Nutrient reduction 101 reaches Kossuth
By CLAYTON RYE
WESLEY – Iowa State University brought its basic nutrient reduction strategy team to Wesley on March 14 to outline for about 55 farmers what they can do to help Iowa meet its goal of reducing, by 45 percent, its nutrient pollution of surface waters in the Upper Mississippi River Valley.
ISU department of economics associate dean John Lawrence and ag engineer Matt Helmers said the nutrient management strategy is in its early stages of development, but that early efforts were to implement existing soil conservation practices. These include keeping nitrogen and phosporus from leaching and eroding from farm fields, reduced tillage, cover crops and buffer zones.
The nutrient reduction strategy had its beginning in Washington, when the Gulf Hypoxia Task Force set Iowa’s goal of reducing nitrogen and phosphorus load. There are 41 states that shed water into the Mississippi River. Of those states, Iowa, Illinois and Indiana have the highest percentage of nutrient escapes to stop, all at 45 percent. The other 38 states were assigned lower percentage goals.
In a departure from most legislation that is top down, states that drained into the Mississippi River were directed to create their own plans in a bottom-up, volunteer approach to achieve this goal.
It’s an ambitious goal that Lawrence described as, “not simple and not impossible.”
Sources of nutrient runoff have been identified as point and non-point.
Point sources are water treatment facilities for cities the size of Ames and larger, Lawrence said.
Non-point sources are primarily from farm land.
The concept of nutrient trading is being considered, he said, where a large water treatment facility, to meet its goal, may pay a farmer for practices to reduce that farm’s runoff.
Lawrence presented a map that showed the Corn Belt states accounting for at least five percent of the nutrient load with Iowa and Illinois in the 10-17 percent range.
Responsibility for achieving Iowa’s goal has assigned to the Water Resources Coordinating Council, a division within the Iowa Department of Agriculture and Land Stewardship.
One of the objectives of this program is to use existing programs to reach the goal.
Currently, baselines are being set establishing a beginning point for measuring future progress.
Soil management practices include nutrient source, such as liquid manure or commercial fertilizer, timing of application, nitrification inhibitor use and cover crops.
Land use practices included land retirement, living mulches and extended rotations.
Edge of field management included drainage water management, shallow drainage, wetlands, buffer strips and bioreactors.
Following this presentation, attendees broke into small groups to discuss which practices they could put in place on their farms and then presented them to the group as a whole.
The small groups preferred simpler solutions that did not require major expense.
They said they could use practices such as nitrogen stabilizers, reduced tillage, controlled drainage, grass around surface intakes, cover crops, strip-tillage, split nitrogen applications with tissue testing for the second application, and timing of nitrogen application.
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