agroforestry question

[TREEFARMER at webtv.net]

Todd we grow corn and soybeans, the only marginally profitable row crops
left in Midwestern agriculture. When we got out of cattle over 20 years
ago we planted the pastures to trees. At the time we went by soil types
and didn't pay much attention to seeps as they were hard to detect in
pasture situations. In addition we were in a dry cycle and many didn't
appear until the next wet cycle. In many cases the areas were small.
What seems to be the pattern is that small seedlings are affected long
before their roots even reach the 1-2' depths. The spots are always the
same. At this point, due to GPS yield mapping, one can pinpoint where
the best and worse areas of the fields will be regardless of the
weather. The seeps will be worse even in times of drought.