5 ways to get more conservation bang for our buck

5 ways to get more conservation bang for our buck


On any field in Iowa, cover crops will improve soil health, sequester carbon, and prevent nutrients from washing down to the Gulf of Mexico.  There are at least six situations where cover crops can add to the farmer’s bottom line, but in other situations, or to help encourage farmers to make that initial investment and get through the troubleshooting stage that comes with any new practice, public cost sharing can make a difference.  Most taxpayers I talk to are quite willing to pay farmers who are employing conservation practices for the ecosystem services they provide.  But we either can’t afford to or aren’t willing to invest at the scale needed to achieve universal adoption of cover crops and other conservation practices, and that means we have to make some decision about where to invest first, so as to get the most nutrient reduction (and hopefully carbon sequestration, soil protection, flood reduction, and other benefits) for our buck.

Most of those discussions are way above my pay grade.  I suppose the legislators who draft the federal farm bill and the NRCS bureaucracy set payment rates and application scoring criteria for EQIP and other cost share programs.  Iowa’s Water Resource Coordinating Council picked priority watersheds that can get special funding.


Planning at the local level can also influence where conservation investments are made.  However, it’s not always clear what influence a Watershed Management Authority actually has over where 1000 acres of cover crops gets planted, or why it’s better to plant them in one part of a county rather than another.  Same goes for other conservation practices.  Here are 5 possibilities.

1. Plant cover crops where they can protect a local lake or water supply


Algae in pond

In addition to Gulf Hypoxia, phosphorus that washes off the land is causing algae blooms in many of Iowa’s lakes.  Overnight, these algae blooms can use up the oxygen that fish and other aquatic critters need to breathe.  Some kinds of cyanobacteria can produce toxins that can harm people and pets.  Algae blooms are nuisance for those who would like to swim, fish, boat, or water-ski in those waters.  We can address two problems at once if those 1000 acres of cover crops are planted in the watershed of Hickory Grove Lake, Saylorville Lake or other water bodies suffering from an excess of green.

In addition to Gulf Hypoxia, nitrogen that washes off Iowa farmland can cause a problem for cities that pull their water from a river, or from wells close to and influenced by a river.  The Des Moines Waterworks and the Raccoon River watershed have rightly gotten a lot of attention, but other cities in other watersheds (like Boone, on the Des Moines River) also are dealing with high nitrate in their source water.  Cover crops in the right watersheds can help protect those water supplies.

Nitrogen and phosphorus can also cause algae blooms in creeks and rivers, but the science is more complicated than in lakes, and not often done.  For example, while the Squaw Creek Watershed Management Plan demonstrates that nitrogen and phosphorus levels in the creek are high, it does not make the case that meeting our nutrient reduction goals will protect drinking water, improve fisheries, make for safer recreation in Squaw Creek.  Maybe that’s a safe assumption, but I honestly don’t know.

2. Plant cover crops where they can reduce the most nitrogen

Here’s a map of nitrogen load by HUC-12 watershed in Story County, based on landcover.  This kind of model would be handy if you wanted to guess which stream has higher nitrate levels at its outlet.  If I plant 1000 acres of cover crops south of McCallsburg (in the “Drainage Ditch 81” hydrologic unit) will I get more nitrogen reduction than if I plant them west of Ames (in the Squaw Creek-Worrell Creek hydrologic unit)?  Nope.  The pounds/acre estimate here is for the whole watershed, and it’s based purely on landcover in that watershed.  Unlike the larger watershed, a field west of Ames wouldn’t be 20% developed, it’d be 100% agriculture, so with this model we can’t assume it’d be different than a field anywhere else in the county.   More sophisticated computer models like SWAT or SPARROW incorporate things like soils, slope, and county-level fertilizer sales as well as landcover, but it’s hard to tell which of those things is driving the results.

Other models like the Nutrient Tracking Tool are field scale, and can be used for this kind of prioritization.  Running through some quick scenarios, I estimated that cover crops on a tile-drained field in the Squaw Creek watershed could prevent 9 lbs/acre of nitrogen loss each year, versus 3 lbs/acre in an undrained field in the watershed.  Computer models can be helpful, if we’re clear about their purpose and limitations.

3. Plant cover crops where they can reduce the most phosphorus and sediment

Cover crops have gotten more traction in hilly southern Iowa, where soil erosion is a more visible problem and no-till is common.  From a standpoint of tons of soil erosion prevented, or pounds of phosphorus loss avoided, it makes sense to plant on fields with steep slopes and erodible soils.  Models like RUSLE can be helpful for this.

