August 30, 2026

Rice Straw Burning: Managing Air Quality Restrictions

Rice straw is the most tightly regulated crop residue in the country. Here's how California's disease-only conditional permit system works, what growers in Arkansas and Louisiana face instead, and what the research says about the alternatives.

Most crop residue burning is regulated by asking whether the smoke will bother anyone. Rice straw in California's Sacramento Valley is regulated by asking whether your field is sick enough to justify the fire.

That's not a rhetorical flourish. It's the actual legal test. A county agricultural commissioner has to walk into your field, count diseased stems, and put a written finding on paper before an air district can hand you a permit — and even then you're capped at a quarter of your planted acres. No other crop residue in the United States is regulated this tightly. If you grow rice in Arkansas or Louisiana, none of it applies to you.

Quick answer:

In California's Sacramento Valley Air Basin, rice straw burning is capped by statute. The Connelly-Areias-Chandler Rice Straw Burning Reduction Act of 1991 limits annual burning to the lesser of 25% of each grower's planted acres or 125,000 acres basin-wide.
Disease is the entry ticket. Since September 2001 the county agricultural commissioner must independently find a significant, yield-reducing rice pathogen in the specific field before a conditional permit can issue. One burn, per field, per year.
A permit is not permission to burn today. CARB sets permissive burn days and daily acreage allocations; your district allocates acres field by field off a ready-to-burn list, and unburned acres have to be returned.
Outside California, it's voluntary smoke management, not acreage caps. Arkansas — the largest rice state — runs a call-in dispatch system with fuel-loading tables and category-day limits rather than permits.
The alternatives are real but not free. Eight years of UC Davis trials found no yield penalty from incorporation, baling, or rolling, but more weeds when straw was incorporated without winter flooding — and baling removes only about half the straw.

California: the only acreage cap of its kind

The 1991 Act phased rice straw burning down over a decade rather than banning it outright. The final step landed in September 2001, and that's the regime still in force.

Under Health and Safety Code § 41865(i), the maximum annual acreage burned in the basin is the lesser of two numbers: 25% of each individual applicant's planted acres that year, or 125,000 acres basin-wide, with the air pollution control council determining annually which binds. Growers who own or operate 400 acres or less and otherwise qualify get a useful carve-out — they may burn their entire acreage once every four years, as long as the overall cap isn't breached.

Three structural details matter more than growers expect. A conditional permit is valid for only one burn, per field, per year. Permission to burn cannot be transferred, sold, or traded to another applicant. And "administrative burning" — vegetative material along roads, ditches, and levees adjacent to a rice field, plus research-facility burning, capped at 2,000 acres — sits outside the section entirely.

The enforcement side has teeth that don't exist for most ag burning elsewhere. Negligent or intentional violation is a misdemeanor carrying a fine of up to $10,000, up to nine months in county jail, or both, plus a separate civil penalty of up to $10,000 — and those provisions apply only to agricultural burning in the Sacramento Valley Air Basin.

What "proof of disease" actually means

This is where the California program stops resembling a permit process and starts resembling a field inspection.

Under 17 CCR § 80156, an air pollution control officer may only grant a conditional permit after the county agricultural commissioner has done three things: independently determined the significant presence of a pathogen in the specific field during the growing season; made a written finding that the pathogen will likely cause a significant, quantifiable yield reduction in that field this season or next; and documented that the applicant hasn't violated § 41865 in the previous three years.

The regulation also specifies how you count. It sets out stem sampling, visual assessment, and soil sampling procedures — minimum 50 stems per inspection site, a maximum of one biased site per field, a minimum biased-to-unbiased site ratio of one to three in fields of 50 acres or less and one to five above that. Commissioners may accept reports from qualified rice disease inspectors, but must review them and field-verify at least 5% themselves. Inspectors performing fraudulent inspections face permanent revocation of certification.

The codified disease significance thresholds are 15% of sampled stems for stem rot (Sclerotium oryzae), 15% for aggregate sheath spot (Rhizoctonia oryzae-sativae), and 1.8% for neck blast (Pyricularia grisea). One honest caveat: the regulation frames those numbers as governing "until May 31, 2003," after which the Basinwide Council may propose alternative evaluation methods. Treat them as the codified baseline and confirm the current screen with your county agricultural commissioner.

The daily layer: burn day status and the ready-to-burn list

Holding a conditional permit gets you into the queue. It does not get you a match.

As Butte County AQMD explains, CARB determines permissive burn days and the acres allocated for the basin based on meteorology and air quality, and the Sacramento Valley Basinwide Air Pollution Control Council — nine air districts — writes an annual burn plan, subject to CARB approval, setting burn hours and daily basin-wide allocations. Individual districts run day-to-day operations. It's the same two-layer structure covered in agricultural burn notifications: a standing permit gated by a daily go/no-go decision.

