Poeplau, Ch is ophe e al.
Wo king Pape
In e im epo o he epea ed Ge man ag icul u al soil
in en o y
Thünen Wo king Pape , No. 277a
P o ided in Coope a ion wi h:
Johann Hein ich on Thünen Ins i u e, Fede al Resea ch Ins i u e o Ru al A eas, Fo es y and
Fishe ies
Sugges ed Ci a ion: Poeplau, Ch is ophe e al. (2025) : In e im epo o he epea ed Ge man
ag icul u al soil in en o y, Thünen Wo king Pape , No. 277a, Johann Hein ich on Thünen-Ins i u ,
B aunschweig,
h ps://doi.o g/10.3220/253-2025-235
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Thünen Wo king Pape 277a
In e im epo o he
epea ed Ge man
Ag icul u al Soil
In en o y
Ch is ophe Poeplau, Lau a Sofi e
Ha bo, Flo ian Schneide , Ma cus
Schiedung, Axel Don, S e an Heilek,
Rene Dechow, Elli Vasylye a,
A ne Heidkamp, Roland P ie z,
Heinz Flessa
Ch is ophe Poeplau, Lau a So ie Ha bo, Flo ian Schneide , Ma cus Schiedung, Axel Don, S e an Heilek,
Rene Dechow, Elli Vasylye a, A ne Heidkamp, Roland P ie z, Heinz Flessa
Thünen Ins i u e o Clima e-Sma Ag icul u e
Bundesallee 65
38116 B aunschweig
Con ac :
PD D . Ch is ophe Poeplau
Phone: +49 531 2570 1239
E-Mail: C[email p o ec ed]
Thünen Wo king Pape 277a
©2025 he au ho , Thünen Ins i u e. This is an open access publica ion dis ibu ed unde he e ms and
condi ions o he C ea i e Commons A ibu ion 4.0 In e na ional (CC BY 4.0) license
B aunschweig/Ge many, Dezembe 2025
I
Summa y
The dynamics o o ganic soil ca bon (SOC) play an impo an ole in a mosphe ic CO2 concen a ions and
a e he e o e included in na ional g eenhouse gas in en o ies. SOC is also essen ial o soil e ili y. On
behal o he Fede al Minis y o Food and Ag icul u e, he Thünen Ins i u e o Clima e-Sma Ag icul u e
he e o e conduc ed he i s na ionwide ep esen a i e in en o y o ag icul u al soils (BZE-LW) be ween
2010 and 2018. A o al o 3,104 a able, g assland and pe manen c op si es we e sampled in an 8x8 km g id
and analysed o SOC con en s and s ocks, as well as o he pa ame e s, down o a dep h o 1 m. The BZE-
LW epea in en o y p ojec began in 2022, and since he beginning o 2023, esampling o he si es
iden i ied a ha ime has been in ull swing. In addi ion o soil sampling, annual managemen da a is also
being collec ed. The main objec i e o his p ojec is o quan i y and explain po en ial changes in SOC
con en s and s ocks o e he pas decade. This in e im epo p esen s he ini ial esul s o he ongoing
epea in en o y.
Compa ed o he ini ial BZE-LW, he e we e some de ia ions in he implemen a ion o he epea in en o y.
Only he op 50 cm a e sampled and o ganic soils a e no esampled. Ins ead o a cen al p o ile pi and
eigh addi ional co e d illings, ou small pi s a e now exca a ed o sampling. Some pa ame e s a e no
eco ded again (e.g. soil ype, g ain size dis ibu ion, s one con en ), while o he s ha e been added (e.g.
agg ega e s abili y, ai capaci y, ca ion exchange capaci y). By Oc obe 2025, app oxima ely 1,350 si es in
eigh ede al s a es had been esampled and almos 1,000 had been analysed o bulk densi y and SOC
con en in o de o calcula e mass-co ec ed SOC s ock changes. Du ing he ini ial e alua ion, i was no iced
ha he ini ial SOC con en o he opsoil om he p o ile pi was sys ema ically sligh ly oo high, leading o
an o e es ima ion o SOC losses. Fo his eason, he SOC con en s om addi ional co e samples o he
ini ial BZE-LW we e used ins ead. Howe e , analysis o hose has no been comple ed ye , which is why only
587 si es ha e been included in he e alua ion a his s age.
Sligh changes in SOC con en ha e been obse ed in a able soils o e he pas decade. While a sligh ly
posi i e end in SOC con en was obse ed on a e age in 0-10 and 10-30 cm, he change in SOC s ocks in
0-30 cm (-1.6%) and 0-50 cm (-2.7%) was signi ican ly nega i e due o a sligh dec ease in bulk densi y
despi e mass co ec ion. A a dep h o 0-10 cm, howe e , he change in SOC s ocks was also sligh ly posi i e
(0.9%), which can possibly be explained by a na ionwide decline in illage in ensi y and he esul ing
edis ibu ion o SOC in he soil p o ile. Howe e , he e alua ion o he managemen da a om he
ques ionnai e was so a ocused on one pa ame e : he equency o co e c opping. In his espec , he
BZE-LW da a co espond well wi h na ional da a, which show app oxima ely a doubling o he annual co e
c op a ea in he pe iod unde e iew. Howe e , his g adual inc ease in SOC inpu in o Ge man a able soils
was appa en ly no su icien o compensa e o po en ial nega i e in luences on SOC. Fo g assland, he e
was a mo e p onounced dec ease in SOC s ocks, which was mos p onounced a a dep h o 0-10 cm (-8.1%).
A dep hs o 0-30 cm and 0-50 cm, he signi ican ela i e dec eases we e -5.9% and -5.1%. Nega i e ends
we e also obse ed on a e age a all dep h le els o he 14 pe manen c op si es o da e. The in es iga ion
o he causes o hese SOC losses is s ill ongoing.
Acco ding o he hypo heses de eloped he e, i is land use his o y and soil genesis, apidly ad ancing clima e
change, and ecen changes in cul i a ion p ac ices ha a e a ec ing he SOC dynamics cu en ly being
obse ed: The his o ically we and o en SOC- ich sandy soils o no h-wes e n Ge many end o su e
pa icula ly se e e SOC losses unde cu en land use, which is consis en wi h he esul s o long- e m soil
obse a ions in Lowe Saxony and he neighbo ing Ne he lands. O e he las 50 yea s, he e has been an
a e age ai empe a u e inc ease o 2.1°C a he BZE-LW si es, abou hal o which has occu ed in he las
1-2 decades. Acco ding o modelling and expe imen al wo k, wa ming alone is su icien o explain he
II
magni ude o a e age SOC losses. Finally, na ional s a is ics clea ly indica e a educ ion in li es ock a ming
and ni ogen e ilisa ion, which is also likely o ha e a nega i e impac on SOC s ocks.
Sepa a ing he a ious ac o s in luencing SOC s ocks equi es complex me hodology and will be a cen al
pa o he nex p ojec phase, alongside he comple ion o esampling and he emeasu emen o he ini ial
co e samples. Ano he challenge will be he p epa a ion and implemen a ion o new epo ing
equi emen s, in pa icula he EU Soil Moni o ing Law. The ends obse ed o da e only apply o pa o
he Fede al Republic o Ge many. The a e age a es o change p esen ed he e should he e o e no be
ex apola ed.
Keywo ds: Ag icul u al soils, soil moni o ing, soil o ganic ma e , soil ca bon, g eenhouse gas epo ing
III
Table o con en s
Summa y I
1 In oduc ion 7
2 Ma e ials and me hods 9
2.1 Sampling and ield da a collec ion 9
2.1.1 Gene al cha ac e is ics o he BZE-LW sampling design 9
2.1.2 Gene al cha ac e is ics o he i s epea in en o y 9
2.1.3 Sampling and ield da a collec ion o he epea in en o y 12
2.2 Sample p epa a ion, labo a o y analyses, and calcula ions o ele an pa ame e s 12
2.2.1 Bulk densi y o ine soil and g a ime ic con en o coa se soil and wa e 12
2.2.2 O ganic and ino ganic ca bon con en and o al ni ogen con en 13
2.2.3 Soil o ganic ca bon s ock 14
2.2.4 pH alue and elec ical conduc i i y 15
2.2.5 Addi ional pa ame e s 15
2.2.6 A chi ing o soil samples 16
2.3 Collec ion o managemen da a 16
2.4 Ex e nal da a 17
2.4.1 Land use his o y 17
2.4.2 Clima e da a 17
2.5 S a is ics 17
3 Compa ison o SOC esul s om he ini ial p o ile pi and soil co es 19
4 Resul s 22
4.1 Tempo al dynamics o o ganic soil ca bon con en 22
4.2 Tempo al dynamics o o ganic soil ca bon s ocks 25
4.3 Changes in key en i onmen al and managemen in luences 29
4.3.1 Changes in clima ic condi ions 29
4.3.2 Co e c opping 29
5 Discussion 31
5.1 Soil ca bon dynamics in ag icul u al soils in Ge many 31
5.2 An unscheduled cou se co ec ion in he ag icul u al soil condi ion su ey 35
6 Ou look 37
IV
Re e ences 38
Acknowledgemen s 42
Appendix 43
V
Table o Figu es
Figu e 1 Sampling scheme o up o eigh epea in en o ies (ma ked by numbe s 2-9) and d one image
o a join sampling o a si e wi h ou simul aneously opened p o ile pi s. No. 1 ma ks he
loca ion o he cen al soil p o ile o he ini ial BZE-LW. ...........................................................10
Figu e 2 Loca ion o si es sampled in he epea in en o y by Oc obe 31, 2025, by land use, as well as
si es s ill o be sampled. .............................................................................................................11
Figu e 3 Densi y unc ion o z- ans o med SOC con en s (uni o mly scaled pe si e and dep h le el, wi h
0 as he mean alue o he si e ac oss all a ailable measu emen s) o he da a om co e d illing
and p o ile pi s om he ini ial in en o y, as well as he alues om he epea in en o y. ...19
Figu e 4 Change in SOC s ock based on he co e d illing plo ed agains he change in SOC s ock based
on he ini ial p o ile pi wi h linea eg essions and co esponding co ela ion coe icien s (R²).
