methane and nitrous oxide fluxes, and carbon dioxide production in boreal forest soil fertilized...

Methane and nitrous oxide fluxes, and carbon dioxideproduction in boreal forest soil fertilized with wood ash andnitrogen

M. Maljanen1

, H. Jok inen2

, A. Saar i1

, R. Str ommer2

& P. J . Mart ika inen1

1Department of Environmental Sciences, University of Kuopio, Bioteknia 2, PO Box 1627, FI-70211 Kuopio, Finland, and2Department of Ecological and Environmental Sciences, University of Helsinki, Niemenkatu 73, FI-15140 Lahti, Finland

Abstract

Wood ash has been used to alleviate nutrient deficiencies and acidification in boreal forest soils. How-

ever, ash and nitrogen (N) fertilization may affect microbial processes producing or consuming green-

house gases: methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2). Ash and N fertilization

can stimulate nitrification and denitrification and, therefore, increase N2O emission and suppress CH4

uptake rate. Ash may also stimulate microbial respiration thereby enhancing CO2 emission. The fluxes

of CH4, N2O and CO2 were measured in a boreal spruce forest soil treated with wood ash and/or N

(ammonium nitrate) during three growing seasons. In addition to in situ measurements, CH4 oxidation

potential, CO2 production, net nitrification and N2O production were studied in laboratory incuba-

tions. The mean in situ N2O emissions and in situ CO2 production from the untreated, N, ash and

ash + N treatments were not significantly different, ranging from 11 to 17 lg N2O m)2 h)1 and from

533 to 611 mg CO2 m)2 h)1. However, ash increased the CH4 oxidation in a forest soil profile which

could be seen both in the laboratory experiments and in the CH4 uptake rates in situ. The mean in situ

CH4 uptake rate in the untreated, N, ash and ash + N plots were 153 ± 5, 123 ± 8, 188 ± 10 and

178 ± 18 lg m)2 h)1, respectively.

Keywords: Haplic podzol, wood ash, carbon dioxide, fertilization, methane, nitrate, ammonium,

nitrous oxide

Introduction

Methane (CH4), nitrous oxide (N2O) and carbon dioxide

(CO2) are greenhouse gases. CH4 has a 23 times and N2O a

296 times greater warming effect than that of CO2 over a

100-year time horizon (IPCC, 2001). CH4 is produced in

soils by anaerobic methanogenic microbes and consumed by

aerobic methanotrophic bacteria (Le Mer & Roger, 2001).

Well-drained forest soils are globally important sinks for

atmospheric CH4, as the sink strength (about 30 Tg CH4) is

similar to the annual increase (22 Tg CH4) in atmospheric

CH4 (IPCC, 2001; Le Mer & Roger, 2001) and thus any

changes in sink strength may be critical for global warming.

Although N2O emissions from boreal upland forest soils are

generally small (Klemedtsson et al., 1997; Simpson et al., 1997;

Brumme et al., 2005), possible changes in microbial processes

responsible for N2O production (nitrification, denitrification;

Davidson, 1991) also raises concern about global warming.

The Finnish wood industry and bioenergy production

annually produce approximately 300 000 t of wood ash. This

creates a remarkable waste problem, but the ash could be

recycled in forests as fertilizer (Malkonen, 1996; Demeyer

et al., 2001). Wood ash contains nutrients such as K, Ca,

Mg and P (e.g. Levula et al., 2000; Demeyer et al., 2001;

Saarsalmi et al., 2001). Ash may also improve the water-

holding capacity of coarse-textured soils (Pathan et al.,

2003). Wood ash contains heavy metals, such as cadmium

(Cd), and, therefore, it is considered as an environmental risk

in forests (Pasanen et al., 2001). Wood ash has been used to

counteract soil acidification and to improve nutrient balance

in nutrient-poor forest sites (Malkonen, 1996; Demeyer

et al., 2001; Saarsalmi & Malkonen, 2001). N fertilizers

have been used in Finnish upland forests since the 1960s

to improve timber production (Finnish Forest Research

Institute, 2000). Because of the lack of N in wood ash,Correspondence: M. Maljanen. E-mail: [email protected]

Received August 2005; accepted after revision February 2006

Soil Use and Management, June 2006, 22, 151–157 doi: 10.1111/j.1475-2743.2006.00029.x

ª 2006 The Authors. Journal compilation ª 2006 British Society of Soil Science 151

applying wood ash together with nitrogen has been suggested

as a novel practice for fertilizing forests.

