Pedobiologia - Jou nal o Soil Ecology 93–94 (2022) 150819
A ailable online 16 June 2022
0031-4056/© 2022 The Au ho (s). Published by Else ie GmbH. This is an open access a icle unde he CC BY license
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C op esidues in co n-whea o a ion in a semi-a id egion inc ease CO
2
e lux unde con en ional illage bu no in a no- illage sys em
Mo ad Mi zaei
a
,
*
, Manoucheh Go ji Ana i
a
, Ehsan Raza y-Toosi
b
, Mohammad Zaman
c
,
Ne mina Sa onjic
d
, Seyed Mo eza Zami
e
, Sa wan Mohammed
, And ´
es Caballe o-Cal o
g
,
*
a
Depa men o Soil Science and Enginee ing, Facul y o Ag icul u al Enginee ing and Technology, Uni e si y o Teh an, Ka aj, I an
b
Depa men o Plan , Soil and Mic obial Sciences, Michigan S a e Uni e si y, MI, USA
c
Soil and Wa e Managemen & C op Nu i ion Sec ion, Join FAO/IAEA Cen e o Nuclea Techniques in Food & Ag icul u e, Depa men o Nuclea Sciences and
Applica ions, In e na ional A omic Ene gy Agency, Vienna, Aus ia
d
Ins i u e o Soil Resea ch, Depa men o Fo es and Soil Sciences, Uni e si y o Na u al Resou ces and Li e Sciences (BOKU), Vienna, Aus ia
e
Facul y o Chemical Enginee ing, Ta bia Moda es Uni e si y, Teh an, I an
Ins i u e o Land U iliza ion, Technology and Regional Planning, Facul y o Ag icul u al and Food Sciences and En i onmen al Managemen , Uni e si y o Deb ecen,
Deb ecen, Hunga y
g
Depa men o Regional Geog aphical Analysis and Physical Geog aphy, Facul y o Philosophy and Le e s, Campus Uni e si a io de Ca uja, Uni e si y o G anada,
18071 G anada, Spain
ARTICLE INFO
Keywo ds:
Ag icul u al managemen
G eenhouses gases
Soil CO
2
e lux
Con en ional illage
No- ill
ABSTRACT
App op ia e managemen o c op esidue plays a key ole in mi iga ing g eenhouse gas emissions. Howe e , i
has been inadequa ely implemen ed in gene al ag icul u al managemen p ac ices. In a ield in es iga ion using
s a ic chambe s, we e alua ed he e ec s o c op esidue a h ee di e en a es - 100 % (R
100
), 50 % (R
50
), and
esidue emo al (R
0
) - on ca bon dioxide (CO
2
) e lux. The ield s udy was conduc ed in co n-whea o a ion
unde con en ional (CT) and no- illage (NT) sys ems in a semi-a id egion. The main esul s showed ha CO
2
e lux was posi i ely co ela ed wi h highe soil empe a u e (0.43–0.79) and mic obial biomass ca bon
(0.66–0.89). The c op esidue ea men s a ec ed hese ai s. A s ong posi i e ela ionship be ween CO
2
e lux
and he c op esidue (R
2
=0.96, CT and R
2
=0.9 o NT) was obse ed. In he CT sys em, signi ican inc eases
we e de ec ed among esidue a es on cumula i e CO
2
e lux, whe e R
100
and R
50
esul ed in 36 % and 25 %
highe cumula i e CO
2
e lux, espec i ely, han R
0
. In con as , he e was no signi ican di e ence in cumula i e
CO
2
e lux among he c op esidue e en ion (R
100
and R
50
) and emo al (R
0
) ea men s unde he NT sys em.
Ou s udy e ealed ha c op esidue e en ion led o inc eased CO
2
e lux unde he CT sys em in semi-a id
condi ions du ing he i s yea o applica ion, while unde he NT sys em, CO
2
e lux was no impac ed by
c op esidue. Ou esul s indica e ha he e is conside able po en ial o imp o ing soil managemen p ac ices in
he con ex o soil deg ada ion, clima e change, inc easing c op p oduc i i y, and ca bon (C) seques a ion.
1. In oduc ion
The con inuous inc ease in he concen a ion o g eenhouse gases
(GHGs) p oduced by human ac i i ies has become a majo conce n due
o hei di ec impac on global wa ming and clima e change (Oe el
e al., 2016). The concen a ion o CO
2
in he a mosphe e inc eased om
278 ppm in 1750 o 390.5 ppm in 2011 (Ciais e al., 2013), and hen up
o 418 ppm in 2021 (Tanhua e al., 2021). CO
2
emission is he p ima y
mechanism o soil C loss and con ibu es o he ele a ed CO
2
concen-
a ion in he a mosphe e (Pa kin and Kaspa , 2003). Mos o he CO
2
emi ed om he soil is due o he decomposi ion o plan esidue and
oo s, due o mic obial me abolism and espi a ion (Sainju e al., 2008;
Campbell e al., 2014).
I was es ima ed ha 75–120 Pg C pe yea is emi ed om soil o he
a mosphe e (Hibba d e al., 2005). The e o e, main enance and build-up
o soil C a e essen ial in imp o ing soil unc ions and o se ing a mo-
sphe ic CO
2
concen a ion (Smi , 2004; Delgado-Baque izo e al., 2017),
which is a key challenge o humankind (Lal, 2004; Scha lemann e al.,
2014; Rod igo-Comino e al., 2020a). C op esidue managemen a ec s
CO
2
emissions, p ima ily ia al e ing C and ni ogen (N) cycling
* Co esponding au ho s.
