This article was downloaded by: [University of Guelph]On: 07 December 2014, At: 09:48Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954 Registered office: MortimerHouse, 37-41 Mortimer Street, London W1T 3JH, UK

Scandinavian Journal of Forest ResearchPublication details, including instructions for authors and subscription information:http://www.tandfonline.com/loi/sfor20

Growing Picea abies container seedlings in peat andcomposted forest-nursery waste mixtures for forestregenerationAnna-Maria Veijalainen a , Marja-Liisa Juntunen a , Juha Heiskanen a & Arja Lilja ba Finnish Forest Research Institute, Suonenjoki Research Unit , Suonenjoki, Finlandb Finnish Forest Research Institute , Vantaa, FinlandPublished online: 21 Nov 2007.

To cite this article: Anna-Maria Veijalainen , Marja-Liisa Juntunen , Juha Heiskanen & Arja Lilja (2007) Growing Piceaabies container seedlings in peat and composted forest-nursery waste mixtures for forest regeneration, ScandinavianJournal of Forest Research, 22:5, 390-397, DOI: 10.1080/02827580701647271

To link to this article: http://dx.doi.org/10.1080/02827580701647271

PLEASE SCROLL DOWN FOR ARTICLE

Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) containedin the publications on our platform. However, Taylor & Francis, our agents, and our licensors make norepresentations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose ofthe Content. Any opinions and views expressed in this publication are the opinions and views of the authors,and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be reliedupon and should be independently verified with primary sources of information. Taylor and Francis shallnot be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and otherliabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to orarising out of the use of the Content.

This article may be used for research, teaching, and private study purposes. Any substantial or systematicreproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in anyform to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/terms-and-conditions

ORIGINAL ARTICLE

Growing Picea abies container seedlings in peat and compostedforest-nursery waste mixtures for forest regeneration

ANNA-MARIA VEIJALAINEN1, MARJA-LIISA JUNTUNEN1, JUHA HEISKANEN1 &

ARJA LILJA2

1Finnish Forest Research Institute, Suonenjoki Research Unit, Suonenjoki, Finland, and 2Finnish Forest Research Institute,

Vantaa, Finland

AbstractThe suitability of using composted forest-nursery waste as a component in growing medium was studied. Norway spruce[Picea abies (L.) Karst.] seedlings were grown in containers filled with sphagnum peat (100P), forest-nursery waste compost(100C) and in peat mixtures containing 25 or 50% compost by volume (75P25C and 50P50C, respectively). Morphologicaland chemical characteristics of the seedlings and the water and nutrient contents of the growing media were studied during22 weeks of nursery cultivation. The seedlings were outplanted the following spring, and the survival and growth werefollowed for 3 years. Compost additions decreased seedling height, diameter and shoot dry mass, but root dry mass was thesame in 100P and 75P25C after nursery cultivation. Foliar nutrient concentrations were optimal in all the seedlings,although foliar nitrogen content was lower the greater the proportion of compost in the medium. Compost additions did notaffect the root-egress potential tested before outplanting. The 100P seedlings grew significantly more than the otherseedlings during the first summer at the forest site. Thereafter, compost additions did not affect growth, but the final heightand diameter were still the lowest in 100C. The results suggest that forest-nursery waste compost has potential to be used asa component of peat-based growing medium. However, specially adjusted nursery-cultivation practices need to be used forcompost-containing media.

Keywords: Biowaste, conifers, growing medium, outplanting, recycling.

Introduction

Low-humified sphagnum peat is used extensively as

a growing medium for the production of container

seedlings in the Nordic countries, and also globally

in other plant-production systems (Bunt, 1988;

Juntunen & Rikala, 2001). The research and use of

other alternative growing-medium materials and soil

amendments have greatly increased during recent

decades (Bunt, 1988; Carlile, 2005; Davis et al.,

2006), because of the need to cut costs associated

with the use of growing media and also partly

because of the increasing concern about overextrac-

tion of peat. The beneficial effect of compost

utilization on plant growth has been reported in

many greenhouse- and nursery-crop production

systems (e.g. Holopainen et al., 2002; Wilson

et al., 2002; Davis et al., 2006). However, the

studies also show that the plant response to compost

addition depends on the plant species (Wilson et al.,

2002), the inherent properties of the compost and

the functionality of the composting method (Raviv,

2005).

