Field Burning of Crop Residues

Transcription

1 SMED Report No Feld Burnng of Crop Resdues Heléne Wkström, Rolf Adolfsson, Statstcs Sweden Commssoned by the Swedsh Envronmental Protecton Agency

2 Publshed at: Publsher: Swedsh Meteorologcal and Hydrologcal Insttute Address: SE Norrköpng, Sweden Start year: 2006 ISSN: SMED s short for Swedsh Envronmental Emssons Data, whch s a collaboraton between IVL Swedsh Envronmental Research Insttute, SCB Statstcs Sweden, SLU Swedsh Unversty of Agrcultural Scences, and SMHI Swedsh Meteorologcal and Hydrologcal Insttute. The work cooperaton wthn SMED commenced durng 2001 wth the long-term am of acqurng and developng expertse wthn emsson statstcs. Through a long-term contract for the Swedsh Envronmental Protecton Agency extendng untl 2014, SMED s heavly nvolved n all work related to Sweden's nternatonal reportng oblgatons on emssons to ar and water, waste and hazardous substances. A central objectve of the SMED collaboraton s to develop and operate natonal emsson databases and offer related servces to clents such as natonal, regonal and local governmental authortes, ar and water qualty management dstrcts, as well as ndustry. For more nformaton vst SMED's webste

3 INDEX SUMMARY 3 1. INTRODUCTION AIM OF STUDY 4 2. METHOD OF ANALYSIS 4 3. METHODOLOGY FOR EMISSIONS ESTIMATES 4 4. FIELD BURNING IN SWEDEN 5 5. A PRELIMINARY CALCULATION 6 6. RESULTS 7 7. DISCUSSION 7 8. APPENDIX 8 Summary Emssons of greenhouse gases from feld burnng of crop resdues have been estmated to very low levels n The emssons of CO and NOx may however be consdered as not neglgble. Informaton provded by experts support a decreasng trend of feld burnng as an agrcultural practce, but there are only usable actvty data for one sngle year (1997). Due to lack of actvty data from begnnng of the nnetes and very low emsson levels, the study concludes that Sweden should report trace gas emssons from feld burnng of crop resdues as not occurrng NO n the emsson nventores. 3

4 1. Introducton Burnng of crop resdues n the felds s an agrcultural practce, whch causes emssons of methane, carbon monoxde, ntrous oxde and ntrogen oxdes. But because t s nonfossle t s not treated as a net source of carbon doxde by IPCC. Accordng to the IPCC Gudelnes 1 and the Good Practce Gudance 2, emssons of CH 4, CO, N2O and NOx from feld burnng of agrcultural resdues should be reported n the CRF table 4F. Feld burnng has been consdered as very rare n Sweden, and therefore, by usng the decson tree n IPCC Good Practce Gudance, chapter 4.6, Fgure 4.6, ths source has been reported as not occurrng (NO) n the Swedsh greenhouse gas nventory. 1.1 Am of study The am of ths study was to nvestgate whether Sweden should nclude emssons from feld burnng of crop resdues n the nternatonal reportng of emssons to ar. Sweden has up to date not calculated these emssons because they have been consdered as neglgble. The collected data should nclude the whole tme seres from The fndngs should thereafter serve as a bass for a decson whether emssons from feld burnng of crop resdues should be reported n the Swedsh Submsson Method of analyss Contact has been made wth the Swedsh Board of Agrculture, the Swedsh Assocaton of Local Authortes, Norrköpng County and Hushållnngssällskapet Malmöhus. The IPCC methodology has been appled to avalable background data, for makng a prelmnary estmaton of the emssons. 3. Methodology for emssons estmates The methodology s descrbed n the workbook of the Revsed 1996 IPCC Gudelnes for Natonal Greenhouse Gas Inventores. The emssons of dfferent non-co 2 trace gas emssons from burnng of agrcultural resdues are based on the total bomass burned of each crop multpled wth the specfc carbon and ntrogen content respectvely. For estmatng the emssons, emsson factors for CH 4 and CO are appled on the total carbon released, and emsson factors for N 2 O and NO x are appled on the total ntrogen released. 1 Revsed 1996 IPCC Gudelnes for Natonal Greenhouse Gas nventores: Reference Manual IPCC NGGIP. Good Practce Gudance and Uncertanty Management n Natonal Greenhouse Gas Inventores, 15 June