Butte County AQMD's 2025 conditional rice straw burn permit shows what that looks like on the ground. These are one district's numbers, but the shape is representative:

Fees. A $25 base fee, $5 Sacramento Valley council fee, and $60 program registration fee — $90 total — plus $3.50 per acre billed after the fields are actually burned.
Burn day status posts by 8:45 a.m. on the district's ag burn line and website, and every rice burn must be authorized by the on-duty inspector before ignition.
The ready-to-burn list. Only completely harvested fields go on it. During the intensive fall season, September 1 through December 31, the district contacts growers and allocates acres off the list in order. Switching fields without prior approval is prohibited, and allocated acres you don't burn must be returned by 2 p.m. or the field drops to the bottom.
Ignition hours. September through February, 10 a.m. to 3 p.m. with flames out by 4 p.m.; March through August, 10 a.m. to 5 p.m. Ignition is by strip firing into the wind or backfiring.
Drying times. Spread straw needs three days, rowed straw ten, unless it passes the crackle test — and after 0.15 inches or more of rain, a representative sample must pass the crackle test regardless. Straw pulled from under the mat, the center of the mat, and several areas of the field is dry enough if it crackles when bent sharply.

Field swapping is allowed within a grower's own registered acreage, with a 10% size-increase limit and a $25 fee, but swapping between permittees is barred by state law.

Outside California: voluntary smoke management instead

Arkansas grows more rice than anywhere else in the country — USDA reporting put it near 45% of U.S. planted rice acreage in 2025 — and it regulates burning in almost the opposite fashion.

The Arkansas Voluntary Smoke Management Guidelines for Row Crop Burning, developed by the Arkansas Department of Agriculture with the Arkansas Rice Federation, the Farm Bureau, and the University of Arkansas, are exactly what the name says. There is no acreage cap and no disease test — instead there's a call-in system to the Department Dispatch Center, a safe burning checklist, and hard weather thresholds: don't burn if winds exceed 15 mph, don't burn if humidity is below 20%, don't burn when wind direction sends smoke into roadways or communities.

What makes it work is the airshed math. Growers estimate available fuel from the guideline's crop table — rice runs 2.5 tons per acre at a low yield, 3.7 at medium, 4.9 at heavy — then combine that with a category day rating from 1 (poor dispersal) to 5 (excellent) and the downwind distance to the nearest smoke-sensitive area. The result is a tonnage ceiling for a 36-square-mile airshed. A receptor a quarter mile downwind on a category 4 day allows 720 tons; move it 20 miles out on a category 5 day and the ceiling rises to 11,600. Dispatchers track everyone else's reported burns and will tell you if the airshed is already full.

Louisiana takes yet another approach, leaning on the Certified Prescribed Burn Manager program run by its Department of Agriculture and Forestry, with smoke management guidelines co-developed with the LSU AgCenter. The takeaway across all three states is the one we make in the state-by-state permit guide: the regulatory model, not the crop, decides your paperwork.

What the alternatives actually cost

California's phase-down forced a genuine agronomic experiment, and the results are worth knowing wherever you farm. Starting in 1993, UC Davis researchers ran an eight-year comparison of burning, incorporation, rolling, and baling and removal, with and without winter flooding. Their published findings are more encouraging than growers expect on yield and less encouraging on weeds: none of the practices reduced grain yield on the experimental plots, but weeds increased when straw was incorporated, particularly without winter flooding. On the other side of the ledger, incorporation returns nutrients to the soil, allowing less nitrogen fertilizer and lower production costs, and winter-flooded fields deliver substantial habitat value for Pacific Flyway waterfowl.

The practical wrinkle is water. As UC ANR's rice specialists note in guidance on managing straw when winter flood water is uncertain, baling removes only about half the straw — a good start, not a solution — and chopping and leaving residue on the surface likely won't decompose it in a dry winter. Good soil-water-straw contact is what drives decomposition, which means incorporation; the California trials found it produced the greatest decomposition and the least straw remaining the following spring, in flooded and unflooded fields alike.

That matters beyond tidiness. Undecomposed straw ties up early-season nitrogen and hosts the very stem rot and aggregate sheath spot sclerotia that qualify a field for burning in the first place.

Planning around what you can't change

Whichever system you're in, the weather that decides a good rice burn is the same, and it's the part you can actually forecast. Rice straw burns put a lot of smoke close to sensitive receptors, which makes vertical dispersion the controlling factor more often than wind speed — our explainer on mixing height covers why smoke lofts some mornings and lies flat on others, and the smoke management guide covers plume planning around the roads, towns, and schools that both regulatory models are built around.

If you're working multiple fields with a queue position to protect, a written plan is worth the hour — our burn plan walkthrough covers what belongs in one. And an emergency ban overrides a valid permit entirely, a distinction we break down in burn bans vs. burn permits.

Frequently asked questions

Can I get a California rice burn permit without documented disease?

Not under the conditional program. Since September 2001, § 41865(f) and (h) require the county agricultural commissioner to have independently determined a significant pathogen presence in the specific field and made a finding of likely quantifiable yield reduction before an air pollution control officer may issue the permit. Administrative burning of levees, ditches, and roadsides adjacent to rice fields is handled separately under § 41865(k).

Does the 25% cap apply per grower or per basin?

Both, in sequence. Each qualifying grower is eligible to burn up to 25% of their own planted acres, but the basin-wide total may not exceed 125,000 acres. The air pollution control council determines annually which limit binds and sets the maximum percentage applicable to all growers accordingly.

Do other rice states cap acreage the way California does?

Not that we found. Arkansas and Louisiana both manage rice residue burning through smoke management programs — dispatch notification, weather thresholds, fuel loading and airshed limits, and in Louisiana a certified burn manager framework — rather than statutory acreage caps or disease qualification. Local burn bans still apply on top.