Rice Straw Burning
1999 Report to the Legislature
Executive Summary

This page last reviewed June 20, 2008

The Connelly-Areias-Chandler Rice Straw Burning Reduction Act of 1991 (Act) requires the Air Resources Board (ARB or Board) and the California Department of Food and Agriculture (CDFA) to prepare and submit a report to the Legislature every two years on progress in reducing the amount of rice straw burned in the Sacramento Valley (Assembly Bill 1378, Statutes of 1991, Chapter 787, Section 2; California Health and Safety Code, Sections 41865-41866). The 1999 report documents that the requirement to phase down rice straw burning continues to be met on schedule.

This report is the third such report and focuses on the activities occurring since the last report submitted to the Legislature in October 1997. The proposed report was released for public comment on November 10, 1999, for consideration at the November 18, 1999, Board meeting. As a result of public comments made at the Board meeting, the Board extended the public comment period and continued the Board meeting until December 10, 1999. After review of the written comments and testimony at the December meeting, the Board directed the staff to make several changes to the report and, upon approval from CDFA, forward the report to the Legislature. The Report of the Advisory Committee on Alternatives to Rice Straw Burning is being issued as a separate report.


About 500,000 acres of rice are grown in the Sacramento Valley. Before the Act, most of these acres were burned. Starting in 1992, the Act required progressive reductions in rice straw burning according to a schedule of decreasing percentages of planted acreage. In 1997, the schedule was modified to limit the burning to 200,000 acres annually for three years, starting September 1998 (Senate Bill 318, Statutes of 1997, Chapter 745, Section 2; California Health and Safety Code, Section 41865). For these three years only, the law set a separate limit for fall burning. Of the 200,000 acres allowed to be burned annually, up to 90,000 acres are allowed to be burned during the fall, subject to the acreage allocations of the Sacramento Valley Agricultural Burning Program. The final step of the phase down starts September 2001, when the law will allow burning only for disease control. The disease control burning will be limited to 25 percent of planted acres or 125,000 acres, whichever is less.

Public Health and Smoke Management

The burning of rice straw results in the emissions of smoke and other pollutants, which affect public health and visibility. Smoke of all kinds, including rice straw smoke, contains inhalable particulate matter. Although studies have not been done on rice straw smoke specifically, over 300 individual health studies on the impacts of particulate matter on public health were cited in the United States Environmental Protection Agency's document supporting the change in air quality standards. A bibliography of these  studies is available on request.

Exposures during smoke episodes can result in high concentrations of fine particulate matter (less than 2.5 microns) over a several hour period during the afternoon and early evening periods. These levels may be 3 to 4 times higher on an hourly average basis than the rest of the day. People with respiratory illnesses, such as asthma, bronchitis, and allergies, are especially susceptible to the effects of smoke.

While the Act limits the total rice acres allowed to be burned, it is critical to manage when, where, and how all agricultural burning, including rice straw burning, is done to minimize the public's exposure to smoke. These activities are addressed with the smoke management program administered by the ARB and the air pollution control districts (districts) within the Sacramento Valley. The heart of this program is the Sacramento Valley Agricultural Burning Plan (Burn Plan). The Burn Plan is prepared in accordance with regulations adopted pursuant to section 41856 of the Health and Safety Code.

The amount of burning allowed each day depends on prevailing meteorological and air quality conditions. The Burn Plan allows more acres to be burned on days with good ventilation, restricts the acres burned on days with limited ability to disperse smoke, and allows no agricultural burning on days with adverse meteorological and air quality conditions. The Burn Plan encourages spring burning by increasing the allocation by a factor of 1.5.

Relative to the spring, the fall is more critical for managing smoke primarily due to more stagnant meteorological conditions. Therefore, the smoke management program is more restrictive during the fall than in the spring. Burning during the fall is most effective for disease control. Consequently, growers try to burn as much acreage as possible during the fall, subject to the provisions of the Burn Plan and the phase down schedule. Historically, hundreds of thousands of acres of agricultural residue were burned during the fall. Over the last decade, the combination of the phase down and the Burn Plan have reduced the acres burned during the fall months. Since the phase down started in 1992, most of the reduction in burning rice straw has taken place during the spring. While growing practices and other factors call for fall burning, shifting as much burning as possible from the fall to the spring would lessen the air quality impacts of burning in most years.

