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Friday, November 7, 2014

Cover Crops Seminar in Elsberry, MO

By Janette Swartz - Consultant with Soil Right Consulting Services:

Yesterday I attended a Soil Health/ Cover Crop Workshop in Elsberry, MO. If you haven’t been to the Elsberry Plant Materials Center it is very interesting. They have many plots of different cover crops seeded at different planting dates. They also had a rainfall simulator demonstrated by Doug Peterson. If you haven’t seen a rainfall simulator demonstrated YouTube has some pretty interesting videos done by the NRCS that would be good to watch.

 The first thing Doug did was perform a slake test. He placed a soil aggregate from a no-till field into a jar of water and also placed a soil aggregate from a conventionally tilled field in another jar of water. Immediately the conventionally tilled soil aggregate started falling apart compared to the no-till field where very little soil fell apart. This shows that tillage is destroying the soil glomalin which holds the soil together.

He then started the rain fall simulator. The first soil tray was a conventionally tilled soil. The second tray was a conventional till soil with cover crops. The third tray was a no till soil which has no cover crops (only because the grower didn’t have time to get them on this year). The fourth tray was a pasture soil with short grass on it. The fifth tray was a pasture soil with well managed grazing and a better grass cover. For each tray there are two jars underneath the front one was to catch the run off, and the back jar was to catch water that had infiltrated through the soil. As you can see from the pictures the first tray had a lot of muddy runoff and almost no infiltrated water. The second tray had a little more runoff (it received a little more “rain”) and quite a bit more water that infiltrated the soil. The third tray had no significant runoff and a lot of infiltration. The fourth tray had quite a bit of runoff and some infiltrated. The fifth tray had no runoff and all of the water infiltrated. I think this demonstration speaks a lot for no-till.

What was really interesting to me was how important managing your pasture ground is. I was surprised at how much runoff there was in the short pasture ground. I would have thought the grass roots would have held the soil and allowed for more water to infiltrate. The well managed pasture had almost no runoff. This shows how keeping the soil covered can be a benefit. In another picture you can see that Doug dumped the first tray out upside down. The top of the tilled soil was completely saturated and the soil that was on the bottom of the tray was completely dry. That shows that the tilled soil didn’t have any pore space and the water wasn’t able to penetrate anything but the surface. That is how the soil forms that top hard concrete crust when you get a rain.  

Slake Test

Rainfall Simulator

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