Owing to the prevailing environmental, political

and economical goals, there is considerable pressure

to minimize the generation and landfilling of waste

materials and to decrease energy consumption. The

EU Landfill Directive 1999/31/EC supports the

composting of biodegradable waste for utilization

in agricultural or ecological applications. The biode-

gradable waste formed in forest nurseries consists of

rejected tree seedlings, which do not meet the size

and shape requirements, or are affected by plant

diseases or pests, as well as the growing media,

weeds, grass clippings and fallen leaves. Windrow

Correspondence: A.-M. Veijalainen, Finnish Forest Research Institute, Suonenjoki Research Unit, FI-77600 Suonenjoki, Finland. E-mail: anna-maria.

veijalainen@metla.fi

Scandinavian Journal of Forest Research, 2007; 22: 390�397

(Received 10 April 2007; accepted 24 August 2007)

ISSN 0282-7581 print/ISSN 1651-1891 online # 2007 Taylor & Francis

DOI: 10.1080/02827580701647271

Dow

nloa

ded

by [

Uni

vers

ity o

f G

uelp

h] a

t 09:

48 0

7 D

ecem

ber

2014

composting of forest-nursery waste with organic

nutrient addition, such as horse manure, is a

practical solution for the on-site treatment of biode-

gradable waste with low capital and management

costs (Veijalainen et al., 2005, 2007b). However, the

suitability of the compost for use as a growing

medium in container tree-seedling production is

not well known. Moreover, the effect of compost-

containing growing medium on the outplant-

ing performance of tree seedlings needs to be

evaluated.

The aims of this study were to determine (1)

whether composted forest-nursery waste can be used

as a component (0, 25, 50 or 100% by volume) of

peat-based growing medium for container seedlings

of Norway spruce, i.e. how the added forest-nursery

waste compost affects the height and diameter

growth, biomass production, foliar nutrient concen-

trations, foliar nitrogen (N) content and root-egress

potential of Norway spruce seedlings, and (2)

whether these growing media affect the outplanting

performance of the seedlings.

Materials and methods

Preparation of growing media

The mixtures of peat and compost were prepared by

hand-mixing the components in a 10 litre bucket.

Peat (P) and compost (C) were used, respectively, in

ratios (% by volume) of 100/0 (100P), 75/25

(75P25C), 50/50 (50P50C) and 0/100 (100C).

The peat was unfertilized, but limed (2 kg m�3),

light sphagnum peat (Finnpeat M02; Kekkila, Fin-

land). The compost was pure forest-nursery waste

(e.g. bareroot and container tree seedlings, peat and

weeds), which had been composted in a windrow for

4 years. The compost was sieved through a mesh size

of 4 mm before mixing to remove coarse, unde-

graded woody twigs, and it was not sterilized

separately. A detailed description of the physical

properties of the growing-media mixtures is given in

Veijalainen et al. (2007a).

Six, hard plastic seedling trays (PL-81F; Lannen

Plant Systems, Finland) were hand-filled with each

growing medium. Each tray (0.4�0.4 m) had 81

cells (volume�85 cm3 per cell, 546 cells m�2), with

air slits to promote air-pruning of the roots. Two

Norway spruce seeds from a regional seed orchard

(SV 177) were sown in each cell at the beginning of

May 2002. The container surface was covered with a

6�8 mm thick layer of gravel (grain size 3�4 mm)

after sowing. The germlings were thinned to one per

cell after 3 weeks or a new germling was pricked into

the cell if the seeds had not germinated.

Nursery cultivation and root-egress test

The seedlings were grown in an unheated green-

house without artificial lighting in central Finland

for one growing season (1 May to 1 October 2002)

(Table I), apart from a 2 week period outdoors after

14 August. The positions of trays (replicates) were

randomized, and experimental trays were sur-

rounded by additional trays. The tray positions

were changed weekly. Each tray represented one

treatment (growing medium), and each treatment

had six replicate trays. The total number of seedlings

in each growing-medium treatment was 486.

The surface of the growing medium was kept

moist by hand-spraying during the 3 week germina-

tion period, after which the seedlings were irrigated

manually once or twice a day. The water was applied

independently to each tray according to its total mass

to maintain the mean water content of each growing

medium optimal for plant growth (5095% of total

porosity; Puustjarvi, 1977; Hillel, 1980). All the

seedlings were fertilized with a 0.1% nutrient solu-

tion (Taimi-Superex; Kekkila Corp., Finland), con-

taining macronutrients, N, phosphorus (P) and

potassium (K) (190, 44 and 202 mg l�1, respec-

tively), and micronutrients. The seedlings received

nutrient solution once or twice a week, resulting in a

total of 26.9 mg N, 6.2 mg P and 28.3 mg K for each

seedling during 20 May to 9 September.

The electrical conductivity of the growing medium

was measured (SigmaProbe; Delta-T Devices, UK)

in six randomly selected cells (approx. 4 cm depth)

in each tray 1 or 2 days after fertilization at the

optimum water content (0.5�1 h after irrigation).