E-mail add esses: [email p o ec ed] (M. Mi zaei), [email p o ec ed] (A. Caballe o-Cal o).
Con en s lis s a ailable a ScienceDi ec
Pedobiologia - Jou nal o Soil Ecology
jou nal homepage: www.else ie .com/loca e/pedobi
h ps://doi.o g/10.1016/j.pedobi.2022.150819
Recei ed 16 Decembe 2021; Recei ed in e ised o m 31 May 2022; Accep ed 10 June 2022
Pedobiologia - Jou nal o Soil Ecology 93–94 (2022) 150819
2
(Guzman e al., 2015; Nawaz e al., 2017). Howe e , mul iple ac o s
egula e CO
2
emissions om he soil. Changes in soil empe a u e and
mois u e le els (Dong e al., 2017), o ganic ma e (OM) inpu s om
decomposing esidues- and hei e ec on aunal and mic obial ac i -
i ies, all in luence soil espi a ion (Toosi e al., 2012).
Due o he complexi y o ac o s go e ning soil espi a ion ollowing
he addi ion o c op esidues and hei in e ac ions, con as ing obse -
a ions ha e been epo ed in he li e a u e, i.e., inc eases (Badía e al.,
2013; Sugas i and Pinz´
on, 2020) o dec eases in soil CO
2
emissions
ollowing he applica ion o c op esidue in soil (Bai e al., 2017). Mos
c opping lands in I an a e semi-a id egions (i.e., high pH and CaCO
3
,
low OM, and supp essed biological s a us) whe e co n-whea o a ion is
a common g ain p oduc ion c opping sys em. Despi e i s alue as a
sou ce o OM, much o he pos ha es c op esidue is g azed o
collec ed as a eed sou ce. Residue emo al and excessi e illage a e he
main cause o soil OM deple ion in g ain c ops in he egion (Mi zaei
e al., 2021). E o s ha e been made a he na ional le el o encou age
a me s o e u n c op esidues o he soil. The e ec o esidue e en ion
on CO
2
emission om he soil, ypical o semi-a id condi ions, has no
been adequa ely s udied.
P e ious s udies ha e shown ha equen d ying-we ing cycles in
a id and semi-a id condi ions could lead o subs an ial C losses in soil
om newly added OM (Bo ken and Ma zne , 2009). We hypo hesized
ha : i) he addi ion o c op esidue o he soil esul s in highe CO
2
e lux
compa ed o esidue emo al, independen o he illage e ec ; ii) he
cumula i e CO
2
e lux would inc ease wi h an inc easing amoun o c op
esidue o he soil.
To es he abo e-men ioned hypo heses, we moni o ed CO
2
e lux in
a ield s udy, using c op esidue a h ee a es – 100 % (R
100
), 50 % (R
50
),
and esidue emo al (R
0
) in co n-whea o a ion unde con en ional
(CT) and no- illage (NT) sys ems. As key egula o s o soil espi a ion,
mic obial biomass and soil mois u e and empe a u e we e also moni-
o ed du ing he expe imen o link hei possible associa ion wi h he
soil CO
2
e lux.
2. Ma e ials and me hods
2.1. Si e cha ac e is ics and expe imen al design
The s udy was conduc ed in 2018 a he Ag icul u e Resea ch S a ion
o he College o Ag icul u e and Na u al Resou ces, Uni e si y o Teh-
an, Ka aj, I an (35◦48′32" N, 50◦58′06" E, 1308 m a.s.l.). This a ea has
semi-a id clima e condi ions wi h a mean annual empe a u e o 13.7 ◦C
and p ecipi a ion o 245 mm (Fig. 1). Two ields unde con as ing
illage managemen , con en ional illage (CT) and no- illage (NT), we e
selec ed. Bo h sys ems we e unde a whea (T i icum aes i um L.) - co n
(Zea mays L.) o a ion o a leas i een yea s be o e he s udy. Each
ield o 11 ×16 m was di ided in o nine 3 ×4 m sub-plo s. The
expe imen al design was a andomized comple e block wi h h ee ep-
lica es pe ea men . Table 1 summa izes he main physical and
chemical soil p ope ies. Ten soil samples we e collec ed andomly using
an auge sample (8 cm diame e ) om 0 o 10 cm and 10–20 cm dep hs
in each ield. Subsequen ly, soil samples we e uni o mly mixed o one
composi e sample pe soil dep h. Soil samples we e ai -d ied, sie ed (2
mm), and s o ed un il analyzes we e ca ied ou . Soil ex u e was
de e mined by he hyd ome ic me hod (Gee and Baude , 1986). Soil
o ganic ca bon (SOC) using he Walkley and Black me hod (Walkley and
Black, 1934), pH, and elec ical conduc i i y (EC) we e measu ed in
sa u a ed soil ex ac s (Richa des, 1954). A ailable phospho us was
de e mined using he NaHCO
3
me hod (Olsen and Somme s, 1982). The
ammonium ace a e me hod was used o de e mining a ailable po as-
sium (Knudsen e al., 1982). To al ni ogen (TN) was measu ed using he
Kjeldahl me hod desc ibed by B emne and Mul aney (1982). Mic o-
nu ien s we e measu ed in DTPA ex ac s (Lindsay and No ell, 1978)
using a omic abso p ion spec opho ome y.
