50 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



The total amount of Federal aid actually appropriated for use up 

 to and including the fiscal year 1923 was $375,000,000. Of this 

 amount, $364,250,000 was apportioned among the States. 



The total mileage of highways in existence at the time of the 

 i:)assage of the Federal highway act, as certified by the State highway 

 departments, was 2,859,575 miles. Under the law the maximum 

 rnileage that can be included in the entire system is 200,170 miles. 

 The mileage included in the 35 systems approved up to the close of 

 the year was 111,699 miles, and- the total length of the whole system, 

 when it is finally designated and approved, will probably not exceed 

 179,000 miles. 



Analysis of the approved systems for the 35 States shows that of 

 the 1,111 cities of 5,000 population or more in these States 1,049 of 

 them lie directly on the approved system. When the Federal-aid 

 system is correlated with roads constructed by the States and coun- 

 ties, as it doubtless will be, the remaining cities of this class will cer- 

 tainly be connected with the main interstate system, and one will be 

 able to travel from any point in the country to almost any hamlet, 

 however remote, without leaving an improved road for more than a 

 iew miles at most. 



The indications are that these roads, when they are completed, will 

 pass within 10 miles of the homes of 90 per cent of the people of the 

 United States, considering the country as a whole. In some States 

 the percentage of the population thus served will be still greater, 

 reaching close to 100 per cent in a number of instances. 



TOBACCO GROWERS BENEFITED. 



Field tests conducted on "tobacco-sick" soils in the Connecticut 

 Valley have brought out marked differences in the effects of various 

 crops on the growth of tobacco following in the rotation. 



In extensive field tests in the southern manufacturing and export 

 tobacco districts it has been demonstrated that mixed fertilizers con- 

 taining 2 to 3 per cent potash and applied at the usual rate of 

 800 to 1,000 pounds per acre frequently do not supply sufficient pot- 

 ash for the tobacco crop. As a result, characteristic symptoms of pot- 

 ash hunger are frequently observed in the field. On light soils, and 

 especially in comparatively wet years, equally unfavorable results 

 may be expected when a sufficient quantity of magnesia is not con- 



