全 文 ：第 27 卷 第 6 期 作 物 学 报 V o l. 27, N o. 6
2001 年 11 月 A CTA A GRONOM ICA S IN ICA N ov. , 2001
M ethane Em iss ion from Irr iga ted R ice F ields and Its Con trolΞ
W AN G Zeng2Yuan1 XU Yu2Chang1 L I Zhen1 GUO Y i2X ian1 R W assm ann2
H U N ene2 R S L an t in2 L V Buendia2
(1 Institu te of C rop B reed ing and Cu ltiva tion, CA A S , B eij ing 100081, Ch ina; 2 In terna tiona l R ice R esearch Institu te, L os
B anos, L ag una, P h ilipp ines)
Abstract M ethane em ission from irriga ted rice fields as affected by w ater m anagem en t,
o rgan ic am endm en t and rice cu lt ivar w as m easu red u sing an au tom atic sam p ling2m easu ring
system w ith a clo sed cham ber m ethod in 1995～ 1998. T he resu lts show ed tha t m ethane
em ission from irriga ted rice fields in N o rth Ch ina ranged from 4 to 364 m g m - 2 day- 1, w ith
average em ission of 82 m g m - 2 day- 1. O n ly one m ethane em ission peak w as ob served du ring
the w ho le rice season. Seasonal m ax im um occu rred a t t illering stage. M ethane em ission a t
th is stage accoun ted fo r 85% of the annual m ethane em ission ra te. M ethane em ission w as
very lim ited from m id season field drying un t il harvest. F ield drying a t early and m idseason
stage had a strong effect on m ethane em ission. In term it ten t irriga t ion reduced m ethane
em ission by 46% and 59% as com pared to loca l fa rm er′s p ract ice of irriga t ion and con t inuou s
flooding, respect ively. A pp lica t ion of o rgan ic am endm en ts h igh ly increased m ethane
em ission. How ever, on the sam e carbon basis, m ethane em ission po ten t ia l varied h igh ly
am ong differen t o rgan ic am endm en ts. M ethane p roduct ion po ten t ia ls of ca t t le m anu re and
com po st w ere m uch low er than tho se of p ig m anu re and rice st raw. A pp lica t ion of ca t t le
m anu re and com po st reduced m ethane em ission by 86% and 90% respect ively, as com pared
to p ig m anu re; and the sam e trea tm en ts reduced m ethane em ission by 72% and 80%
respect ively, as com pared to rice st raw. R ice cu lt ivars w ere efficien t fo r reducing m ethane
em ission. U se of cu lt ivar Zhongzhuo 93 (m odern jap on ica ) reduced m ethane em ission by
55% and 50% respect ively, as com pared to J ingyou ( jap on ica hyb rid) and Zhonghua 94-
1017 ( ta ll jap on ica ). Genera lly, m ethane em ission affected by the o rgan ic am endm en ts
under d ifferen t w ater reg im es w as m uch po ten t than the effect of rice cu lt ivar. It w as a lso
show n tha t m it iga t ion op t ion s p ract iced a t early grow th stage w ere m o re effect ive than tho se
p ract iced a t la te stage. T hese find ings p rovide a bet ter m it iga t ion stra tegy fo r m ethane
em ission from rice fields.
Key words M ethane em ission; R ice field; W ater reg im e; R ice cu lt ivar; O rgan ic
am endm en t
M ethane is an im po rtan t greenhou se gas and it affects the chem istry and ox ida t ion
capacity of the a tm o sphere [ 1～ 3 ]. T he m ethane concen tra t ion in the a tm o sphere has doub led
du ring the last 200 years[ 4 ]. R ice fields have been iden t if ied as m ajo r sou rce of a tm o sphericΞ T he research described in th is paper w as funded by the UND P2Global Environm ent Facility GLO ö91öG31 under
agreem ent w ith the In ternational R ice Research Institu te ( IRR I) and the Institu te of C rop B reeding and Cultivation,
Ch inese A cadem y of A gricu ltu ral Sciences Co llabo rative P ro ject.
