Posted 11/16/2012 12:15 (#2700460) Subject: no till and water runoff
Gettysburg, PA (SC PA)
You hear all these stories about how no-till dramatically reduces runoff, but, I have to say that, here, that doesn't seem to be happening. Our soils, I think, aren't ever going to see those dramatic decreases I hear about. We have old weathered soils whereby we might have 12 inches of topsoil that fades into shale and clay. Now, I can believe that runoff is reduced when you are discussing 3 feet of topsoil and the no-till process is breaking through the plowpan exposing 2 more feet of topsoil to water infiltration. But, here shale and clay don't exactly absorb much water. Nearly every producer I speak with here feels that they have greater runoff in no-till than in conventional. Some of that might be attributed to the simple fact that harvest equipment and our clay tends to seal off the soil surface. Of course tillage would "correct" that problem. We definitely see gully erosion in no-till fields that seems more severe, leading me to think that runoff is increasing (although I suspect the overall erosion in the field is reduced).
So, who on here has shallow soils and has been long term no-till. What do you see in terms of runoff?? I talk with farmers who have fields in no-till for upto 10 years and they are still waiting to see this decrease in runoff that no-tillers talk about.