4.  Plant cover crops where their water quality benefits can best be measured

1000 acres of cover crops will make a bigger splash in a small watershed than in a big one.  A small change in water quality is difficult to detect.  Just like a poll that talks to a small number of people has a margin of error, a water testing program that samples only 12 or 24 days out of the year will have some uncertainty attached to the results.   I’ll be talking more about “minimum detectable change” in future posts, but suffice to say that margin of error is usually closer to 10 or 20 percent than 1 or 2 percent.  That means we need to give some thought to where conservation practices will be located relative to long-term water monitoring sites if we hope to document their effects with water monitoring.

Location of monitoring sites in Story County, and agency monitoringRow-cropped acres in watershedExpected N and P reduction at monitoring station from 1000 acres of cover crops in watershed
CREP wetland inflow (Conservation Learning Labs)1,27023.62 %
Walnut Creek @ 530th Ave, near Kelly (USDA)3,7567.99%
Onion Creek @ Reactor Woods, Ames (ISU)10,1042.96%
E. Indian Creek @ S27 (SCC/PRI/Ames)63,8520.47%
Squaw Creek @ Moore Park (IIHR)99,9190.30 %
Squaw Creek @ Lincoln Way (SCC/PRI/Ames)107,7750.27%
South Skunk River @ Riverside Drive (DNR)162,7180.18%
South Skunk River @ 280th St, Story County (DNR)297,5470.10%

5. Plant cover crops where it is most cost-effective for the producer

We do some of this unintentionally.  A farmer who can figure out how cover crops will make financial sense for their operation–cutting a pass for weed control or loosening compaction, providing forage for cattle, or protecting yields in wet or dry years–is more likely to sign up when the cost share being offered is $25-$35/acre.  Those that think they will lose money will pass until we offer better incentives–for example, Maryland was paying up to $90/acre and has gotten more takers.

This is also the idea behind “precision conservation” promoted by Land O’Lakes and other retailers.  With precision yield monitoring, conservation practices like wetlands, prairie strips, or buffers can be placed so as to minimize lost revenue.  Poorly draining or steep parts of a field might actually cost more to plant, till, and fertilize than it generates in revenue, so farmers could install conservation practices and even come out ahead.

That’s 5 ways to get more conservation bang for our buck.  Let’s be more clear about which of these we’re hoping to achieve when we do watershed planning, and more creative about how we support good stewardship.

Does this make sense?  Are there other ways to be more cost-effective with conservation?  Leave a comment!

2020 Spring Water Quality Snapshot

2020 Spring Water Quality Snapshot

It turns out that stream monitoring is quite compatible with social distancing.  28 volunteers participated in the Squaw Creek Watershed Coalition’s 13th spring water quality snapshot on May 30 and 31.  Together we tested water quality at 43 sites on Squaw Creek, its tributaries, and the South Skunk River!  This time, Prairie Rivers of Iowa assembled the equipment, organized the event, and entered the data.  We’re happy to support this dedicated group of citizen scientists in better understanding and drawing attention to our local rivers and creeks.  Here’s a few selfies taken by participants, a mix of long-term volunteers and new faces.

selfie of Kopecky family

The Kopecky family by the South Skunk River

Jeff White at Gilbert Creek

Kelly Nascimento Thompson at Glacial Creek

Kurt Plagge and Mary Burnet at Onion Creek

As the name implies, this is a snapshot in time.   The water quality on one sunny weekend in May is not necessarily representative of the month, let alone the year.  As described here and here, water quality can change dramatically in response to a big rainstorm.  But for this moment in time, testing many sites gives us a very detailed picture of the Squaw Creek watershed.

For example, during May 30 and 31, nitrate in Squaw Creek at Moore Park and other locations in Ames was quite high (11-12 mg/L) exceeding the drinking water standard (10 mg/L).  Where is that nitrate coming from?  All over its 147,000 acre watershed, but in some tributaries more than others, as you can see in the color-coded chart below.  Nitrate was especially high in the upper reaches of Squaw Creek, Gilbert Creek and Clear Creek and especially low in Glacial Creek (which has a series of constructed wetlands and a lot of pasture) and College Creek (which has an urban watershed).  The upstream, rural parts of College Creek and Clear Creek have higher nitrate, which appears to be diluted they move through town.

For phosphorus some of the patterns are flipped.  Glacial Creek has especially high orthophosphate (the dissolved form of phosphorus) while Clear Creek is especially low.

There’s lots of interesting patterns to explore, and more data from this and previous snapshot events here.  If you’re curious about water quality, subscribe to our blog, I’ll be continuing to interpret data from this and other sources.

Thanks to all our volunteers for collecting it!

Questions about stream monitoring, or observations from our volunteers?  Post a comment.


May showers bring awesome graphs!

May showers bring awesome graphs!

Last weekend’s rains (5-17-2020) provide a clear illustration of how water and nitrate make their way to Squaw Creek.

