34 



various State organizations to solve as many as possible of 

 these diverse farm problems. It is the province of the field 

 work of the Bureau of Soils to solve one of the several im- 

 portant factors of crop growing namely: how to select soils 

 so that the different crops, and where possible the different 

 varieties of the same crop, may be grown with most profit. 

 It is for this economic reason that the study of soil adapta- 

 tion to crops is of so much importance. 



It may be said that the so-called "corn-belt" states owe 

 their title largely to the character of one soil type which oc- 

 curs in relatively large extent. The type is a black clay 

 loam and Iowa is the state that happens to possess the 

 highest percentage of this kind of soil. In Illinois, In- 

 diana and Ohio, it also occurs largely, and other kinds 

 of soil in the same climatic locality do not equal, and 

 rarely approach this in yield of corn. 



It may be worth while, to note here that our natural for- 

 est growth also indicates clearly that many varieties of 

 trees succeed best on certain kinds of soil. The local name 

 ^ 'black walnut land" is still used where that hardy tree 

 grows to indicate a heavy type of soil. In southeast Michi- 

 gan this is the Miami clay loam. The hickory thrives in the 

 northeastern states on the heavier soils. Black walnut and 

 hickory are both deep rooted trees. In the same region 

 "hemlock land" always indicates a sandy soil and the hem- 

 lock is not a deep rooted tree. In the orchard districts of 

 West Virginia the leading peach growers will not tolerate 

 "White oak" land but a mixed growth of " rock oak and 

 chestnut." about one-third of the former and two-thirds of 

 the latter, indicates a soil which has been instrumental in 

 making one of the most famous fruit districts in the world. 

 The rock oak and chestnut growth indicates a soil somewhat 

 stronger than that of chestnut alone, as a better supply of 

 moisture is maintained, newly cleared it is more productive, 

 and oven on old ground better results are secured from fer- 

 tilization. The subsoil is finer textured, that is more clayey, 

 than the chestnut subsoil, but soil is not so heavy as the 

 white oak soil. Yet on the latter some varieties of apple 

 thrive. Carrying a step further the matter of soil adapta- 

 tion to the different varieties of oak, it is a matter of com- 

 mon observation that poor and thin soils often support only 

 the dwarfish black jack oak and post oak. 



Shreve has found in his forestry studies in Maryland 



