How Tile Drainage Impacts Yield, Nitrogen

As most kids know, a big pile of mud can be a load of fun, writes Eric Hamilton at Soil Science Society of America. But not for farmers. Muddy fields mean too much water. And too much water means crops might not grow well.


Farmers often install underground drains, called tile drains, in waterlogged soils to help move the excess water away quickly. The drier soils are beneficial to their crops. But there is one potential downside: nitrogen. In the form of nitrate, nitrogen contaminates waterways. Plus, any nitrogen that leaves the field means wasted money for the farmer, who paid for fertilizer.

How can farmers balance draining their fields with holding onto nitrogen? For starters, they can turn to a decades-long experiment out of Purdue University. Results were published in the Journal of Environmental Quality.

For 31 years, researchers have studied how different farming practices and drainage strategies affect crop growth and nitrogen loss from fields.

“Drainage is a necessary practice on naturally wet soils. So it’s common on our productive soils in much of the Midwest,” says Eileen Kladivko, a member of the Soil Science Society of America. “But since the soil is leaky by nature, we want to know how we can reduce that nitrate concentration and load and still have good drainage.”

In their latest research, scientists share how fields performed in the last 16 years compared to the prior 15 years. In particular, they focused on the effect of different degrees of drainage.

Read more at Soil Science Society of America.