A disadvantage of applying wood ash and nitrogen may

be the stimulation of microbial activities such as respiration

(Martikainen et al., 1994; Fritze et al., 2000; Zimmermann &

Frey, 2002), nitrification and denitrification (Martikainen,

1985; Schutter & Fuhrmann, 1999) in forest soil. Nitrifica-

tion and denitrification are the microbiological processes pro-

ducing N2O. By increasing N mineralization, ash may,

however, decrease CH4 oxidation as ammonium (NH4þ) is a

potential inhibitor of this process (Steudler et al., 1989; Saari

et al., 1997).

We hypothesized that wood ash would decrease CH4 oxi-

dation potential in forest soil and thus decrease in situ CH4

uptake rate. Wood ash stimulates microbial respiration, nitri-

fication and denitrification and, therefore, may increase N2O

and CO2 emissions. As nitrogen fertilization may enhance

nitrification and denitrification and it may inhibit CH4 oxida-

tion, we further hypothesized that N would strengthen the

effects of wood ash. We studied the effects of ash and N on

the fluxes of these gases in a spruce forest during three grow-

ing seasons. In addition, laboratory incubations were used to

examine the effects of ash or N applications to forest soil on

the microbial processes responsible for the gas fluxes.

Materials and methods

Study site

The study site was located in southern Finland (61�19¢N,

24�97¢E) on a Haplic podzol developed in unsorted postglacial

deposit. The dominant tree species are Picea abies (87%),

Betula pendula (9%) and Pinus sylvestris (4%). The mean

depth of the organic (O) horizon is 3.1 cm. Mineral (eluvial

and illuvial) horizons under the O horizon are incompletely

formed and thus the O horizon is partly mixed with mineral

soil. The concentrations of total C and N were 130 and

5.9 mg g)1 in the O horizon, and 48 and 0.20 mg g)1 in the

uppermost mineral soil (A) horizon, respectively. Organic mat-

ter content in the A horizon was 56% and in the uppermost A

horizon 13%. The mean annual precipitation in the area is

680 mm and the mean annual air temperature 3.3 �C (Finnish

Meteorological Institute, 2002).

The experiment followed a randomized block design with

factorial treatments. Three randomly established blocks were

set up, each consisting of four plots of 30 m · 30 m in size

with buffer zones of 5 m between the plots. The treatments

were an unfertilized control, ash (7000 kg ha)1 of loose

wood ash corresponding to 30 kg P ha)1), nitrogen

(200 kg N ha)1, 50% as NH4þ and 50% as NO3

�) and both

together. The applications were made by hand in early June

2000. After treatment application, soil physical and chemical

characteristics were determined for background data

(Tables 1 and 2).

Gas flux measurements in the field

The chamber measurements for the gas fluxes were per-

formed on permanent subplots at each experimental plot

once a month (June, July and August) in 2000, 2001 and

2003. The first measurements in 2000 were made 3 weeks

after treatment application. The soil temperatures at depths

of 3, 5 and 10 cm and air temperatures were recorded (Fluke

51 K J)1 thermometer; Fluke Corporation, Everett, WA,

USA) simultaneously with the gas flux measurements.