2.2. T ea men applica ions
The whea esidue was applied ollowing whea ha es (Jul 2018) in
bo h NT and CT ields. The h ee le els o esidue we e 3.5 ha
−1
Fig. 1. Mon hly p ecipi a ion and mean ai empe a u e du ing he pe iod o he expe imen .
Table 1
Soil p ope ies o 0–10 and 10–20 cm soil dep hs in he ields in 2019.
Soil p ope ies Con en ional illage (CT) No- illage (NT)
0–10 cm 10–20 cm 0–10 cm 10–20 cm
pH *7.8 ±0.1 7.7 ±0.1 7.8 ±0.0 7.6 ±0.1
EC (ds m
−1
) 0.9 ±0.0 0.7 ±0.2 1 ±0.0 0.7 ±0.2
OC (mg/g) 0.9 ±0.1 0.8 ±0.2 1.2 ±0.0 1.01 ±0.1
TN (mg/g) 0.09 ±0.01 0.07 ±0.01 0.1 ±0.0 0.08 ±0.0
A ail K (mg kg
−1
) 167 ±4 134 ±3 279 ±5.2 237.4 ±6.0
A ail P (mg kg
−1
) 9 ±0.2 9.5 ±0.6 15 ±1.5 15.3 ±0.7
Bulk densi y (g cm
−3
) 1.52 1.56 1.32 1.38
To al Po osi y (%) 54 ±2 52 ±1.1 48 ±1.9 45 ±1
Sand (%) 57 ±1 53 ±1 28 ±0.3 27 ±0.7
Sil (%) 25 ±1 28 ±1 42 ±0.2 42 ±0.6
Clay (%)
Soil ex u e
18 ±1
Sandy Loam
19 ±2
Sandy Loam
30 ±0.4
Clay Loam
31 ±0.7
Clay Loam
EC: elec ical conduc i i y, OC: o ganic ca bon, TN: o al ni ogen, A ail K:
a ailable po assium, A ail P: a ailable phospho us.
*
Values a e Mean ±S anda d De ia ion (n =3).
M. Mi zaei e al.
Pedobiologia - Jou nal o Soil Ecology 93–94 (2022) 150819
3
(100 %, R
100
), 1.75 ha
−1
(50 %, R
50
), and no esidue ( esidue was
comple ely emo ed, R
0
). The selec ion o esidue le els was based on
c op yield, which was almos simila in bo h CT and NT sys ems. The
plan esidue was weighed acco ding o he ea men and was hen
homogeneously and manually dis ibu ed o e he su ace o each plo .
In he CT ield, all he h ee esidue le els we e illed and inco po a ed
in o he soil, while in he NT hey we e jus le on he soil su ace. Fo
he esidue emo al ea men (R
0
), unde bo h CT and NT sys ems, he
whole esidue om he p e ious c op was emo ed om he plo , and
he soil su ace was le unco e ed. A e his, silage co n was plan ed by
using a ow c op plan ed a a dose o 35 kg ha
−1
wi h a dis ance o 15 cm
wi hin he ow and 75 cm be ween he ows. In he NT ield, seed
placemen was made using a plan e wi h a single coul e o elimina e
esidue and loosen he soil be o e he s anda d plan e uni . In he CT
ield, be o e seeding, he soil was plowed o a dep h o 35 cm wi h a
moldboa d plow, disked, and le eled. Bo h NT and CT ecei ed equal
basal NPK e ilize s equal o 50 kg ha
−1
U ea, 70 kg ha
−1
Po assium
sul a e, and 150 kg ha
−1
Supe phospha e. Addi ional N was op-d essed
a eigh lea es (80 kg U ea ha
−1
) and en lea es (270 kg U ea ha
−1
)
s ages. Plo s we e i iga ed a e cul i a ion and 7–10 days in e als
he ea e using he sp inkle i iga ion me hod. A e ha es ing he
co n (Oc 2018), h ee le els o esidue we e applied equally o 1.8
(100 %, R
100
), 0.9 on ha
−1
(50 %, R
50
), and no esidue (0 %, R
0
).
Win e whea was plan ed in No 2018, a a dose o 208 kg ha
−1
seed
wi h a ow dis ance o 13 cm by a mechanical d illing machine. Basal
e iliza ion included he equi alen s o 50 kg ha
−1
u ea, 200 kg ha
−1
supe phospha e, and 150 kg ha
−1
po assium sul a e. Addi ional N e -
ilize was supplied du ing la e ille ing (110 kg U ea ha
−1
), s em
elonga ion (110 kg U ea ha
−1
), and spiking (50 kg U ea ha
−1
).
2.3. Plan esidue analyses
A sub-sample o whea and co n esidues was d ied and inely g ound
o chemical analyses (Table 2). O ganic ca bon (OC) was measu ed by
we oxida ion (Walkley and Black, 1934), and he Kjeldahl me hod was
used o de e mining o al ni ogen (TN) con en . Fo measu emen o
o al phospho us (P) and po assium (K), he samples we e combus ed a
500 ◦C, and P and K we e de e mined using spec opho ome ic and
lame pho ome ic me hods, espec i ely.