The dashed diagonal line ep esen s he 1:1 line. The sec ion selec ed o be e isualiza ion
(-20 o 20 Mg ha⁻¹) led o he exclusion o 15 si es in 0-10 cm, 51 si es in 10-30 cm, and 66 si es
in 30-50 cm. The eg essions a e no a ec ed by his. ..............................................................20
Figu e 5 Loca ion o si es ha ha e al eady been esampled o which da a om he ini ial co e d illing
and he ele an analysis esul s om he epea in en o y a e a ailable. ..............................21
Figu e 6 Dis ibu ion o SOC con en s om he ini ial in en o y and epea in en o y by dep h le el and
land use wi h median and mean alues. ...................................................................................22
Figu e 7 Dis ibu ion o changes in SOC con en by dep h le el and land use wi h mean and median. The
black do ed line ep esen s no change (ze o line). The sec ion selec ed o be e isualiza ion
(-20 o 20 g kg(-1) )led o he exclusion o 18 si es in 0-10 cm, 6 si es in 10-30 cm, and 4 si es in
30-50 cm. The ep esen a ion o he median and mean alues a e no a ec ed by his. ........23
Figu e 8 Changes in SOC con en so ed by size (colo ed do s) o all c opland and g assland si es a
h ee dep h le els wi h minimum de ec able di e ence (MDD) o he espec i e si e (g ay
ba s). The MDD is a posi i e alue ha , depending on he a iabili y a he si e, indica es how
la ge a change (amoun ) in SOC con en mus be in o de o assume a change wi h s a is ical
ce ain y. Fo he igu e, he MDD was mi o ed in o nega i e alues o enable a di ec
compa ison wi h he losses in SOC con en . Nega i e changes in SOC con en a e colo ed ed,
posi i e changes blue, and alues g ea e han he MDD a e shown in da k colo s. Changes
wi hin he MDD, and he e o e no signi ican ly signi ican , a e shown in ligh colo s. The
sec ion -25 o 25 g kg-1 selec ed o be e isualiza ion led o he exclusion o 4 g assland si es
in 0-10 cm, one c opland and one g assland si e in 10-30 cm, and 3 c opland and 2 g assland
si es in 30-50 cm. .......................................................................................................................24
Figu e 9 Box plo s (wi h 1s , 2nd, and 3 d qua iles) o SOC s ock changes in he h ee cumula i e dep h
le els wi h numbe o obse a ions (n) o all land uses. ..........................................................26
Figu e 10 Spa ial dis ibu ion o SOC s ock changes a a dep h o 0-30 cm o all si es esampled o da e
o which co e d illing da a we e a ailable (n=578). A eas ma ked wi h an as e isk ha e
de ia ions o mo e han 25 Mg ha-1) (n=21, 6 c oplands, 15 g asslands). ................................27
Figu e 11 Changes in SOC s ocks a a dep h o 0-30 cm as a unc ion o he mean SOC s ock o he si e
(mean o bo h in en o ies), sand con en , and ini ial C:N a io o all h ee land use classes wi h
co ela ion coe icien s (R²). ......................................................................................................28
Figu e 12 Box plo s (wi h 1s , 2nd, and 3 d qua iles) o he change in SOC s ock a a dep h o 0-30 cm in
c opland (b own) and g assland si es (g een), g ouped acco ding o land use his o y (c opland
= long- e m c opland, g assland o c opland = c opland wi h g assland his o y, c opland o
g assland = g assland wi h c opland his o y, g assland = long- e m g assland). Only hose si es
a e shown ha had no con i med g assland o a ion in he 10 yea s p io o he ini ial sampling,
VI
o we e cha ac e ized by o he p e ious uses (e.g., moo , hea h, o es ). The land use change
is based on he las 136 yea s acco ding o Emde e al. (2024). ...............................................28
Figu e 13 Dis ibu ion o mean annual empe a u e, mean mon hly empe a u e, annual po en ial
e apo a ion, and annual clima ic wa e balance o all 3104 BZE-LW si es o he las six calenda
decades. .....................................................................................................................................30
Figu e 14 Time se ies showing he p opo ion o si es wi h in e c opping o each yea in he pe iod 2001-
2022. Blue = ini ial in en o y ques ionnai e, g een = epea in en o y ques ionnai e. Whe e
he wo ques ionnai es o e lapped (possible in he yea s 2011-2015), he in o ma ion om he
epea in en o y ques ionnai e was used o he sake o simplici y.........................................30
Figu e 15 Annual a es o change in a e age na ional SOC s ocks in a ious Eu opean coun ies and
Ge many o c opland and g assland in he espec i e in en o y pe iods, di e en ia ed by
opsoil, subsoil (de ined sligh ly di e en ly depending on he s udy) and he en i e soil p o ile
(i ele an ). The da a a e aken om a p e iously unpublished li e a u e e iew and a e
p esen ed he e in modi ied o m (Ha bo e al., submi ed). .....................................................32
Ma e ials and me hods 13
s aw), and oo s. All ou componen s a e weighed indi idually. An h opogenic ma e ial is gi en special
conside a ion, as i could p o ide clues abou he his o y o he si e and he gene al deg ee o ma e ial
admix u es in ag icul u ally used soils. The oo s a e no washed, bu weighed di ec ly a e sie ing and
so ing. Fu he mo e, no dis inc ion is made be ween dead and li ing oo s. I is he e o e a e y ough
indica o o he ac ual oo biomass. The bulk densi y o he en i e soil BD o al (g cm-3) and he bulk densi y
o he ine soil BD ine (g cm-3) a e calcula ed as ollows:
𝐵𝐷𝑡𝑜𝑡𝑎𝑙=𝑀𝑡𝑜𝑡𝑎𝑙
𝑉𝑜𝑙𝑡𝑜𝑡𝑎𝑙
𝐵𝐷𝑓𝑖𝑛𝑒=𝑀𝑡𝑜𝑡𝑎𝑙-𝑀𝑟𝑜𝑐𝑘𝑠
𝑉𝑜𝑙𝑡𝑜𝑡𝑎𝑙-𝑀𝑟𝑜𝑐𝑘𝑠
𝜌𝑟𝑜𝑐𝑘𝑠
He e, M o al deno es he o al mass o he sample (g), Vol o al he o al olume o he sample (cm³), while M ine
deno es he mass o he ine soil <2 mm (g), M ocks deno es he mass o he ock agmen ac ion >2 mm
(g), and ρ ocks deno es he bulk densi y o he ock agmen ac ion (g cm-3) in he sample. The la e was
se o 2.65 g cm-3 (bulk densi y o qua z) as s anda d i he e we e no indica ions o signi ican de ia ions
om his alue. Fo ce ain sedimen s o olcanic ocks, he bulk densi y o he skele on may de ia e
signi ican ly om his alue. In such cases, ha bulk densi y was analyzed in he ini ial BZE-LW in o de o
adjus he calcula ion o he BD( ine) acco dingly (Jacobs e al., 2018) . These speci ic bulk densi ies we e also
used in he epea in en o y.
2.2.2 O ganic and ino ganic ca bon con en and o al ni ogen con en
The samples o chemical analysis a e d ied a 40°C un il hei weigh emains cons an and sie ed o 2 mm.
Fo o ganic and ino ganic ca bon (SOC, SIC) and o al ni ogen (N o ), he samples om each indi idual pi
and dep h le el a e measu ed sepa a ely. This se es o iden i y small-scale luc ua ions and possible
ou lie s. I also p o ides a measu e o unce ain y, which helps in he classi ica ion and s a is ical analysis
o obse ed changes. In addi ion, i opens up he possibili y o calcula ing he SOC ese e o each indi idual
pi and hus mo e accu a ely on a e age, as he bulk densi y pe pi and dep h le el is also de e mined. P io
o elemen al analysis, aliquo s o app oxima ely 20 g a e g ound o <63 µm o homogenize he sample. O
hese homogenized samples, 300-800 mg a e used o elemen al analysis. Ca bona e- ee soils a e analyzed
o ca bon and ni ogen using a CN analyze ( a io MAX cube, Elemen a , Langenselbold), while ca bona e
soils (as iden i ied in he ield o ia pH measu emen ) a e analyzed using a TOC analyze (soli TOC cube,
Elemen a , Langenselbold) wi h di e en ia ed empe a u e inc ease. The h eshold be ween SOC and SIC
is se a 550°C acco ding o VD-LUFA. The N o con en in ca bona e soils is subsequen ly measu ed using a
ni ogen analyze ( apid N exceed, Elemen a , Langenselbold).
Since he e was a change in he elemen al analyze s be ween he ini ial in en o y o he BZE-LW and he
epea in en o y ( om LECO o Elemen a ), a compa ison be ween he di e en ins umen s was ca ied
ou on a sys ema ically selec ed sample se by measu ing a chi ed samples om he ini ial BZE-LW again
wi h he new elemen al analyze s. A o al o 50 ca bona e- ee and 50 ca bona e-con aining samples
be ween 0 and 100 g kg-1 SOC we e selec ed and measu ed again. No sys ema ic de ia ions o SOC and N o
could be de ec ed.