The fluxes of N2O, CH4 and CO2 were measured simulta-

neously by a static dark chamber method. The chamber was a

galvanized steel cylinder (diameter 30 cm, height 30 cm) cov-

ered with a gas tight plastic lid with two holes closed with a

rubber septum. The holes were opened and the sharp edge of

the chamber was twisted into the soil to depth of 3–5 cm. Gas

samples (40 mL) were drawn from the headspace of the cham-

bers with 50-mL polypropylene syringes (Terumo Medical

Corporation, Tokyo, Japan) equipped with a 3-way stopcock

(Connecta Corporation, Indianapolis, IN, USA) 5, 15 and

Table 1 Chemical characteristics of the O horizon in control (C),

ash, nitrogen (N) and ash + N treatments. The concentrations of

exchangeable cations in the O horizon were analysed from pooled

samples for each treatment using acid ammonium-acetate extracts

and an inductively coupled plasma (ICP) method (512 P) at the Geo-

logical Survey of Finland in 2003. Values are in mg kg)1

Treatment K Ca P Mg Mn Cd Na Al

C 742 5 170 93 586 407 0.15 19.3 139

Ash 867 8710 102 822 316 0.29 91.7 265

N 772 5830 130 602 510 0.19 23.4 82

Ash + N 932 11 300 178 851 384 0.40 135 346

Table 2 The mean soil pH (0.01 M CaCl2 suspension 1:5) and

ammonium and nitrate concentrations (1 M KCl extracts, calorimet-

ric analysis with a Lachat automated N analyser; Lachat Instru-

ments, Hach Company, Loveland, CO, USA) in the O and A

horizons in control (C), ash, nitrogen (N) and ash + N treatments.

Soil samples (pooled from 10 random subsamples) from each

treatment were taken in autumn 2001 three months after treatment

application

Treatment

pHCaCl2

NH4þ-N

(lg g)1 DW)

NO3�-N

(lg g)1 DW)

O A O A O A

C 3.6 3.7 34 2.3 2.3 0.3

Ash 4.3 3.7 33 4.8 0.5 0.1

N 3.6 3.6 82 25.0 17.0 14.0

Ash + N 4.1 3.7 65 12.0 8.5 4.2

152 M. Maljanen et al.

ª 2006 The Authors. Journal compilation ª 2006 British Society of Soil Science, Soil Use and Management, 22, 151–157

25 min after the chambers were closed. The gas concentrations

were analysed within 24 h of sampling with a gas chromato-

graph (Hewlett-Packard 5890 Series II; Hewlett-Packard, Palo

Alto, CA, USA) equipped with flame ionization (FI), electron

capture (EC) and thermal conductivity (TC) detectors (Saari

et al., 1997). The flux rates were calculated from the linear

changes in the gas concentrations. Compressed air containing

2.16 ppm CH4, 452 ppm CO2 and 0.375 ppm N2O was used

for hourly calibration. The negative CH4 flux from soil to

atmosphere is here referred to as CH4 uptake rate.

Laboratory incubations

The N2O and CO2 production and net nitrification in the O

horizon (0–3 cm) were measured using a soil slurry technique

for soils collected in autumn 2001. Samples were stored at

)20 �C for 16 months. Three replicate samples, each consist-

ing of 15 mL of field-moist soil and 100 mL of distilled water

in 550-mL infusion flasks were incubated at 20 �C in a

shaker (175 rpm). At the beginning of the experiment a 10-

mL sample for NO3� analysis was taken from the liquid

phase after 1 hour of shaking, after which the flasks were

sealed with a rubber septum, and air added to give an over-

pressure of 23 kPa. Gas samples (20 mL) were taken from

the headspace of the bottles immediately after closing them

and after 92 h. The gas concentrations were analysed by gas

chromatography as described above. N2O and CO2 produc-

tion were calculated as a difference between these two samp-

ling occasions. Samples for NO3� analysis were taken again

after 166 h. The soil slurry samples were centrifuged for

20 min (2000 rpm) and the concentrations of NO�3 in the

supernatant liquid determined by ion chromatography (Dio-

nex DX-120; Dionex Corporation, Sunnyvale, CA, USA).

Preliminary tests showed that the O horizon (0–3 cm) in

this soil did not consume CH4 (A. Saari, unpubl. data). Thus

the CH4 oxidation potential and CO2 production were deter-

mined only from the A horizon samples (3–10 cm) collected

in autumn 2003 and stored at +4 �C for 2 weeks. A 20-g

sample of field-moist soil was placed in a 550-mL infusion

flask (two replicates) and CH4 was added to the bottles

through the rubber septum to achieve a headspace concen-

tration of 10 ppm. Air (100 mL) was added to enable samp-

ling. The bottles were incubated at 20 �C and the gas

samples (20 mL) from the headspace of the bottles were

taken through the rubber septum with a 50-mL syringe 0, 2

and 4 h after CH4 addition. The CH4 oxidation potential

and CO2 production rate were calculated from the decrease

(CH4) or increase (CO2) in the gas concentrations in the

headspace during the first 4 h of incubation.

