The kind of major and expensive efforts that have helped to improve rivers in many ways are needed in agriculture to reverse the nitrogen and sediment trends.
Better technology that helps farmers target fertilizer applications has helped reduce overall usage, but continued reductions will be more limited going forward.
Use of low- and no-till farming, in which crop residue is left on fields after harvest, also helps in reducing nitrogen loss — as well as wind and water erosion — but even more use of tillage conservation won't make a big dent in nitrogen loss to lakes and rivers.
There have been promising technologies developed to tackle the root of the problem of nitrogen and sediment loss in farm drainage. While varying in design, the systems either collect water from fields in holding areas to be released more slowly, and/or shut off the tile drainage lines in fields when the surface of the field is dry enough — holding the remaining water and nitrogen in the subsurface. That not only keeps the nitrogen out of the waterways, but keeps it in the fields where crops can use it for growth.
The systems are more expensive and require more attention. Incentives should be given for part of the costs for farmers who upgrade their systems, just as some state and federal assistance was given to cities for upgrading treatment plants. But just as urban residents pay significantly higher water and sewer fees to cover much of the cost of those upgraded systems, ag operators will need to bear a burden for pollution caused by their businesses' drainage systems.
A failure to act will inevitably lead to a federal crackdown on Minnesota. If and when that happens, the costs and regulatory burden of reversing the trend will be much higher than by acting now.