By Tom Driscoll, Director of NFU Foundation and Conservation Policy

Extreme precipitation is a serious concern for farmers as the climate continues to change. In many areas, downpours will be concentrated earlier in the year. Standing water and moist soil will work against farmers trying to get into the fields in time for crop insurance planting requirements and ideal yields.

While the installation of surface ditch or subsurface “tile” effectively addresses drainage issues exacerbated by climate change, the practice has serious downsides, both immediate and long-term, for farmers. There is substantial cost associated with purchasing materials and designing and installing drainage systems. Depending on the ultimate conveyance and characteristics of the ground in question, drainage systems may also trigger permitting concerns with legal or administrative costs. Further, the cumulative effect of many farmers choosing to increase drainage can contribute to water quality problems and flooding downstream. Perhaps most importantly to the farmer, drainage might send water downstream that, if instead retained in the soil, could help cope with dry spells later in the season or ongoing droughts, both of which are also expected to increase in frequency and intensity as the climate continues to change.

Before turning to drainage, farmers observing increased early season precipitation can consider practices to increase the health of their soils. We’ve discussed a number of these practices, such as rotational grazing and cover crops, here on the Climate Column. These practices can help many farmers on many different types of ground increase the ability of their soil to absorb and retain moisture, avoid the cost of drainage, hedge against yield-impairing dryness, and even save on inputs by encouraging soil fertility. Considering alternatives to installing drainage systems will also help farmers take part in efforts to protect water quality and mitigate damaging floods.

Have you observed increases in early season precipitation? Have you experienced interference with planting due to excessive water in the fields? Would you consider soil health practices to mitigate this in the future? Please share your thoughts in the comments below.


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4 Comments

  • As a small fruit, small farm, in Pickens county SC we are being impacted by climate change. I/we have spent several years studying the issue and have an adaptation and mitigation plan for our farm (www.thehappyberry.com under carbon). At the core of this plan are three principles. They are perennialization, biomass storage, and returning carbon to the soil (as char from a farms waste stream) to promote soil health, absorptive capacity , infiltration rate, cation and lastly anion exchange. There is a lot “between the cup and lip” in this plan and our land grant Has been unable to help us.

  • Anecdotally, our more heavily cover cropped fields seem to drain better and also hold more moisture, which gives us a bit more flexibility on planting date compared to neighbors. Less stuck tractors!

  • I disagree about how significant some of the downsides that are listed for drainage tile are…
    When talking about down stream flooding increases due to drainage you need to differentiate between surface drainage (diversion ditches) and subsurface tile…
    Yes massive amounts of drainage tile and effect water flow patterns, but 99% of the time they reduce flooding and erosion due to deluges from rain because they effectively “wring out the sponge” If the soil is fully saturated when a rain event occurs almost all of that new rain will run right off of the surface. When a field has adequate subsoil drainage (especially if it is coupled with cover crops/ improved OM and soil structure) the water infiltration rate is improved exponentially. Also subsoil drainage improves the depth of root penetration especially in permaculture such as orchards and vineyards which drastically helps protect the plants from droughts later in the year as the water table drops the roots are already deep.
    Diversion ditches on the other hand can be dangerous in terms of virtually unlimited runoff overflowing streams during a deluge… The nice thing about drainage tile is that they slowly and consistently drain excess water out of the soil. The key it to have improved OM in the soil to help hold more available water in the soil for your crops.
    If you are really lucky you can run your drainage tile into an irrigation pond that overflows into a ditch. This allows you a buffer that you can irrigate out of and helps keep the water table up…

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