Received on: 2000208229, A ccep ted on: 2001202215
m ethane. R ecen t est im ate of g loba l m ethane em ission from rice fields ranges from 20 to 100
T g (1T g = 1 m illion ton ) year- 1, w h ich con tribu tes abou t 10%～ 15% to globa l m ethane
em ission [ 5～ 6 ]. Ow ing to the rice dem and of rap id ly grow ing popu la t ion, rice cu lt iva t ion and
p roduct ivity w ill con t inue to increase in the com ing decades. T h is increase in the yield and
harvest a rea of rice m ay fu rther increase m ethane em ission if the p resen t p ract ices are
con t inued.
Ch ina is the la rgest rice p roducing coun try in the w o rld. R ice harvest a rea in 1994 w as
est im ated a t 30. 1 m illion ha and average rice yield w as 5. 83 t ha- 1[ 7 ]. Ch inese rice fields are
con sidered as an im po rtan t sou rce of m ethane and have been a m ajo r concern in con tex t of
increasing m ethane concen tra t ion in the a tm o sphere. In recen t years, research on m ethane
em ission from Ch inese rice paddy fields w as accum u la t ing [ 8～ 17 ].
T he study p resen ted here w as conducted w ith in an in terna t iona l netw o rk of m easu ring
sta t ion s fo r determ in ing m ethane em ission s from rice fields[ 18 ]. T he sta t ion rep resen ts typ ica l
a rea of sing le rice cropp ing system in N o rth Ch ina and w as the on ly netw o rk sta t ion in a
tem pera te clim ate. T he ob ject ives of the stud ies a t the sta t ion in Beijing w ere:
1) to quan t ify m ethane fluxes from rice fields in N o rth Ch ina;
2) to assess the im pact of m anagem en t p ract ices comm on to th is reg ion;
3) to eva lua te p rocesses tha t con tro l m ethane em ission in a tem pera te clim ate;
4) to develop m it iga t ion stra teg ies w ith low m ethane em ission in a su sta inab le rice
system fo r th is reg ion.
Table 1 Some character istics of r ice
so il in Be ij ing site
pH 7. 99
O rganic carbon (gökg) 9. 95
To tal n itrogen (gökg) 0. 91
CEC (cmo lökg) 13. 20
O lsen pho spho rus (m gökg) 133. 00
Exchangeable po tasium (cmo lökg) 0. 11 1 M a ter ia ls and M ethods1. 1 F ield prepara tion F ield experim en ts w ereconducted on silty clay loam at ICBC farm , Beijing,Ch ina fo r fou r rice season s sta rt ing in 1995. Som echaracterist ics of the so il a re show n in T ab le 1. T he
deta ils of field tria ls conducted from 1995 to 1998 are
show n in T ab le 2. Experim en t in each rice season con sisted of fou r t rea tm en ts in random ized
com p lete b lock design w ith fou r rep lica tes. F ield w as flooded one o r tw o days befo re
tran sp lan t ing fo r harrow ing and leveling. T he ind ividua l p lo t w as 4. 5 m ×5 m.
1. 2 M ethane em ission M ethane em ission s w ere m on ito red by an au tom atic sam p ling
and m easu ring system [ 18 ]. T h is system con sisted of the au tom atic cham bers (1 m ×1 m ×1. 2
m ) and the sam p ling2m easu ring system , w h ich are bo th con tro lled by a m icro2com pu ter.
M ethane em ission w as con t inuou sly m easu red every tw o hou rs from each cham ber du ring the
w ho le rice season. M ethane concen tra t ion s of a ir sam p les w ere m easu red w ith Sh im adzu GC2
8A equ ipped w ith Po rapak N co lum n and a flam e ion iza t ion detecto r.
1. 3 Tem pera ture, so il pH and Eh T em pera tu res of a ir, f loodw ater and so il a t 5, 10 and
15 cm dep th s w ere m easu red by tem pera tu re p robes connected to a da ta logger. So il pH and
so il Eh at 7. 5 cm dep th w ere m easu red m anually w ith Ph ilip s pH öEh m eter every tw o days
from tran sp lan t ing un t il harvest.