2.4. Soil CO
2
e lux
Gas sampling was s a ed in la e July and ea ly Augus 2018 in he
Table 2
Elemen al composi ion o whea and co n esidue.
Plan
esidue
N P K C C/N
% –
Whea *0.84
±0.12
0.09
±0.01
1.75
±0.07
55.4
±1.80
66
±2.56
Co n 0.92
±0.06
0.25
±0.02
1.08
±0.01
53.65
±1.30
58
±1.63
*
Values a e Mean ±s anda d de ia ion (n =3).
Fig. 2. The e ec o esidue le els on soil empe a u e a he gas sampling e en s unde he no- illage (NT) (a) and con en ional illage (CT) (b) sys ems. Ba s
ep esen s anda d e o (n =3). An as e isk (*) shows a signi ican di e ence be ween esidue le els wi hin a day a P <0.05.
M. Mi zaei e al.
Pedobiologia - Jou nal o Soil Ecology 93–94 (2022) 150819
4
co n c opping sys em unde he NT and CT sys ems espec i ely and
ended in ea ly June 2019 in he whea c opping sys em unde bo h
sys ems. Gas sampling was pe o med a 7–10 d in e als gene ally, and
e e y wo weeks in win e (Decembe –Feb ua y), based on he
GRACEne Chambe -based T ace Gas Flux Measu emen p o ocol (Pa -
kin and Ven e ea, 2010). The s a ic closed chambe me hod was used o
measu e he amoun o CO
2
e lux om he soil. The me hod has been
widely used o he measu emen o soil gas e lux, including ca bon
dioxide, me hane, and ni ous oxide (Oe el e al., 2012). Poly inyl
chlo ide (PVC) chambe s (15 cm diame e , 12.5 cm heigh ) wi h po s
o gas sampling we e g adually hamme ed in o he soil su ace o
dep hs o 5 cm du ing he whole moni o ing pe iod. Chambe s we e
only emo ed du ing cul i a ion e en s. To enable chambe ope a ion,
he c ops we e mowed when hei heigh exceeded he chambe ’s
heigh . Gas samples we e collec ed a leas 24 h a e chambe ins al-
la ion o a oid dis u bance e ec s. Gas sampling was pe o med om 9
o 10 am a 0, 30, and 60 min ime poin s by inse ing a needle a ached
o a 20 mL sy inge in he sampling po and ans e ing in 12 mL
p e- acuumed ials sealed wi h bu yl ubbe sep a (Labco Exe aine ,
UK). The concen a ion o CO
2
in he ials was measu ed using gas
ch oma og aphy (Tei Gos a Fa az, TG 2552, I an), equipped wi h a
he mal conduc i i y de ec o (TCD).
The CO
2
e lux was calcula ed as he changes in linea concen a ion
g adien o e ime and om he a io be ween chambe olume and soil
su ace a ea (Liebig e al., 2010). The CO
2
e lux was con e ed o i s
ca bon equi alen (CO
2
-C) by mul iplying i by he a io o he molecula
weigh o ca bon o ha o ca bon dioxide (12/44). Cumula i e amoun s
o CO
2
e lux we e calcula ed using linea ly in e pola ing da a poin s
and in eg a ing he unde lying a ea (Sainju e al., 2012; Wegne e al.,
2018).
2.5. Ancilla y measu emen s
To e alua e he ela ionship be ween soil condi ions and CO
2
e lux,
soil empe a u e, and mois u e con en s, as well as mic obial biomass C,
we e de e mined a each gas sampling e en . Soil empe a u e was
measu ed wi h a he mome e a 10 cm dep h nex o he colla s. Th ee
soil samples (0–10 cm) we e aken wi h a co e sample (100 cm
3
ol-
ume) om each plo ha was hen mixed in o one composi e sample.
The soil mois u e con en o he samples was de e mined using o en-
d ying a 105 ◦C mul iplied by soil bulk densi y. Soil bulk densi y was
measu ed using s ainless s eel cylinde s (100 cm
3
olume). Mic obial
biomass ca bon (MBC) was de e mined by he chlo o o m umiga ion
ex ac ion me hod (Jenkinson e al., 2004).
2.6. S a is ical analyses
The da a we e analyzed using he Analysis o Repea ed Measu es
p ocedu e in gene al linea models (GLM) o SAS so wa e e sion 9.4
(SAS Ins i u e, Ca y, NC, USA). Residue a e, illage ype, and sampling
ime we e he ixed e ec s. Soil pa ame e s (mois u e, empe a u e,
MBC) and CO
2
e lux we e he epea ed measu e a iables. Means o
each esidue a e, illage ype, and sampling ime we e compa ed by he
Duncan me hod a he 0.05 p obabili y le el. Pea son linea co ela ion
Fig. 3. The e ec o esidue le els on soil mois u e a he gas sampling e en s unde he no- illage (NT) (a) and con en ional illage (CT) (b) sys ems. Ba s ep esen
s anda d e o (n =3). An as e isk (*) shows a signi ican di e ence be ween esidue le els wi hin a day a P <0.05.
M. Mi zaei e al.
Pedobiologia - Jou nal o Soil Ecology 93–94 (2022) 150819
5
analysis was used o de e mine he ela ionships be ween soil pa ame-
e s (mois u e, empe a u e, MBC) and CO
2
e lux.
