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Drain Brain

Posted on October 14th, 2019

Note: This essay was co-written with my colleague Professor Silvia Secchi.

Some people read these essays and say I (CJ) don’t offer solutions. I disagree with this: apply nutrients at recommended rates, accurately take credit for manure nutrients, don’t apply manure to snow, plant stream buffers, quit cropping in the 2-year floodplain, and so forth. Yes I understand some people don’t like my solutions or think they’re impractical. But I think they’re simple, common sense ideas. I’m not an over-thinker.

So Silvia and I were interested to read a new paper that appeared recently in the journal Nature Sustainability where some researchers from the university 120 miles west of here proposed a new solution to our nutrient problems:

Put in more drainage tile.

Admittedly, we never thought of that one.

Now we wish to say that the Nature journals are very prestigious and we respect this achievement. But if you’re a regular reader here, you may recall that I (CJ) assert tile is a big part of the problem, not the solution.

These other researchers (for simplicity, referred to as the “Drainers” from here on out) argue that in order to achieve sustainable agricultural intensification in Iowa, we need to invest in massive upgrades in our drainage infrastructure. Linking this to edge-of-field entrapment of wasted nitrogen with constructed wetlands and woodchip bioreactors, they assert, would improve water quality and provide other environmental benefits. Further, they contend that theirs is a system approach.

It is unfortunate that neither economists or geographers were involved in the Drainers’ analysis, so in the spirit of Iowa’s much talked-about collaborative, interdisciplinary approach, here’s how we may want to think about agricultural systems while setting the boundaries more broadly, and how we should think about the costs of the upgrade of our drainage system proposed in the Nature Sustainability paper.

First off, the Drainers presuppose that the best use of Iowa’s land as the climate changes is to keep on keepin’ on: corn and soybeans will rule, and we’ll feed both to livestock in confinements and corn to ethanol refineries. The separation of crop and animal agriculture will continue, and so will the massive production of manure.

The Drainers include no analysis of alternative land uses and production systems that could produce more carbon sequestration benefits, for example.

It is standard practice in policy-making to look at alternative scenarios, estimate costs, and consider winners and losers. We think it’s prudent for scientists proposing large-scale solutions to consider the policy implications of their work. In the Drainers’ analysis, the boundaries of the system have been set as if any other choices are impossible.

The system that the Drainers examine also does not include any economic analysis of the costs of their plan, which would necessarily rely on taxpayer subsidies. As our agricultural sector is hurting because of a trade war and ethanol waivers, we say it’s time to consider alternatives that promote resilience through diversification, and policy solutions that would not encourage overproduction, pollution and consolidation.

Iowa areas requiring tile drainage according to Jaynes and Miller (

What would the Drainers’ plan cost? According to the criteria determined by Dan Jaynes (USDA) and Gerry Miller (retired ISU), there are ~8.25 million acres of Iowa cropland that require tile drainage to achieve full productivity (see the figure at right for their location). Some folks that study these things think that is a vast underestimate, but it’s the best objective analysis we know of. One reason for the skepticism is that since the 1970s, USDA no longer tracks drainage (hmm). We do know, however, that a lot of the drainage infrastructure is old. The first drainage survey (1920 Ag census) reported 7.3 million acres of Iowa farmland were drained, though the canvassing done specifically for drainage found only 5.2 million acres in drainage enterprises (that is, in multi-farm efforts; see the figure below), and over 2 million additional acres needed to be drained.

Iowa areas in multi-farm drainage projects, according to 1920 Census of Agriculture (USDA).

Many of the old drainage tiles have already been replaced. Let’s conservatively assume that the Drainers are talking about 3 million more acres needing drainage or upgrades. At a cost of $1000/acre, replacing the tile would cost $3 billion. The Drainers admit that to make this truly sustainable, wetlands or bioreactors will be needed to intercept and treat (clean) high-nitrate tile discharges.

