Can pond dredging be a soil amendment?

Recent research looks at the pros and cons of using dredged material to enrich soil and improve drainage.


Filed to: Weeds, Soil, Water

Pond being dredged at The Links at Sierra Blanca in Ruidoso, N.M.
A pond at The Links at Sierra Blanca in Ruidoso, N.M., is an attractive element in the golf landscape at this scenic course, but not all golf course ponds are so well cared for and may require dredging. Photo by Darrell J. Pehr

Is it a good idea to use the material dredged from the depths of a golf course pond as a turfgrass soil amendment, to build up low areas to help improve drainage or for any other purpose on the course?

Dredging is a necessity from time to time to keep ponds from becoming stagnant, smelly or discolored. Dredging removes sand, muck and sediment, as well as algae and weeds that have grown over time. When the pond is drained and the heavy equipment is scooping out the goo that has accumulated at the bottom of the pond, one question must be answered: what to do with the organic material that has been removed from the pond.

Of course, it could be trucked off the property, but what about simply spreading all that rich and nutritious dirt somewhere out on the course as kind of an inexpensive soil amendment? The turf would love it.

Another idea would be to fill in some low spots on the course to improve drainage, or maybe build up some flower beds.

But what about the consequences of scattering all this dirt around the golf course? Who knows what may lurk within the dredged material, such as weed seeds that washed into the pond?

A study just published from Ohio State University addresses this question. Although targeted at farmers who dredge their ditches, some of the findings may be helpful to golf course superintendents.

“Many ditches require regular maintenance to remove deposited sediments due to reduced hydraulic capacity and blockage of subsurface tile outlets,” says the study, titled “Are weeds a concern when dredged ditch sediments are applied to agricultural fields?” The study was published May 24 in Crop, Forage & Turfgrass Management.

“Dredge material is often spoiled along the edge-of-field as an economical means of disposal. Placement of dredge materials at the top of a ditch can impede surface drainage, creating depressional areas in fields that can negatively impact crop growth,” says the study. “An alternative approach to spoil management would be to place dredge materials further into fields to level the ground or as a soil amendment. Studies have shown the potential beneficial effects of lake and river dredge soil amendments on crop yields. ... However, farmers may be reluctant to spread dredge materials in fields due to concerns over redistribution of weed seed banks accumulated in deposited ditch sediments.”

The OSU scientists collected sediment from ditches in three regions of Ohio and germinated the weed seed banks in a greenhouse. They tested for regional differences in the types of weeds and dry biomass and assessed ways to control the weeds that were expected to germinate, using common chemical herbicides.

They found 50 different weeds, ranging from annual rye and bull thistle to quackgrass and yellow nutsedge. Overall, the dredged material contained 41 species of broadleaf weeds totaling 78% of the biomass, compared with nine grass species representing 22% of the biomass.

Of course, the contents of dredged material at each pond would vary from these results and would likely reflect what is growing in the areas closest to the pond.

“With concerns about the many types of weeds that could be introduced, we confirmed that the majority of them were broadleaves, which are treatable with common chemicals,” the study says. “Lastly, we could conclude that the type of weeds would vary depending on where the sediment was sourced. Obtaining sediment samples from three different regions of Ohio demonstrated weed types will not always be consistent, which will need to be considered when creating a weed management plan.”

While not providing a definitive answer to the question of whether to use dredged soil as an amendment for turf, the study does outline factors to be considered. The full study can be accessed at

 The OSU scientists added this note to their conclusions — “Further research may examine ways to minimize the viability of weed seeds in dredge sediment prior to application to reduce this concern in the future” — so more detailed answers to these questions may be available after additional research is conducted.

Should dredged material be used on the golf course? When it comes to answering that question, we’re not out of the weeds yet.

Darrell J. Pehr is GCM’s science editor.