More farmers are using cover crops to keep pollutants out of lakes and streams

Crop-dusting planes were in the skies over Allegan and Ottawa counties earlier this week, providing an exciting show of aerial acrobatics. However, they were not dropping chemicals on growing crops as one would assume.
A green blanket of cover crop holds soil and nutrients in place while rippened soybeans await harvest. The cover will become dormant in winter but still hold soil from running off with rainfall or melting snow. (Photo by Ben Jordan)
Instead, they were sowing seeds into fields of growing corn and soybeans for a cover crop, which will eventually create a sort of “blanket” for the soil. This blanket helps keep soil and contaminating molecules that attach to soil particles — like phosphorus — in place on the fields where they belong, and out of lakes and streams.

Now is the ideal time to plant this soil blanket to take advantage of sunlight before days get much shorter. 

Dragging heavy planting equipment behind a tractor through crops entering their final growth stages, just before harvest, would spell disaster for the crop. But crop-dusting planes, guided by a skilled pilot, can drop seeds into fields that will work their way into the ground, encouraged by late summer breezes and gentle rains.

More than 600 acres were seeded in the two counties this week alone. Kent and Muskegon counties combined saw an additional 900 acres of aerial seeding in the same operation.

Purpose of cover crops

The purpose of planting cover crops is two-fold, according to Ben Jordan, Watershed Coordinator for the Ottawa Conservation District, which includes the Bass River, Deer Creek, Sand Creek and Pigeon River watersheds.
A crop duster plane is loaded is seed. (Photo by Bev Berens)
“First, on the environmental side of things, cover crops help in reducing runoff and erosion of sediment and nutrients; they keep manure and any potential pathogens hiding in manure in the fields and on the soil, and not entering rivers,” Jordan says. “The second part of that is improved soil health by building organic matter and nutrients within the soil, giving the soil an agronomic benefit.”

More cover crops will be planted using other equipment as harvest removes one crop to make room for the next. Some farmers will use a drill to plant seed into the ground. Others will broadcast seed on top of the ground with a spreader. Both are good options, and the choice comes down to whatever equipment the farmer owns or can rent. 

Another 4,250 acres will receive a cover crop treatment this fall through projects with the Macatawa Area Coordinating Council (MACC) and Ottawa Conservation District. That total does not include plantings outside of these organizations.

Impacting local waters

Rob Vink is the Macatawa Watershed Project Manager for MACC, a partner in Project Clarity, an effort to improve the health of Lake Macatawa. He helps growers implement conservation practices, including cover crops, throughout the Macatawa Watershed in both Allegan and Ottawa counties. The Macatawa Watershed Project has many targeted areas, and Vink says he “handles all the ag stuff” within the project.

Crop dusting planes served as seed planting tools as hundreds of acres were planted to cover crops this week. (Photo by Ben Jordan)
“We are working to encourage and support the adoption of conservation practices with the goal of improving water quality in Lake Macatawa,” Vink says. “The goal is cleaning up Lake Mac by reducing and eliminating phosphorus inputs into the water.”

Realistically, eliminating phosphorus in the lake is impossible. So, the project bases its goals on a Total Daily Maximum Load standard created by the Michigan Department of Environment, Great Lakes and Energy (EGLE). Grand Valley State University measures some sediment and phosphorus entry into the lake, but overall progress is measured using a spreadsheet model for estimating pollutant loads. 

The program makes formulations based on data collected over many years on how different conservation practices yield results in relation to the soil type in which it is used. For example, cover crops planted on clay soils have a greater capacity to keep sediment and phosphorus in the field than the same treatment on sandy soils.

Cover crops provide the greatest protection for decreasing runoff, but practices like reduced tillage, grassed waterways and buffer strips along ditches, streams, or wetlands also make a difference, especially when stacking multiple practices together in one location.

During the nearly four years since Vink began working at MACC, the number of participating producers has grown from 14 to more than 40. In the past five years, more than 10,000 acres within the watershed have been treated with some type of conservation practice.

Ag not alone in responsibility

There are many contributors to Lake Macatawa’s sediment and phosphorus problems. Agriculture takes the brunt of the blame, “but it’s not all ag,” Vink says. “It’s important to know that farmers are doing their part in conservation, and there are so many other inputters.”

“We really are only learning the effects of long-term continuous manure applications to the same fields. The science and research on this just weren’t there 30, 40, 50 years ago.” 

Participation in either program is strictly voluntary, and farmers that do participate receive some compensation for their added costs and time.

“Farmers are doing a lot of work to improve water quality,” Vink says. “That is something we should be proud of, and proud of the growers in our area. We’ve come a long way in the past five years, for sure.”

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Read more articles by Bev Berens.