Farm Fresh: Farm Drainage and the Environment

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by Brian Hefty

In the 1970s, the Natural Resources Conservation Service (NRCS) or Soil Conservation Service (SCS) as it was called back then, had programs to help farmers pay for drain tile. By tiling, farmers were able to reduce soil erosion (the number one stated goal of the SCS) by 40% to 60% in many cases, because lowering the water table in the soil allowed rains to soak in rather than run off of fields, carrying valuable topsoil with that water. In addition, farmers benefited from healthier soils due to less compaction, more microbial life since there was more oxygen in the soil, fewer disease issues and the ability to keep salt levels moderated. All this gave farmers significantly higher yield and helped keep the U.S. food price down. In much of the Midwest, the last couple of years have been wet, and thanks to heavy fall and winter precipitation, this spring most fields have very high water tables. Hopefully that does not lead to delayed planting, but it is concerning. Adding drain tile to a field, even when crop prices are low, almost always pays in both the short-term and long-term when farmers have occasional high water tables. Since plant roots die when they hit the water table, high spring water levels mean roots can’t get deep. This is especially troublesome when the summer turns dry and deep roots are desperately needed.

The big concern lately with drain tile hasn’t been the economic benefits for farmers, highway departments and all those who reap the direct rewards. Questions have come from the media and others about the effect tile has on the environment. Here are the top 3 misconceptions:

1) Tiling will lead to increasedflooding. The opposite is true, as data has shown a 15% to 30% reduction in peak water flows where tile is used. Think about it this way. The only way a farmer pays for more tile is by increased yield. Does 200 bushel corn remove more water from the soil than 100 bushel corn, leaving less to flow downstream? Of course it does. Plus, most tile systems in our region are set up on 0.4” drainage coefficients or less. In other words, if a 4-inch rain hits, that could all run off an untiled field immediately. If it soaks into a tiled field, it would take a minimum of 10 days to flow out of the field. Which do you think causes flooding?

2) Tiling will pollute the downstream water. Aslong as tile inlets are not used in fields, this is also untrue. Soil is about the best water filter there is. Pull water quality samples coming out of tile lines. As long as the farmer has properly fertilized, which most do, that water will likely be drinking-water quality.

3) Tiling decreases wildlife populations. Sincethe world is demanding more food, farmers have two choices. Either they can increase production on ground they currently have, or they can farm more acres. If they farm more acres, that means fewer acres for wildlife and recreation. Also, most states have a lot of acres where wildlife can thrive today. For example in my state, South Dakota, there are approximately 50 million total acres, with less than 20 million acres of cropland. That means there are roughly 30 million acres left for wildlife. In the grand scheme of things, tiling actually increases wildlife populations, because more acres are able to be left for them.

Tiling remains a viable practice on farms today, just like it did 100 years ago. Thanks to modern technology and all the improvements in tile and installation practices, it is more effective and cost-efficient than ever. That means more crops, more food and a better environment when tiling is done correctly.

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Farm Fresh: Farm Drainage and the Environment

by Brian Hefty

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