5 When decomposng the total bomass burned, smlar as n the IPCC Workbook, the formula for calculatng the total emssons of for example N 2 O can be stated: Pr, emssons * FracRC * DM * FracBr * Ox * FracC * FracNC * EFN 2O where Pr s the annual producton n ggagrams of crop, FracRC the resdue to crop rato for each crop type, Dm the dry matter content, FracBr the fracton burned n felds, Ox the fracton oxdsed, FracC the carbon fracton, FracNC the ntrogen-carbon rato for each crop, and EF N2O the emsson factor based on the total ntrogen released. The actvty data needed for the calculatons are therefore annual crop producton statstcs and crop specfc data on ratos of resdue to crop producton, fracton of resdue burned, dry matter content of resdue and carbon and ntrogen contents of resdue. IPCC provdes selected crop statstcs and default emsson factors, see appendx. Accordng to appendx 4 A.2 of the IPCC Good Practce Gudance and Uncertanty Management n Natonal Greenhouse Gas Inventores the weakness n the computaton s estmatng the percentage of resdue burned n the feld. Each nventory agency has to collect actvty data on dsposton of each crop resdue, especally the percentage of resdue burned on-ste, after harvest. 4. Feld burnng n Sweden In the Ordnance (1988:899) concernng envronmentally hazardous actvtes and the protecton of publc health 3, whch s n accordance wth Chapter 9 of the Swedsh Envronment Code, t says under Muncpal regulatons n secton 40 that f necessary n order to prevent the development of condtons that pose rsk to human health wthn ts boundares, a muncpalty may specfy regulatons concernng burnng of straw on cropland. Ths means that f no regulatons are specfed t s possble to burn straw on cropland. However there does not seem to exst a complete lst of the muncpalty regulatons. Searchng the Internet by ndcates that there seems to be regulatons at least n Skåne and Halland. Accordng to an advsor at Malmöhus Hushållnngssällskap 4 feld burnng of crop resdues s very rarely practced and s becomng more and more unusual n Skåne, whch s one of the most mportant cereal growng countes n Sweden. Norrköpng Muncpaltes responsble nspector for agrculture shares ths vew and states that t s very rare that the farmers practce feld burnng. 5 Also staff at the Swedsh Board of Agrculture 6 and the Swedsh Assocaton of Local Authortes 7 consdered feld burnng Johansson , June Båld , June Alfredsson , June Edholm , June