Du ing he ini ial e alua ion o he esul s, se e al si es s ood ou whe e mean SOC con en s a ied g ea ly
be ween he wo in en o ies. Ve y high spa ial a iabili y was iden i ied as a majo eason o he signi ican
changes a e a decade. Wi hin he ou p o iles o he epea in en o y, anges in SOC con en o up o 100
g kg-1 o 10 pe cen age poin s we e obse ed. These we e o en si es wi h o ganic ho izons o bu ials in
14 Ma e ials and me hods
deepe soil a eas. I can be assumed ha he sampling design o he BZE-LW, especially wi h he peculia i y
o he non- eplica ed ini ial p o ile pi , eaches i s limi s a such and o he si es wi h ex eme, small-scale
a iabili y, o does no allow o a meaning ul e alua ion o SOC con en changes. Based on he dis ibu ion
o hese anges, h eshold alues we e de ined o each land use and dep h le el, abo e which a si e was
excluded om he e alua ion in his in e im epo . In c opland and pe manen c op soils, hese anges
we e 20 g kg-1 in 0-10 cm and 10-30 cm, and 40 g kg-1 in 30-50 cm, and 40 g kg-1 in all dep h le els in g assland
soils. The a ia ion pa e ns in N o con en we e e y simila o hose in SOC con en , which is why he
educ ion o si es was limi ed o il e ing based on SOC con en . Any si e whe e an exceedance was ound
a any dep h le el was excluded om u he e alua ion. A o al o 21 o he esampled si es we e excluded
om his in e im epo .
2.2.3 Soil o ganic ca bon s ock
The key pa ame e o he BZE-LW is he SOC s ock (Mg C ha-1 and gi en dep h). This is de e mined o each
indi idual p o ile pi and dep h le el using he ollowing o mulas and hen cumula ed o he dep h le els
0-30 and 0-50 cm:
𝐹𝑆𝑆 = 𝐵𝐷𝑓𝑖𝑛𝑒×𝑡ℎ𝑖𝑐𝑘𝑛𝑒𝑠𝑠×(1-𝑟𝑜𝑐𝑘𝑠
100)×100
SOC s ock = 𝐹𝑆𝑆 ×𝑆𝑂𝐶 𝑐𝑜𝑛𝑡𝑒𝑛𝑡
1000
FSS is he ine soil s ock (Mg ha-1), which can be calcula ed om he BD ine, he hickness o he espec i e
dep h le el (cm), he olume ic ock agmen ac ion ( ocks, ol. %) and a con e sion ac o o 100
(Poeplau e al., 2017). The olume ic ock agmen ac ion o he soil was aken om he ini ial BZE-LW,
as his can be conside ed app oxima ely cons an o e a 10-yea in e al and would o he wise cause
excessi e noise wi h ega d o SOC s ock changes (Mune a-Eche e i e al., 2025). The SOC s ock (Mg ha-1)
a any dep h le el can be ob ained by mul iplying he FBV by he SOC con en (g kg-1) and a con e sion ac o
o 1000.
Changes in he bulk densi y o he ine soil lead o a change in he soil mass o he ine soil s ock a he
espec i e dep h le el. Howe e , a compa ison o SOC s ocks be ween wo poin s in ime should be based
on iden ical ine soil s ocks in o de o ack ac ual changes in he SOC s ock in a de ined amoun o soil
(Elle and Be any, 1995; on Haden e al., 2020). Since sampling iden ical ine soil s ocks in he ield is
p ac ically impossible, a ma hema ical co ec ion mus be made. In his case, he ine soil s ock in a gi en
soil package (0-10, 0-30, and 0-50 cm) was speci ied by he ini ial in en o y. Fo his pu pose, i s
de e mined he cumula i e ine soil s ock o he soil package o be co ec ed o each o he ou soil
p o iles in he epea in en o y.
The p ocedu e o mass co ec ion is ha soil packages wi h an excessi ely high ine soil s ock (compa ed
o he e e ence) a e educed ma hema ically a he lowe end o simula e a co espondingly shallowe
sampling, while soil packages wi h an excessi ely low mass a e ex apola ed o each he e e ence mass.
This is done sepa a ely o all h ee soil packages (0-10, 0-30, and 0-50 cm) and each indi idual p o ile,
always using he espec i e ine soil s ock o he ini ial in en o y as a e e ence. The educ ion o a soil
package and he subsequen co ec ion o he co esponding SOC s ock o a p o ile in he epea in en o y
is ca ied ou as ollows: ∆𝐹𝑆𝑆 = 𝐹𝑆𝑆𝑟𝑒𝑝𝑒𝑎𝑡-𝐹𝑆𝑆𝑖𝑛𝑖𝑡𝑖𝑎𝑙
Ma e ials and me hods 15
𝑆𝑂𝐶 𝑠𝑡𝑜𝑐𝑘𝑠ℎ𝑜𝑟𝑡𝑒𝑛𝑒𝑑 =SOC s ock -∆𝐹𝑆𝑆× 𝑆𝑂𝐶 𝑐𝑜𝑛𝑡𝑒𝑛𝑡𝑙𝑜𝑤𝑒𝑠𝑡 𝑖𝑛𝑐𝑟𝑒𝑚𝑒𝑛𝑡
1000
He e, FSS epea deno es he ine soil s ock o a p o ile pi in he epea in en o y down o he dep h o he
espec i e soil package (Mg ha-1), while FSSini ial deno es he ine soil s ock o he espec i e soil package o
he ini ial p o ile (Mg ha-1 ). The di e ence be ween hese wo ine soil s ocks is hen used o de e mine a
SOC s ock, which is sub ac ed om he p e iously de e mined SOC s ock o he soil package. To do his,
ΔFSS is mul iplied by he SOC con en (g kg-1) o he lowes dep h le el o he soil package o be co ec ed.
The ex apola ing co ec ion o a soil package is ca ied ou acco dingly o each indi idual soil p o ile o he
epea in en o y as ollows:
𝑆𝑂𝐶 𝑠𝑡𝑜𝑐𝑘𝑠ℎ𝑜𝑟𝑡𝑒𝑛𝑒𝑑 = SOC s ock -∆𝐹𝑆𝑆×𝑆𝑂𝐶 𝑐𝑜𝑛𝑡𝑒𝑛𝑡𝑢𝑛𝑑𝑒𝑟𝑙𝑦𝑖𝑛𝑔 𝑖𝑛𝑐𝑟𝑒𝑚𝑒𝑛𝑡
1000
In compa ison o he p eceding o mula, he SOC con en o he unde lying inc emen is now used. Fo he
soil package 0-10 cm, his is he SOC con en om 10-30 cm, and o he soil package 0-30 cm, i is he SOC
con en om 30-50 cm. Fo he soil package 0-50 cm, ex apola ion wi h SOC con en om he epea
in en o y is no possible, as no unde lying inc emen is sampled below 50 cm. I ex apola ion is
ne e heless necessa y, he SOC con en o he unde lying inc emen (50-70 cm) om he ini ial in en o y
is used. Howe e , in o de o pe o m he ex apola ion wi h as li le " o eign" da a as possible ha was no
measu ed in he espec i e p o ile, a wo-s ep app oach is used o ex apola ion below 50 cm: Fi s , he
SOC s ock o each p o ile is adjus ed o he hea ies mass o he ou p o iles in he epea in en o y. Fo
his pu pose, he SOC con en o he 30-50 cm dep h le el om he espec i e p o ile is used. Only he
di e ence be ween he ine soil s ock o he hea ies p o ile o he epea in en o y and he p o ile o he
ini ial in en o y is ex apola ed using he SOC con en below 50 cm om he ini ial in en o y.
2.2.4 pH alue and elec ical conduc i i y
The pH alue is de e mined bo h in dis illed wa e (pHH2O) and in calcium chlo ide (pHCaCl2). Fo he analysis
o pH and elec ical conduc i i y, pool samples a e i s c ea ed o each dep h inc emen o a si e. To do
so, app oxima ely equal p opo ions o he indi idual samples om he ou p o ile pi s a e mixed in o one
sample a e sie ing in o de o educe he analy ical e o and he numbe o a chi e samples. Only o he
selec ed ocus si es (co e si es) a e all indi idual samples analyzed in o de o ob ain a measu e o he small-
scale a iabili y o he espec i e pa ame e s. Fo he analysis, i e ml o d ied ine soil is shaken upside
down o 20 minu es wi h 25 ml o dis illed wa e o a 0.01 mola CaCl2 solu ion. A e subsequen 10-
minu e cen i uga ion, he measu emen is ca ied ou using a pH-me e (P oLab 4000, SI-Analy ics, Mainz)
in a measu ing obo (SP2000, Skala , B eda).
2.2.5 Addi ional pa ame e s
Spec a we e also eco ded in he labo a o y in he mid-in a ed ange (2500-25000 nm; 4000-400 cm-1)
using di use e lec ion in a ed Fou ie ans o m spec oscopy (DRIFT-MIR, Nicole iS50 wi h Collec o II,
The mo Fishe , Wal ham). A o al o 7000 spec a ha e been collec ed ou o a planned 28000 spec a.
Toge he wi h he spec a in he nea -in a ed ange (900-3400 nm; 11000-3000 cm-1 (FT-NIRS MPA, B uke ,
Bille ica) wi h a ound 14000 spec a (Jaconi e al., 2017; Vos e al., 2018), his will esul in he "Ge man
Ag icul u al Soil Spec al Lib a y" (GASSL).
In a ed spec oscopy enables he es ima ion o a ious soil pa ame e s, such as o ganic ca bon, i s
dis ibu ion in ac ions o a ying s abili y, bu also ex u e and pH, as well as o he pa ame e s (Sande man
e al., 2020). The DRIFT-MIR spec a in pa icula con ain di ec in o ma ion abou he chemical and
16 Ma e ials and me hods
unc ional composi ion o he o ganic soil subs ance as well as abou he p ope ies o he mine al phase
(Ma geno e al., 2023; Schiedung e al., 2025). The ad an age he e is ha spec oscopy is a less complex
han con en ional me hods and can he e o e be used o pe o m quali a i e and quan i a i e assessmen s
o all samples, no jus a selec ion, using he GASSL in he u u e. A he same ime, se e al pa ame e s can
be es ima ed om a single spec um. Thus, in he u he cou se o he BZE-LW, models o he quan i a i e
es ima ion o a ious soil pa ame e s and also quali a i e pa ame e s will be in eg a ed in o he e alua ion.
