THE WABASH CLAY. 7 



Very little attempt has been made in any of the areas where the 

 Wa basli clay has been encountered in the soil surveys to produce 

 other than a few general farm crops. All tree fruits are eliminated 

 because of drainage conditions and because of the depressed position 

 of the Wabash clay, precluding also proper air drainage. The char- 

 acteristic stiff clay is also poorly suited to the production of small 

 fruits or early garden vegetables. Only the later market crops, such 

 as cabbages, tomatoes, and eggplant, may be produced to advantage 

 upon land of this nature. In consequence, the chief crops produced 

 upon the Wabash clay are corn and, to a limited extent, wheat in the 

 more northern areas, and cotton, rice, and sugar cane in all of the 

 more southern areas sufficiently protected from inundation. 



IMPROVEMENT IN SOIL EFFICIENCY. 



Protection from inundation is the first requisite in the tillage of 

 additional areas of the Wabash clay. This is easily possible in many 

 instances through the construction of earth embankments or levees 

 which shall inclose and protect considerable areas of bottom lands, 

 including the Wabash clay and other valuable alluvial soils. Such 

 embankments have been constructed, not only in building the levees 

 which protect the Mississippi bottom lands from inundation, but also 

 for the agricultural occupation of the smaller areas along tribu- 

 tary streams in the more northern States. In all instances the won- 

 derful fertility of the Wabash clay where it is properly protected 

 from overflow has marked this soil type as one of those best repaying 

 the expense involved in the construction of such embankments. It is 

 probable that only the Wabash silt loam, which is generally associ- 

 ated with the Wabash clay, will better repay the establishment of 

 embankments and of drainage. 



Frequently in providing protection for this and other alluvial 

 soils, broad earth embankments are built within the alluvial bottom 

 lands to such height as is required to exclude even the highest over- 

 flows. In the case of the smaller streams these embankments usually 

 do not need to be particularly massive. The top of the embankments 

 may be no more than 2 or 3 feet broad. In the case of the larger 

 streams and of all subject to wide fluctuations in water level broader 

 embankments are required, and in the case of the levees of the 

 Mississippi and its major tributaries embankments 20 to 30 feet high 

 are not infrequently built, sufficiently broad at the top to furnish an 

 excellent roadway along the levee. In each particular instance the 

 area of the land to be drained, its probable agricultural value when 

 reclaimed, the -cost of constructing and maintaining the levee, the 

 interest charge upon the investment, and the proximity of the area 

 either to transportation or to near-by markets must all be consid- 

 ered as economic factors which will influence the success or the failure 