The Iowa CREP program currently provides taxpayer money for denitrification wetlands. The program recommends wetland size from 0.5 to 2% of the area draining into it; in other words, 200 acres of cropland would require capture by a 1- to 4-acre wetland. Conservatively estimating construction at $300/acre, and ignoring maintenance, operations and easement outlays, these wetlands would require tens of thousands of acres and cost between $10 and $42 billion (just so you know, the CREP program pays 100% of construction costs with taxpayer dollars). To put this in perspective, Iowa has received ~$20 billion in agricultural subsidies over the last 25 years. Note that the costs of a “sustainable” project would be additional to those programs, as more drainage would do nothing to increase crop prices. Indeed by increasing production, they could actually cause lower prices.

Adding the worst case $42 billion (remember these types of government programs often exceed worst case scenarios) to $20 billion is $62 billion, or $775,000 per Iowa farmer. More perspective: the average American spends $2,641 per year on food, and the median Iowa household income is $59,000.

In promoting this approach, the Drainers also seem to imply that the Iowa Nutrient Reduction Strategy and its voluntary approach is unlikely to work. Will farmers voluntarily give up tens of thousands of acres to wetlands? If you recall last year’s legislative session, you know that the industry is openly signaling they want MORE land in production. In almost 20 years, the CREP program has enrolled less than 4,000 acres, or 1 in 6500 Iowa crop acres.

We assert that the Drainers’ proposal is not sustainable. Its approach is encapsulated by the Drainers’ view of wetlands. They argue that Swampbuster, the 1985 Farm Bill provision that shuts farmers out of federal subsidies if they drain on-farm wetlands, should allow the draining of these wetlands to be mitigated with constructed wetlands. In other words, we should get rid of wetlands to build new wetlands (of course by necessity with taxpayer dollars) that serve the specific purpose of getting rid of the wasted nitrogen. This will be needed to produce more corn that will be fed to more confined animals that will produce more manure. One can easily foresee the day when some researcher somewhere will use taxpayer dollars for the creation of superduperbioreactors and other such treatments that will TRULY achieve sustainable agriculture in Iowa cheaply and painlessly (for the industry, anyway).

We think to promote sustainable intensification of agriculture in Iowa, we need to expand our system boundaries, and stop doing more of the same that creates positive feedback loops. Going beyond the simple ideas CJ mentions in the opening, here are some others:

  • Policies that promote crop and enterprise diversification (including perennialization)
  • Decoupling of payments from production while tying them to environmental performance
  • Payments for ecosystem services to farmers doing more than the minimum required
  • Anti-trust laws that break down monopolies in the supply chain
  • Real incentives for beginning farmers
  • Meaningful enforcement of CAFO regulations and tools to better manage manure distribution, including digitized manure management plans

Farmers aren’t getting the economic outcomes that they want, and the public isn’t getting the environmental outcomes that we want. Hardly anybody would argue that.

To paraphrase a golden oldie, we say, if you find yourself in a hole, stop draining.



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3 Responses

  1. Cindy Hildebrand says:

    Having attended local drainage-district meetings, I’ve seen that some landowners are not enthused about paying for drainage repairs, let alone upgrades and water quality measures. One recent meeting featured an attorney who hinted at a lawsuit because his clients, like some other Iowa landowners, don’t want their land to be added to drainage districts.

    So I certainly understand why many landowners might be happy to have taxpayers pay for expensive drainage upgrades. Why taxpayers might want to do that is another question.

    I’ve talked with other Iowans who are very willing to subsidize and encourage sustainable agriculture. But we’d rather pay for cover crops, extended crop rotations, prairie strips, riparian buffers, grassed waterways, pollinator habitat, perennial vegetation, etc., than pay for more and faster drainage.

    Apart from the financial and practical problems discussed by the Jones and Secchi post, the NATURE proposal, as described by J & S, sounds depressing. It sounds like intensification of an already-intensive unsustainable system.

    One summary of the NATURE paper includes the following: “…much of the drainage infrastructure has outlived its design life and was built for a different era in agriculture, when pastures and forage crops that require less drainage than grain crops were more commonly grown.” Couldn’t we encourage more pastures and forage crops? Wouldn’t that also help address a host of other agricultural problems that range from soil degradation to biodiversity loss?