Statistical methods

Two-way repeated-measures analysis of variance (ANOVA)

was used to analyse the responses of the dependent variables

over the 3-year period after treatment applications in the

field. The independent variables were the sampling time and

its interactions with the treatments (within-subject factors)

and ash and N treatments and their interactions (between-

subject factors). The correlation between the variables, and

soil and air temperatures on each sampling occasion was cal-

culated using Spearman’s correlation coefficient. The laborat-

ory incubations were analysed using two-way ANOVA with

ash and N and their interactions as between-subject factors.

In the event of significant interaction between the factors, a

simple effects ANOVA (Zar, 1999) was applied. The hetero-

geneity of the variances was determined using the Levene test

(Levene, 1960). The statistical tests were performed using the

SPSS statistical package (SPSS, 2001).

Results

CH4 uptake rates and oxidation potential

In situ CH4 uptake rates (mean ± standard error) in the

control, ash, nitrogen and ash + nitrogen treatments were

153 ± 5, 188 ± 10, 123 ± 8 and 178 ± 18 lg m)2 h)1,

respectively. Wood ash significantly increased CH4 uptake

rate (P ¼ 0.006), but nitrogen had no effect, and there was

no interaction between the factors. The variation between

the sampling occasions was significant (P < 0.001, Figure 1).

The CH4 uptake rate increased with increasing soil tempera-

ture in all treatments (Figure 1), as exemplified by the con-

trol (Table 3). In the laboratory incubation with field-moist

soil from the A horizon, ash significantly increased the CH4

oxidation potential (P ¼ 0.020) but nitrogen had no effect

(Figure 2a).

N2O fluxes and net nitrification

Ash or nitrogen did not affect the in situ N2O emissions

(mean ± standard error 14.0 ± 4, 11.2 ± 3, 14.5 ± 4 and

16.7 ± 5 lg m)2 h)1 in the control, ash, nitrogen and ash +

nitrogen treatments, respectively; Figure 1). The variation

between the sampling occasions was significant (P ¼0.014) but N2O emissions did not correlate with the soil or

air temperatures (Table 3). In the laboratory incubation of

slurried O horizon nitrogen increased N2O production (P ¼0.009) and net nitrification (P ¼ 0.013) (Figure 3a,b).

CO2 production rates

Ash or nitrogen did not affect the in situ CO2 production

rates, which were 611 ± 13, 533 ± 28, 594 ± 27 and

516 ± 55 mg CO2 m)2 h)1 (mean ± standard error), in the

control, ash, nitrogen and ash + nitrogen treatments,

respectively. The variation between the sampling occasions

was significant (P < 0.001) and the CO2 production rates

correlated positively with the air and soil temperatures at

Effect of wood ash on greenhouse gas emissions from forest soils 153


each sampling occasion (Figure 1), as exemplified by the con-

trol (Table 3). In the laboratory incubation with field-moist

soil from the A horizon, there was significant interaction

between ash and nitrogen (P ¼ 0.023) but the individual

effects were not significant (Figure 2b). In the laboratory

incubation of slurried O horizons ash or nitrogen did not

affect the CO2 production rate (Figure 3c).

Discussion

In our study, the CH4 uptake rate was very high in all soils,

including the N-fertilized plots, compared with other boreal

forests (e.g. Kasimir-Klemedtsson & Klemedtsson, 1997;

CO

2 flu

x ra

te (

mg

m–2

h–1

)C

H4

flux

rate

(µg

m–2

h–1

)N

2O fl

ux r

ate

(µg

m–2

h–1

)

0

200

400

600

800

1000

0

20

40

60

80(a)

(b)

(c)

(d)

ControlAshNAsh+N

–250

–200

–150

–100

–50

0

Jun

2000

Jul 2

000

Aug 2

000

Jun

2001

Jul 2

001

Aug 2

001

Jun

2003

Jul 2

003

Aug 2

003

Tem

pera

ture

(°C

)

0

5

10

15

20

25

30

Pre

cipi

tatio

n (m

m)

0

50

100

150

200

250Air temperatureSoil temperature (5 cm)Monthly precipitationMonthly mean air temperature

Figure 1 N2O emission (a), CH4 uptake rate

(b) and CO2 production rate (c) from con-

trol, ash, nitrogen and ash + nitrogen treat-

ments during three growing seasons. Air and

soil temperature at 5 cm depth measured

simultaneously with gas sampling occasions,

monthly mean temperature and monthly

precipitation are shown in (d). Mean and

standard error for replicate plots, n ¼ 3.