857 作 物 学 报 27 卷
Table 2 Treatmen ts of exper imen t in the r ice f ield
Year W ater m anagem ent
A S (kgN öha)
Basal Topdr.
O rganic m anure
T ype O rg
. N
(kgöha) O rg. C(kgöha) V ariety T rans2p lan t. & H arvest
1995 3) Continuo s Irriga. 30 60 P ig m anure 60 1783 M odern japonica 06ö04 10ö17
1) L ocal P ractice 30 60 P ig m anure 60 1783 (Zhongzhuo 93)
4) L ocal P ractice 40 110 N one
2) In term itten t Irrig. 30 60 P ig m anure 60 1783
1996 L ocal p ractice 40 80 N one
1) M odern
japonica
(Zhongzhuo 93)
05ö24 10ö08
40 80 N one
2) Japonica
H ybrid (J ingyou)
40 80 N one
3) T all japonica
(Zhonghua
9421017)
40 80 N one
4) M odern indica
( IR 72)
1997 L ocal p ractice 40 80 4) N one M odern Japonica(Zhong zhuo 93) 05ö214 10ö06
20 60 1) p ig M anure 40 1059
27 80 2) catt le M anure 13 1059
31 80 3) R ice straw 9 1059
1998 1) L ocal P ractice 28 60 Compo st 32 1059 M odern japonica(Zhongzhuo 93) 05ö19 10ö06
2) Early and m id
season drainage
( type A ) 3 28 60 Compo st 32 1059
4) Early and m id
season drainage
( type B) 3 28 60 Compo st 32 1059
5) Early season
drainage ( type C) 28 60 Compo st 32 1059
&D ate (mm ödd)
3 L ocal p ractice drying at 55- 68 DA T; type A : D rying at 25- 31 dat & 45- 51 dat; type B: D rying at period of 35-
41 dat & 55- 61 dat; type C: D rying at 35- 48 DA T
1. 4 M ethane ebull it ion and so il d issolved m ethane M ethane ebu llit ion w as m easu red
w eek ly by in sta lling p lex ig lass boxes ( size of 40 cm ×15 cm ×20 cm ) betw een rice h ills.
Boxes w ere held by PV C pegs, w h ich w ere sunk in to the paddy righ t after f looding the so il.
T he PV C pegs rem ained at the sam e po sit ion du ring the season. Gas sam p les w ere co llected
after 24 hou rs of box in sta lla t ion and imm edia tely ana lyzed fo r CH 4. D isso lved m ethane in
so il so lu t ion w as m easu red w eek ly from so il dep th s of 0, 5, 10 and 15 cm w ith po rou s tub ing
system fo r so il so lu t ion sam p ling. A bou t 5 m l of so il so lu t ion w as co llected in 10 m l
vacu ta iners. T he so il so lu t ion sam p les w ere shaken fo r 30 second and gas sam p les in
headspace w as taken fo r m ethane analyzed.
2 Results and D iscuss ion s
2. 1 Character iza tion of sea sona l f luxes A typ ica l pa t tern of m ethane em ission s under a
loca l crop m anagem en t is d isp layed in F ig. 1 jo in t ly w ith pa t tern s of w ater dep th,
9576 期 WAN G Zeng2yuan et a l. : M ethane Em ission from Irrigated R ice⋯⋯
tem pera tu re, so il Eh and pH. T he fert ilizers in th is experim en t, conducted in 1997,
con sisted of a m inera l and o rgan ic (ca t t le m anu re) am endm en ts (T ab le. 2). L oca l w ater
m anagem en t encom passed persisten t f looding ( a t 4 cm w ater dep th ) tha t w as bo th
in terrup ted by a m id2season field dra inage and dried a t the end of the season.
F ig. 1 Seasonal pattern of temperature and w ater level (a) , m ethane em ission (b) , and so il
pH and Eh (c)of T 2 (catt le m anure+ m ineral fert ilizer) during the 1997 rice season.
