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RicestrawburninaAlte rna ivepol cyimplications

Richard L. NelsonPeter K . Thor

Christine R . Heaton Into-the-wind s t r ip lighting, on e of two accepted bur n i ng methods.0 en field burning of agricultural resi-dues, particularly rice straw, ha s become acontroversial source of visible pollution inthe Sacramento Valley Air Basin. Becauseof the high visibility and potential hazardof the smoke, many residents and publicofficials are dem anding severe curtailmentof burning. Rice producers contend thatother waste disposal methods are expen-sive, unreliable during wet weather, andtoo demanding of labor and equipmentduring the busy harvest season .Both local and state policymakers arebeing pressured to find an efficient andequitable solution to th e problem.Nature of the problem

From 1968 to 1977 an average of 392,000acres of rice was harvested annually in Cal-ifornia. Approximately 91 percent of th estates 1977 rice acreage was in the Sac-ramento Valley Air Basin (SVAB) countiesof Colusa, Butte, Sutter, Glenn, Yuba,Yolo, and Sacramento. Their productiongrossed more than $162 million. The sheervolume of post-harvest residue (groundstubble and cut straw) from so many acresof rice is one of t he largest obstacles to t heacceptance and implem entation of alterna-4 CALIFORN IA AGRICULTURE. FEBRUARY 1980

tive disposal methods. An average annualCalifornia rice crop produces between 1.4and 2.0million tons of straw.The composition of rice straw is also anobstacle. Its fibrous nature and highcontent of silicon d ioxide (SOz) cause it toresist decay when incorporated into the soiland can lead to a reduction in yield thefollowing season because of the formationof toxic gases and accompanying seedlingmortality. Furthermore, the straw can bephysically difficult to incorporate and agreater number of tillage operations maybe required to prepare the field for plant-ing. Increased infesta t ions of yield-reducing stem rot disease can also occurwith soil incorporation.Unce r ta in ty and va r iab i l i ty of th eweather create problems for open-fieldburn ing and o the r d isposa l schemes .Because rice harvest begins in early Sep-tember and continues until mid-November,the straw becomes available for disposalwhen the risk of bad w eather is high. Rainand humid weather affect the ease withwhich straw may be burned, collected andstored, or plowed back into the soil. Sincewet straw bur ns dirtier, early rainsincrease particulate pollution fro m burning

and may limit access to fields with theheavy machinery necessary for plowingunder or collecting straw.It is not su rprising, therefore, th at post-harvest open-field burning is commonlyused. The California Air Resources Board(ARB) reports that in 1976 growers utilizedopen-field burning on 379,000 acres, or90.5 percent of the states total harvestedrice acreage. This was equivalent to 45percent of the total acreage of field cropresidues burned in California during thatyear.Open-f ie ld burning has these ad-vantages: ( 1 ) It is effective, reliable, an d in-expensive. (2) It places fewer demands onscarce labo r and equipm ent during harvest-ing. (3) It is reliable under a wide range ofweather and field conditions. (4) It isevidently effective in limiting the seasonalcarryover and subsequent buildup of stemro t (Sclerotium oryzae), a yield-reducingdisease prevalent in California rice fields.Burning of agricultural debris releasesinto the atmosphere particulates and car-bon m onoxide, bo th potentially serious airpollutants in their own right, and hydro-carbons, which may undergo chemical re-actions with nitrogen dioxides (in the pres-

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ence of sunlight) and produce photochem-ical oxidants, a common example of whichis ozone. These oxidants are primary com-ponents of photochemical smog.Most rice straw burning takes place inautumn when the probability of inversionconditions and the air basins inability toadequately disperse emissions are at theirhighest. Of the 1,403,854 tons of agricul-tural residue burned in the SVAB in 1977,1,115,886 tons were field crop residues,mostly rice straw. Roughly 66 percent ofthese residues was burned in October andNovember. Monthly averages of 38 .7percent of hydrocarbons, 54.7 percent ofcarbon monoxide, and 47 .6 percent ofparticulate matter present in the air weregenerated from agricultural burning in theSVAB in October, 1975.Burning of agricultural residues isregulated by state and local agencies. Inaccordance with California law, whichprevents any regulatory agency from com-pletely prohibiting agricultural burning,the ARB attempts to maintain air qualityby allowing open-field burning of agricul-tural residues only on designated days.These permissive-burn days are declaredwhen expected meteorological conditionsmeet a minimum number of atmosphericcriteria regarding existing air quality, dif-ferent temperatures at different elevations,and daytime wind speed and direction. Avalid burn permit, issued by the local AirPollution Control District (APCD), isrequired before burning can take place on apermissive-burn day. Agricultural burningis prohibited (on the no-burn days)unless a special permit is issued to aproducer who can demonstrate that failureto burn would cause imminent and sub-stantial economic loss.Pollutants from agricultural burningraise concerns abou t potential publichealth hazards. Although the extent towhich air pollutants affect human health isnot known, it has been shown that particu-lates in the size range of those produced byagricultural burning can penetrate the pul-monary spaces of human lungs, where theymay cause respiratory disorders, includingacute bronchitis. Large concentrations ofcarbon monoxide and photochemicaloxidants in the air have been stronglyimplicated in causing health problems.While further research needs to beconducted, available evidence appears tosupport concerns about the public healthaspects of agricultural burning.Existing National Ambient Air QualityStandards (NAAQS)have not been strictlyobserved in the Sacramento Valley AirBasin. These standards have been violated

