Ditch Work

By Kevin Seifert

Linn Soil and Water has recently been working on projects relating to erosion in ditches in production grass seed fields. For years farmers have known that to get a successful crop of grass seed you need the field not to be saturated with water for extended periods of time. The problem was how to effectively remove the water from the fields without causing erosion.

This year we have had people from Agricultural Research Service (ARS) in Mississippi come and visit the Willamette Valley and do some studies on how to shape ditches that will be stable and not erode. These soil scientists were lead by Andrew Simons and brought here by Jeff Steiner from the local ARS. In collaboration with Mark Mellbye, our local extension expert, they were able to work with two local farmers to get studies done on the erosion and sheer factors of our soils. The data was used to create a 3-d model of a design that will fit our field applications. This should help us in future design and hopefully cure some of the problem that we are currently having with ditch bank erosion.

We are also working on some Sustainable Agriculture Research and Education (SARE) projects in the valley that use hydro seeding and erosion control mats to get an establishment of creeping red fescue to help stop erosion and also act as big filter strips. The ditch is first reshaped and graded to remove water but not create a trough or a raging gulley. Then we used a process of hydro-seeding the banks with creeping red fescue and annual ryegrass and a soil stabilizer. At this point we spread a layer of straw to retain moisture and help get the grass established. Then we install woven biodegradable erosion control mats that are pinned and stapled with large 8-10 inch staples into the contours of the ditch. This process helps hold the soil against massive flows until the grass has a time to establish itself. Once the grass is established it will hopefully help prevent any further erosion and also help in control of weeds in our ditches by competing with and crowding out weeds.