Howe e , GASSL will no be discussed u he in his epo .
In addi ion, he samples om he epea in en o y a e analyzed o ca ion exchange capaci y and base
sa u a ion (all dep h le els) as indica o s o nu ien supply, as well as agg ega e s abili y ( opsoil, 0-10 cm)
and ai capaci y (subsoil, 30-40 cm and 40-50 cm) as indica o s o s uc u al s abili y and subsoil compac ion.
In addi ion, opsoil samples (0-10 cm) we e selec ed om 300 c opland si es o cha ac e ize he mic obial
communi y and in es iga e a ious unc ional mic obial p ope ies. An analysis o he p opo ion o
py ogenic ca bon in he soils o he co e si es is also planned. P e ious esul s o hese addi ional pa ame e s
a e no co e ed in his epo .
2.2.6 A chi ing o soil samples
The inely g ound aliquo o each sample (app ox. 20 g o d y soil), which was also used o elemen al
analysis, is a chi ed. In addi ion, 2 kg o each mixed sample om he indi idual dep h le els o he ou
p o iles is se aside o u u e analysis, i a ailable. No mixed samples a e kep om he co e si es; ins ead,
all indi idual samples a e e ained. The a chi e is da k (UV-p o ec ed), cool, and d y o ensu e minimal
change and maximum shel li e o he soil samples and con aine s.
2.3 Collec ion o managemen da a
In o de o in e p e changes in soil p ope ies, ield- and a m-speci ic managemen in o ma ion since he
ini ial in en o y is o g ea impo ance. This in o ma ion is collec ed using a ques ionnai e, which is a ailable
in bo h digi al and analog o ma s. The ollowing da a is eques ed, which is limi ed o he cen al ques ion
o he BZE-LW: Type o a m, a ming me hod (con en ional/o ganic, since when), land a ea o he a m,
a e age pu chase and sale quan i ies o o ganic e ilize s o subs a es, c opland and g assland a ea o he
sampled pa cel, size o he sampled ield, and dis ance o he sampling poin om he cen al a m loca ion.
Annual da a is collec ed on he ype and yield o he main c op, emo al o s aw and by-p oduc s, ype,
sowing da e, inco po a ion da e and use o any ca ch c ops, ype o pe manen g assland use, numbe o
cu s in g assland, da e o 1s and 2nd cu , ype and dep h o g assland enewal, ype, numbe and du a ion
o li es ock a ming on he sampled plo , ype and amoun o e iliza ion, ype and amoun o liming, ype
and dep h o g assland enewal, ype, numbe and du a ion o li es ock a ming on he sampled plo . cu ,
ype and dep h o g assland enewal, ype, numbe and du a ion o li es ock a ming on he sampled plo ,
ype and amoun o e iliza ion, ype and amoun o liming, ype and dep h o illage, addi ional measu es
such as d ainage, i iga ion, deep loosening, soil o plan addi i es, o al e na i e land use. The
ques ionnai es ecei ed a e quali y assu ed and, i in o ma ion is missing o oo inaccu a e, he a me s a e
con ac ed by elephone. This is also he case i ques ionnai es a e no ecei ed e en a e mul iple
eminde s. Since pa icipa ion in he BZE-LW is olun a y and comple ing he ques ionnai e equi es a
conside able amoun o e o , some a me s a e unwilling o pa icipa e. As a esul , he esponse a e o
he ques ionnai es is no op imal, bu his can only be in luenced o a limi ed ex en . To da e, 1,756
ques ionnai es ha e been sen ou and 889 ha e been comple ed and e u ned (51%).
Quali y assu ance and p ocessing o he managemen in o ma ion a e ongoing. Ha monizing he da a om
bo h ques ionnai es in o a consis en ime se ies is a pa icula ly challenging ask. Fo his eason, he ocus
Ma e ials and me hods 17
a his s age has been on a single pa ame e ha is cen al o SOC dynamics in c opland soils: he p opo ion
o ca ch c ops in c op o a ion. In o de o calcula e his end o all ques ionnai es ecei ed o da e and o
c ea e a gene al ime se ies, 1) only hose si es ha epo ed o a leas 5 yea s in bo h ime pe iods (be o e
he ini ial sampling and be ween samplings) we e used, 2) in he case o empo al o e laps be ween he
wo ques ionnai es, only in o ma ion om he second ques ionnai e was used, 3) he las wo yea s (2023
and 2024) we e igno ed due o he signi ican ly lowe sample size. This esul ed in a sligh ly di e en
numbe o ques ionnai es (223-368) o each yea be ween 2001 and 2022 o which in o ma ion on he
cul i a ion o ca ch c ops was a ailable. F om his, he p opo ion o loca ions whe e ca ch c ops we e
cul i a ed in a speci ic yea was calcula ed.
2.4 Ex e nal da a
2.4.1 Land use his o y
P e ious land use o land co e can ha e a s ong in luence on soil p ope ies and hei cu en empo al
dynamics (Emde e al., 2024) . Da a on land use his o y a he sampling poin s come om a ious sou ces.
One sou ce was he ini ial in en o y ques ionnai e, which al eady asked whe he in o ma ion on he
his o ical use o co e o he a ea was a ailable. A dis inc ion was made be ween c opland, g assland,
pe manen c ops, o es , moo land, hea hland, and o he uses. Since only some o his da a is a ailable o
oday's a me s, he ques ionnai e da a se con ained la ge gaps and did no go back u he han ou
decades on a e age. The e o e, a ious a chi es and eposi o ies o his o ical maps and o hopho os we e
consul ed in o de o ob ain as comple e a da a se as possible. The aim was o ha e land use in o ma ion
a ailable o e e y loca ion o a leas 100 yea s, e e y 30 yea s. Con inuous ime se ies we e gene a ed
om hese incomple e ime se ies by in e pola ion, om which app oxima e da es o land use changes can
be de i ed. Mo e de ailed in o ma ion on he gene a ion o his da a se is desc ibed by Emde e al. (2024).
This epo uses only pa o his da ase o enable meaning ul e alua ion: long- e m c opland and long-
e m g assland (no land use changes in he pas 136 yea s), as well as c opland wi h a g assland his o y and
g assland wi h an a able his o y in he pas 136 yea s. Loca ions wi h equen changes be ween c opland
and g assland we e excluded, as we e hose wi h o he his o ical land uses.
2.4.2 Clima e da a
Clima e condi ions a e highly ele an o he de elopmen o SOC s ocks, as hey di ec ly in luence
mic obial ac i i y and hus he deg ada ion kine ics o o ganic ma e in he soil on he one hand, and
biomass g ow h and hus he amoun o c op and oo esidues ha can be e u ned o he soil on he o he .
The wea he da a used he e comp ise mon hly a e age empe a u es (DWD, 2025a) and mon hly o als o
p ecipi a ion (DWD, 2025b) and sunshine du a ion (DWD, 2025c). The da a we e ob ained as g id maps wi h
a esolu ion o 1x1 km and o he pe iod 1970 o 2024 om he Open Da a Cen e o he Ge man Wea he
Se ice. Time se ies o he BZE-LW loca ions we e hen ex ac ed om hese maps. Global adia ion was
calcula ed om sunshine du a ion acco ding o (Allen e al., 1998) and po en ial e apo a ion was es ima ed
acco ding o Tu c (Wendling e al., 1991).
2.5 S a is ics
A e age changes in SOC con en , BD ine and SOC s ocks we e analyzed using a boo s apping me hod o
enable e o es ima ion and de e mine signi icance. Fo his pu pose, he change in a pa ame e be ween
he ini ial in en o y and he esampling was de e mined o all a ailable loca ions. F om hese n changes, a
18 Ma e ials and me hods
new sample was gene a ed by d awing n imes wi h eplacemen , and he mean alue was calcula ed. This
p ocess was epea ed a o al o 5000 imes, esul ing in 5000 boo s ap mean alues o he change. The
in e al be ween he 2.5% and 97.5% pe cen iles o he boo s ap means was de ined as he 95% con idence
in e al (CI95) o he mean change. I his in e al o change was comple ely beyond ze o, i.e., exclusi ely
in he posi i e o nega i e ange, he mean change was in e p e ed as signi ican (Ho e al., 2019). The
boo s apping me hod was chosen because i is nonpa ame ic, does no equi e no mal dis ibu ion o he
da a, and, in addi ion o signi icance, con idence in e als o he changes could also be calcula ed
(Çe inkaya-Rundel and Ha din, 2024). By swi ching om he ini ial p o ile pi o he su ounding co e
d illings (see Chap e 3), he spa ial a iabili y o he SOC con en s could be de e mined o bo h ime poin s.
Wi h his unce ain y, a minimum de ec able di e ence (MDD) could be calcula ed o each si e, which is
di ec ly p opo ional o he small-scale a iabili y o a gi en sample size and allows a s a emen o be made
abou he s a is ical signi icance o he measu ed SOC con en change. The o mula acco ding o (Valk e al.,
2000) was used o his pu pose:
𝑀𝐷𝐷=√(𝑍𝛼+𝑍𝛽)²×𝜎²
𝑛
Whe e α exp esses he s a is ical signi icance le el (he e α=0.05), β is a measu e o he p obabili y ha a
s a is ical e ec can be ound (1 - s a is ical powe , he e 0.8), and he Z- alue indica es how many s anda d
de ia ions a alue is om he mean o a s anda d no mal dis ibu ion. Wi h an α o 0.05, Zα is he 95%
pe cen ile o a s anda d no mal dis ibu ion and hus 1.96 s anda d de ia ions om he mean, while Zβ is
0.84 s anda d de ia ions om he mean. The s anda d de ia ion o he measu ed alues is included in he
o mula as σ, and n desc ibes he numbe o measu emen epe i ions. An MDD was de e mined o bo h
he ini ial BZE (8 soil co es) and he epea in en o y (n=4). The change in SOC con en was conside ed
signi ican i i was g ea e han bo h MDD alues.