Table 3 Spearman’s correlation coefficients between CH4 uptake rate

(CH4) (designated here as positive), N2O emission (N2O), CO2 pro-

duction rate (CO2) and soil and air temperatures in the control plots,

n ¼ 3

CH4 CO2 N2O

CO2 0.070

N2O )0.131 )0.075TAir 0.010 0.515** 0.316

T3 cm 0.463* 0.504** 0.158

T5 cm 0.503** 0.454* 0.005

T10 cm 0.493** 0.366 )0.031

*P < 0.05; **P < 0.01.



Saari et al., 1998; Brumme et al., 2005). The laboratory incu-

bations showed that CH4 was oxidized in the upper mineral

layer of the forest soil, thus supporting several previous

studies, e.g. Saari et al. (2004) and Kahkonen et al. (2002).

The in situ CH4 uptake correlated well with mineral soil tem-

peratures reflecting the importance of this soil layer in CH4

oxidation.

Ash application enhanced the in situ CH4 uptake and also

increased CH4 oxidation rate in the laboratory incubations.

Contrary to our hypothesis, wood ash and nitrogen applica-

tion did not decrease in situ CH4 oxidation potential or

uptake rate. Several forest management practices have a

potential to change CH4 uptake rates or CH4 oxidation

potential, e.g. clear cutting may decrease (e.g. Kahkonen

et al., 2002; Huttunen et al., 2003; Saari et al., 2004), but

burning may enhance them (Burke et al., 1997; Bosse &

Frenzel, 2001). Liming has been found to enhance (Borken

& Brumme, 1997) or decrease (Butterbach-Bahl & Papen,

2002) CH4 uptake rates. In some cases, liming combined

with nitrogen application have been found to have no effect

on soil CH4 uptake rate or the effects are variable (Kasimir-

Klemedtsson & Klemedtsson, 1997; Saari et al., 2004). The

effects of forest management practices, in general, thus still

seem to be unpredictable.

The mean in situ N2O emission from the control in our

experiment, 15 lg m)2 h)1, was much higher than the mean

emission reported for boreal upland forest soils,

3.0 lg m)2 h)1 (Brumme et al., 2005). The levels were similar

to those measured from drained nutrient-rich peatland for-

ests in Finland (Martikainen et al., 1993; Huttunen et al.,

2003; Maljanen et al., 2003). The N2O emissions from forest

soils in Finland are not well documented, and are generally

thought to be small. Our results show that fertile forest soils

may emit substantial quantities of N2O indicating that over-

all N2O emissions from Finnish forests are probably underes-

timated.

The in situ N2O emissions were not increased by ash alone

or by ash together with nitrogen, as we hypothesized, even

when the NH4þ and NO3

� concentrations in the O horizon

of the nitrogen treatment and pH of the ash treatment were

greater than those in the control (Table 2). The effects were

negligible although the amounts of wood ash and nitrogen

applied here were greater than generally used in forest soils

in Finland (Saarsalmi & Malkonen, 2001). Increased N2O

emission because of increased soil pH (Struwe & Kjøller,

1994) was not supported by our results. In the laboratory

incubations nitrogen enhanced nitrification. The higher avail-

ability of NO3� could enhance N2O production, which was

seen in laboratory incubations but not in the in situ measure-

ments. Explanation for this apparent discrepancy may be

that in the boreal forest soils, the additions to the pool of

available nitrogen are rapidly used by plants and microbes.

Because N2O production and emissions in situ are highly

variable (Brumme et al., 2005), it is possible that during the

critical high emission periods, e.g. during freezing and during

thawing of soil, the differences between treatments can be

pronounced. However, these winter emissions are not

known.