6 to be carred out only n exceptonal cases and that the use s less frequent today than earler. The above mentoned vew expressed by varous actors that feld burnng of crop resdues s very uncommon n Sweden today can be verfed through a survey carred out 1997 by Statstcs Sweden 8. Accordng to the survey on utlzaton of straw and tops from agrculture crops n 1997 one per cent of the harvest resdues from cereals were burnt on the feld. Ths s the only avalably source of ratos of resdue to crop producton for Sweden. Snce that tme burnng has become even more rare as mentoned above. 5. A prelmnary calculaton The emssons of trace gases from agrcultural resdue burnng n Sweden have been prelmnary calculated on crop level. The major crops, of whch a mnor fracton was burned on felds n , are stated n the actvty data n table 1 below. All data, except for Carbon fracton and the fracton of resdue burnng, are background data used n the calculatons of N2O-emssons from crop resdues left on felds (CRF Table 4D1 Drect sol emssons ). For estmatng Carbon fracton IPCC default values on the specfc crop, or a smlar crop, were used, see appendx. Table 1. Actvty data for estmatng emssons from feld burnng of crop resdues n Sweden. Crop Area 2002, ha Fracton Fracton oxdsed Standard yeld 2002, kg/ha resdues n relaton to harvest, (FracResdues) Dry matter content, fracton Resdue burnng n 1997, % Carbon fracton, % of dm Ntrogen fracton, % of dm Pr FracRC DM FracBr Ox FracC FracN Wnter wheat ,3 0,85 2 0,9 0,4853 0,71 Sprng wheat ,1 0,85 1 1,9 0,4853 0,82 Wnter rye ,4 0,85 2 2,9 0,4853 0,82 Sprng barley ,9 0,85 1 3,9 0,4567 0,94 Trtcale ,3 0,8 1 4,9 0,4567 0,82 The calculated emssons of the green house gases CH4 and N2O from feld burnng are very small. Compared wth Sweden s greenhouse gas nventory for the agrcultural sector n 2002, the total CH4 emsson from feld burnng amounts to 0.002% and the total N2O emsson amounts to 0,04 %. See table 2 below. The emssons of CO and NOx are small, but however of the same magntude as some emssons from other sources reported to LRTAP and UNFCCC. Table 2. Estmated carbon and ntrogen released from agrcultural resdue burnng and trace gas emssons n 2002 Crop Total carbon released,gg Emssons Emssons of CH 4, Gg of CO, Gg Emssons Total ntrogen released, Gg Emssons of N 2 O, Gg of NOx, Gg Wnter wheat 0,175 0,256 0,001 0,010 0,002 0,031 Sprng wheat 0,024 0,041 0,000 0,001 0,000 0,005 8 MI 63 SM 9901 Utlzaton of straw and tops from agrculture crops n Ibd 6

7 Wnter rye 0,045 0,075 0,000 0,003 0,001 0,009 Sprng barley 0,305 0,627 0,002 0,018 0,004 0,076 Trtcale 0,046 0,082 0,000 0,003 0,001 0,010 Total 0,594 1,081 0,003 0,036 0,008 0, Results The nvestgaton confrms that feld burnng s very rare n Sweden. A one tme study of utlzaton of straw and tops from agrculture crops n 1997 shows that n ths year only small fractons (0-1 %) were burned, whch has been confrmed by contacts wth experts. Feld burnng s not prohbted n Sweden, but there are examples of local regulatons. There are no statstcs confrmng a trend, but nformaton gathered from several ndependent sources supports a decrease of feld burnng. A prelmnary calculaton confrms that emssons from feld burnng of crop resdues are very low (0,002% of the total CH 4 emssons and 0.04% of the total N 2 O emssons) and thus do not contrbute sgnfcantly to the emssons level. The emssons of CO and NOx are small, but however of the same magntude as emssons from other sources reported to LRTAP. 7. Dscusson The study shows that t would be possble to estmate and nclude the very low estmates n the GHG nventory, by usng a one tme study of utlzaton of straw and tops, whch would mean low qualty actvty data for the other years. The calculated emssons of green house gases accordng to feld burnng of crop resdues are very low, whch justfes the decson taken to report the emssons as not occurrng (NO). The emssons of CO and NOx may however be consdered as not nsgnfcant. Informaton provded by experts ndcates a decrease n feld burnng of crop resdues over tme n Sweden, there are however no statstcs confrmng ths. Such nformaton s falng to enable a relable estmate for the base year A new survey of utlzaton of straw and tops would probably confrm that the feld burnng s neglgble. Good estmates of small fractons may however be hard to obtan by standard surveys. It s hence recommended that the emsson source of feld burnng from agrcultural sols s reported as not occurrng (NO) also n next submssons. 7

8 8. Appendx Data from Revsed 1996 IPCC Gudelnes for Natonal Greenhouse Gas Inventores: Workbook. 8

9 9