To es whe he land use his o y had a signi ican e ec on he ecen change in SOC s ocks in 0-30 cm, an
analysis o a iance (ANOVA) o he changes was pe o med. The aim was o speci ically es whe he SOC
s ocks om long- e m c opland o long- e m g assland ha e a signi ican ly di e en dynamic han hose
wi h known land use change ( om c opland o g assland) o e he pas 136 yea s. The no mal dis ibu ion
o he esiduals was checked using QQ plo s. Due o he non-no mal dis ibu ion o he ANOVA esiduals, a
non-pa ame ic K uskal-Wallis es was pe o med wi h Wilcoxon as a pos hoc es .
Due o he educed size o he da a se (see Chap e 3), he limi ed spa ial ep esen a ion o he si es ha
ha e been esampled and analyzed o da e, and he ac ha only pa ial managemen in o ma ion is
a ailable, no global s a is ical model was calcula ed in his in e im epo o explain changes in SOC con en
and ese es, as well as o he soil p ope ies. Only simple co ela ion analyses (linea eg essions) wi h
indi idual soil p ope ies and changes in clima e a iables we e pe o med.
Resul s 19
3 Compa ison o SOC esul s om he ini ial p o ile pi and soil co es
An ini ial analysis o he changes in SOC con en and s ocks om he eigh ede al s a es sampled o da e
e ealed signi ican dec eases a e he i s esampling compa ed o he ini ial in en o y. This was obse ed
ega dless o land use. To e i y he plausibili y o he supposed ends, addi ional am co e sampling
(he eina e e e ed o as soil co es) om he ini ial in en o y was used whe e a ailable. I u ned ou ha
i) he de ia ion be ween he mean alue o he soil co es and he p o ile pi s ongly de e mined he
di e ence be ween he ini ial p o ile pi and he esampling, and ii) he di e ence be ween he esampling
and he ini ial co e sampling was on a e age signi ican ly smalle han he di e ence be ween bo h and he
ini ial p o ile pi (Fig. 3).
Figu e 3 Densi y unc ion o z- ans o med SOC con en s (uni o mly scaled pe si e and dep h le el,
wi h 0 as he mean alue o he si e ac oss all a ailable measu emen s) o he da a om
co e d illing and p o ile pi s om he ini ial in en o y, as well as he alues om he
epea in en o y.
Sou ce: Thünen Ins i u e
In addi ion, he di e ence be ween he ini ial p o ile pi and he esampling was mos p onounced a
p ecisely hose dep h le els ha had al eady been iden i ied as p oblema ic du ing he ini ial in en o y (10-
30 cm in c opland land and 0-10 cm in g assland) (Fig. 3). These dep h le els a e hose in which s ong
g adien s in SOC con en o en occu o which a e unde lain by signi ican ly SOC-poo dep h le els. I seems
likely ha sampling o he ini ial p o ile pi sys ema ically led o sligh ly lowe SOC con en s and SOC s ocks.
One possible explana ion is ha a eas poo e in SOC (appea ing ligh e in he p o ile) ended o be omi ed
o sampled disp opo iona ely.
20 Compa ison o SOC esul s om he ini ial p o ile pi and soil co es
Fu he mo e, he e is a su p isingly low deg ee o ag eemen be ween he SOC changes de e mined on he
basis o he esul s o he ini ial p o ile pi and he ini ial am co e d illing (Fig. 4). This also leads o he
conclusion ha he SOC con en s o he ini ial p o ile pi a e a poo e e e ence han he esul s om he
d ill co es. I was he e o e decided o emeasu e he SOC and N o con en s on some o he d ill co es ha
had no ye been analyzed ( ou o eigh d ill co es, h ee dep h le els) and o use he exis ing esul s om
he co e d illing as he ini ial alues o he SOC con en s o his epo . SOC changes a e now epo ed
acco dingly o 578 loca ions o which co e d illing om he ini ial in en o y and esampling a e cu en ly
a ailable (Fig. 4). I is unclea whe he o o wha ex en o he chemical soil p ope ies show simila
sys ema ic di e ences be ween he sampling me hods (p o ile pi o d ill co es). Changes in pH alues a e
he e o e no add essed in his epo , as hey ha e ye o be de e mined o he d ill co es. One ad an age
o his change is ha a es o change can now also be checked o signi icance on a si e-speci ic basis o
assigned an unce ain y alue, which allows o a be e classi ica ion o di e ences be ween he wo
in en o y ounds.
Figu e 4 Change in SOC s ock based on he co e d illing plo ed agains he change in SOC s ock
based on he ini ial p o ile pi wi h linea eg essions and co esponding co ela ion
coe icien s (R²). The dashed diagonal line ep esen s he 1:1 line. The sec ion selec ed o
be e isualiza ion (-20 o 20 Mg ha⁻¹) led o he exclusion o 15 si es in 0-10 cm, 51 si es
in 10-30 cm, and 66 si es in 30-50 cm. The eg essions a e no a ec ed by his.
Sou ce: Thünen Ins i u e
Resul s 21
Figu e 5 Loca ion o si es ha ha e al eady been esampled o which da a om he ini ial co e
d illing and he ele an analysis esul s om he epea in en o y a e a ailable.
Sou ce: Thünen Ins i u e
22 Resul s
4 Resul s
4.1 Tempo al dynamics o o ganic soil ca bon con en
The con e sion o SOC con en s om he co e d illing samples ini ially esul ed in a signi ican ly educed
sample size o he SOC pa ame e . O he o iginal 1,000 o so esampled and analyzed si es, an e alua ion
o SOC con en and s ock changes could be ca ied ou o a o al o 578 si es o which co e d illing da a
had al eady been collec ed (see Chap e 3). The undamen ally igh -skewed dis ibu ions o SOC con en s
in he h ee land uses and dep h le els and o bo h in en o ies a e shown in Fig. 6. The change in SOC
con en s is shown in Fig. 7 and Table A1. These a e app oxima ely no mally dis ibu ed. While he SOC
con en in he opsoil o c opland (0-10 and 10-30 cm) inc eased sligh ly (signi ican ly in 0-10 cm), signi ican
dec eases we e obse ed on a e age in he subsoil (30-50 cm). The mos signi ican o e all change in SOC
con en was obse ed in he opsoil o g assland soils, especially a a dep h o 0-10 cm. A signi ican dec ease
in SOC con en was obse ed a his dep h o he 140 g assland soils sampled o da e. Dec eases we e also
measu ed on a e age a he dep hs below. This was also ue o pe manen c ops, whe e he e was also a
endency owa d dec eases on a e age a all dep hs. Howe e , due o he small sample size o pe manen
c ops, his end could no be s a is ically e i ied.
Figu e 6 Dis ibu ion o SOC con en s om he ini ial in en o y and epea in en o y by dep h
le el and land use wi h median and mean alues.
Sou ce: Thünen Ins i u e
Resul s 29
A p elimina y e alua ion o he land use his o y showed ha p e ious use as c opland o g assland had a
signi ican in luence on he ecen dynamics o SOC s ocks a a dep h o 0-30 cm (Fig. 12). While c opland
wi h a g assland his o y ended o show SOC losses, he SOC s ocks o long- e m c opland (no land use
change in he las 136 yea s) ended o be in equilib ium. Con e sely, a clea nega i e end in SOC s ocks
was obse ed o long- e m g assland, which di e ed signi ican ly om g assland wi h a his o y o a able
use.
4.3 Changes in key en i onmen al and managemen in luences
4.3.1 Changes in clima ic condi ions
Since he 1970s, he mean annual empe a u e o he ai nea he g ound (2 m abo e g ound le el) has isen
signi ican ly a he 3104 BZE-LW si es (Fig. 13). While he mean annual empe a u e in he 1970s was 8.4°C,
i has been 10.5°C in he pas 5 yea s. A signi ican inc ease in he annual mean empe a u e has been
obse ed, pa icula ly in he las 15 yea s, ep esen ing a non-linea inc ease o e he pas 50 yea s (Fig.
A1). Acco dingly, po en ial e apo anspi a ion (e apo a ion) has also inc eased signi ican ly wi h each
decade. Annual p ecipi a ion, on he o he hand, has changed li le o e all, causing he annual clima ic
wa e balance o become mo e nega i e o smalle . The p opo ion o po en ially a id si es (mo e po en ial
e apo a ion han p ecipi a ion on a e age o e he calenda decade) has inc eased om 11% in he 1970s
o 23% in he pas i e yea s. C opland si es (26%) a e mo e a ec ed han g assland si es (14%). The spa ial
dis ibu ion o wa ming is much mo e homogeneous han he change in he clima ic wa e balance (Fig. A2).
The al eady d y eas o Ge many has become e en d ie o e he pas 50 yea s. Almos all BZE-LW si es in
B andenbu g and Saxony-Anhal , as well as pa s o Mecklenbu g-Wes e n Pome ania and Saxony (Fig. A3),
ha e been a id on a e age o e he pas 15 yea s. The p opo ion o a id si es has also inc eased signi ican ly
in Rhineland-Pala ina e, Hesse, and Ba a ia. In con as , he clima ic wa e balance in he a no h-wes o
Ge many has become mo e posi i e o e he pas 15 yea s. I can he e o e be assumed ha he e will be
egion-speci ic e ec s o changed clima ic condi ions on soil p ope ies.