To minimize smoke impacts, regional smoke management programs are crucial. These programs must include prescribed burning as well as agricultural burning. In March of 2000, the ARB staff is proposing amendments to smoke management program requirements for all the districts in California to ensure that an effective statewide program is maintained. The proposed amendments are an integral component of California's collective efforts to minimize the impacts of the burning agricultural waste and forest materials. The smoke management program used in the Sacramento Valley is being used as a model for the rest of the State.

Alternatives to Burning

Over the last two years, there has been an ongoing effort to pursue alternatives to rice straw burning, including the ARB's rice straw grant program and the CDFA's rice straw utilization tax credit program. In 1998, the Board developed a rice straw diversion plan in consultation with CDFA, the Trade and Commerce Agency, and the Alternatives Advisory Committee.

Despite these programs, alternative uses have not materialized as quickly as hoped. Effective alternatives are critical to the long term success of the phase down. Currently, about 97 percent of the rice straw that is not burned is incorporated into the soil. Incorporation is likely to remain the primary alternative to burning for the next few years. This situation will improve if several promising demonstration programs are successful. However, financial incentives are needed to expand the use of rice straw. In the interim, the smoke management program will continue to be an essential component of the overall program to minimize the public's exposure to smoke.

The following discussion on alternatives addresses the status of five major activities designed to promote alternatives: ethanol and biomass products; the Rice Straw Grant Program; the recommendations of the Advisory Committee on Alternatives to Rice Straw Burning; the Rice Straw Diversion Plan; and the Rice Straw Utilization Tax Credit Program.

Ethanol and Biomass Products

A new opportunity for the use of rice straw may result with the phase out of methyl tertiary butyl ether (MTBE) in California's gasoline. With the phase out, significant quantities of ethanol may be needed for California gasoline both in the short term and the long term. The total market potential of ethanol will depend on refiner decisions related to the production of California Phase 3 reformulated gasoline (CaRFG3) and the U.S. EPA's decision related to California's request for a waiver from the federal oxygenates mandate. However, CaRFG3 will establish a minimum ethanol market of about 120 million gallons a year to meet oxygenate demands in the South Coast Air Basin.

A California ethanol production industry will develop only if investors feel assured that the ethanol market in California can be sustained over a long period of time to allow a reasonable return on their investment. Otherwise, investment capital may not become available. Due to the amount of rice straw potentially used in these biomass-to-ethanol plants, several commercial plants could substantially contribute to meeting the 50 percent diversion goal for rice straw. Public policy can encourage ethanol production and use by providing incentives such as financial assistance for biomass-to-ethanol plant construction. The ARB and CDFA are very supportive of efforts to develop biomass-to-ethanol facilities in California, specifically rice straw  biomass.

In July 1999, the California Legislature adopted Assembly Joint Resolution 4 (AJR-4, Maldonado) to encourage the use of rice straw for erosion control by State and federal agencies. This resolution highlights the benefits of using California-grown rice straw for erosion control and fire rehabilitation. The ARB will work with the appropriate State and federal agencies to direct them to available sources of rice straw. The ARB will also inform these agencies that the resolution specifies that weed-free certification for rice straw is not considered necessary.

The Rice Straw Grant Program

During the last two years, the ARB awarded rice straw grant funds for five demonstration and commercialization projects. If all are successful, the five projects could use 25 to 50 percent of the available rice straw by 2003. For year 2001, when the last step of the phase down limits burning to a maximum of 25 percent, it is estimated that off-field uses will consume only about 5 to 10 percent of the rice straw. Soil incorporation will remain the primary method for complying with the 2001 requirement.

In looking towards the future there are some promising developments. One of the grant recipients, FiberTech, started manufacturing particleboard out of rice straw in October 1999. In this project, FiberTech expects to use 40,000 to 60,000 tons of rice straw annually. This would amount to about 22,000 acres of rice straw or about 4 percent of planted acres.

In spring 2000, the Board will allocate the remaining $1.2 million in rice straw grants. The ARB staff will particularly seek out and encourage proposals for ethanol production projects. The potential for this alternative is substantial because a single commercial plant could use from 80,000 to 200,000 tons of straw annually. As the total potential annual yield of rice straw is  about one million tons, a single plant could represent up to about a 20 percent diversion of rice straw to alternatives.

