45Z Tax Credit for Corn Farmers: What to Know and Do Next
The short version
The 45Z Clean Fuel Production Credit goes to ethanol plants, not directly to farmers. Each ethanol plant will determine how any value generated through the credit is passed back to farmers.
How you grow your corn affects how much that credit is worth. Plants that buy lower-carbon corn can earn more, and some are already sharing part of that value with the farmers who supply it. To be ready to take advantage of this opportunity, keep good records, stay current on soil tests, and ask your ethanol plant how its 45Z program works.
Here is what you need to know, and what to do next:
What is the 45Z tax credit?
45Z is a federal tax credit for producers of lower-carbon transportation fuels, including ethanol. It applies to fuel produced after Dec. 31, 2024 and sold by Dec. 31, 2029.
The fuel producer claims the credit, and its size depends on the fuel’s carbon intensity (CI) score. A lower score earns a bigger credit. Farming practices make up about half of ethanol’s carbon intensity, which is how the credit connects back to your fields.
Each ethanol plant decides how much of the credit to pass back to farmers, how to structure it (per-bushel premiums, tiers, contracts or programs), and which practices and documentation it requires. A lower CI score does not automatically mean a higher price, so the details of each plant’s program matter.
The federal pieces farmers were waiting on are largely in place, and the first plant payments have been announced. Current rules use a mass balance system, so your corn has to be delivered to an ethanol producer to count.
Understanding and estimating CI Scores
USDA’s calculator gives each field its own CI score, based on where the field is and the practices and inputs you record for it (the same practice can be worth different amounts in different . These are the details to have on file for every field:
| Practice or input | What to keep on file |
|---|---|
| Tillage | Your passes for the field. USDA’s T-DISC tool uses them to set whether the field counts as no-till or reduced-till |
| Cover crops | Cover crop details for each field, including whether it was grazed |
| Nitrogen | Total synthetic nitrogen per acre, and the share treated with a nitrification inhibitor |
| Manure | Manure applied to the field, with application details |
| Yield | Actual yield and expected yield (usually your APH yield) |
| Soil tests | Current soil test results |
Two free tools let you see how your location and practices affect a field’s score:
- IL Corn CI Score tool: an interactive map built on the USDA calculator that shows how location and practices change CI scores across Illinois. It is for information only, so work with your biofuel producer to get your official score.
- USDA FD-CIC web tool: enter a field’s location, acres, actual and expected yield, nitrogen rate and practices to see its score.
What to do now
- Keep field-by-field records. Track practices, inputs and yields for each field, and hold on to receipts for fertilizer and inhibitors. Under the federal rules, producers keep records of their calculator inputs and how each practice was carried out for five years, and those records can be audited by an accredited third-party verifier.
- Talk to your ethanol plant. Ask whether it has a 45Z program, how value will be shared with farmers, which practices and documentation it requires, and how to enroll.
- Estimate your score. Run one of your fields through the calculators below so you know where you stand before the conversation with your plant.
- Plan fertilizer with the paperwork in mind. Federal guidelines call for a nutrient budget before nutrients are applied. Treasury has given transition relief for fuel produced in 2025 and 2026, so ask your plant or advisor what applies to your 2027 crop before you spread fall or spring nitrogen.
- Stay current on soil tests, and read contracts before you sign. Many private carbon and sustainability programs limit enrolling the same acres twice, so check what you have already agreed to.
Get your records in order with PCM
Whether or not your plant has announced a 45Z program, the first step is the same: clean, field-level records. Precision Conservation Management (PCM) gives farmers in Illinois, Kentucky, Missouri and Nebraska free one-on-one support from a regional PCM Specialist, secure analysis of their own field data, and a clear view of what each practice does for their bottom line.
- New to PCM? Enroll with PCM to get your data in order.
- Already working with a Specialist? Reach out to your Specialist about opportunities in your area.
Additional resources
- farmdoc daily (University of Illinois): The 45Z Biofuel Tax Credit, Part 4: Inside the Updated USDA Feedstock Carbon Intensity Calculator and The Clean Fuel Production Tax Credit (45Z): Introductory Discussion
- IL Corn: CI Score tool, What Illinois Corn Farmers Need to Know About 45Z, 45Z Is Taking Shape and IRS guidance for 45Z implementation
- Nebraska Corn Board: Voluntary Carbon Programs and the 45Z Tax Credit
- USDA: FD-CIC web tool and IRS Notice 2026-53