3. Resul s and discussion
3.1. Soil empe a u e and soil mois u e
In he NT sys em, du ing he co n season (Jul–Oc ), and also in he
allow pe iod be ween co n and whea seasons (14/10/2018 and 24/10/
2018), soil empe a u e was highe in plo s ecei ing esidue a lowe
a es, whe e a signi ican inc ease (P <0.05) in soil empe a u e was
obse ed in he R
0
compa ed o R
50
and R
100
ea men s (Fig. 2a). On he
o he hand, in mos cases, no signi ican di e ences we e obse ed be-
ween R
100
and R
50
. F om he beginning o he whea -g owing season in
au umn (26/11/2018) un il he end o win e (22/3/2019), he opposi e
end was no iced, whe e high esidue a e led o inc eased soil em-
pe a u e, and R
100
and R
50
esul ed in a signi ican inc ease (P <0.05)
in soil empe a u e compa ed o R
0
. He e, in mos cases, he di e ences
be ween R
100
and R
50
we e no signi ican . In addi ion, om he
beginning o sp ing un il he end o he expe imen al pe iod, he soil
empe a u e in R
0
ea men inc eased compa ed o R
100
and R
50
ea men s. The esul s o his s udy a e consis en wi h p e ious ind-
ings (Guzman e al., 2015). The inc easing soil empe a u e in R
0
in
summe and R
100
and R
50
in au umn and win e unde he NT sys em can
be a ibu ed o he insula ing e ec o plan esidue. The p esence o
plan esidue on he soil su ace in he NT sys em p o ec s he soil
agains se e e he mal luc ua ions and modula es su ace adia ion
ene gy and he mal changes be ween soil and a mosphe e (Ho on e al.,
1996). In he summe , plan esidue on he soil su ace p e en s he
abso p ion o mo e adia ion, hus p e en ing he soil su ace om
wa ming. In au umn and win e , plan esidue on he soil su ace p e-
en s hea exchange and, hus causes he soil o wa m up compa ed o
ba e soil.
Du ing c op o a ion unde he CT sys em, soil empe a u e inc eased
wi h inc easing esidue a e a all sampling imes, and, in mos cases,
hese inc eases in R
100
and R
50
ea men s we e signi ican (P <0.05)
compa ed o R
0
. S ill, in some cases, no signi ican di e ence was
obse ed be ween R
100
and R
50
ea men s (Fig. 2b). Resul s ob ained in
he CT sys em a e cong uen wi h Zhang e al. (2018) in hei s udy in
China. In he CT sys em, c op esidue is inco po a ed in o he soil ins ead
o emaining on he soil su ace, lea ing a small amoun o plan esidue
on he soil su ace, which educes he e ec o c op esidues and causes
he soil o abso b mo e hea , and leads o inc eases in soil empe a u e
(Dendoo en e al., 2012).
In almos all sampling imes, R
100
and R
50
ea men s caused a sig-
ni ican inc ease (P <0.05) in mois u e compa ed o R
0
unde bo h CT
and NT sys ems (Fig. 3a,b). Howe e , in se e al cases, no signi ican
di e ences we e obse ed be ween R
100
and R
50
. Inc eased soil mois u e
in R
100
and R
50
ea men s compa ed o R
0
unde bo h CT and NT sys-
ems could be explained by he ac ha c op esidue educes mois u e
e apo a ion and inc eases wa e -holding capaci y and soil wa e con-
en . P e ious s udies ha e also sugges ed ha c op esidue inc eases
Fig. 4. The e ec o esidue le els on soil mic obial biomass ca bon (MBC) in no- illage (NT) (a) and con en ional illage (CT) (b) sys ems a he gas sampling e en s.
Ba s ep esen s anda d e o (n =3). The bold black a ows indica e e iliza ion e en s. An as e isk (*) shows a signi ican di e ence be ween esidue le els wi hin
a day a P <0.05.
M. Mi zaei e al.

Pedobiologia - Jou nal o Soil Ecology 93–94 (2022) 150819
6
soil wa e con en (Sainju e al., 2012; Chalise e al., 2019) as well as
o he ypes o co e c ops o mulches (Rod igo-Comino e al., 2020b).
3.2. Soil mic obial biomass ca bon
The e we e signi ican di e ences o mic obial biomass ca bon
(MBC) ac oss all ea men s o esidue a es du ing he o a ion cycle
unde bo h illage sys ems (Fig. 4a,b). MBC was he highes in summe
du ing he co n season; and declined du ing he cold season and again
inc eased wi h ising soil empe a u e. In bo h CT and NT sys ems, MBC
was posi i ely co ela ed wi h he le el o c op esidue, i.e., he annual
means o 335, 236, and 125 (mg kg
−1
) in R
100
, R
50,
and R
0
unde CT, and
590, 500, and 300 (mg kg
−1
) o R
100
, R
50
, and R
0
unde NT (Fig. 5c).
