No. 7. DEPARTMENT OF AGRICULTURE. 213 



it is possible that we may find some other material or method of 

 destroying such substance, either more effective or more economical. 

 In coming- into this State it seemed to the Director of your Station 

 that this rotation fertilizer experiment, which has been carried on 

 for a quarter of a century, offered an opportunity for study of 

 soil problems on a scale and in a manner not heretofore attempted. 

 The previous chemical studies which have yielded some splendid 

 results have been mostly on soils handled in a highly artificial 

 manner and not on soils in which differences in yield have been 

 obtained under ordinary field conditions. The Pennsylvania Ex- 

 periment Station has, therefore, organized a laboratory for the 

 study of soil problems and the extended study of the various pos- 

 sible factors of plant grow^th is being made during the growing 

 season and, in some instances, during the whole year on plots which 

 give striking differences in yield. 



To summarize briefly, then, the problem of soil investigation as 

 it relates to Pennsylvania appears to the Director of your Station to 

 consist of three steps: (1) a soil survey by which the soil types of 

 the State may be located and correlated; and the general character- 

 istics and crop adaptation carefully described; (2) a study by plot 

 tests in co-operation with farmers or otherwise of the XJi'incipal soil 

 types, so that the influence of fertilizers or cultural methods may 

 be reasonably predicted; (3) a study of the different factors of plant 

 growth on these different soil types when dift'erent treatments ex- 

 hibit marked differences in yield or quality of product in order, if 

 possible, to determine the fundamental reasons for such differences. 



A soil survey of this State is w^ell advanced, having been begun 

 in 1890 by the Bureau of Soils of the United States Department of 

 Agriculture. In two or three years it is hoped that a reconnoiss- 

 ance map of the whole State may be completed. The Pennsylvania 

 Experiment Station is carrying on co-operative fertilizer tests in 

 different parts of the State to determine the fertilizer require- 

 ments of the soil. When the soil t^-pes have been determined, it 

 will be desirable to prosecute this work in a more systematic man- 

 ner. A study of the fundamental questions relating to plant growth 

 was begun in March. 190S, at the Experiment Station upon Hagers- 

 town clay loam. If this leads to important results it will be ex- 

 tended to other soil types. In the meantime, if the farmer will 

 raise an abundance of leguminous crops, establish a proper crop- 

 ping system, keep one mature neat animal or its equivalent to each 

 four acres of land, he need not be alarmed over the question of soil 

 fertility on most of the soils of Pennsylvania. 



SOIL RESOURCES AND THEIR UTILIZATION. 



Bt M. Earl Carr, B. S., of the U. S. Department of Agriculture, Bureau of Soils, 



Washington, T>. C. 



Tlie soils of the United States are by far the greatest natural 

 resources of the country, and as such should not only be intelligently 

 utilized but carefully conserved that their productivity for future 