Squaw Creek at Brookside Park

How water reaches Squaw Creek after a rain

It started raining late Saturday night and stopped around 3AM Sunday. The rain gage outside my house in Ames showed 0.9 inches.  The water hitting my driveway and other paved surfaces in my neighborhood enters a storm sewer that goes directly to a tributary of Squaw Creek.  (In newer neighborhoods, the water would be slowed down by a pond or detention basin).  This runoff takes about an hour to make its way down Squaw Creek to the USGS stream gage at Lincoln Way.  In response to urban runoff and the rain that fell directly on the channel, we can see a quick rise in the water level, and quick fall. Over the next 15 hours, Squaw Creek rose another foot as it was joined by water that fell as far away as Stratford and Stanhope. Other than urban areas, we probably didn’t see much runoff from the storm, which was relatively gentle and fell on soils that weren’t particularly steep or waterlogged. The fall in water level Sunday afternoon and Monday was more gradual, reflecting the release of water from drain tiles and groundwater.

Figure adapted from University of Michigan Extension

How nitrate reaches Squaw Creek after a rain

It’s well-known that tiles and ditches provide a direct pathway for nitrogen to leak out of the soil in corn and soybean fields.  Think of cover crops as a way to plug the leak, and bioreactors, saturated buffers, and wetlands as a bucket placed underneath.  You can watch the leak from last weeks’ storm with IIHR’s nitrate sensors.  This graph is from a sensor installed in Squaw Creek in Moore Park, where it enters Ames. (The colors are the reverse of what you’d expect–brown is streamflow, blue is nitrate). The nitrate concentration in Squaw Creek fell from 5 to 4 mg/L overnight, diluted by direct precipitation and urban runoff, and then rose to 14 mg/L as water from drainage tiles made its way downstream.  As tile flow tapers off, nitrate concentrations gradually fall toward the lower levels seen in groundwater.

Nitrate drops as you move downstream

In Hardin County, there’s a nice set of three sensors that clearly showed what happens as water moves downstream during this storm.  Not every stream demonstrates this behavior, but many do. At the tile outlet, nitrate levels are highest to begin with (10.9 mg/L) and show the sharpest increase, spiking to 18.3 mg/L by 5AM after some initial dilution.  Since the water takes some time to reach the next downstream sensor, Tipton Creek near Hubbard, the peak doesn’t happen until 8 PM, rising from 8.6 mg/L to 17.1 mg/L. Further downstream in the South Fork of the Iowa River, near New Providence, water is reaching the sensor from several tributaries, smoothing out some of the changes.  Nitrate rises from 4.5 mg/L Saturday night to a peak of 16.2 on Monday morning at 11:00. There are several reasons why nitrate tends to decline as you move downstream.  First, tile systems drain mostly agricultural land, while a larger stream will also drain some field margins, pasture, and woodland.  Second, nitrate is removed from the water by algae, plants, and microbes.  Waterlogged organic matter, whether in a low spot in a field, a wetland, a stream bottom, or a woodchip bioreactor, is good habitat for denitrifying bacteria.  Third, many Iowa streams flow from northern Iowa southeast to the Mississippi River, or southwest to the Missouri River, and as you get into southern Iowa, the land  becomes hillier, tile drainage becomes less frequent, and pasture more common. Tile drained fields lose a lot of nitrogen in spring.   That’s not news to anyone, but hopefully this helps you visualize and understand the process. Update, 5/29/2020: We had even bigger rains the following week, but spread over several days, so the pattern was less clear.  We’re still seeing nitrate concentrations >10 mg/L in the rivers, and >15 mg/L at tile outlets.

Spring flowers by College Creek

We’re all a bit stir-crazy and can benefit from spring weather and spring flowers.  If you’re in Ames, I recommend walking east of the ISU campus, where (as of April 5) the ground is carpeted with blue flowered squills, Scilla siberica.  It’s not often that you see that color blue in nature, or in that quantity!

While you’re there, take a peek in College Creek.  When I visited, the water was clear, the bottom was rocky, and it was full of 4-6 inch fish.

fish in College Creek

This was great to see.  College Creek used to be a dump, but between legal action against businesses and mobile home parks that were discharging sewage, urban conservation projects, and the annual trash clean-up event, it’s become a lovely place.  Most of our backyard streams have the same potential, if we treat them right.

I should caution you that that E. coli levels in College Creek and other streams in Ames often exceed the primary contact recreation standard, but you’re washing your hands constantly anyway, right?  (Bold values in the table below exceed the single-sample maximum of 235 colonies/100mL.  Data are collected and posted by the City of Ames.)