by emissions from many mobile andstationary sources, including agriculturalburning. The Federal Clean Air ActAmendments of 1977, which are imple-mented by the U.S. Environmental Protec-tion Agency (EPA), require that allNAAQS be attained by 1982 unless awaiver is granted allowing postponement inso-called nonattainment areas until 1987.Substantial portions of the SVAB havebeen designated nonattainment areas forthose pollutants generated by agriculturalburning. The Clean Air Act further stipu-lates that state policies provide for both at-tainment and maintenance of standards t oavoid financial sanctions from the federalgovernment. These considerations, as wellas continued pressure because of publichealth and aesthetic concerns, make it in-cumbent upon policymakers to considerpossible policy alternatives.

Policy optionsAlthough final resolution of the prob-lems related to rice straw burning awaitmore thorough research and implementa-tion of long-term solutions, there are sev-eral short-run policy options currentlysuggested: (1) To continue the present per-missive burdno-burn designations, but torestrict more severely or actually discon-tinue issuing variance exemptions, (2) toupgrade and increase the flexibility of ARBcriteria designating which residues can beburned, and when and where, (3) toincrease dramatically enforcement (pri-marily by local APCDs) of existing regula-

tions, especially those relating to timing

and methods of open-field burning, (4 ) toestablish an economic disincentive to burnin the form of a per-acre burn tax thatcould be administered within the purviewof a permissive burn policy, and ( 5 ) tocall for a ban on all agricultural burning.It should be noted that these options areneither all-inclusive nor mutually exclusive.It is, in fact, likely that a short-run solutionmay involve a combination of approaches.Before any choice can be made, objectivesmust first be defined in the political arena.Questions of political, technical, and eco-nomic feasibility will be important. Theeconomic impacts on rice producers (and,consequently, on input suppliers, proces-sors, and other industry participants) mustalso be considered.

Impacts of alternative policies(1 ) To estimate the effect of policyoption number one, reducing the numberof variances issued, an analyst needs

specific information regarding the numbergranted each year and the economic resultif some or all of the waiver requests weredenied. Economic impacts would dependupon the acreage and crop involved, andthe nature of agricultural burning con-ducted under variances. Information as toestimated economic losses is not readilyavailable, but ARB data do indicate anuneven distribution of variances amongcounties and a substantial increase invariance permits issued in recent years. Ingeneral, it seems likely that delays inproper field preparation resulting fromvariance denials or outright prohibition

Disposal of rice straw presents a major problem to producers. A swather windrow sthe heavy straw for baling.CALIFORNIA AGRICULTURE, FEBRUARY 1980 5

