BLOOMINGTON, Ill. — Producers seeking information on conservation drainage tools and practices for use in their operations have a new resource available in the University of Illinois at Urbana-Champaign’s “Illinois Drainage Guide” website.

“It seems like we are spending a lot of time talking about what is happening in the Gulf of Mexico in terms of hypoxia, and this is driving research into water quality,” said Richard Cooke, associate professor and drainage specialist for the U of I Department of Agricultural and Biological Engineering.

“It is estimated that Illinois contributes 16.8 percent of the total annual flux of nitrogen and 12.9 percent of the total annual flux of phosphorous to the Gulf. Hypoxia affects algae and oxygen in water, resulting in die-offs. The goal is to bring down Illinois’ percentages to 12.”

Cooke made his remarks during the 2012 U of I Corn & Soybean Classic in Bloomington Jan. 16. Installing conservation drainage practices in a cost-efficient manner without restricting yields was the topic of his presentation. He told the farmers in attendance subsurface drainage systems and artificial subsurface (tile) drainage systems have been implicated in the increase of nutrient runoff into the Gulf, via the Mississippi River basin.

“Illinois is in the highest category (for N runoff) and the central part of the state has the highest concentration of nitrates,” Cooke said. “I want to assure you we are aware of this situation. We’re working on a system which reduces the movements of nitrates from drainage systems. We call this ‘conservation drainage.’”

Cooke spoke of two conservation drainage practices currently being encouraged by the university. He explained how bioreactors – subsurface trenches filled with a carbon source, such as wood chips – break down nitrates through biochemical processes.

“Just before it leaves the field, drainage water passes through a trench where wood chips break down the nitrates,” Cooke said, adding that bioreactors cause no adverse effects on production and yields, and require no modification of current practices, no new land to be taken out of production and little or no maintenance.

Many farmers are hesitant to install bioreactor systems, however, because there are no financial incentives in place to encourage them. The Illinois Natural Resources Conservation Service (NRCS) is currently developing a design practice standard for bioreactors, which Cooke believes may be the first step toward providing cost share funds for the systems. The Illinois Drainage Guide provides a template for determining the proper bioreactor size for meeting nitrate load reduction goals for individual operations.

Drainage water management, or the practice of using a control structure to set the outlet of a drainage system, allows producers to adjust the intensity of drainage and remove only the amount of water necessary to ensure optimum crop growth.

“Drainage water management changes drainage intensity during harvest and other times. The producer can change the system during the four seasons to mirror the growth of the roots,” Cooke explained. “Long-term estimations show we can increase our yields by about 2 or 3 percent. Some years it will make no difference in yields, but there is the potential for an increase.”

Drainage water systems tested by the U of I and adjusted for varying soil types and topographies all resulted in a reduction in N losses, according to Cooke. “We have environmental benefits without any adverse effects on yields under the drainage water management system,” he said.

Cooke concluded the decision to install or improve a drainage system is based on principles of good economics and good husbandry. If the benefits outweigh the associated costs for a producer, then drainage makes sense.

He encourages those who are unconvinced about the benefits of drainage to begin with a single field and run comparisons – with the help of the Illinois Drainage Guide – on how drainage may effect yield and other factors. “In terms of a drainage system, there is no one-size-fits-all system,” said Cooke.

The U of I Illinois Drainage Guide may be accessed at http://wq.illinois.edu/dg