M ethane em ission ra tes rap id ly increase in the first 35 days after t ran sp lan t ing (DA T )
(F ig. 1b ). In th is period, tem pera tu re show s an increasing tendency and reached seasonal
m ax im um at la te t illering stage (F ig. 1a). M ethane em ission flux sharp ly decreased w hen
field w as dra ined a t m id2season stage ( 50 DA T ). A fter reflooding, m ethane em ission
067 作 物 学 报 27 卷
rem ained a t a very low level. A t the end of the season, tem pera tu res w ere below 15℃ and
m ethane em ission w as virtua lly zero. M ethane em ission in early season accoun ted fo r 85% of
to ta l seasonal em ission. M ethane em ission after m id season field dra inage un t il harvest is
on ly a sm all fract ion of the to ta l m ethane em it ted from rice fields in the tem pera te zone of
Ch ina.
T he seasonal pa t tern of m ethane em ission is reflected the influence of tem pera tu re
changes and m id2season field dra inage. T he pat tern can be b roken up in to 3 phases (F ig.
1b) : (1) em ission s increase a t t illering stage triggered by rising tem pera tu re; (2) em ission s
fluctua te a t a h igh level in the ho t season; (3) em ission s decrease a t la te grow th stages due
to a tem pera tu re drop and field dra inage.
T he redox po ten t ia l w as governed by the loca l p ract ice in w ater m anagem en t. F looding
resu lted in so il Eh decrease w h ile field drying p rom o te so il Eh increase (F ig. 1c). Genera lly,
so il Eh decreased from po sit ive va lues to the crit ica l va lue of m ethane fo rm at ion (- 120 to -
150 m v) w ith in 1 to 3 w eek s after f ield flooding. A naerob ic condit ion s p rom o ted m ethane
fo rm at ion. D ra inage resu lted in a sudden increase in redox po ten t ia ls (F ig. 1c).
F ig. 2 Seasonal patterns of m ethane em ission as affected by w ater regim e during the 1995 rice season
T he effect of so il pH on m ethane em ission w as neglig ib le under field condit ion in
Beijing. T hese find ings w ere co rrobo ra ted by sim ila r t rends in Eh and pH th roughou t the
en t ire ob serva t ion period from 1995 to 1998.
2. 2 Effect of wa ter reg im e T he pat tern s of m ethane em ission from rice fields as
affected by w ater reg im e are show n in F ig. 2. T he experim en t in 1995 com pared th ree
1676 期 WAN G Zeng2yuan et a l. : M ethane Em ission from Irrigated R ice⋯⋯
differen t w ater reg im es: ( 1) loca l p ract ice, i. e. no rm al irriga t ion w ith m id2season field
dra inage, (2) in term it ten t irriga t ion w ith a lterna te flooding and dra inage in app. 102days
in terva l, and (3) con t inuou s flooding. A ll f ields w ere fert ilized w ith p ig m anu re. M ethane
em ission sta rted to increase after abou t one w eek of flooding and becam e rela t ively con stan t
after f ive days. Fo r a ll t rea tm en ts, seasonal m ax im um occu rred a t the t illering stage.
Con t inuou s flooding resu lted in the h ighest em ission ra tes w h ile in term it ten t irriga t ion p lo ts
gave the low est m ethane fluxes am ong 3 w ater reg im es. T he p lo ts w ith m id2season field
dra inage2tha t w ere essen t ia lly rep lica tes of con t inuou s flooding du ring the first 40 days2
sh if ted from h igh values to low values rough ly co rresponding to the em ission ra tes in
in term it ten t f looding. L ow tem pera tu res du ring the period befo re harvest resu lted in
un ifo rm ly low em ission ra tes.