In the present study, wood ash fertilization did not

increase soil respiration in contrast to previous findings

(Baath & Arnebrant, 1994; Fritze et al., 1995; Zimmermann

& Frey, 2002). In this kind of nutrient-rich forest site other

factors than nutrients or acidity may thus be limiting the

decomposition processes and root activity, the two processes

which are mainly responsible for the CO2 production from

soil. Large variations in the in situ measurements of CO2

production were noticeable, and seemed to be related to var-

iations in surface soil temperatures in the O horizon; CH4

production rates, on the other hand, were better related to

the mineral soil temperatures.

Ash application increases the concentration of exchange-

able Cd in mineral soils (Pasanen et al., 2001). However,

CH

4 upt

ake

rate

(ng

g–1

h–1

)

0

10

20

30

40

50(a)

(b)

Without nitrogenWith nitrogen

Without ash With ash

CO

2 pr

oduc

tion

(µg

g–1 h

–1)

0

1

2

3

4

5

Figure 2 CH4 oxidation potential (a) and CO2 production rate (b) in

laboratory incubation with field-moist soil from the A horizon

(depth 3–10 cm). Mean and standard error, n ¼ 3.



in the present study, ash stimulated the CH4 uptake rate

and oxidation potential even though the concentration of

exchangeable Cd was higher in the ash treatment than that

in the control (Table 1). Thus, our results support the sug-

gestion that ash may protect soil microflora from the

harmful effects of Cd (Fritze et al., 2000; Perkiomaki

et al., 2003).

In conclusion, wood ash or N application did not increase

in situ N2O or CO2 emissions whereas ash increased the in

situ CH4 uptake rate in boreal forest soil. These results show

that in this type of fertile forest soil, wood ash can be

applied without increasing greenhouse gas emissions from

the soil.

Acknowledgements

The study was financed by the Academy of Finland. Maarit

Lauronen is acknowledged for gas analysis and laboratory

experiments.

References

Baath, E. & Arnebrant, K. 1994. Growth rate and response of bac-

terial communities to pH in limed and ash treated forest soils. Soil

Biology & Biochemistry, 26, 995–1001.

Borken, W. & Brumme, R. 1997. Liming practice in temperate forest

ecosystem and the effects on CO2, N2O and CH4 fluxes. Soil Use

and Management, 13, 251–257.

Bosse, U. & Frenzel, P. 2001. CH4 emission from a West Siberian

mire. Suo (Mires and Peat), 52, 99–114.

Brumme, R., Verchot, L.V., Martikainen, P.J. & Potter, C.S. 2005.

Contribution of trace gases nitrous oxide (N2O) and methane

(CH4) to the atmospheric warming balance of forest biomes. In:

The carbon balances of forest biomes (eds H. Griffiths & P. Jarvis).

Garland Science, BIOS Scientific Publishers, Cromwell Press,

Trowbridge, UK.

Burke, R.A., Zepp, R.G., Tarr, M.A., Miller, W.L. & Stocks, B.J.

1997. Effect of fire on soil-atmosphere exchange of methane and

carbon dioxide in Canadian boreal forest sites. Journal of Geophy-

sical Research, 102, 29289–20300.

Butterbach-Bahl, K. & Papen, H. 2002. Four years continuous

record of CH4-exchange between the atmosphere and untreated

and limed soil of a N-saturated spruce and beech forest. Plant and

Soil, 240, 77–90.

Davidson, E.A. 1991. Fluxes of nitrous oxide and nitric oxide from

terrestrial ecosystems. In: Microbial production and consumption of

greenhouse gases: methane, nitrogen oxides and halomethanes (eds

J.E. Roggers & W.B. Whitman). American Society for Microbiol-

ogy, Washington, DC.

Demeyer, A., Voundi, Nkana, J.C. & Verloo, M.G. 2001. Character-

istics of wood ash and influence on soil properties and nutrient

uptake: an overview. Bioresource Technology, 77, 287–295.

Finnish Forest Research Institute. 2000. Finnish statistical yearbook of

forestry, Vol. 14. Gummerus Kirjapaino Oy, Jyvaskyla (in Finnish).