The addi ion o N esul ed in mic obial g ow h, as measu ed by MBC, in
bo h CT and NT, consis en wi h he li e a u e (S ewa e al., 2018;
Mgelwa e al., 2019). The soil mic obial biomass pool is one o he
biological p ope ies ha s ongly egula es he dynamics o nu ien s
and C in soil (Toosi e al., 2012). I has also been shown ha mic obial
biomass esponds mo e apidly o plan esidue managemen compa ed
o he o al soil OM pool (Yang e al., 2012). Ou indings a e in line wi h
p e ious s udies, indica ing ha inc easing he le el o c op esidues
posi i ely a ec s he MBC pool size (Chowdhu y e al., 2015; Li e al.,
2017). These could be due o he ele a ed MBC in soils co e ed by c op
esidue, namely enhanced soil mois u e con en , and also a supply o
soluble C (and o he nu ien s) de i ed om he decomposing esidue
(Yang e al., 2012). The lowe a e o MBC du ing he cold season could
be a ibu ed o he lowe soil empe a u e du ing his pe iod. A sig-
ni ican and posi i e co ela ion be ween soil empe a u e and MBC also
con i ms his (Table S1). Low soil empe a u e may limi soil mic obial
ac i i y and hei popula ion. Tempe a u e and mois u e a e he mos
impo an ac o s in luencing soil mic obial biomass (Babu and Din-
da oglu, 2020).
3.3. CO
2
e lux
CO
2
e lux o all esidue a es ollowed a simila pa e n o all
esidue le els in bo h NT and CT (Fig. 6a,b). Highe soil CO
2
e lux
du ing summe and sp ing is a ibu ed o highe soil empe a u e
(Fig. 2a,b), and as a esul , enhanced biological (mic obial, aunal, and
oo ) ac i i y. Seasonal luc ua ions in soil empe a u e and hei in-
luence on CO
2
(and o he GHGs) e lux om he soil a e well docu-
men ed (Schau le e al., 2010).
The CO
2
-C e lux a e dec eased wi h inc easing esidue e en ion a
all sampling da es du ing he co n season in summe (26/7/2018–4/10/
2018) unde he NT sys em, whe e soil espi a ion was signi ican ly
highe (P <0.05) unde R
0
han R
100
and R
50
ea men s (Fig. 6a). A
highe in ensi y o soil espi a ion in unco e ed soil has also been e-
po ed p e iously (Guzman e al., 2015). A key eason o he signi ican
inc ease in soil CO
2
e lux in R
0
compa ed o R
100
and R
50
ea men s
du ing he co n season unde he NT sys em appea s o be g ea e
luc ua ions in soil empe a u e (Fig. 2a,). A posi i e and signi ican
co ela ion be ween soil empe a u e and CO
2
e lux also con i ms his
(Table 3). Soil empe a u e is he main ac o in luencing he emission o
CO
2
om he soil (Dendoo en e al., 2012). Yin e al. (2016) and Wegne
e al. (2018) also epo ed a posi i e co ela ion be ween CO
2
emissions
and soil empe a u e. In addi ion, ano he eason o he inc easing CO
2
e lux in R
0
compa ed o R
100
and R
50
can be possibly a ibu ed o he
high C/N a io (66) o whea esidues (Table 2) applied be o e he co n
Fig. 5. The e ec o c op esidue a es on annual mean soil empe a u e (a) mois u e (b), mic obial biomass ca bon (MBC) (c), and CO
2
-C e lux (d) du ing co n-
whea o a ion unde con en ional illage (CT) and no- illage (NT) sys ems. Means wi h he same le e a e no signi ican ly di e en . Ba s ep esen s anda d
e o (n =3).
M. Mi zaei e al.
Pedobiologia - Jou nal o Soil Ecology 93–94 (2022) 150819
7
g owing season, which educes he decomposi ion a e and elease o
CO
2
. I has also been epo ed ha he C/N a io o an o ganic esidue
applied o he soil mos ly de e mines he a e o i s mine aliza ion
(Nguyen and Ma schne , 2016).
When esidue was added, he e was no di e ence in soil espi a ion
be ween R
100
and R
50
. In con as , om he s a o he whea season
un il he end o he expe imen , CO
2
e lux inc eased wi h an inc easing
esidue e en ion a e a all sampling e en s compa ed o R
0
. Howe e ,
he di e ences among he esidue ea men s we e no signi ican om
ea ly o la e win e in 2019, which could be ela ed o lowe soil em-
pe a u e and limi ed mic obial ac i i y and oo espi a ion du ing his
pe iod. In he sp ing o 2019, signi ican inc eases (P <0.05) we e
eco ded o R
100
and R
50
compa ed o R
0
on se e al sampling da es,
especially a e u ea e iliza ion e en s. A signi ican inc ease in CO
2
e lux a e e iliza ion ac i i ies could be a ibu ed o imp o ed plan
g ow h, pho osyn hesis, and espi a ion (Holou, 2010), s imula ing and
inc easing he mine aliza ion o c op esidue (Dendoo en e al., 2012;
Sainju e al., 2012). In he CT sys em, he CO
2
-C e lux a e inc eased
wi h inc easing esidue a e, and hese inc eases we e signi ican
(P <0.05) a almos all sampling imes in R
100
and R
50
ea men s
compa ed o R
0
, bu he signi ican di e ences (P <0.05) be ween R
100
and R
50
ea men s we e only no iced in a ew sampling da es, mainly
a e u ea e iliza ion e en s in sp ing 2019, and o he mos o he
da es he di e ences we e no signi ican (Fig. 6b).