    The proposal also sounds like Son Of The Iowa Plan. The Iowa Plan, which came out about a decade ago, also proposed using large amounts of public money to upgrade farm drainage. Here is a quote from the Iowa Policy Project study of the Iowa Plan:”Investing in enhanced drainage would likely further cement the continuation of industrial row-crop agriculture in Iowa long into the future, when other forms of agriculture are believed to be much less environmentally destructive and more sustainable.”

    And the various types of wetlands in Iowa are not interchangeable. If Swampbuster were changed, per the J & S analysis of the NATURE proposal, to legally allow the elimination of temporary sheetwater wetlands in return for deeper CREP wetlands, the new CREP wetlands would benefit some wildlife. But other wildlife, including some endangered shorebirds, could lose vital habitat. From the Iowa Policy Project:

    “Furthermore there is not a good understanding of the ecological value of either the CREP-style constructed wetlands or the farmed wetlands that appear intermittently during wet periods and are believed to serve an important role for migrating waterfowl. These in-field wetlands could become even less common as drainage capacity increased. Without a firm understanding of the habitat and ecological value of either type of wetland, favoring one at the expense of the other seems premature.”

    As someone who lives close to the town that hosts “the university 120 miles west of here,” I know that ISU researchers have done some very good sustainable-ag research. I hope there will be more good research in the future, and I hope it will, as J & S put it, expand our system boundaries.

  2. Silvia Secchi says:

    Ms. Hildebrand,

    thank you very much for your thoughtful reply, which provides a lot of important historical context.

    I wholeheartedly agree with you that taxpayers should have a really good understanding on the costs and benefits of these massive infrastructure investment proposals – particularly as we struggle with overproduction, consolidation, environmental degradation, and their effects on rural communities.

    I myself am a graduate of the university 120 miles west of Iowa City, and worked there for almost a decade. I am incredibly saddened by the failure of imagination regarding the future of agriculture in our state at my alma mater.

  3. John Norwood says:


    I think some of your math is off on the build out costs for green constructed wetland infrastructure using programs like CREP. We also need to better understand the longevity of infrastructure well built vs. annual practices.

    230,000 acres of a 23 million acre row crop system converted to wetland infrastructure and providing filtering and habitat and so forth for 50, 100, 150 years is not unreasonable, I don’t believe. I suspect some of this ground which is best suited for wetland use, is marginal and looking for a higher “best use” which Mother Nature originally intended.

    Isn’t it interesting we recognize farm roads and bridges are necessary for production and getting input into the field and crops to market. How much land do rural roads take? How much money do we spend maintaining them annually?

    I think we need to put these sorts of contemplated “water, soil and pollinator habitat” investments in a similar frame / context and consider opportunity costs of no action.

    When farmer legislators created drainage (watershed) districts in this state they recognized the need for collective action to deliver both public and private benefit. They gave districts taxing authority, maintenance obligations and even eminent domain powers.

    A history buff, I was surprised to learn recently drainage was considered so fundamental to the public welfare of our state, the state Constitution referenced their public purpose.

    What the Legislators did not anticipate at the time, was that protection of public welfare would eventually require drainage districts to do more than just drain water off fields to make them economically productive. What we now know through research (including your seminal work) and plain observations across our bucolic landscapes is the simple fact we need these districts to serve multiple functions if we are going to protect human and animal health and ensure the sustainability of this prodigious, world leading agricultural system.

    We need a new vision for our 3700 Iowa drainage districts to serve as water management districts. It will take time and substantial public resources ($60-$100 million per year?), and a focused system by system approach, to modernize them but I think it’s possible. Just think how much we spend on our road infrastructure each year.

    Beyond the infrastructure lift, we need some new big picture thinking and a clear eyed vision for what we want Iowa Agriculture to look like moving forward in a more globalized world. The US is no longer the sole agricultural superpower of the world. We need a modern, more competitive and resilient system.

    A system that will reward agronomic practices that build soil health and a more diverse portfolio of agricultural crops and services that will deliver better long term returns to farmers with less volatility compared to concentrated conventional rotations while also delivering superior public goods delivery, water quality, carbon storage, methane capture, habitat preservation, flood control, etc.

    Thanks for another great thought piece!

    John Norwood
    Commissioner, Polk County Soil and Water District

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