Finnish Meteorological Institute. 2002. Climatological statistics in

Finland 1971–2000. Ilmastotilastoja Suomesta No. 2002:1. Edita

Prima Oy, Helsinki.

Fritze, H., Kapanen, A. & Vanhala, P. 1995. Cadmium contamina-

tion of wood ash and fire-treated coniferous humus: effect on soil

respiration. Bulletin of Environmental Contamination and Toxicol-

ogy, 54, 775–782.

N2O

pro

duct

ion

rate

(ng

g–1

h–1

)

0

1

2

3

4

Without nitrogen With nitrogen

Nitr

ifica

tion

rate

((N

O3,

NO

2)-N

ng

g–1 h

–1)

0

100

200

300

400

Without ash With ash

CO

2 pr

oduc

tion

rate

(µg

g–1

h–1

)

0

20

40

60

80

100

(a)

(b)

(c)

Figure 3 N2O production (a), net nitrification (b) and CO2 produc-

tion rate (c) in the laboratory incubation of slurried O horizons.

Mean and standard error, n ¼ 3.



Fritze, H., Perkionmaki, J., Saarela, U., Katainen, R., Tikka, P.,

Yrjala, K., Karp, M., Haimi, J. & Romantschuck, M. 2000. Effect

of Cd-containing wood ash on the microflora of coniferous forest

humus. FEMS (Federation of European Microbiological Societies)

Microbiology Ecology, 32, 43–51.

Huttunen, J.T., Nykanen, H., Martikainen, P.J. & Nieminen, M.

2003. Fluxes of nitrous oxide and methane from drained peatlands

following forest clear-felling in southern Finland. Plant and Soil,

255, 457–462.

IPCC. 2001. Climate change 2001: the scientific basis. In: Contribu-

tion of Working Group I to the third assessment report of the Inter-

governmental Panel on Climate Change (eds J.T. Houghton, Y.

Ding, D.J. Griggs, M. Noguer, P.J. van der Linden, X. Dai,

K. Maskell & C.A. Johnson). Cambridge University Press,

Cambridge.

Kahkonen, M., Wittmann, C., Ilvesniemi, H., Westman, C.J. & Sal-

kinoja-Salonen, M.S. 2002. Mineralization of detritus and oxida-

tion of methane in acid boreal coniferous forest soils: seasonal and

vertical distribution and effects of clear-cut. Soil Biology & Bio-

chemistry, 34, 1191–1200.

Kasimir-Klemedtsson, A. & Klemedtsson, L. 1997. Methane uptake

in Swedish forest soil in relation to liming and extra N-deposition.

Biology and Fertility of Soils, 25, 296–301.

Klemedtsson, L., Kasimir-Klemedtsson, A., Moldan, F. & Weslien,

P. 1997. Nitrous oxide emission from Swedish forest soils in rela-

tion to liming and simulated increased N-deposition. Biology and

Fertility of Soils, 25, 290–295.

Le Mer, J. & Roger, P. 2001. Production, oxidation, emission and

consumption of methane by soils: a review. European Journal of

Soil Biology, 37, 25–50.

Levene, H. 1960. Robust test for equality of variances. In: Contribu-

tions to probability and statistics: essays in honor of Harold Hotell-

ing (eds I. Olking, S.G. Ghurge, W. Hoeffding, W.G. Madow &

H.B. Mann), pp. 278–292. Stanford University Press, Stanford,

CA.

Levula, T., Saarsalmi, A. & Rantavaara, A. 2000. Effects of ash fer-

tilization and prescribed burning on macronutrient, heavy metal,

sulphur and 137Cs concentrations in lingonberries (Vaccinium vitis-

idaea). Forest Ecology and Management, 126, 269–279.

Maljanen, M., Liikanen, A., Silvola, J. & Martikainen, P.J. 2003.

Nitrous oxide emissions from boreal organic soil under different

land-use. Soil Biology & Biochemistry, 35, 689–700.

Malkonen, E. 1996. Tuhka kangasmetsien lannoitteena (Ash as a

forest fertilization on mineral soils). In: Puun ravinteet tuhkana

takaisin metsaan (eds L. Finer, A. Leinonen & J. Jauhiainen). The

Finnish Forest Research Institute. Metsantutkimuslaitoksen tiedo-

nantoja 599 (in Finnish).