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will lead to increased producer costs. upon the natu re and the level of the tax. tion clearly means that this method ofAdministrative and enforcement costs The imp ortan t question here is: At what residue disposal is especially costly towould probably decrease under a pro- level would the tax have to be levied to in- growers.hibition of variances since any burning on a duce changes in producer behavior - hat Straw utilization is the other no-burnno-burn day would be easy to identify as a is, how large would the economic disincen- alternative. Rice straw has proven potentialviolation. There could be a substantial tive have to be before producers stopped for cattle feed, fiber products, and fuel-positive impact on environmental quality: burning rice straw? The answer would de- related uses. Total costs to producers ofrestrictions in granting variances could pend upo n the magnitude of the tax, the net any straw utilization scheme would dependlower total emissions, especially on days cost of other straw disposal alternatives, upon t he difference between the extraexhibiting poor air quality, poo r air dis- and the profitability of cropping alterna- expenses associated with straw drying,persion capability, or inversion conditions. tives in cases where no alternative straw removal, packaging, handling, and trans-(2) The second option, to upgrade and disposal method is feasible and land must porta tion , and th e revenue derived fromincrease the flexibility of ARB designa- be shifted out of rice prod uctio n. A bill in- selling the stra w. At present there are notions, could result in substantially improv- troduced by Assemblyman G reene (AB wid espre ad uses no r d o t he re existed air quality. Criteria for designating 681) would impose a $2-per-acre tax on established, reliable markets to absorb ab u r n h o - b u r n d ay s- ow dependent upon burning of field crop residues. Ou r analysis large volume of rice straw. Even with suchbasin-wide meteorological and air quality indicates that this level of taxation would mark ets , substa ntia l problems, man yinformation - ould be made to vary by do little to alter producer behavior. weat her-relate d, with field collectio n,crop residue type, elevation, geographical Any impact on air quality under this handling, transp ortatio n, and processingregion, humidity, and time of day. (The option would depend on how much open- need to be overcome.ARB is considering implementing some of field burning is reduced. T he impact on ad-these criteria in a revision of agricultural ministrative and enforcement costs is also COnClUSiOnburning guidelines .) Specif ic residues indeterminate, but burn tax revenues could It is apparent that soil incorporation iswould be burned at m ore approp riate times be used to offset costs or to subsidize other the only currently available no-burnan d places with sub stan tiall y lower straw disposal methods. straw disposal method. This method canemissions. Burning could be limited to ( 5 ) The fi fth policy alternative would substantially increase costs to rice produc-times when residue moisture content is su f- lead to an absolute ba n On all agricultural ers. This implies that a relatively small per-ficiently low, and to geographical areas residue burning; the impact would depend acre bu rn tax would be ineffective in signif-where local atmospheric conditions favor o n the a l tern ative appro ach p roducers icantly reducing the amount of burning. Aburning. Such a policy would, however, en- adop ted. soi l incorporation and straw relatively large burn tax would likely be re-tail increased costs for forecasting, admin- utilization are the only disposal systems quired in most rice-growing areas beforeistration, and enforcement. Costs to pro- which do not involve burning residues. soil incorporation would be widely adoptedducers would depend upon the extent to soil incorporation requires more tillage or before growers would sh ift to alternativewhich new regulations resulted in delays in to remove residue th an if a field were crop s. Th e level at which such a tax wouldburning and associated increases in field burned. Extra costs Of Soil inCOrPOratiOn begin to induce shifts from growing rice de-preparation costs. It is also likely that pro- vary substantially, depending u pon local pends upo n the profitability of other usesducers would view such a policy as inequit- soil characteristics, equipment used, and of acreage now in rice. Unfortunately,able, since burning regulations could not be cultural practices employ ed. These ext ra much rice acreage is not particularly well-applied uniformly am ong them. costs can range from approximately $ 5 to suited to cultivating other crops. Until(3 ) Increased enforcement of existing $25 per acre under very good fall and straw utilization technologies and marketsregulations, the third option, would also Spring tillage conditions. Inco rpora tion in are adequately developed, a substantialimprove air quality. It h as been estimated, more difficult soil types Or under wetter burn tax or an outr ight ban on burningfor example, that increased enforcement of conditions could be expected to be much would probab ly reduce rice acreage andrequirements fo r backfire and into-the- more expensive. create a shift to o ther crops where feasible,wind strip lighting techniques (instead of Other expenses are associated with Soil rather than a major shift to other straw dis-headfire burning) and waiting periods until inco rpo ratio n. Exp erim ental results posalstraw is dry could reduce emissions from indicate that in fields where rice was Although short-term solutions have po-agricultural burning by 38 percent in Sac- harvested at 8 to 12 inches, followed by tential for improving air quality, most oframento County. Effective prohibition of incorporation Of Straw fo r thre e COnSeCu- th e costs of these policies would be borneheadfire burning can reduce particulate tive years, stem rot reduced yields an by rice producers who may not be able toemissions by as much as 50 percent. average 14 percent compared with fields in pass them on to rice consumers. since it isExpanded enforcement would necessitate which the straw was burned. Using the likely tha t agricultural burning will besubstantial costs - specially for th e local average value of $8.40 per hundredweigh t severely restricted eventually, an d since soilAPCD s. Since estimated per-acre costs are fo r rice during the test period (1975-1977), incorporation does no t appear to be aat least 16 t o 25 cents for headfire, 33 cents this yield reduction of 4.7 hundredweight viable long-run alternative, one may con-for strip lighting, an d 87 cents for backfire Per ac re represents a Per-aCre ~evenueoss clude that public support for the develop-burning, changes in producer costs would of approximately $40 (o r 8 percent) of the ment and implem entation o f straw utiliza-depend on whether, and to what extent, a average total revenue per acre. Because tion schemes is necessary for the continuedproducer is currently abiding by existing Stem rot severity increases over time, this prosp erity of Californias rice industry.regulations. estimate may overestimate costs during the(4) Impact of the fourth option, a per- first several years and u nderestimate costs Richard L. Nelson, Peter K. Thor an d Chrisrine R.acre b urn tax and continuance of the for later years. This revenue loss added to ~ ~ ~ ~ m k ~ f i~ ~ ~ , $ l~ $bu rn ln o- bu rn regim en, would depen d the increased tillage costs of soil incorpora- u.c.,avis.6 CALIFORNIA AGRICULTURE,FEBRUARY 1980