Lesson 6 of 9 · about 17 minutes

Protecting Farmland and Capping Cumulative Impact

You'll be able to

Write a soil protection rule that specifies irrigated or nonirrigated land capability class
Describe the findings of Hu et al. (PNAS 2025) and Elmallah et al. (2023) on solar and property values, accurately
Explain what the NRCS solar guidance and the federal Farmland Protection Policy Act do and do not require
Compute a cumulative acreage cap and apply it to a queue of applications

The heart of Jeff's package is one sentence: no energy generation, storage or transmission facility on Class I or Class II soils, with no variance and no waiver. It is binary, it is mapped by a federal agency, and it cannot be negotiated away at a hearing. Those are its strengths. This lesson shows how to draft it so it does what it is meant to do, then turns to the evidence that supports it and to the other half of farmland protection: limiting how much total land the county gives up.

Drafting the soil rule

NRCS rates soils from Class I to VIII for field crops. The definitions used in NRCS soil reports: Class 1 soils "have few limitations that restrict their use," and Class 2 soils have moderate limitations that reduce the choice of plants or require moderate conservation practices. Reports also note that the classes show suitability only in general terms.

In southern Idaho the detail that decides cases is water. NRCS soil reports list an irrigated capability class, and a nonirrigated class where one applies. Ground that rates Class 2 under irrigation can rate far lower dry. A Canyon County land use case in 2025 attached an NRCS soil report showing a site that was about 78 percent irrigated Class 2, which the local soil conservation district cited in recommending denial. Jeff's draft defines the protected land as Class I or II "in the most current NRCS soil survey" without saying which condition. An applicant will argue for the nonirrigated rating. Close it.

Example: the Owlcreek soil rule

Draft text: No commercial energy generation, storage, substation or transmission facility, including access roads, laydown areas and fencing, may be located on land mapped as Land Capability Class I or II under irrigated conditions in the most current NRCS soil survey, or under nonirrigated conditions where no irrigated rating is given. No variance, waiver or administrative adjustment may authorize it. The applicant shall submit an NRCS soil map of the entire footprint plus a 1,000-foot buffer; for disputed boundaries, a field verification by a qualified soil scientist chosen by the county and paid by the applicant governs.

Applied to Highline Solar: the 1,800-acre site maps as 1,240 acres irrigated Class II, 410 acres Class III and 150 acres Class IV. Under the rule, 1,240 acres are off limits. The remaining 560 acres could host roughly 560 / 6 = 93 MW at the applicant's own 6 acres per MW, but only if the use table allows it in that zone and the other standards are met.

Put a topsoil standard next to the soil rule for any disturbance that is allowed: strip, stockpile and replace topsoil without mixing it with subsoil, under an approved soil management plan. Add a separate line in the decommissioning bond for soil restoration, so compaction repair is funded rather than assumed.

What the evidence supports, and what it does not

Soils. The USDA NRCS Conservation Guidance for Utility-Scale Solar Projects (December 2024) lists the resource concerns of solar on farmland: sheet, rill and wind erosion, sediment, compaction, organic matter depletion, habitat changes and wildfire hazard from vegetation. It recommends keeping all topsoil and reapplying it on site, minimizing grading, keeping machinery off wet ground and planning restoration "to an agreed upon condition." It is voluntary, and it says so. Jeff's package cites it accurately as federal recognition of the harms. His package also cites university and Welsh government studies on how many years compaction takes to recover. Those specific recovery figures could not be confirmed for this course; if you use them, go to the original studies and quote them exactly.

Federal farmland law. The Farmland Protection Policy Act, 7 U.S.C. 4201 and following, uses the phrase "irreversible conversion" and directs federal programs to minimize their role in it. It binds federal agencies and federally assisted projects. It does not apply to a county permit for a privately financed solar farm. Cite it for its policy finding; the developer has no duty under it.

Property values. Jeff's package attributes a 2025 PNAS study to Ben Hoen of Berkeley Lab. The PNAS paper is by Chenyang Hu, Zhenshan Chen and colleagues, led from Virginia Tech. Get the citation right, because the findings help the farmland case.

Study	Data	Homes	Farm and vacant land	Where effects concentrate
Hu et al., PNAS 122(24), 2025	About 8.8 million transactions near 3,699 facilities of 1 MW or more	About 4.8% lower within 3 miles shortly after installation; fading, back to normal after about 10 years; no effect beyond 3 miles; no effect on lots over 5 acres	About 19% higher within 2 miles	Greenfield sites (farmland, open space) lowered nearby values; brownfield sites raised them; no significant effect in the South region
Elmallah, Hoen et al., Energy Policy, 2023 (Berkeley Lab)	Over 1.8 million home sales near more than 1,500 projects in six states	About 1.5% lower within 0.5 mile versus 2 to 4 miles away; nothing significant beyond 1 mile	Not studied	Only in some states, and only for projects on agricultural land, larger projects and rural homes

Read together, the studies let an advocate say several things with confidence. Effects are real but modest and local. They are worst exactly where this course wants protection: big projects on farmland next to rural homes. And the money splits. Farm and vacant land near solar gains value because it can be leased; the homeowner next door loses. That is the core fairness argument for protecting non-participating neighbors.