Table 3 M ethane em ission rates, biomass and y ields (1995～ 1998)
Year M odifying
treatm ent
M ean
em ission
(m göm 2. d) Cum ulatedem ission(kgöha. yr) B iom ass( töha) Grainyield( töha)
1995 1 Continuo s irrigationöp ig
m anure
364 503 18. 73 8. 14
2 L ocal p racticeöp ig
m anure
279 385 20. 66 9. 24
3 In term itten t irrigationöp ig
m anure
150 207 19. 98 9. 09
4 L ocal p racticeöm ineralfert ilizer 19 26 17. 73 7. 84
1996 1 M odern japonica(Zhongzhuo 93) 16 22 16. 62 8. 17
2 Japonica hybrid(J ingyou) 36 49 15. 06 7. 27
3 T all japonica(Zhonghua9421017) 32 44 18. 14 7. 75
4 M odern indica( IR 72) 23 32 14. 17 6. 35
1997 1 P ig m anure 139 191 15. 83 7. 76
2 Catt le m anure 31 43 14. 72 7. 43
3 R ice straw 102 141 14. 71 7. 23
4 M ineral fert il 4 6 15. 27 7. 68
1998 1 L ocal p racticeirrigation 20 28 17. 05 7. 73
2 Early and m id s. drainage( type A ) 3 15 21 16. 94 7. 75
3 Early and m id s. drainage( type B) 3 19 26 17. 61 7. 82
4 Early seasondrainage 11 15 15. 68 7. 60
3 T ype A : D rying at period of 25- 31 DA T & 45- 51 DA T; type B: D rying at period of 35- 41 DA T & 55- 61 DA T
T ab le 3 p resen ts the m ean and seasonal m ethane fluxes, b iom ass and gra in yields fo r 4
years. In 1995, m ethane em ission from the loca l p ract ice of irriga t ion w as 86 % h igher than
in term it ten t irriga t ion and 23 % low er than con t inuou s flooding. Farm er′s p ract ice of
irriga t ion p rovided the h ighest b iom ass and gra in yields, a lthough on ly d ifferences w ith
con t inuou s flooding w ere sign if ican t (P < 0. 05). T hese resu lts revea l tha t m id2season field
dra inage and alterna te floodingödrying can be a p rom ising m it iga t ion stra tegy tha t does no t
affect yields.
267 作 物 学 报 27 卷
T h is resu lt st im u la ted ano ther experim en t to exp lo re d ifferen t m odes of dra inage fo r
fu rther reducing em ission ra tes. In 1998, the field experim en t included 4 differen t types of
field dra inage (T ab le 2). A s in p reviou s years, loca l p ract ice (T 1) encom passed drying a t 55
～ 68 days after t ran sp lan t ing (DA T ). T 2 had a sligh t ly sho rter drying period a t la te
t illereing stage (55～ 61 DA T ) p lu s a p reced ing one from 35～ 41 DA T. T 3 encom passed tw o
dra inage periods (25～ 31 DA T & 45～ 51 DA T ) w ith an earlier t im ing than T 2. T 4 con sisted
of one early, bu t sligh t ly p ro longed dra inage period ( 35～ 48 DA T ). A ll f ields received
m inera l fert ilizer and com po st resu lt ing in rela t ively low levels of em ission ra tes even befo re
the drying periods (F ig. 3 a, b ). L oca l p ract ice of irriga t ion gave the h ighest m ethane
em ission flux, w h ich w as obviou sly rela ted to the rela t ively la te on set of the dra inage period
after 55 days. T he m o st effect ive dra inage period fo r m it iga t ing m ethane em ission is 35～ 48
DA T as conducted fo r T 4. A n earlier dra inage (T 2) as w ell as a sligh t sho rten ing of th is
dra inage period (T 3) yielded h igher em ission ra tes (T ab. 3). T he second dra inage period in
F ig. 3 M ethane em ission rates as affected by com bination of drying tim e and compo st during the 1998 rice season
3676 期 WAN G Zeng2yuan et a l. : M ethane Em ission from Irrigated R ice⋯⋯
T 2 and T 3 apparen t ly had a rela t ively sm all im pact on em ission ra tes, so tha t T 4 w as
reco rded w ith the low est overa ll em ission.
A verage em ission fluxes w ere 20 m g m - 2 day- 1 in the p lo ts w ith loca l p ract ice of
irriga t ion (T 1) , 15 m g m - 2 day- 1 in the p lo ts w ith early and m id season dra inage (T 2) , 19
m g m - 2 day- 1 in the p lo ts w ith m odified early and m id season dra inage (T 3) , and 11 m g m - 2
day- 1 in the p lo ts w ith early season dra inage (T 4). M ethane em ission s in T 2 and T 3 w ere
reduced by 25% and 5% , respect ively, as com pared to T 1 w h ile sim ila r yields w ere
ob ta ined. T 4 gave as h igh as 46% reduct ion in m ethane em ission as com pared to T 1 and
yields w ere a lso sim ila r. T he resu lts ind ica ted tha t early and m id season field dra inage can
fu rther be op t im ized to reduce m ethane em ission w h ile su sta in ing rice yields.
