Introduction to Soil Chemistry

4 soil basics i
Ultisol
Ap 0 – 12.5 cm; very dark grayish brown (10YR 3/2) fine sandy loam, weak
fine granular structure.
E 12.5 – 22.5 cm; yellowish brown (10YR 5/4 ) fine sandy loam, weak fine
granular structure.
BE 22.5 – 35 cm; strong brown (7.5YR 5/6) fine sandy loam, weak medium
subangular blocky structure.
Bt1 35 – 55 cm; yellowish red (5YR 4/6) sandy clay loam; weak medium
subangular blocky structure.
Bt2 55 –104 cm; red (2.5YR 4/8) sandy clay loam, weak medium subangular
blocky structure.
Bt3 104 – 173 cm; red (2.5YR 4/6) sandy clay loam, weak medium
subangular blocky structure.
Bt4 173 – 188 cm; red (2.5YR 4/8) sand clay loam, weak coarse subangular
blocky structure.
Figure 1.3. An example of an Ultisol; this is the Bama soil series, which is the state soil of Alabama
(from Ref. 2).
material will be acted on by the other factors but will in turn provide the
support and minerals needed for plant growth and other activity.
Consideration of the larger components of soil might seem like a strange
place to start a discussion of soil chemistry, analysis, and instrumental methods.
However, these larger structures can and do affect the chemistry of a soil. For
instance, in many cases the larger features control the movement of air and
water in soil. Sandy textured soils will have higher infiltration and percolation
rates than will clayey soils. The same can be said for soils with good, strong