The Advisory Committee on Alternatives to Rice Straw Burning

The Advisory Committee on Alternatives to Rice Straw has made a number of recommendations which could enable alternative uses for rice straw to develop. In summary, the Committee's draft recommendations include: supporting financial incentives to develop rice straw products, such as loans, grants, and tax credits; providing financial assistance, such as a tax credit program, for building barns to store rice straw to make it available year-round; and encouraging the use of ethanol made from rice straw if environmental, technical, and economic studies are supportive.

The ARB and the CDFA support these recommendations as necessary and appropriate to stimulate the alternative uses of rice straw.

Rice Straw Diversion Plan

In December 1998, the ARB issued the Rice Straw Diversion Plan which suggested approaches for achieving 50 percent rice straw usage by 2000 and 2003. The plan also recognized that, without additional government assistance, only about 20 percent would likely be used by 2003. The additional measures needed to increase use include financial incentives and assistance with infrastructure related to rice straw harvesting, distribution, and storage.

Rice Straw Utilization Tax Credit Program

The CDFA has issued tax credit certificates for the purchasing of about 6,000 tons of rice straw in both 1997 and 1998. This accounted for about 60 percent of the total amount of rice straw harvested and used in 1998. This harvested rice straw was used primarily for bedding for dairy cows, erosion control, and cattle feed. In its draft 1999 Report to the Legislature on the Rice Straw Utilization Tax Credit Program, the CDFA is recommending that the Legislature consider the following:

  • Expanding the program by lifting the annual $400,000 cap in order to attract larger and more diverse projects and

  • Allowing a purchase or trading program so that new rice straw projects with little or no California income tax liability could sell their tax credits to a profitable entity that could take advantage of the tax credit.

Progress of the Burning Phase Down

The burning phase down has proceeded as specified in the Act, with growers exceeding the phase down mandates basin wide. Table 1 shows that the total rice acreage burned annually has declined from 303,000 acres in 1992, the first year of the phase down, to about 141,000 acres in 1998. Most of the unburned rice straw continues to be incorporated into the soil. Since the phase down started in 1992, most of the reduction in burning has taken place during the spring. However, fall burning has been reduced due to both the phase down and the Burn Plan.

Table -1
Rice Straw Burning Phase Down
Maximum Allowable and Actual Burned
Sacramento Valley

 Burn Year
(Sept 1 - Aug 31)

Rice Acres

Rice Acres

Phase Down Act:
% Acres Allowed
to be Burned

% Acres
Actually Burned


































200,000 acres 


Environmental Assessment

The phase down has resulted in a decrease in smoke and emissions from rice straw burning on an annual basis. While most of the reduction has taken place in the spring, the combination of the phase down and the Burn Plan has also reduced acres burned in the fall. During the last two years, fall air quality has improved and public complaints about agricultural burning during the fall have decreased, which is most likely a result of better smoke management under the Burn Plan.

Overall, fine particulate emissions are greater from burning rice straw than from the alternatives of soil incorporation or offsite removal. In addition, atmospheric simulation modeling shows that the particles in smoke travel farther and remain in the air for a longer time than diesel and dust emissions, thus increasing the potential of affecting populated areas.

From an overall air quality standpoint, the phase down has had a positive public health and environmental impact due to reduced air emissions. However, some growers have indicated that there may be adverse environmental effects resulting from the change in rice straw management practices and the variety of techniques employed. These include: effects on water quality and use, increased methane emissions contributing to global warming, flooding potential, additional fuel use, additional use of pesticides and herbicides, and effects on waterfowl and pheasant habitats during winter. However, the ARB and CDFA staff currently have insufficient data available to adequately assess these effects. Staff will work with stakeholders to identify the available information on potential environmental effects and evaluate the need to conduct additional research.

Economic Assessment

The phase down has had varying economic impacts on individual growers depending primarily on the farmer's capability to incorporate straw. The cost of soil incorporation, the primary alternative to burning, has added to the costs of growing rice. The average cost of soil incorporation is estimated at about $36 per acre, compared with about $2 per acre for burning. A weighted average impact over all planted acres shows that soil incorporation costs have added about $20 per planted acre to production costs during 1997 and 1998.