F ig. 4 Seasonal patterns of m ethane em ission as affected by rice cu lt ivars during the 1996 rice season.
2. 3 Effect of r ice cultivar Seasonal pa t tern s of m ethane em ission from rice cu lt ivars are
show n in F ig. 4. M ethane fluxes w ere very low and did no t d iffer am ong rice cu lt ivars du ring
the first w eek after t ran sp lan t ing. W hen m ethane em ission sta rted to increase in the second
w eek after t ran sp lan t ing, rice cu lt ivars d ifferen t ia ted in their m ethane em ission po ten t ia l.
Bo th of J ingyou (J ap on ica hyb rid ) and Zhonghua 94 - 1017 (T all jap on ica ) gave h igher
m ethane em ission fluxes w h ile the m ethane em ission from Zhongzhuo 93 (M odern jap on ica)
w as low er. F ield dra inage and low tem pera tu res a t the end of the season sub stan t ia lly
reduced m ethane em ission s fo r a ll cu lt ivars.
467 作 物 学 报 27 卷
A verage em ission ra tes from Zhongzhuo 93, J ingyou and Zhonghua 94- 1017 w ere 16
m g m - 2 day- 1, 36 m g m - 2 day- 1 and 32 m g m - 2 day- 1, respect ively (T ab le 3). T ab le 3 a lso
lists the resu lts fo r IR 72, a m odern ind ica variety. How ever, the grow th of th is t rop ica l
cu lt ivar w as obviou sly affected by low tem pera tu res, so tha t the low em ission ra tes m ay be
rela ted to in sufficien t b iom ass assim ila t ion. Am ong the tem pera te variet ies, Zhongzhuo 93
had low est em ission ra te and h ighest yield (T ab le 3). T herefo re, it appears feasib le and
effect ive to m ain ta in su sta inab le yield and to m it iga te m ethane em ission by cu lt ivar select ion.
2. 4 Effect of m inera l and organ ic fertil izers Fert ilizer im pacts w ere invest iga ted in the
season s of 1995 and 1997; bo th experim en ts w ere conducted w ith loca l fa rm er′s p ract ice of
irriga t ion. O rgan ic m anu re grea t ly p rom o ted m ethane em ission s as com pared to m inera l
fert ilizers (T ab le 3). M ethane fluxes in the p lo ts w ith p ig m anu re exceeded tho se in the p lo ts
w ith amm on ium su lfa te by a facto r of 15 in 1995 and a facto r of 35 in 1997 (T ab le 3). T he
experim en t in 1997 included ca t t le m anu re and rice st raw (F ig. 5). M ethane em ission fluxes
w ere low and did no t d iffer am ong 4 trea tm en ts du ring the first 7 days. M ethane em ission s
increased steep ly and the d ifference becam e w ider after 10 days after t ran sp lan t ing. T he
m ax im um m ethane em ission fluxes w ere reco rded 26 DA T fo r p ig m anu re, 36 DA T fo r rice
st raw and 52 DA T fo r ca t t le m anu re respect ively. P ig m anu re gave the h ighest m ethane
em ission flux, fo llow ed by rice st raw w h ile m ethane em ission flux in ca t t le m anu re trea ted
p lo t w as the low est am ong 3 o rgan ic am endm en ts. A s in 1995, the p lo ts t rea ted pu rely w ith
m inera l fert ilizers em it ted a lm o st no m ethane gas.
