THE TRINITY CLAY. 5 



tered in the soil survey work have received any systematic protection 

 through the construction of levees or embankments to shut out the 

 spring floods. 



The Trinity clay is very little subject to erosion, the principal 

 damage being done along the convex bends where the larger streams 

 occasionally cut into their banks disastrously. Over the surface 

 of the type the slopes are so gentle that deposition rather than erosion 

 takes place at the time of high water and of abundant rainfall. 



LIMITATIONS IN USE. 



The Trinity clay, because of its fine-grained texture and dense 

 structure, is not well suited to the production of any except the staple 

 crops of the regions where it occurs. It is recognized universally as 

 a strong productive soil for the growing of cotton and of corn, and 

 in areas where it is naturally or artificially protected from overflow 

 it is also suited to the growing of alfalfa. These are the dominant 

 crops over the entire tilled area of the Trinity clay. 



The organic-matter content of the surface soil is unusually high, 

 both because of the character of the original material and because of 

 its mode of deposition as a stream sediment frequently laid down in 

 small quantities over and among the remnants of previously existing 

 vegetation. 



Probably one of the greatest difficulties encountered in the cultiva- 

 tion of the Trinity clay, aside from its liability to overflow, lies in 

 the stiff plastic nature of the soil materials and the difficulties which 

 are experienced in the proper plowing and subsequent tillage of this 

 type. Whenever the soil is plowed with an excess of moisture pres- 

 ent in the surface soil the furrow is turned in the form of a con- 

 tinuous unbroken ribbon of clay which subsequent tillage operations 

 are usually unable to reduce to proper seed-bed condition. On the 

 other hand, if the soil is allowed to become too dry before being 

 plowed the furrow consists of a succession of hard clods, which are 

 with difficulty reduced to favorable tilth. If, however, the Trinity 

 clay is plowed when it is at or near the optimum moisture content 

 it is possible to secure a well-granulated, friable seed bed, which 

 is easily kept in condition during the remainder of the season. 

 It is sometimes difficult to accomplish this proper plowing and prepa- 

 ration of the Trinity clay, owing to the fact that freshets may have 

 remained above the banks of the stream to an unusually late date 

 in the spring, thoroughly saturating both soil and subsoil and pre- 

 venting the preparation of the land at the proper season for the 

 planting of crops. Under such circumstances fields which otherwise 

 would produce excellent crops, annually, are of necessity left un- 

 planted to any tilled crop and not infrequently grow up to grass 

 and weeds. There is practically no remedy for these conditions 



