THE MEMPHIS SILT LOAM. 7 



or band of partly compacted pebbly material. In all such instances, 

 also, the deeper subsoil is marked by a prevailingly light-gray color 

 only slightly mottled by yellow iron-stain along joints, crevices, and 

 root holes. The indications above mentioned are practically infalli- 

 ble in detecting poor drainage conditions in the areas of the Memphis 

 silt loam and its associated type, the Richland silt loam. 



Erosion is by far the most important problem in connection with 

 the tillage of the Memphis silt loam. Owing to the soft, noncohesive 

 character of the materials, not only of the surface soil and subsoil, 

 but also of the underlying silt ; because of the elevated position of a 

 large proportion of the type above adjoining drainage ways and the 

 great alluvial bottoms; and because of an almost universal tendency 

 to produce the intertilled crops upon this type, particularly cotton, 

 through a long series of years, great difficulty has been experienced 

 in preventing erosion. In fact this soil may only be maintained 

 against ruinous washing in the vicinity of the bluffs by allowing a 

 large proportion of its surface to remain in the native forest growth 

 of post oak, scarlet oak, Spanish oak, hickory, beech, and tulip 

 poplar. Even the ordinary pasture grasses are not competent to 

 serve as effective soil-binders upon the steeper slopes near the edge of 

 the bluff. The bond formed by the grass roots and the surface vege- 

 tation is not infrequently undermined by the cutting back of the gul- 

 lies to such an extent that great masses of the surface soil fall into the 

 gullies beneath and are dissolved and carried away by the torrents, 

 resulting from heavy rainfalls. In the more gently sloping areas, 

 however, the covering of the native grasses, such as Bermuda, lespe- 

 deza, and crab grass, is competent to maintain the soil against 

 erosion. Each has a low habit of growth and each develops an intri- 

 cate root system well suited to soil-binding purposes. All of these 

 grasses have a value, not only for pasturage purposes, but also for the 

 cutting of hay, and would be more generally appreciated for these 

 uses except for the cotton farmers' universal objection to any form 

 of grassy growth within the areas of cultivated fields. 



Upon the more level uplands, which are not threatened by the back- 

 ward cutting of gullies and the larger streams, the principal occupa- 

 tion of the type occurs. In such areas the surface water is usually 

 absorbed to a great degree by the deep surface soil, and erosion is not 

 serious. However, the areas possessing these gentle slopes occupy 

 but a small percentage of the total extent of the typical Memphis 

 silt loam, and these, particularly in the more southern localities, are 

 anually occupied to their full limit for the production of intertilled 

 crops like cotton and corn. Unless considerable care is taken in lay- 

 ing off the rows to form contours around the slopes, and unless in- 

 cipient gullies are immediately checked by the construction of brush 

 dams, erosion is liable each year to invade even these upland portions 