A verage fluxes w ere 139 m g m - 2 day- 1 in p ig m anu re trea ted p lo ts, 31 m g m - 2 day- 1 in
ca t t le m anu re trea ted p lo ts, and 102 m g m - 2 day- 1 in rice st raw trea ted p lo ts and 4 m g m - 2
day- 1 in pu re m inera l fert ilizer t rea ted p lo ts (T ab le 3). Q uality and quan t ity of added o rgan ic
am endm en ts h igh ly affected m ethane fo rm at ion. H igher m ethane em ission ra tes from p ig
m anu re and rice st raw w ere due to h igher con ten ts of easily decom po sab le o rgan ic carbon
than in ca t t le m anu re (da ta no t show n). In the 1997 experim en ts, a ll o rgan ic m anu re types
resu lted in sim ila r gra in yield, ind ica t ing tha t o rgan ic m anu re m anagem en t is an im po rtan t
m it iga t ion op t ion in su sta inab le rice system. Fu rtherm o re, it shou ld be no ted tha t com po st
am endm en t in 1998 yielded in sub stan t ia lly low er em ission s than any o ther o rgan ic
am endm en t tested in 1995 and 1997. Em ission ra tes are even less than som e of the
experim en ts w ith m inera l fert ilizer in 1995 and 1996, w h ich can be taken as clear ind ica t ion
of the beneficia l effect of com po st ing o rgan ic am endm en ts fo r ach ieving low m ethane
em ission from rice fields.
2. 5 Ebull it ion and d issolved m ethane in so il solution T he seasonal pa t tern s of m ethane
ebu llit ion and disso lved m ethane in the 1997 experim en t are show n in F ig. 6. Ebu llit ion s of
m ethane in the p lo ts t rea ted p ig m anu re and ca t t le m anu re w ere h igher than tho se trea ted
rice st raw and m inera l fert ilizer. Ebu llit ion s of m ethane du ring the 1997 rice season under
d ifferen t o rgan ic am endm en ts w ere averaged 26. 51 m g m - 2 day- 1 in p ig m anu re trea ted
p lo ts, 16. 59 m g m - 2 day- 1 in ca t t le m anu re trea ted p lo ts, 6. 86 m g m - 2 day- 1 in rice st raw
5676 期 WAN G Zeng2yuan et a l. : M ethane Em ission from Irrigated R ice⋯⋯
t rea ted p lo ts and 1. 45 m g m - 2 day- 1 in pu re m inera l fert ilizer t rea ted p lo ts. T hese va lues
accoun ted fo r 36. 3 % (m inera l) , 22. 1 % (ca t t le m anu re) , 16. 3% (rice st raw ) and 19. 1%
( p ig m anu re) of the to ta l m ethane em ission. T he difference in m ethane ebu llit ion am ong
trea tm en ts w as p robab ly rela ted to the quality and quan t ity of o rgan ic am endm en t.
F ig. 5 Impact of o rgan ic am endm ent on m ethane em ission from rice fields during the 1997 rice season.
D isso lved m ethane concen tra t ion s w ere rela t ively h igh in the p lo ts t rea ted o rgan ic
am endm en ts w h ile the p lo ts t rea ted m inera l fert ilizer had low m ethane concen tra t ion s (F ig.
6). Seasonal pa t tern s of d isso lved m ethane w ere sim ila r am ong trea tm en ts. A t t illering
stage, h igher d isso lved m ethane concen tra t ion occu rred co incided w ith h igh ebu llit ion ra tes
of m ethane. D isso lved m ethane w as po sit ively co rrela ted w ith m ethane ebu llit ion ( r2 = 0.
583 3 , n = 32) and em ission ( r2 = 0. 673 3 , n = 32) a t t illering stage. It w as ob served tha t
d isso lved m ethane concen tra t ion w as so il Eh dependen t ( r2= 0. 413 3 , n= 56) and negat ively
co rrela ted to so il Eh (r2= - 0. 623 3 , n= 56).
D isso lved m ethane concen tra t ion w as h igh a t so il dep th of 5, 10 and 15 cm w h ile the
concen tra t ion of d isso lved m ethane a t f loodw ater a lw ays rem ained at low level. D isso lved
m ethane concen tra t ion in the so il w as d ifferen t from year to year bu t the seasonal pa t tern
w as sim ila r in the m easu ring years (da ta no t show n).