4.3.2 Co e c opping
Acco ding o an ini ial e alua ion o he wo ques ionnai e da a se s, he p opo ion o c opland si es wi h
ca ch c ops has inc eased signi ican ly o e he pas 10 yea s (Fig. 14). While be ween 2000 and 2013 he
a e age was a ound 12% o si es, he da a om he epea in en o y ques ionnai e shows a clea upwa d
end. The pas wo yea s (2023, 2024) we e no included in he ime se ies due o insu icien da a, bu by
2022 he p opo ion o si es wi h a co e c op had isen o jus unde 20%.
30 Resul s
Figu e 13 Dis ibu ion o mean annual empe a u e, mean mon hly empe a u e, annual po en ial
e apo a ion, and annual clima ic wa e balance o all 3104 BZE-LW si es o he las six
calenda decades.
Sou ce: Thünen Ins i u e wi h da a om he Deu sche We e diens (DWD 2025a, b, c)
Figu e 14 Time se ies showing he p opo ion o si es wi h in e c opping o each yea in he pe iod
2001-2022. Blue = ini ial in en o y ques ionnai e, g een = epea in en o y ques ionnai e.
Whe e he wo ques ionnai es o e lapped (possible in he yea s 2011-2015), he
in o ma ion om he epea in en o y ques ionnai e was used o he sake o simplici y.
Discussion 31
5 Discussion
5.1 Soil ca bon dynamics in ag icul u al soils in Ge many
In he BZE-LW c opland si es analyzed epea edly, only small, albei in some cases signi ican changes in SOC
con en and s ocks ha e been obse ed. While he e was a sligh su plus o si es wi h a posi i e end (SOC
inc ease) in he opsoil (0-10 and 10-30 cm), sligh losses we e obse ed in he subsoil (30-50 cm). Analysis
o he minimum de ec able di e ence (MDD) o SOC con en e ealed ha a la ge p opo ion (60%) o he
changes obse ed a si e le el we e below he de ec ion limi (Fig. 8). This means ha no eliable s a emen s
can be made abou changes a hese si es. Fo hose si es wi h e y small changes in pa icula , his can be
in e p e ed as meaning ha he posi i e o nega i e end was mo e likely o be andom. Ne e heless, a
signi ican inc ease in SOC con en was obse ed in he 0-10 cm dep h o he c opland soils o 24% o he
si es, while only 16% o he si es showed signi ican SOC losses (Table 1). E en hough his was no e lec ed
in he a e age cumula i e SOC s ock o c opland soils (Fig. 9), i could be an indica ion ha bo h inc eased
in e c opping and mo e conse a ion-o ien ed, and hus shallowe , illage a e ha ing a ce ain posi i e
e ec . Acco ding o he Fede al S a is ical O ice, con en ional illage using plows has declined om 53% o
40% in Ge many o e he pas se en yea s (Des a is, 2025b). Conse a ion illage, o no- ill a ming, ensu es
a leas a edis ibu ion o SOC wi hin he soil p o ile, i.e., an en ichmen in he a ea o he highes C inpu s
(close o he su ace) and a endency owa d a dec ease in he a ea below (abandoned opsoil) (Meu e e
al., 2018). In e c opping has inc eased signi ican ly o e he pas decade a he BZE si es al eady sampled
(Fig. 14). This is consis en wi h s a is ics on a na ional scale: acco ding o he Fede al S a is ical O ice,
in e c opping has inc eased om jus unde 1.2 million hec a es o jus unde 2.2 million hec a es since
2010 (Des a is, 2024). This inc ease can be explained p ima ily by changes in ag icul u al subsidies and new
egula ions. Wi h he e o m o he Common Ag icul u al Policy in 2013, he c ea ion o ecological p io i y
a eas, including he cul i a ion o co e c ops, was speci ically p omo ed o he i s ime. In addi ion, wi h
he en y in o o ce o he new Fe ilize O dinance (2020), he cul i a ion o co e c ops be ween win e
and summe c ops has become manda o y in ni a e-pollu ed, so-called ed a eas. The e ec s o hese
posi i e de elopmen s in soil managemen on SOC con en s and s ocks can he e o e only be obse ed o
a limi ed ex en so a .
Despi e he sligh ly posi i e ends in SOC con en and s ocks a a dep h o 0-10 cm in c opland soils, he e
ha e been signi ican dec eases in SOC s ocks in all land use classes conside ed in he dep h ange ele an
o g eenhouse gas epo ing (0-30 cm) o e he pas decade. This is compa able o he esul s om o he
egions in Eu ope. Va ious na ional in en o ies (Fig. 15) and he Eu opean Commission's Eu ope-wide soil
in en o y (LUCAS Soil) cu en ly epo nega i e ends in SOC con en s and s ocks (De Rosa e al., 2024).
This also applies in pa o he long- e m soil moni o ing o he ede al s a es (Höpe and Meesenbu g, 2021;
Wiesmeie e al., 2025). The lack o measu able posi i e e ec s o imp o ed soil managemen on a e age
SOC con en s and s ocks in c opland soils, as well as he e en mo e p onounced loss o SOC om g assland
soils and hose unde pe manen cul i a ion, can ha e a ious causes.
32 Discussion
Figu e 15 Annual a es o change in a e age na ional SOC s ocks in a ious Eu opean coun ies and
Ge many o c opland and g assland in he espec i e in en o y pe iods, di e en ia ed by
opsoil, subsoil (de ined sligh ly di e en ly depending on he s udy) and he en i e soil
p o ile (i ele an ). The da a a e aken om a p e iously unpublished li e a u e e iew
and a e p esen ed he e in modi ied o m (Ha bo e al., submi ed).
Sou ce: Thünen Ins i u e
1) Inc easing co e c op cul i a ion om 10% o 20% o he annual cul i a ed a ea has a ela i ely small
e ec on he SOC ese es o all c opland soils. A sha e o 10% means ha , ma hema ically speaking, e e y
ield has a co e c op once e e y 10 yea s on a e age. Doubling his cul i a ion a ea is no only a posi i e
de elopmen o SOCin he soil, bu is also ele an o many soil and ecosys em unc ions (Shackel o d e
al., 2019) . Doubling he annual cul i a ion a ea means ha , on a e age, a co e c op is cu en ly cul i a ed
wice in 10 yea s. The a e age e ec o g een manu e om co e c ops on he SOC s ock is app oxima ely
0.3 Mg ha-1 y -1 wi h annual cul i a ion (Poeplau and Don, 2015). Howe e , i only one mo e co e c op was
g own in he pas decade, hen he expec ed e ec is e y small compa ed o o he possible e ec s on he
SOC s ock (see ollowing poin s) and compa ed o he magni ude o he andom sampling e o . The andom
sampling e o was es ima ed a an a e age o abou 3 Mg ha⁻¹ when sampling and esampling c opland
soils using h ee soil p o iles on he same day (Poeplau e al., 2022). In addi ion, he p opo ion o ca ch
c ops has no inc eased sha ply o e he las decade, bu a he g adually. I is he e o e likely ha he
e ec o an o e all doubling o he a ea unde ca ch c op cul i a ion on SOC s ocks is s ill oo small o be
de ec able as such in he epea in en o y o he BZE-LW on a na ional scale. Howe e , i in e c opping is
included in a la ge s a is ical model in he u u e, i is likely ha pa o he a iabili y in SOC s ock changes
will be explained by his end.
2) Clima e change is highly likely o ha e a nega i e impac on global SOC s ocks (Ga cía-Palacios e al.,
2021). In ecen decades, and especially in he cu en decade, Cen al Eu ope has wa med signi ican ly. An
inc ease in he annual mean empe a u e o 2°C since he 1970s has now been exceeded a all BZE-LW si es
Discussion 33
(Fig. 13 and Fig. A1). In he pe iod be ween he ini ial and epea in en o ies alone, a wa ming o he ai
nea he g ound o abou 1°C was measu ed. I has also been shown ha he soil empe a u e in c opland
soils ises mo e s ongly han he ai empe a u e (Do au e al., 2022). This has consequences o mic obial
ac i i y and hus he u no e o o ganic ma e in he soil.
Acco ding o model calcula ions and wa ming expe imen s in di e en clima e zones, he magni ude o he
ela i e loss o SOC due o wa ming is app oxima ely 3-5% pe °C inc ease in nea -su ace ai empe a u e
(Peplau e al., 2021; Poeplau and Dechow, 2023; Ve b igghe e al., 2022). Wi h an a e age ini ial SOC s ock
o 65 Mg ha-1 ini ial mean alue in 0-30 cm o he c opland si es sampled o da e would co espond o
app oxima ely 1.9-3.3 Mg ha⁻¹; o g asslands (ini ial mean alue o 89 Mg ha⁻1 his would al eady be 2.7-
4.5 Mg ha⁻¹. In addi ion, highe e apo a ion and an accumula ion o d y yea s in many places a e leading o
a end owa d d ie condi ions (Fig. A2), which can ha e a nega i e impac on yield o ma ion and hus on
C inpu s. Al hough he a e age yields o he mos impo an c ops ha e con inued o ise sligh ly o e he
pas 20 yea s, in e annual yield a iabili y has also inc eased signi ican ly, and he size o i iga ed c opland
in Ge many has isen om 370,000 hec a es in 2009 o a ound 500,000 hec a es in 2019 (Des a is, 2023).
In g asslands, wea he condi ions ha e a pa icula ly s ong in luence on biomass de elopmen (Liu e al.,
2023), and so he d y yea s o 2018 and 2022 esul ed in wo yea s o low yields in g asslands be ween he
wo sampling pe iods (Des a is, 2025a).
