Tag Archives: soil erosion

Severe erosion and lack of conservation progress cause for alarm among Iowa experts

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Former Iowa Environmental Council executive director Linda Appelgate captured this image of a corn field eroding into the Nishnabotna river in 2010. According to the Iowa Farm and Rural Life Poll, nearly 80% of Iowa farmers agree they need to do more to “reduce nutrient and sediment runoff into streams and lakes.”

Last week was Soil and Water Conservation Week in Iowa, a time to reflect on how well we are protecting one of Iowa’s most precious natural resources.  Unfortunately, soil erosion remains a serious problem in our state. Recently several top experts on Iowa soil conservation weighed in and expressed alarm about the state of our soil.

The Iowa Daily Erosion Project can create estimates of soil erosion the morning after a rainfall event occurs.  Here, estimates are shown for a 2-day precipitation event on April 12-13, 2014.  Still, without advances in modeling, project manager Rick Cruse says these models do not tell the whole story of Iowa soil erosion.

The Iowa Daily Erosion Project can create estimates of soil erosion the morning after a rainfall event occurs. Here, estimates are shown for a 2-day precipitation event on April 12-13, 2014.   Still, without advances in modeling, project manager Rick Cruse says these estimates do not tell the whole story of Iowa soil erosion.

Most unsettling was a reminder from Iowa State University agronomist Rick Cruse that our present methods of estimating soil erosion are badly flawed and may be missing between 20 and 90% of the erosion in the state.  In total, Cruse estimates the economic harm to agricultural yields Iowa suffers from historic soil erosion may be as great as $1 billion each year–harm that will grow as erosion continues.

Cruse, who manages the Iowa Daily Erosion Project, said current models only account erosion that occurs evenly across the soil’s surface and fail to account for ephemeral gullies that form when heavy rainwater forms channels and washes out a trench along a slope.  He answered questions about soil erosion recently in the Des Moines Register and spoke about his research at length in an Iowa Learning Farms webinar, which is available free online.

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278 organziations sign letter in support of farm bill conservation

farmbillblogAs work on the long-stalled Farm Bill resumes in a Congressional conference committee this week, across the nation, 278 organizations including many in Iowa have signed a new letter calling on Congress to take responsible action for conservation.

The groups urge Congress to reconnect taxpayer subsidies for crop insurance to common-sense conservation protections for soil and water–a part of the farm bill known as “conservation compliance.” The letter also calls on Congress to support a national “sodsaver” provision to reduce taxpayer subsidies for converting native grasslands to crop production.

“Both of these provisions, included in the Senate bill, ensure that taxpayer dollars are not used to incentivize risky or environmentally destructive practices,” the 278 groups say.  “Conservation compliance and sodsaver are among the top farm bill priorities for our groups, and both will be determining factors as we consider our support for a final bill.”

As the letter explains, much is at stake as Congress considers this policy:

Without these key protections, billions of taxpayer dollars spent on crop insurance over coming years will subsidize soil erosion that will choke our waterways, increase the cost of water treatment and dredging, and reduce the long term productivity of farmland. It will also allow for the destruction of tens of thousands of acres of valuable wetlands, resulting in increased downstream flooding, loss of wildlife habitat and decreased water quality.

A diverse group of organizations representing Iowans, including the Iowa Environmental Council, have signed the letter.  Other Iowa organizations signing include Citizens for a Healthy Iowa, the Des Moines Water Works, the Driftless Chapter of Iowa Trout Unlimited, the Iowa Bowhunters Association, the Iowa Chapter of the American Fisheries Society, the Iowa Farmers Union, the Iowa Natural Heritage Foundation, the Iowa Wildlife Federation, the Izaak Walton League of America, Maquoketa Valley Chapter, the North Bear Chapter of Trout Unlimited, the Quad City Audubon Society, the Spring Creeks Chapter of Trout Unlimited, the Iowa Council of Trout Unlimited, and the Wagner Conservation Coalition.  The Environmental Law and Policy Center, a regional organization with offices in Iowa, also signed, as did the Environmental Working Group, whose national agriculture program is based in Ames.

The National Sustainable Agriculture Coalition (NSAC) coordinated this national effort.  NSAC’s website has the full letter and list of organizations.  You can also read about the latest grassland loss data from USDA by clicking here.

With heavy spring rain, Iowa’s need for conservation preparedness becomes evident

Extreme levels of runoff stream from a farm field following a heavy rain May 29. (Iowa Environmental Council photo; click to view larger)

Extreme levels of runoff stream from a farm field following a heavy rain May 29. (Iowa Environmental Council photo; click to view larger)

This has been yet another extraordinary spring for Iowa.  After a record drought in 2012, spring 2013 is the wettest ever in 141 years of state records.  According to National Weather Service estimates over the last sixty days, some portions of eastern Iowa have received between 200 and 300% of normal rainfall.  As a result, river levels around the state are on the rise, especially in eastern Iowa, where fears of a repeat of the record 2008 floods continue to loom.

Estimated rainfall received in the 60 days ending June 2 show parts of Iowa have received greater than twice normal precipitation.  This heavy rainfall has placed Iowa's natural resources under considerable stress. (Source:  National Weather Service)

Estimated rainfall received in the 60 days ending June 2 show parts of Iowa (shown in dark blue) have received greater than twice normal precipitation. This heavy rainfall has placed Iowa’s natural resources under considerable stress. (Source: National Weather Service)

According to the DNR, heavy rains caused numerous municipal waste treatment systems to release raw sewage into waterways, and “a number” of open feedlots have also overflowed.  In a release, the agency urged Iowans to avoid contact with floodwaters:

“People are urged to avoid ingesting or directly contacting flood waters, especially if they have cuts or abrasions that may be susceptible to infections from contact with bacteria. People with weakened immune systems should also avoid contact with flood water due to the potential contact with bacteria. Swimmers and anglers should thoroughly wash after coming in contact with water during flooding conditions.”

