6 SOILS OF THE EASTERN UNITED STATES. 



over any portion of either type of soil which, through continued cul- 

 tivation, is exposed to washing. As a result many fields, particularly 

 of the Porters loam, which have been cleared and brought under 

 cultivation in the past have been so severely gullied and washed 

 that further cultivation has become impossible, and a considerable 

 proportion of the area of the type once cleared has been allowed to 

 revert to a forested or a brushy condition. Over other considerable 

 areas the persistence of at least some portion of the original forest 

 has prevented the excessive erosion, but the cutting of the forest 

 cover would undoubtedly result in the rapid bodily removal of the 

 surface soil and of considerable portions even of the subsoil. 



In consequence of rough topography, of the remote location of con- 

 siderable areas of both types from transportation and from market, 

 and of a strong tendency toward excessive erosion, only small propor- 

 tions of the Porters loam and Porters black loam are now occupied 

 for agricultural purposes. 



LIMITATIONS IN USE. 



The Porters loam is well suited by its texture and other physical 

 characteristics to the production of the general farm crops adapted 

 to the climate in which it occurs. It is not particularly well suited 

 to any special crops, with the possible exception of Irish potatoes and 

 cabbages. There are many restrictions upon its possible uses which 

 are imposed, not by the character of the soil itself, but by the topog- 

 raphy of the region which it occupies and by the limitations of trans- 

 portation facilities. Frequently after a few years of cultivation the 

 organic matter content of the surface soil of the Porters loam be- 

 comes decidedly reduced, and if at the same time this is accompanied 

 by serious erosion, large areas of the surface soil are bodily removed 

 and the farmer finds himself dealing with the less tractable and less 

 productive subsoil materials. 



Erosion is probably the most serious problem which is encountered 

 in the agricultural occupation of the Porters loam or Porters black 

 loam. Torrential rainfall occurs not only during the earlier spring 

 months, but at all periods of the growing season. The slopes within 

 the areas of these two types range from a 7 or 8 slope to maximum 

 slopes of 30 and 35. The latter are altogether too steep for culti- 

 vation and should never hare been cleared. Even the lighter slopes 

 are so great as to give rise to rapid run-off of the rain water and to 

 the speedy removal of surface soil, unless special precautions are 

 taken to retain it in its place. As a result, deep gashes and gullies 

 have been cut through many cultivable fields, and entire farms and 

 even districts have been ruined for all present agricultural purposes 

 through the excessive erosion of the soil. A part of this damage has 

 been needless, since ordinary precautions would have made possible 