In a he d y loca ions, he pe manen dec ease in soil mois u e can ha e a nega i e e ec on he
mine aliza ion o SOC (Kuka e al., 2025), bu in a he we loca ions, he opposi e can also be he case
(Smi h e al., 2007; Van Wesemael e al., 2010), as d ying leads o inc eased ae a ion and hus s imula ion
o mic oo ganisms. The e ec s o apid clima e change a e complex, and a leas he empe a u e inc ease
is omnip esen o a simila ex en . Fo his eason, he empe a u e inc ease, o o he clima e a iables,
could no explain he a iabili y o SOCchanges in simple eg ession analyses (da a no shown). This will be
simila in mo e complex s a is ical models, which is why only he use o p ocess models can isola e he
po en ial clima e change signal in SOC dynamics om o he in luences. Howe e , i is impo an o ca e ully
check whe he hese models can co ec ly ep esen clima e change e ec s (Ha a uk e al., 2015). The ac
is ha , in many places, imp o ed soil managemen in he ace o ad ancing clima e change can no longe
be abou en iching SOC, bu me ely abou limi ing losses (Don e al., 2024b; Rigge s e al., 2021).
3) Changes in he SOC con en o he soil occu o e long pe iods o ime, which means ha pas condi ions
can pe sis o ha e a las ing e ec o a long ime, he eby also in luencing cu en ends (Fig. 12). A e
ex ensi e esea ch in o land use his o y, i was shown o he ini ial BZE da a se ha g assland o a able
land use can ha e an e ec las ing se e al decades (Emde e al., 2024). The new s eady s a e o he SOC
s ock in c opland soils a e g assland use was es ima ed a a ound 180 yea s. In line wi h his, he p esen
epo also showed ha ields ha had been used as g assland in he pas 136 yea s ended o lose SOC on
a e age, whe eas his was no he case o long- e m c oplands. A e e se end was obse ed o g assland
si es, which indica es he in luence o land use his o y.
Fundamen ally, and iewed o e a e y long pe iod o ime, all o oday's c opland soils a e highly likely o
ha e a his o y o highe SOC con en s (Sande man e al., 2017), which may con inue o ha e an impac o
his day. Fo example, losses o SOC in Finnish c opland soils ha e been linked o de o es a ion ha ook
place decades ago (Heikkinen e al., 2013). In con as , he e a e long- e m g asslands ha ha e p esumably
no been used as c opland due o si e cha ac e is ics. These si e cha ac e is ics include, o example,
wa e logging and low g oundwa e le els, which do no allow cul i a ion as c opland. In ac , pe manen
g asslands wi h high losses con ain an abo e-a e age numbe o ma shes and gley soils (da a no shown),
which also ha e ele a ed SOC s ocks due o high g oundwa e le els (Poeplau e al., 2020). Figu e 12 o he
land use his o y shown he e should he e o e no be misin e p e ed o mean ha plowing up g assland can
lead o a educ ion in SOC loss; he opposi e is ue. Ra he , i shows ha si e cha ac e is ics and land use
34 Discussion
his o y a e closely in e wined and ha bo h ha e an impac on ecen SOC dynamics.
SOC dynamics.
In no hwes e n Ge many in pa icula , he e we e massi e educ ions in he g oundwa e le el in he las
cen u y in o de o con e o me ly ma shy a eas and moo s o ag icul u al use. E en hough many o hese
soils a e now classi ied as mine al soils, some o hem a e e y SOC ich, and hei SOC s ocks a e ce ainly
no ye in equilib ium and he e o e end o decline. These losses a e unlikely o be o se by cul i a ion.
Many o hese soils a e also cha ac e ized by wide C:N a ios and a sandy ex u e and we e al eady
highligh ed as black sands in he ini ial BZE-LW (Poeplau e al., 2021; Vos e al., 2018). Acco dingly, changes
in SOC s ocks in all h ee land use classes ended o co ela e nega i ely wi h he ini ial C:N a io, he mean
SOC s ock, and he sand con en ( endency o SOC o dec ease a si es wi h a wide C:N a io, high SOC s ock,
and high sand con en ). These ini ial ends a e consis en wi h he esul s o long- e m obse a ions in
Lowe Saxony, whe e c opland and g assland si es close o g oundwa e (sandy gley soils) showed he
g ea es SOC losses compa ed o less sandy soils u he away om g oundwa e (Höpe and Meesenbu g,
2021). The highes losses o SOC in g assland soils shown in Fig. 15 also conceal he SOC - ich soils o he
Ne he lands, a egion bo de ing Lowe Saxony wi h compa able soil genesis.
Howe e , he high SOC con en s o he p edominan ly no hwes e n Ge man black humus sands may also
ha e o he causes and hus ha e di e en e ec s on he cu en dynamics. Fo example, sod cu ing was
e y widesp ead in Lowe Saxony, en iching he e y nu ien -poo sandy soils wi h o ganic ma e (Blume
and Leinwebe , 2004) . In addi ion, some o oday's c opland was once co e ed by hea hland, which may
ha e le behind e y s able o ganic ma e in he soil (Sp ingob and Ki chmann, 2010). A mo e de ailed
e alua ion o he land use his o y, oge he wi h a cha ac e iza ion o he o ganic ma e , will p o ide mo e
in o ma ion abou he po en ial SOC dynamics o hese soils in he u u e.
4) In addi ion o declining li es ock numbe s, mine al e iliza ion in Ge many has also been g adually
educed o e he pas decades. Ni ogen su pluses in he soil ha e hus allen om 177 kg pe hec a e o
ag icul u al land in he 1990s o a ound 77 kg in he ea ly 2020s (Fede al En i onmen Agency, 2024).
O e all, ni ogen inpu s in o ag icul u al sys ems and soils ha e also been educed na ionwide. These ends
can also be e lec ed in he dynamics o SOC con en s and s ocks in c opland and g assland soils i he
educed N inpu s mean lowe yields and hus less biomass inpu in o he soil. Va ious e iliza ion
expe imen s on bo h g assland and c opland soils ha e shown ha he SOC s ock is linea ly co ela ed wi h
he amoun o ni ogen e iliza ion and ha app oxima ely one kilog am o SOC is buil up in he soil pe
kilog am o mine al ni ogen e ilize (Kä e e e al., 2012; Poeplau e al., 2018) . Con e sely, ex ensi e
ag icul u al p oduc ion also ca ies he isk o a sh inking SOC ese e in a o o o he posi i e
en i onmen al e ec s. A p elimina y e alua ion o 45 g assland ques ionnai es om he epea in en o y
showed an a e age dec ease in ni ogen e iliza ion (o ganic and mine al) o 32 kg N (-19%) compa ed o
he ini ial in en o y (da a no shown). Howe e , whe he a educ ion in N e iliza ion has an e ec on
humus depends c ucially on i s yield e ec i eness. In he case o he educ ion o high N su pluses ha a e
ha m ul o he en i onmen and clima e, i can be assumed ha he yield and o ganic ma e e ec i eness
is low.
The SOC dynamics o a soil a e he e o e in luenced simul aneously by ecen soil managemen , indi idual
p e ious use o his o y, and changes in abio ic si e cha ac e is ics (Heikkinen e al., 2013). A mo e in-dep h
analysis o he ac o s con olling he SOC dynamics o he BZE-LW si es was no possible a his poin in
ime, o a he , i did no make much sense due o he s ill agmen ed da a si ua ion. In he cu en ly
sampled popula ion, he soils o Lowe Saxony play a majo ole in e ms o quan i y, which, as desc ibed,
a e s ongly in luenced by hei some imes e y speci ic his o y in e ms o hyd ology and land use. Fig. 10
clea ly shows ha he mos ex eme SOC changes also occu ed in his egion. I he e o e emains o be
seen whe he he esul s ob ained so a will be con i med o he whole o Ge many. The mean alues
Discussion 35
epo ed he e a e he e o e o limi ed signi icance and should no be ex apola ed as such. Howe e , he
ac ha a nega i e end in SOC s ocks was ound o all land uses and ac oss di e en egions sugges s
ha global wa ming is al eady ha ing a nega i e impac on SOC s ocks in ag icul u al soils in Ge many. This
has ecen ly been coun e ac ed in c opland soils, p ima ily h ough he inc eased cul i a ion o ca ch c ops,
while in g assland soils, changes in e iliza ion in ensi y and o ganic e iliza ion may ha e had an addi ional
nega i e impac on SOC s ocks (Poeplau e al., 2018).
5.2 An unscheduled cou se co ec ion in he ag icul u al soil condi ion su ey
A e y undamen al di icul y o la ge-scale soil moni o ing o e long pe iods o ime is ha many soil
p ope ies change ela i ely slowly and he e o e ela i ely li le pe uni o ime. The amewo k condi ions
o soil in en o ies, on he o he hand, can change signi ican ly om one i e a ion o he nex . In o de o
be able o de ec he small changes in soil p ope ies wi h ce ain y, an exac and, in he bes case,
unchanging p ocedu e in he ield and labo a o y is an impo an heo e ical p e equisi e, bu a ely a
eali y. Changes in poli ical, inancial, o ganiza ional, con en - ela ed, o analy ical condi ions all oo o en
lead o changes ha can ha e a mo e o less signi ican impac on he quali y o ime se ies. Classic examples
include changes in analy ical me hods, con ac labo a o ies, o e en indi idual de ices (E en e al., 2025;
Wollmann e al., 2025), he no en i ely accu a e eloca ion o si es (Heikkinen e al., 2020), a ia ion in he
numbe o si es (Poeplau e al., 2015), o e en changes in sampling dep h (Jones e al., 2024). Such se ious
changes should be a oided i possible o , i necessa y, mi iga ed by co ec i e unc ions. While he la e is
es ablished p ac ice o analy ical me hods, a di ec ional sampling e o can ha dly be co ec ed.
E en hough he BZE-LW has always placed g ea emphasis on consis ency and con inui y, i is no ee om
sys ema ic e o s. Du ing he e alua ion o he ini ial BZE-LW, i was al eady es ablished ha he wo
me hods used o de e mine SOC -con en s and SOC s ocks (p o ile pi s, co e d illing) led o di e en esul s.
