• 29 



Carringtoii J.odiit. There is considerable variation in texture 

 within the in(Hvichuil tieUls and from field to field (Table 17) on the 

 Kansan. tiiis beini,"" more pronounced in the third foot, sugsestinsr that 

 at this depth, disintegration has not proceeded as far on the younger 

 drift. ( )n the Late Wisconsin, the variation within the same field and 

 from field to field is not so great. Rurke and Kolbe (11, p. 22), in 

 describing this type, state that "the texture of the surface soil is for 

 the most part uniform, but the color and depth are variable. Areas of 

 minimum depth apparently have resulted from erosion, those of maxi- 

 mum depth representing more probably the natural conditions." 



It is to be observed that the moisture e(|uivalent is in most cases 

 higher for the second foot-section than for the 6-inch section above 

 this. The organic matter in forest soils, such as the Carrington loam, is 

 low even in the surface six inches and a lack of this, coupled wnth the 

 translocation of clay particles downward into the second foot may 

 account for this rather regular variation. The averages range from 

 24.8 in the surface section to 16.9 in the subsoil. 



Marshall Silt Loam. On this type (Table 18) considerable \aria- 

 tion wnthin Fields IT anrl I\' is shown and especially great differences 

 between Set 1 from Field II and Set 2 from b'ield I\', the former aver- 

 aging 16.3 and the latter 27.6, or nearly 70 per cent higher. To elim- 

 inate any chance of differences in speed of the centrifuge, etc., causing 

 this, the corresponding samples from these two fields were run side by 

 side (Table 19). It will be seen that these agree very closely with the 



Table ig. — Moisture equivalents of sain/^lcs from tzvo fields of Marsluill 

 silt loam. 



Field II, Set 1 

 Depth Det. Det. 



Inches 1 2 Av. 



1— 6 18.5 17.8 18.2 



7—12 16.0 16.5 16.3 



13—24 15.9 15.5 15.7 



25—36 15.7 15.1 15.4 



first determinations, so great a variation either within the same field or 

 between the dift"erent fields on this type was not anticipated. From its 

 loessial origin, a texture more uniform than that on a type developed 

 on the till was to have been expected. In Fields IV and V the moisture 

 equivalents for the different sections are distinctly higher than in the 

 three other fields. The area in which the former two are located while 

 originally on the very fringe of the forest has, for many years, been 

 clear even of brush and the fields on both sides of these "fence row" 

 fields have been kept under mixed farming conditions, which has per- 

 mitted an accumulation of organic matter somewhat similar to that 

 which would accrue under prairie conditions. While this might account 

 for the greater moisture holding capacity in the surface foot it could 

 not explain the variation in the lower sections. 