They do not support a rule that any projected diminishment of any parcel is grounds for denial, which is what Jeff's draft says. An average effect of 1.5 to 5 percent, fading with time and varying by region, is hard to project for a single parcel. Lesson 9 covers why that standard draws legal fire and what to use instead.

Capping the total

Case-by-case review has a blind spot: every project looks small next to the whole county. Jeff's rebuttal to his county's planning commission made the point well. A cap answers it by setting the county's total tolerance once, in the record, before any applicant is in the room.

Michigan's state siting law shows the idea has standing. It has the state commission consider the share of a locality's land already devoted to energy generation, though the law sets no cap. A county can set its own.

Example: the Owlcreek acreage cap

Owlcreek's agricultural zone is 210,000 acres. The board adopts a cap: commercial energy facility footprints may not exceed 1 percent of the zone, and no more than 640 acres within any 4-mile radius.

County cap: 210,000 x 0.01 = 2,100 acres.
Already approved: a 600-acre project from 2022. Remaining: 2,100 - 600 = 1,500 acres.
Pending: Highline at 560 eligible acres; Basin Sun at 900 acres; Pell Flats (aggregated) at 305 acres. Total pending: 560 + 900 + 305 = 1,765 acres, which is 265 acres over the remaining room.
Local cluster rule: Basin Sun and Pell Flats sit 3 miles apart. Together 900 + 305 = 1,205 acres, above the 640-acre local limit.

Now the county needs a rule for who gets the room: first complete application, or a periodic window where applications are compared on soils, distance to existing lines and impact on neighbors. Comparative windows are harder to run but reward the best-sited projects, not the fastest filer.

Common mix-ups

Claim: Solar on farmland is temporary, so the land comes back. What the evidence shows: Leases often run decades, and NRCS's own guidance treats compaction, erosion and organic matter loss as concerns that restoration must address. Return is possible but has to be funded and enforced.
Claim: Property values near solar always fall. What the evidence shows: Effects vary by region and fade over time, and farmland near solar tends to rise. The strongest version of the claim is about homes near large projects on farmland in rural areas.
Claim: Prime farmland is protected by federal law. What the evidence shows: Only from federal programs. Local code is what protects it from private development.

Reporting angle

Run every proposed site through Web Soil Survey and publish the irrigated capability breakdown with the acreage.
Ask the local soil conservation district whether it has commented on the application, and request its letter.
Ask the assessor for sales near any existing solar facility in the county since construction. Small samples prove little, but they are local.
Keep a running table of approved, pending and withdrawn energy acreage in the county. Nobody else will.
Ask the applicant whether it considered previously disturbed sites, and request the alternatives analysis.

Research angle

Soil maps and capability classes: NRCS Web Soil Survey.
Federal solar soil guidance: NRCS, December 2024.
Property value research: Virginia Tech extension article reporting Hu et al. (2025) national results, Cardinal News on the PNAS study and Berkeley Lab, Elmallah et al. (2023).
Federal farmland policy: 7 U.S.C. 4201.
Farm economics context: the farmland and land use planning lesson.

Check yourself

1. Why should a soil rule say 'irrigated land capability class' in arid southern Idaho?

2. What did Hu et al. (PNAS, 2025) find for homes within 3 miles of large-scale solar nationwide?

3. In that same study, what happened to agricultural and vacant land within 2 miles of solar sites?

4. Who does the federal Farmland Protection Policy Act (7 U.S.C. 4201 and following) bind?

5. A county caps commercial energy facilities at 1 percent of its 210,000-acre agricultural zone. 600 acres are already approved. How many more acres can be approved?

6. What is the status of the December 2024 NRCS Conservation Guidance for Utility-Scale Solar Projects?

Terms in this lesson

Land capability class: An NRCS rating from I to VIII of how suitable soil is for field crops; Class I has few limitations, Class II moderate limitations.
Prime farmland: USDA term for land with the best combination of physical and chemical traits for producing crops, which in dry regions often depends on irrigation.
Cumulative impact cap: A limit on the total land or capacity a county will allow for a use across all projects combined.
Hedonic study: A statistical method that estimates how one feature, such as distance to a solar farm, affects sale prices while controlling for other features.

Full glossary