Heavy rainfall has placed Iowa’s natural resources under considerable strain.  Removal of needed soil conservation efforts, like buffer strips, as well as the conversion of pasture and grassland to cropland, has accelerated the impact of recent rains.  As was the case during last year’s drought, when Iowans encountered prolific algae blooms across the state, extreme weather conditions made Iowa’s lack of conservation preparedness especially clear.

Climate change appears likely to increase the number of major rain events occurring in our state over time.  It is not possible for Iowans to control the amount of rainfall we receive; therefore, it is essential  to use good conservation practices and other measures to limit the harmful effects of heavy rain. Many of these practices also maintain clean water for drinking, recreation and swimming in times of fair weather.

WASHING AWAY PRECIOUS TOPSOIL

With delayed planting on the state’s roughly 23 million acres of land used for row crops, a significant portion of the state’s land was at its most vulnerable to erosion last month.  We have received numerous reports of extreme runoff from agricultural fields similar to what our own Nathaniel Baer witnessed traveling northeast of Des Moines on May 29:

In the last two months, parts of east central and northwest Iowa have suffered soil erosion at rates several times greater than so-called “tolerable” soil losses of 5 tons per acre in a whole year.  As the map below from the Iowa Daily Erosion Project shows, some townships in Iowa suffered as much as 24 tons of erosion in the last two months alone–nearly 5 times the rate considered “tolerable” in a year.

(Source:  Iowa Daily Erosion Project, Iowa State University)

In the last 60 days, portions of Iowa have suffered erosion at levels multiple times greater than what is considered “tolerable” for an entire year.  (Source: Iowa Daily Erosion Project, Iowa State University)

These erosion impacts are not inevitable, even during heavy rains.  According to the National Resource Conservation Service, many practices exist that can improve the ability of Iowa farmland to withstand major storms.  For example, after 6-8 inches of rain fell on southeast Iowa April 17, Shawn Dettmann, an NRCS conservationist in Fairfield, made this observation:

“In fields where soil was disturbed through tillage, there are some rough areas with a lot of soil erosion,” said Dettmann. “In fields with high amounts of crop residue and little to no tillage, there was significantly less erosion, and in fields with these practices plus cover crops, there was little to no erosion.”

Extreme nitrate losses

Nitrogen and phosphorous pollution is always a serious problem in Iowa, even without heavy rains.  According to the EPA’s 2008-2009 National Rivers and Streams Assessment, in the region including most of Iowa and Illinois, 72% of rivers and streams are rated “fair” or “poor” for total nitrogen.

This year, however, nitrogen pollution has been of particular concern.  Earlier in May, levels in the Raccoon and Des Moines Rivers reached record levels, prompting the Des Moines Water Works to temporarily stop using water from the rivers to serve its customers for fear of violating the federal safe drinking water standard.  Water Works data shows nitrogen and phosphorous levels in the Des Moines and Raccoon have been creeping upward for 30 years.  The City of Cedar Rapids also expressed concern over drinking water when it detected high nitrate levels in the Cedar River.

The Iowa Department of Natural Resources estimated the commercial value of nitrates lost from these watersheds at nearly $93 million--and climbing--since April 1. (Source:  Iowa DNR)

The Iowa Department of Natural Resources estimated the commercial value of nitrates lost from these watersheds at nearly $93 million–and climbing–since April 1. (Source: Iowa DNR)

These losses also represent a major financial loss for Iowa’s farmers who apply nitrogen as a fertilizer.  A recent analysis of initial real-time nitrogen monitoring data between April 1 and June 2 shows the commercial value of nitrate flowing past 9 monitoring sites has been nearly $93 million–so far.  According to the Department of Natural Resources, 186 million pounds of nitrate from nitrogen fertilizer, manure, and other sources has been lost downstream during the last two months alone.  The amount of nitrate being lost continues to climb.

Recently, state agencies released a final version of Iowa’s Nutrient Reduction Strategy which relies on extensive research by Iowa State University to suggest ways in which Iowa could significantly reduce nitrogen and phosphorous pollution, including from agricultural ground.

Unfortunately, the plan to implement that research relies on the same all-voluntary approach to conservation that has not prepared Iowa for the soil erosion and runoff challenges we face today.  As a result, drinking water, the health of aquatic life, and Iowa’s agricultural soils remain at risk.

A CALL TO ACT

In order to resolve these problems, Iowa must successfully utilize additional conservation practices all across the landscape to hold heavy rains where they fall, prevent soil erosion, and keep polluted runoff from reaching rivers and lakes.

The Council’s executive director, Ralph Rosenberg, described Iowa’s challenge in a recent op-ed in the Cedar Rapids Gazette:

“It is time for us to embrace policies that move people and structures out of harm’s way, allowing wetlands and floodplains to slow and absorb excess water during spring floods. Wetland preservation and restoration, cover crops, grass waterways, buffer strips and other soil-conservation practices help the land act like a sponge, recharge groundwaters, and slow soil and nutrient loss from farmlands and urban areas.”

The Iowa Environmental Council supports the conservation action necessary to meet this challenge, and many of our member and cooperator organizations work actively in the area as well.  However, recent evidence suggests Iowa has a long way to go before we can endure heavy rains without major human and environmental consequences.  We need your support to help Iowa build healthier natural systems and be better prepared for the storms (or droughts) that lie ahead.