This is no su p ising. I has al eady been shown elsewhe e ha he ype o sampling alone can ha e a
signi ican in luence on he esul o he analysis (Del Duca e al., 2025; Wal e e al., 2016). Howe e , he
e alua ion o he ini ial in en o y did no e eal which o he wo me hods is less p one o e o , as bo h
app oaches a e known o ha e s eng hs and weaknesses. In addi ion, only some o he co e d illing samples
could be p ocessed and measu ed due o esou ce cons ain s.
Fu he mo e, co e d illing is only o limi ed sui abili y o de e mining bulk densi y and s one con en , ii)
causes ela i ely ex ensi e damage o s anding c ops due o he use o la ge equipmen , iii) equi es a
g ea e amoun o manpowe , and i ) all o he pa ame e s we e also de e mined om he p o ile pi
samples, he epea in en o y was also ca ied ou using p o ile pi s. F om he ou se , ca e was aken o
ensu e ha a ep esen a i e sample was aken om each small es pi a he espec i e dep h le el. This
was achie ed by aking a uni o mly hick slice o soil ma e ial om he p o ile wall o e he en i e leng h o
he pi . In he ini ial in en o y, his was also heo e ically he case, bu wi h one impo an es ic ion: a
ha ime, an a emp was made o ca y ou coupled sampling o dep h le els and diagnos ic ho izons so
ha bo h a ian s could be e alua ed. Howe e , addi ional samples we e only aken a so-called
in e media e dep h le els when he e was a dis ance o i e cm o mo e be ween he ho izon and dep h
le el bounda ies. I , o example, a plow ho izon ended a 27 cm and he dep h le els o he plow ho izon
o be sampled we e 0-10 and 10-30 cm, he o icial ask was o sample he lowe h ee cen ime e s o he
dep h le el o he same ex en and o mix i wi h he 10-30 cm sample.
The g ea es de ia ions be ween he p o ile pi and co e d illing in he ield we e indeed ound p ecisely in
he 10-30 cm dep h le el. In g assland, i is he 0-10 cm dep h le el whe e he e is also a s ong e ical
g adien in he SOC con en o he unde lying soil ma e ial. Unde ce ain ci cums ances, he inclusion o
36 Discussion
ho izon bounda ies in dep h-speci ic sampling may ha e led o un ep esen a i e dep h samples in some
cases. Such an e o is uled ou in sampling wi h d ill co es, as sampling was ca ied ou p ecisely acco ding
o dep h le els and no selec ion can be made du ing d illing as o whe e exac ly he sample ma e ial is aken.
Due o he ixed posi ions o he eigh d ill co es, his is a sys ema ically andom sampling (B us and Saby,
2016) . The e alua ion o he epea in en o y now sugges s ha sampling wi h d ill co es does indeed
p o ide he mo e s able and accu a e SOC con en s o he sampled plo s. E en hough he absolu e
di ec ed de ia ion be ween p o ile pi s and am co e sampling in SOC con en in he mos a ec ed dep h
le els was only 1-2 g kg-1 i.e., abou 0.1-0.2 pe cen age poin s SOC (Jacobs e al., 2018), his has a ela i ely
s ong impac on he SOC s ock and i s change. The e o e, his sys ema ic de ia ion canno be igno ed and
mus esul in an adjus men o he me hodology. In he case o he e alua ion p esen ed he e, i was
decided o combine he ad an ages o bo h sampling sys ems o he ini ial soil in en o y (soil p o ile, d ill
co es) in o de o de e mine he s ocks o o ganic soil ma e . The d ill co es om he co e d illing we e
used o eco d he SOC con en s a de ined dep h le els, while he d y bulk densi y was eco ded a he
cen al soil p o ile.
As a di ec consequence, he numbe o si es ha could be e alua ed o his in e im epo (si es wi h
al eady analyzed d ill co es) dec eased, and i became necessa y o ini ia e emeasu emen s o he samples
om he co e d illing. As shown in Fig. 5, in which he e a e only e y weak co ela ions be ween he SOC
changes based on p o ile pi s and co e d illing, he e a e also ad an ages o aking his ime-consuming s ep
. A single p o ile pi , e en in a cen al posi ion, canno adequa ely ep esen a plo (now 12x12 m) due o
known small-scale a iabili y and, pe se, in oduces a high deg ee o andom unce ain y in o he da a se .
E en a sligh posi i e de ia ion o he SOC con en in he pi om he plo mean al eady inc eases he
p obabili y o a nega i e end in esampling and ice e sa (Slessa e e al., 2023). Spa ial eplica ion is
he e o e impo an e en in he smalles plo s (Poeplau e al., 2022). Spa ial eplica ion wi h subsequen
analysis o all indi idual samples has he g ea ad an age o e a mixed sample in ha he small-scale
a iabili y a he speci ic loca ion is known and hus an unce ain y can be speci ied o each in en o y un.
This can be used o s a is ically alida e measu ed changes a he si e and hus suppo he in e p e a ion
o obse a ions. I can e en be used o de elop speci ic sampling s a egies. Fo example, he p esen
e alua ion has shown ha he minimum de ec able di e ence (MDD) in g assland soils ends o be highe
han in c opland soils. One could conclude om his ha he numbe o samples in g assland soils should
be highe han in c opland soils. Howe e , since he di e ences in MDD be ween indi idual si es wi hin each
land use a e e en mo e ex eme han he di e ences be ween land uses, his is no necessa ily expedien .
Discussion 37
6 Ou look
A his s age o he p ojec , no ep esen a i e pic u e o changes in soil p ope ies o ag icul u al soils in
Ge many has ye eme ged. Ini ial ends ha e been obse ed and possible causes iden i ied. In addi ion o
expanding and imp o ing he da a se , a main objec i e in he coming p ojec phase will be o del e deepe
in o esea ching he causes and explaining changes in key soil p ope ies. The sepa a ion o he in luences
o ecen soil managemen , clima e change, and si e his o y on obse ed changes in soil p ope ies plays a
cen al ole. The sys ema ic use o he collec ed managemen da a, as well as o he ex e nal da a (e.g.,
emo e sensing p oduc s) in p ocess models and s a is ical app oaches will play an impo an ole in his.
Only by using a b oad me hodological spec um can complex and o e lapping spa ial pa e ns be esol ed
in o de o ul ima ely classi y obse ed changes and inco po a e hem in o poli ical decision-making
p ocesses. The second phase o he BZE-LW epea in en o y (un il 2030) also p esen s some pa icula
challenges:
This epo has ocused hea ily on he pa ame e SOC. This pa ame e emains o cen al impo ance o
cu en epo ing equi emen s. Howe e , a numbe o o he pa ame e s a e also being collec ed ha a e
mo e o less closely ela ed o SOC and will p o ide addi ional insigh s ele an o p ac ice, policy, and
science on he de elopmen o ag icul u al soils. These include pH alues, ca ion exchange capaci y, and
base sa u a ion, which p o ide in o ma ion abou he nu ien supply and liming equi emen s o soils; ai
capaci y o he subsoil and agg ega e s abili y o he opsoil as s uc u al pa ame e s; and he quali y o
o ganic ma e . The gene al decline in d y bulk densi y epo ed he e (Table A4) mus also be in es iga ed
and unde s ood in mo e de ail. A simila end was obse ed o c opland and g assland soils in he F ench
soil in en o y (RMQS), bu his has also no ye been explained (Mune a-Eche e i e al., 2025). Due o he
implica ions o SOC s ock calcula ions, he a o emen ioned s udy sugges ed wo king wi h unchanged d y
bulk densi y alues in his case. In he nex phase o he BZE-LW p ojec , a compa ison o di e en me hods
o calcula ing SOC s ocks could p o ide in o ma ion on he in luence o a ia ions in he handling o d y
bulk densi ies on changes in SOC s ocks.
The Soil Moni o ing Law is an impo an en i onmen al policy inno a ion o he Eu opean Union, which
aims o ha monize soil p o ec ion on a con inen al scale and s eng hen i in a legally binding manne . A
his poin in ime, i is unce ain how he Soil Moni o ing Law will a ec soil moni o ing in Ge many as a
whole, and in pa icula he epea in en o y o he BZE-LW. Redensi ica ion and expansion o he g id,
sho ening o he sampling in e al o six yea s, new pa ame e s, and land use classes will inc ease he cos
o soil moni o ing in Ge many, wi h exis ing sys ems in Ge many o ming an impo an basis.
In addi ion o he Soil Moni o ing Law, wo u he epo ing obliga ions ha e ecen ly been in oduced o
which he BZE-LW can and will p o ide da a: he i s is he Ge man adap a ion s a egy o clima e change,
which has se conc e e, measu able a ge s o he i s ime since 2024. One o he a ge s is o p e en
SOC losses om Ge man ag icul u al soils. An e en mo e ambi ious a ge has been se by he Na u e
Res o a ion Law: he e, c opland soils should show an upwa d end in SOC con en s on a e age.
38 Ou look
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Appendix 45
Figu e A1: A) Di e ence in a e age annual empe a u e be ween he pe iods 1970-79 and 2020-24
o all BZE-LW loca ions; B) Linea slope o a e age annual empe a u e o e he las six
calenda decades.
Sou ce: Thünen Ins i u e wi h da a om he Deu sche We e diens (DWD 2025a)
46 Appendix
Figu e A2: A) Di e ence in a e age annual clima ic wa e balance be ween he pe iods 1970-79 and
2020-24 o all BZE-LW si es; B) Linea slope o annual mean empe a u e o e he las six
calenda decades.
Sou ce: Thünen Ins i u e wi h da a om he Deu sche We e diens (DWD 2025a, b, c)
Appendix 47
Figu e A3: Classi ica ion o all si es as po en ially a id (nega i e annual clima ic wa e balance) and
humid (posi i e annual clima ic wa e balance) o he las six calenda decades.
Sou ce: Thünen Ins i u e wi h da a om he Deu sche We e diens (DWD 2025a, b, c)
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