If I were to give my little hobby farmette out here a name, it would likely be something like Gully Acres or Erosion Estate. Despite a couple of decades of levees, berms, pipes, rip-rap and money, there is more work to be done. Some once-tamed gullies are on the move again. There is a washout here and a new hole there. The good folks from the Natural Resources Conservation Service were out this week for a looksee. They are going to draw up a soil-saving plan for me to try to hold on to what I’ve got. They have been here before.
The problem is the combo of water having to go somewhere and the silt loam soil that got here from somewhere else. The story of our loess bluffs being formed eons ago is well known. Mississippi River post-flood sediments were blown in by westerly winds and dropped down this side of the river. Remember, the Mississippi, before it had a name, worked its way back and forth between Vicksburg and Monroe before they had theirs. It was a large area that supplied the sediment that went airborne way back when. We now define the word “loess” in English to mean “wind-blown.” However, it was derived from a German term that translates into “loose.” I say the German dictionary holds true because a good rain can sure cause this dirt to turn loose and leave with the water.
Loess is not a soil classification or soil mixture. Loam, however, is a mixture of the three soil particles sand, silt and clay. These three are actually the size ranges of individual particles. Sand particles are huge by caparison to the others and clay is microscopic small. A single silt particle can be seen by the human eye. Well, make that a healthy human eye. Puny eyes like mine might not make out an individual silt particle, but I recognize a gully when I see one. Silt loam soil like ours is heavy on silt, with about seventy percent of the mix being silt particles. Both sand and clay particles have to be present for the soil to be a silt loam, but those two particles range from ten to twenty percent each.
All three size soil particles come from rock. It’s just a matter of how small the rock pieces are. And sand being the heaviest is less movable by water and wind. Clay particles are so small that the least bit of water causes them to grab hold of one another, swell, and form plates and “globs” and get sticky. So one of the things causing our loess to be erodible is the amount of silt itself. But around here, it is the steep slope of loess that primarily makes it so water erodible.
The good news is silt loam soils are pretty fertile and respond well to good farming and gardening techniques like adding organic matter and getting the acidity right with lime if need be. And paying for fixing gullies.
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Terry Rector writes for the Warren County Soil and Water Conservation District, 601-636-7679 ext. 3.