Because of the dryer weather this spring (1999) we were able to get into some of the waterways for the first time in many years since the Wet 1990s.
The erosion from tilled farm ground has filled up and gullied many of the waterways that we cleaned out less than 8 years ago.
The erosion was much worse than I had thought.

Below is one such example

Less than 8 years ago we cleaned out this waterway. As you can see it has silted in almost 3 feet deep from tilled farm ground above.

I'm just now getting down to the black soil with the dirt scraper.
You can see the clay color silted veins (in the foreground) on the original black bottom waterway.

The clay colored soil is topsoil washed in from a 15 acre watershed above this point.


I estimate I hauled out 400 tons of topsoil in this area just to reshape the waterway.
Even though this is a lot of soil it is only part of what has washed through this waterway. A lot of it has gone down the Missouri & Mississippi.

The white lines below are where the runoff channels out of this tilled field which drains into the area you see in the picture above.

The Black color is 11B soil which is 2.3 acres in size
The Yellow color is 9D2 soil type which is 7.7 acres & 300 feet long at the widest point.
The Blue color is 9B2 soil type which is 4.7 acres & 130 feet long at the widest point.

The longest distance from the discharge into the top of our waterway to the top of the hill is 900 feet.


The water way below used to silt in and gully along side when we tilled this farm in the 1970s and early 1980s.
We also hauled 3 to 4 feet of soil away from the fence line back into our hill when we repaired this waterway.
We started No-Tilling this farm in the late 1980s.
This part of the field doesn't even have Nightcrawlers so the water/soil that does run off in heavy rains will get even less once the Nightcrawlers move in.

To the left is on the same farm but in a different location where only our No-Till crop land drains into the waterway.
It is in the same shape as it was when we repaired it about 8 years ago.

This waterway is 900 feet long and is represented as the white line on the image below.

A 20 acre watershed drains into this waterway but as you can see there are no gullies alongside & No silt.



The Black color is 11B soil which is 3 acres in size
The Yellow color is 9D2 soil type which is 10.2 acres & 300 to 400 feet long at the widest point.
The Blue color is 9B2 soil type which is 1.6 acres & 150 feet long at the widest point.
The Green color is 9C2 soil type which is 5.5 acres in size

The longest distance from the discharge at the bottom of the waterway to the top of the hill is 1330 feet.

Here are the slope angles for the soil types.
11B & 9B = 2 to 5% slope
9C = 5 to 9% slope
9D = 9 to 14% slope

 

The Water infiltration data at the link below partly explains why more soil erodes off a tilled field.

This page shows a water infiltration test that shows the dramatic difference in water infiltration on tilled soil versus No-Tilled soil.

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