October 11, 20195587582681,024378
September 24, 20191,7641,446320 9041,024
August 6, 20191222,9096,8678,6643,448
July 16, 20198395,17224,196>24,1962,098
June 11, 2019173374414583594
May 16, 201963231189265384
April 9, 2019122158852909448
October 16, 2018 187 187 171298 282
September 18, 2018 47910550261
August 14, 2018 275 529 1439 2098 —
Watershed Education With All Ages

Watershed Education With All Ages

Prairie Rivers of Iowa kicked off 2020 with watershed education for both the young and old. Over four sessions in January and February, watershed educator Dan Haug spoke with 20 retirees for an Osher Institute for Lifelong Learning (OLLI) class at the Iowa State University Alumni Center.  In addition to unpacking difficult topics like the Clean Water Act and water monitoring, Dan introduced the class to online resources he uses to find out about water quality in local rivers and lakes, and about landuse and soils in their watersheds.  The class brought back examples and asked questions about rivers, lakes, and drinking water in their home towns and vacation spots, giving us all a better picture of water quality issues and solutions around the state. On February 7-9, high school students from Iowa, Minnesota, Illinois, Missouri, Minnesota, and Oklahoma attended a training on the ISU campus for the 4-H Ag Innovators Experience, sponsored by Bayer and the national 4-H council.  By training teenage facilitators to lead activities at their 4-H clubs, schools, or community events, the program has helped over 5000 youth learn about monarch butterflies and native bees in previous years. This year, the focus is on ecosystem services, water quality, nitrogen, and engineered conservation practices.  The youth will be learning about bioreactors, saturated buffers, bioswales, and rain gardens.  Watershed Educator Dan Haug helped the planning team at ISU Extension create a hands-on activity to show how rain gardens can soak up runoff, as well as creating maps that the youth will use for a simulated watershed planning exercise.  At the training, Dan shared his experience working with real-life watershed management authorities and worked with the teen leaders in the computer lab to track down information on their own watersheds.  This is a far-reaching project with input from a great group of educators and water experts.  We were happy to be a part of it! Contact us if you have an idea that could become our next educational event or project!
New Year’s Resolution: Eat Healthy, Support Local Farmers, Protect Land and Water

New Year’s Resolution: Eat Healthy, Support Local Farmers, Protect Land and Water

Thank you to the board members who brought in donuts and coworkers who brought home-baked desserts to the office in 2019.  As a result, my New Year’s resolution is to lose weight and eat healthier!

Kidding aside, Prairie Rivers of Iowa is an organization with a long track record of supporting local food systems.  Local food is a much better framework for healthy eating than picking processed foods based on high-this or low-that claims on the box.  Whole foods—vegetables from the farmers market or CSA, eggs from my backyard chickens, fruit from U-pick orchards—are not just nutritious but a source of joy in the harvesting, purchasing, and cooking.  “Eat more locally grown fruits and vegetables in 2020” is a pledge that makes me look forward to the coming year rather than dreading it.

But I’m not overweight and in pain because I don’t eat fruits and veg.  Like most members of my extended family, I have chronic health conditions that are exacerbated by sugar, saturated fat, and refined carbohydrates.  Like most Americans, I eat a diet high in those things because of they are socially encouraged (how many times have you accepted cookies to be polite) or cheap, convenient, and well-advertised.  With half a pig in the freezer (raised by Tom and Carman Rosburg), I asked my doctor for dietary recommendations that did not involve giving up ham and got a very sensible response—cut back the red meat to one or two meals a week.  A similar strategy can apply to sweets, white rice, potatoes, and baked goods made without whole-grain flours.

I’ve had one week of planning for moderation and succeeding, after a previous week of planning for abstinence and failing.  I can already see how that shift in perspective could be more sustainable—both in the sense of “being able to keep it up past February” and in the sense of “preserving soil, water, and biodiversity.”

When I budget my pastry intake for the week, it becomes imperative to choose something I really like, rather than something convenient like store-bought donuts, muffins, or cookies.  That has benefits for the environment, as these foods are often made with palm oil, usually produced by cutting down rain forests.

If full fat cheese and red meat are viewed as an indulgence rather than a staple, I can afford to buy premium products directly from local farmers that are employing the most sustainable practices –for example, Lost Lake Farm near Jewell makes delicious hard cheeses with a rotational grazing system that builds soil organic matter.

Currently, 36% of the US corn crop goes to feed livestock, which converts about 20% of that energy into food calories.  40% of the corn crop goes to ethanol and much of the rest goes into processed foods and sweeteners.  This is not an efficient way to feed the world.  Prairie Rivers of Iowa has worked with corn, soybean, and livestock producers of all sizes who are making changes to protect soil and water, but widespread adoption of cover crops, perennials and extended rotations has been limited by a lack of local markets and processing for additional crops.  If consumers ate less meat and processed foods and more whole grains, and Midwestern farmers shifted some acres out of corn*, it would have undeniable benefits for public health, climate, soil, and water.

*We could shift away from sugar beets, which produce even less nutrition per acre than corn and have their own environmental impacts.  You’re not getting off so easy, North Dakota and Minnesota!