6 SOILS OF THE EASTEKN UNITED STATES. 



be growing at the time. In consequence, areas immediately in front 

 of these upland gorges are rarely occupied for the production of hoed 

 crops, remaining either in forest or being used for grazing purpose. 

 This form of damage from erosion taking place over other areas is 

 unusual. 



LIMITATIONS IX 



The chief limitations upon the use of the Wabash silt loam lie in 

 the fact that it is subject to frequent overflow during the spring 

 months and in the additional fact that at all times its lower portions 

 possess but a very poorly established natural drainage. The water 

 table or zone of saturation in the subsoil is frequently found at a 

 depth of only 1 or 2 feet. In consequence the smothering of the 

 crop or its burial through sedimentation at times of overflow con- 

 stitutes a serious limitation upon the acreage which can be planted 

 to corn, small grains, or potatoes. These limitations do not hold, or 

 at least not to the maximum degree, with the grass crops which may 

 suffer a temporary overflow and make new growth through any shal- 

 low deposition of sediment, being often benefited thereby. 



The lack of local drainage and the presence of the water table 

 near the surface soil constitute limitations fully as serious upon the 

 crop use of the land. The type rarely, if ever, suffers from drought. 

 In consequence, during those years when overflows are not serious 

 nor prolonged, and in all locations where the altitude of the surface 

 above the normal water level is sufficient, maximum crop yields are 

 obtained. There is a constant tendency in all areas where the Wabash 

 silt loam is cultivated to plant as large an area as possible in corn each 

 year, despite the well-known danger from overflow. The majority 

 of farmers estimate that if they can produce three full crops out of 

 five plantings they will be amply repaid for the labor spent on the 

 land in all of the five years. 



In a number of instances cooperative organizations have been 

 formed to build neighborhood dikes for the protection of extensive 

 areas of the Wabash silt loam from overflow. In these instances the 

 farmers on large and small tracts in a favorable location within the 

 bottoms organize a diking district which corresponds in many respects 

 to the ordinary drainage districts of the Central States. Working 

 together they throw up dirt embankments to protect some broad 

 extent of the bottoms, usually bounded to the rear by the escarpment 

 of the uplands and circled in front by some wide bend in the river. 

 The dimensions of the dike must in all cases be governed by the 

 maximum stage which may be anticipated in the river waters and 

 by the local configuration of the bottom land. In some instances 

 dikes have been built so broad that a roadway is established upon 

 the top of the embankment. In others, on smaller projects, the top 