Martikainen, P.J. 1985. Nitrification in forest soil of different pH as

affected by urea, ammonium sulphate and potassium sulphate.

Soil Biology & Biochemistry, 17, 363–367.

Martikainen, P.J., Nykanen, H., Crill, P. & Silvola, J. 1993. Effect

of a lowered water table on nitrous oxide fluxes from northern

wetlands. Nature, 366, 51–53.

Martikainen, P.J., Ohtonen, R., Silvola, J. & Vuorinen, A. 1994. The

effects of fertilization on forest soil biology, microbiology. In:

Effect of fertilization on forest ecosystem (ed. J. Sarkka), pp. 40–

79. Biological Research Reports from the University of Jyvaskyla

38, Jyvaskyla University Printing House and Sisasuomi oy, Jyvas-

kyla, Finland.

Pasanen, J., Louekari, K. & Malm, J. 2001. Cadmium in wood ash

used as fertilizer in forestry: risks to the environment and human

health. Ministry of Agriculture and Forestry Publications 5/2001,

Helsinki.

Pathan, S.M., Aylmore, L.A.G. & Colmer, T.D. 2003. Soil proper-

ties and turf growth on a sandy soil amended with fly ash. Plant

and Soil, 256, 103–114.

Perkiomaki, J., Kiikkila, O., Moilanen, M., Issakainen, J., Tervaha-

uta, A. & Fritze, H. 2003. Cadmium-containing wood ash in a

pine forest: effects on humus microflora and cadmium concentra-

tions in mushrooms, berries, and needles. Canadian Journal of For-

est Research, 33, 2443–2451.

Saari, A., Martikainen, P.J., Ferm, A., Ruuskanen, J., De Boer, W.,

Troelstra, S.R. & Laanbroek, H.J. 1997. Methane oxidation in soil

profiles of Dutch and Finnish coniferous forests with different soil

texture and atmospheric nitrogen deposition. Soil Biology & Bio-

chemistry, 29, 1625–1632.

Saari, A., Heiskanen, J. & Martikainen, P.J. 1998. Effect of the

organic horizon on methane oxidation and uptake in soil of a bor-

eal Scots pine forest. FEMS Microbiology Ecology, 26, 245–255.

Saari, A., Smolander, A. & Martikainen, P.J. 2004. Methane con-

sumption in a repeatedly nitrogen fertilised and limed spruce forest

soil after clear cutting. Soil Use and Management, 20, 65–73.

Saarsalmi, A. & Malkonen, E. 2001. Forest fertilization research in

Finland. A literature review. Scandinavian Journal of Forest

Research, 16, 514–535.

Saarsalmi, A., Malkonen, E. & Piirainen, S. 2001. Effects of wood

ash fertilization on forest soil chemical properties. Silva Fennica,

35, 355–368.

Schutter, M.E. & Fuhrmann, J.J. 1999. Microbial responses to coal

fly ash under field conditions. Journal of Environmental Quality,

28, 648–652.

Simpson, I.J., Edwards, G.C., Thurtell, G.W., den Hartog, G.,

Neumann, H.H. & Staebler, R.M. 1997. Micrometeorological

measurements of methane and nitrous oxide exchange above a

boreal aspen forest. Journal of Geophysical Research, 102, 29331–

29341.

SPSS. 2001. SPSS for Windows, release 10.1.3. SPSS, Chicago.

Steudler, P.A., Bowden, R.D., Melillo, J.M. & Aber, J.D. 1989.

Influence of nitrogen fertilization on methane uptake in temperate

forest soil. Nature, 341, 314–316.

Struwe, S. & Kjøller, A. 1994. Potential for N2O production from

beech (Fagus silvaticus) forest soils with varying pH. Soil Biology

& Biochemistry, 26, 1003–1009.

Zar, J.H. 1999. Biostatistical analysis, 4th edn. Prentice Hall,

Englewood Cliffs, NJ.

Zimmermann, A. & Frey, B. 2002. Soil respiration and microbial

properties in an acid forest soil: effect of wood ash. Soil Biology &

Biochemistry, 34, 1727–1737.



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