in cooperation with this 

 Department. This work is doing much to put farming in the dry 

 regions on a safe and enduring basis. 



The New Jersey station has shown that nonleguminous plants, 

 such as corn and cereals, grown in close association with legumes, 

 benefit in some manner by the nitrogen-fixing ability of the legumes. 

 This benefit is quite marked; but the channel through which it is 

 exerted has not yet been determined. 



The experiment stations in several States are supplementing and 

 extending the Department's work on hog-cholera vaccine by testing 

 its use extensively and manufacturing it for distribution under state 

 funds. 



Work at one station for nine years has demonstrated wide rations 

 to be more profitable and economical for dairy cows than the theoret- 