The signi ican inc ease in CO
2
e lux in he R
100
and R
50
compa ed
o he R
0
, which was obse ed in bo h CT and NT du ing he sp ing, can
be explained by a subs an ial inpu om decomposing esidue ha
se es as a subs a e o soil mic obes (Toosi e al., 2017).
Se e al s udies ha e epo ed ha he inco po a ion o plan esidue
inc eases soil CO
2
emissions (Badía e al., 2013; Wang e al., 2019).
Meanwhile, inc eased plan esidue mine aliza ion, soil o ganic ca bon,
mic obial biomass ca bon, and dissol ed o ganic ca bon accoun ed o
inc easing CO
2
emissions (Zhao e al., 2014; Ding e al., 2017; Yang
e al., 2017). Howe e , o he s udies epo ed educed soil CO
2
emis-
sions due o he e en ion o plan esidue in he soil (Bai e al., 2017).
3.4. Cumula i e CO
2
e lux
The annual cumula i e e lux o CO
2
-C did no di e signi ican ly
be ween esidue a e ea men s unde he NT sys em. S ill, he cumu-
la i e e lux o CO
2
-C was highe (p <0.05) in he CT sys em whe e R
100
(4.65 Mg CO
2
-C ha
−1
y
−1
) and R
50
(4.26 Mg CO
2
-C ha
−1
y
−1
) ep e-
sen ed 36.5 % and 25 % g ea e cumula i e CO
2
-C e lux, espec i ely,
han R
0
(3.4 Mg CO
2
-C ha
−1
y
−1
) (Fig. 7). Simila ly, D u y e al. (2021)
epo ed ha co n esidue minimally a ec ed CO
2
e lux in soils unde
he NT. S ill, in he CT sys em, ull e en ion o co n esidue inc eased
soil espi a ion up o 47 %. Con as ing esul s on he e ec o esidue in
soil espi a ion (e.g., Wegne e al., 2018) a e due o he complex
in e ac ion o di e en ac o s such as esidue amoun and quali y, as
well as soil and en i onmen al condi ions.
The s ong posi i e ela ionship be ween cumula i e CO
2
e lux and
he c op esidue (R
2
=0.96 o CT and R
2
=0.9 o NT) sugges s he
Fig. 6. Residue a e e ec on daily soil CO
2
-C e lux a he ime o g eenhouse gas measu emen in co n-whea o a ion unde no- illage (NT) (a) and con en ional
illage (CT) (b) sys ems. Ba s ep esen s anda d e o . The bold black a ows indica e e iliza ion e en s. An as e isk (*) shows a signi ican di e ence be ween
esidue le els wi hin a day a P <0.05.
M. Mi zaei e al.
Pedobiologia - Jou nal o Soil Ecology 93–94 (2022) 150819
8
con ibu ion o he plan esidue o soil espi a ion (Fig. 8).
In he CT sys em, when calcula ed, an addi ional 1.25 Mg C ha
−1
was
espi ed om he R
100
han om he no esidue soil, equi alen o 43 %
o he o al (2.9 Mg C ha
−1
) o he added esidue (Table 4). Fo he R
50
,
his was equi alen o 59 % o he added esidue (1.44 Mg C ha
−1
).
Unde he NT sys em, hese alues we e 5.5 %, and abou 3 % o o al C
added om c op esidue in R
100
and R
50
, espec i ely, compa ed o ha
espi ed om he no esidue ea men . This indica es ha unde bo h
CT and NT sys ems, he e was C accumula ion in he soil ollowing he
addi ion o c op esidue. Howe e , i has been well documen ed ha in
he long e m, he as majo i y o he added C om esidue will espi e
o he a mosphe e and only a small ac ion o esidual C will be
inco po a ed in o soil OM (Kuzyako , 2006; Campos e al., 2011).
3.5. The e ec o illage and in e ac ion e ec s o esidue a e and illage
sys em on soil p ope ies ( empe a u e, mois u e, MBC), and CO
2
e lux
The e ec o illage and he in e ac ion e ec s o esidue a e and
illage sys em on soil empe a u e was no signi ican (Table 5 and
Fig. 9a). Mo e signi ican inc eases (P <0.05) in mean and cumula i e
CO
2
e lux we e obse ed in he CT sys em han in he NT sys em
(Table 5). Soil mois u e and mic obial biomass ca bon we e signi ican ly
highe in he NT sys em compa ed o he CT sys em.
In addi ion, signi ican (P <0.05) in e ac ion e ec s o esidue a e
and illage sys em we e obse ed o soil mois u e, soil mic obial
biomass ca bon, and mean and cumula i e CO
2
e lux (Fig. 9b–e). NT
100
esul ed in he highes alues o soil mois u e (26 %) and mic obial
biomass ca bon (591 mg kg
−1
) among he ea men s, while he lowes
alue o soil mois u e (17.5 %)) and mic obial biomass ca bon
(124.5 mg kg
−1
) we e ob ained om CT
0
(Fig. 9b,c). The highes alues
o mean CO
2
e lux (64.5 mg m
−2
h
−1
) and cumula i e CO
2
e lux
(4.65 Mg ha
−1
y
−1
) we e obse ed in CT
100
(Fig. 9d,e), whe eas he
Table 3
Co ela ions o CO
2
wi h selec ed soil p ope ies o di e en a es o plan
esidues unde con en ional illage (CT) and no- illage (NT) sys ems.
