This farm has mostly D and some E slopes and is the farm that had a 4 inch hail storm the spring of 1998 and is the subject matter of the next 3 pages. The terraces are about 18 years old and were silted almost level full of soil in many places when we started to farm this ground 5 years ago.
I hauled out dirt down to the depth of the hood of this pickup to get to the original soil level. Just think of how much soil would be in Louisiana if these terraces weren't here!
Below you see the different color layers. The silt on top is clay and gets darker as you dig deeper. This same color transition is occuring on our flood bottoms. Our once black bottom ground is becoming lighter as clay silt floods in.
Something else I have noticed by digging down to the 2 to 4 foot depths is that these silted soils are tightly packed unless there are nightcrawlers there. Obviously sub-soilers don't go this deep and even frost and/or drought probably won't heave and fracture the soil at this depth.
I see many tillers subsoiling this fall but I wonder if they are doing much good. Our neighbor deep sub-soiled last fall and this year he had water running off of his fields from only 1 and 2 tenths rains. Our 18 year No-Till field (with nightcrawlers) across the fence didn't lose a drop with 1 inch hard rains.