2025 March Stewardship Advocate

Herbicide Strategy

In August of 2024, the Environmental Protection Agency (EPA) published the herbicide strategy which outlines ways to decrease herbicide drift and runoff from fields by establishing a point-based mitigation approach. The strategy also affects registration of new herbicides and re-registration of existing herbicides. The herbicide strategy has three objectives…decreasing herbicide drift, cutting down on erosion and runoff and aligning herbicide re-registration timing to a standard 15 years.

The herbicide strategy was EPA’s response to lawsuits claiming that EPA did not consider the Endangered Species Act when reviewing and registering herbicides, as they are required to do by law. The lawsuits were settled when EPA began to develop and eventually released their herbicide strategy last year. The key element of the strategy is what’s known as mitigation measures which are landscape parameters and farm practices that reduce erosion and runoff to water bodies containing aquatic species.

What this means to Iowa farmers

In this point system, Iowa farmers can attain points based on where they live and how they farm. For example, each county is scored based on how vulnerable the county is to runoff. About 60% of Iowa countries get two points while the other 40% receive zero points. Other ways farmers can achieve mitigation points is through reduced till or no-till, cover crops, grassed waterways and field buffers. Farmers can also receive points if their field has less than 3% slope and they keep track of mitigations scores. Because runoff is a big concern, not irrigating is equal to three points which is half to 100% of the points some Iowa farmers will need to comply with the herbicide strategy. For most future herbicide registrations and re-registrations, Iowa farmers will need to achieve 0-6 points.

As of now, only Liberty ULTRA herbicide has a label that requires three mitigation points which can be met by not irrigating. Other herbicides will have mitigation requirements on their labels when they are registered or re-registered during the next several years.

Atrazine is a special situation

Atrazine is currently in EPA’s queue for re-registration. It is anticipated that the future label will require 0-6 mitigation points, depending on the Iowa county where it will be used. The vast majority of Iowa farmers can meet a minimum of 6 points due to where they farm and the practices they have implemented in their corn production system.

Mitigation measures calculator

EPA released a mitigation points calculator that famers and other users can utilize to calculate their mitigation points by filling out a straight-forward spreadsheet that keeps track of points accumulated as the user answers a series of questions. At the end, users are shown the number of mitigation points for a particular field or farm and whether they need to achieve more points to meet the number of points needed for the herbicide in question. Farmers and other interested parties can find the herbicide calculator here: EPA Herbicide Runoff Calculator and a user guide to help utilize the calculator is here: EPA Herbicide Runoff Calculator User Guide.