On a regional basis, the phase down has cost growers about $10 million in direct costs from soil incorporation. After applying economic multipliers, the phase down appears to have reduced the output of goods and services produced in the region by about $19 million, with an estimate of 434 jobs lost. This represents about 0.04 percent of the Gross Valley Product and about 0.05 percent of the Valley's total employment. The impacts on Colusa County were most significant since rice growing is a major part of the county's economy, representing less than 2 percent of the Gross County Product.

The estimates of production costs and revenues used here do not represent any individual rice grower. The production cost estimates represent a hypothetical farm using farming procedures considered typical using industry average costs. The revenues also represent industry averages.

Based on the University of California Cooperative Extension data, the average cost of growing rice is estimated to be $823 per acre in 1997 and $842 per acre in 1998. In general, production costs do not vary greatly year to year; however, the revenue received for the rice crop does, because both crop yield and market price vary yearly. Rice growers' total average revenue was estimated to be about $908 per acre in 1997 and $940 per acre in 1998. Considering all costs, on average, growers gained about $85 per acre in 1997 and $98 per acre in 1998. Cash earnings were $254 per acre in 1997 and $274 per acre in 1998 (Non-cash costs include lost opportunity cost of capital invested in land and equipment and unpaid labor of the rice grower).

These estimates include transitional payments, authorized under the federal Agricultural Market Transition Program, of $165 per acre and $172 per acre in 1997 and 1998, respectively. These transitional payments are scheduled to end beginning in 2003. In 1998, growers also received federal emergency assistance payments of about $78 per acre.

Recent studies by the University of California at Davis, Plant Pathology Department, and the University of California Cooperative Extension have shown an increase in the incidence and severity of two major rice diseases, stem rot and aggregate sheath spot, with repeated straw incorporation when compared with burning. Rice experts believe that the new disease levels seemed to have reached a higher plateau and may have resulted in a reduction in yields. Research is needed in order to assess the economic impact of the phase down in terms of potential for reduced yields.

The ARB and the CDFA are concerned about reduced yields. Starting September 2001, the Act allows the burning of rice straw only for the purposes of disease control. To assist the ARB in developing conditional burn regulations authorizing the use of burning to control rice diseases, the Act established the Rice Straw Disease Management Burning Committee. The ARB is tentatively scheduled to consider these regulations in the fall of 2000. As part of its regulatory development effort, the ARB will consult with the Committee, rice growers, and other stakeholders to address this issue.


The phase down requirements are being met. However, alternative uses for rice straw have not developed as quickly as hoped. As such, there is a general consensus among all stakeholders that additional efforts must be placed on developing alternatives to rice straw burning and soil incorporation. These alternatives could be encouraged through the use of additional financial incentives such as grants, loans, or tax credits. The ARB and CDFA agree and recommend that the Legislature appropriate funding to support the development of alternatives, particularly ethanol production from rice straw. The ARB and CDFA staff will also continue to work with all stakeholders to promote the development of promising alternatives to rice straw burning.

Given the status of alternatives, rice growers continue to be concerned about the economic impacts of the phase down. Soil incorporation is more costly than burning, and, according to studies by the University of California, Davis, causes an increase in rice diseases and weeds which may cause a reduction in yields. The ARB and CDFA recommend that the Legislature appropriate funding to research the economic impacts of the phase down in terms of reduced yield potential.

There may be environmental effects associated with the phase down of burning that have not been adequately studied. For the next progress report, staff will work with stakeholders to identify the available information on potential environmental effects of the changes in rice straw management and evaluate whether further research is needed.

From a public health perspective, other stakeholders commented that burning during the fall is the least attractive option because of the less favorable meteorological conditions and that an effective smoke management program is important to minimize the impacts of all burning. In general, rice growers agree that an effective smoke management program has and will continue to help reduce public health impacts. In addition, rice growers urge the ARB and CDFA to educate the public that not all smoke impacts are due to the burning of rice straw.

The ARB and CDFA understand and appreciate these public health concerns and are committed to implementing a smoke management program that effectively balances the needs of rice growers and the public health impacts of the burning of rice straw.

Rice Straw Burning - 1999 Report to the Legislature