Tillage
sys em
Residue
a e
Soil pa ame e s CO
2
emission
Pea son
co ela ion (R)
P-
alue
CT R100 Tempe a u e 0.61** 0.001
Mois u e 0.13 0.49
Mic obial biomass
ca bon
0.68** .000
R50 Tempe a u e 0.49** 0.001
Mois u e 0.11 0.46
Mic obial biomass
ca bon
0.69** .000
R0 Tempe a u e 0.60** 0.001
Mois u e 0.00 0.99
Mic obial biomass
ca bon
0.78** .000
NT R100 Tempe a u e 0.46* 0.01
Mois u e 0.17 0.36
Mic obial biomass
ca bon
0.66** .000
R50 Tempe a u e 0.43** 0.004
Mois u e 0.12 0.44
Mic obial biomass
ca bon
0.70** .000
R0 Tempe a u e 0.79** .000
Mois u e 0.06 0.73
Mic obial biomass
ca bon
0.89** .000
**. Co ela ion is signi ican a he 0.01 le el.
*. Co ela ion is signi ican a he 0.05 le el.
Fig. 7. Residue a e e ec on annual cumula i e CO
2
-C (Mg ha
-1
y
-1
) e lux
unde no- illage (NT) and con en ional illage (CT) sys ems. Means wi h
di e en le e s in each illage sys em indica e signi ican di e ences
(P <0.05). Ba s ep esen s anda d e o (n =3).
Fig. 8. Linea eg ession be ween esidue a es and cumula i e CO
2
-C e lux
pe soil managemen sys em. CT: con en ional illage; NT: no- illage. The
poin s on each CT and NT line ep esen he annual cumula i e CO
2
-C e lux o
di e en a es o esidue (co n and whea ) du ing he whole co n-whea o a-
ion cycle.
Table 4
C op esidue ca bon applica ion a es (d y weigh basis) in co n-whea o a ion
unde each con en ional illage (CT) and no- illage (NT) sys em.
C op esidue
a e (%)
Whea esidue
(Mg C ha
−1
)
Co n esidue
(Mg C ha
−1
)
To al
(Mg C ha
−1
)
100 *1.93 0.96 2.90
50 0.96 0.48 1.44
0 0 0 0
*
C op esidue ca bon applica ion a es (d y weigh basis) we e based on c op
yield and almos simila unde bo h CT and NT sys ems.
Table 5
The e ec o illage on mean soil CO
2
emissions, soil empe a u e, soil mois u e,
mic obial biomass ca bon, and cumula i e CO
2
emissions.
Tillage
sys em
Mean CO
2
emissions
(mg m
−2
h
−1
)
Tempe a u e
(◦C)
Mois u e
(%)
Mic obial
biomass
ca bon
(mg kg
−1
)
Cumula i e
CO
2
emissions
(Mg ha
−1
y
−1
)
CT
a
57.15
±12.36a
15.41
±3.30a
20.62
±3.52b
232.05
±85.80b
4.10
±0.55a
NT 34.86
±10.71b
15.40
±3.01a
23.89
±1.82a
465.96
±117.93a
2.47
±0.10b
Means wi h he same le e in each column a e no signi ican ly di e en .
a
Mean ±s anda d de ia ion, n =3.
M. Mi zaei e al.
Pedobiologia - Jou nal o Soil Ecology 93–94 (2022) 150819
9
lowes alues o mean CO
2
emissions (34 mg m
−2
h
−1
) and cumula i e
CO2 e lux (2.4 Mg ha
−1
y
−1
) we e ound in NT
0
(Fig. 9d,e). Fu he -
mo e, no signi ican di e ences we e ound o cumula i e CO
2
e lux
among NT
100
, NT
50
, and NT
0
(Fig. 9e). In he NT sys em, du ing he co n
c opping season CO
2
e lux was highe in he R
0
compa ed o R
100
and
R
50
, while du ing he whea season, a e e se end was obse ed in
which he a e o CO
2
e lux inc eased in R
100
and R
50
compa ed o R
0
(Fig. 6a). By conside ing he whole co n-whea o a ion, i is possible
ha hese wo di e en ends neu alized he e ec o each o he and
led o no signi ican di e ences among he esidue ea men s. Also,
unde conse a ion illage sys ems including he NT sys em, c op es-
idue is no inco po a ed in o he soil and hey a e no su icien ly ag-
men ed and decomposed, which consequen ly educes he eal po en ial
o c op esidue managemen on CO
2
e lux. In ag eemen wi h ou
indings, D u y e al. (2021) epo ed no signi ican e ec o di e en
c op esidue emo al a es on CO
2
emissions unde he NT sys em. Also,
Teixei a e al. (2013) ound no la ge di e ences in CO
2
emissions om
plo s wi h o wi hou c op esidues unde o a y illage.
Fig. 9. The in e ac ion e ec o esidue a e and illage sys em on annual mean soil empe a u e (a), mois u e (b), mic obial biomass ca bon (MBC) (c), CO
2
-C e lux
(d), and cumula i e CO
2
-C e lux (e). Means wi h he same le e a e no signi ican ly di e en . Ba s ep esen s anda d e o (n =3).
M. Mi zaei e al.