2. 6 M itiga tion stra teg ies M ethane em ission ra tes under loca l p ract ice in N o rth Ch ina
ranged from 4 to 364 m g m - 2 day- 1, w ith average em ission of 82 m g m - 2 day- 1. Seasonal
m ax im um values occu rred a t t illering stage and the em ission du ring th is stage accoun ted fo r
667 作 物 学 报 27 卷
85% of the annual m ethane ra te. T herefo re, it is crucia l to reduce seasonal m ethane flux by
con tro lling m ethane em ission a t early season.
F ig. 6 Seasonal pattrens of m ethane em ission, ebullat ion and disso lved m ethane in the 1997 rice season
M ethane m it iga t ion op t ion s u sed in rice fields m u st bo th reduce m ethane em ission and
su sta in rice p roduct ion. W ater con tro l is one of the m o st im po rtan t facto rs in rice
p roduct ion. A lterna t ive w et t ing and drying m anagem en t reduced m ethane em ission s by 23%
～ 59% w h ile yield increased by 16%. W ater m anagem en t w ou ld be the m o st p rom ising
m it iga t ion op t ion in Ch ina w here irriga t ion w ater is ava ilab le and irriga t ionödra inage system s
are estab lished.
A pp lica t ion of o rgan ic m anu re is a comm on p ract ice to m ain ta in so il fert ility bu t it
increases m ethane em ission from rice fields. T h is effect on m ethane em ission m ay be reduced
th rough choo sing the o rgan ic am endm en t w ith low m ethane po ten t ia l, e. g. com po st ing
7676 期 WAN G Zeng2yuan et a l. : M ethane Em ission from Irrigated R ice⋯⋯
m anu re in stead of p ig m anu re and fresh rice st raw. A n alterna t ive w ay is ro ta t ion app lica t ion
of o rgan ic am endm en t and m inera l fert ilizer in the sequence years.
R ice cu lt ivars d iffer in m ethane em ission s. V ariety select ion is feasib le and effect ive to
find cu lt ivar like Zhongzhuo 93 w ith low m ethane em ission efficiency and h igh harvest index.
U sing rice cu lt ivar as a m it iga t ion stra tegy is an easily adop ted op t ion becau se farm ers m ay
u se it w ithou t any expen sive inpu t.
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稻田CH4 排放及控制技术的研究
王增远1 徐雨昌1 李 震1 过益先1 R W assm ann2 H U N eue2 R S L an t in2
L V Buendia2
(1中国农业科学院作物育种栽培研究所, 北京 100081; 2 菲律宾国际水稻研究所)
提 要 为了探索北方稻田水管理、施肥和水稻品种对稻田甲烷排放的影响, 于 1995 年至 1998 年应
用全自动甲烷采样2测定系统, 测定了水稻田甲烷排放通量。实验探明: 北方稻田甲烷排放通量为 4～
364 m göm 2. d, 平均值为 82 m göm 2. d; 稻田甲烷的季节排放只有一个高峰, 发生在水稻分蘖期, 该期
的甲烷排放量占年排放总量的 85% 以上, 水稻生长中、后期的稻田甲烷非常有限。水管理对稻田甲烷
的生成、排放有显著的影响, 稻田采用间歇灌溉代替常规灌溉和淹灌, 可减排稻田甲烷 46%～ 59% ;
稻田施用有机肥, 甲烷排放量则剧增。但在同等有机碳含量情况下, 不同有机肥的产甲烷潜势存在明
显差异, 猪粪和稻草较高, 堆肥和牛粪较低, 稻田施用堆肥和牛粪, 可比施用猪粪和稻草的稻田减排
稻田甲烷 72%～ 90% ; 试验中选用的水稻品种, 以中作 93 的甲烷排放效率为最低, 其甲烷排放通量比
杂交稻京优和高秆品种中花 9421017 减少 50%～ 55%。实验揭示, 水稻分蘖期是控制北方稻田甲烷排
放的关键时期, 该试验结果为制定稻田甲烷控制策略提供了重要参考。
关键词 甲烷排放通量; 水稻田; 水管理; 水稻品种; 有机肥
867 作 物 学 报 27 卷