The mean electrical conductivity was 0.5�0.7 mS cm�1 in all the growing media (p�0.05).

The height of six randomly selected seedlings in each

tray was measured every second week. Seedling

survival was checked weekly and dead seedlings

were harvested during the 5 week period after

sowing. Isolations were performed according to Lilja

et al. (1998) to assess the presence of microbes in the

dead seedlings. Weeds were rooted out if they

occurred.

Table I. Monthly mean temperature, relative humidity and

amount of irrigation during the first growing season in the nursery.

Month V VI VII VIII IX

Temperature (8C) 19 21 23 19 13

Relative humidity (%) 70 65 66 73 66

Irrigation (mm) 29a 100 109 142b 61

Note: aspray irrigation excluded during the germination period

(1�21 May); bprecipitation (39 mm) included during the outdoor

period (14�31 August).

Growing P. abies in peat�compost mixtures 391

Dow

nloa

ded

by [

Uni

vers

ity o

f G

uelp

h] a

t 09:

48 0

7 D

ecem

ber

2014

After the first growing season, most of the seed-

lings were put in frozen storage (�38C). Before this,

however, 10 randomly selected seedlings were har-

vested from each tray for determination of the

morphological characteristics (diameter, root, stem

and needle dry masses, and root:shoot ratio). Stems,

needles and washed roots were oven-dried at 608Cfor 2 days before weighing. The needles of seedlings

from each tray were pooled, milled and stored at

room temperature for nutrient analysis. Total foliar

N concentration was determined with a CHN

analyser (CHN-1000; Leco Co., USA), and the

total P, K and micronutrient [calcium (Ca) and

magnesium (Mg)] concentrations were determined

following dry digestion (5508C, extraction of the ash

with 2 M HCl) (Halonen et al., 1983) by inductively

coupled plasma atomic emission spectrophotometry

(ICP/AES; ARL 3580, Switzerland).

Each growing-medium mixture was sampled be-

fore (during the filling of trays, n�6) and after the

first growing season (at harvesting, n�6) for nu-

trient analysis. At harvesting, the growing medium

was sampled around the roots of 10 seedlings in each

tray, which were harvested for morphological deter-

minations (see above). The samples representing one

tray (replicate) were pooled before they were oven-

dried at 408C for 3 days, milled and stored at room

temperature before nutrient analysis. Total soluble N

was determined on a 1 M KCl extract by flow

injection analysis (Quikchem 8000 FIA-analyser,

A83200; Lachat Instruments, USA). Plant-available

P, K, Ca and Mg were determined on an acidic

(pH 4.65) 1 M ammonium acetate extract by ICP/

AES.

The root-egress potential (the growth of roots

from root plugs into the surrounding soil) was tested

on 30 frozen-stored seedlings (five randomly se-

lected seedlings from each of the six replicate trays)

from each of the four growing-medium treatments in

a greenhouse in February 2003. After thawing at

�88C for 4 days, each seedling was planted in a

sand-filled plastic pot (0.9 litre). Growing was car-

ried out for 4 weeks under greenhouse lamps with a

16 h day at 208C and at 158C during the dark

period. The photosynthetically active radiation was

174�277 mmol m2 s�1 at the seedling shoot level

during the daytime. The pots were placed in a fully

randomized design, and the pot positions were

changed weekly to ensure homogeneous conditions.

The seedlings were irrigated manually every second

day. After growing, the sand was cleaned from the

roots that had grown out from the growing-medium

plugs and the new roots were cut, washed, oven-

dried at 1058C for 1 day and weighed (9 1 mg).

Outplanting

After 7 months in winter storage and subsequent

thawing, the seedlings were planted in fresh mineral

forest soil (Myrtillus type; Cajander, 1949) in Ruot-

sinkyla, southern Finland (60821? N, 2581? E) in

May 2003. The planting site was clearcut in 2000

and site preparation was performed by mounding

(inverting) in September 2002. The planting site was

divided into six blocks. Each block was divided into

20 plots. Twenty seedlings from each treatment

(100P, 75P25C, 50P50C and 100C) were planted

in each block, so that one seedling from each

treatment was planted in each plot. These 20

seedlings were taken from same replicate tray. The

spacing between seedlings was approximately 1.0�0.2 m. In total, 480 seedlings including 120 seed-

lings from each of the four treatments were planted.

The seedling height was measured at planting and

the height and stem diameter in September for

3 years after planting (2003�2005). The height was

measured from the ground to the top of the seedling

(accuracy of 0.5 cm) and the diameter was measured

2 cm above the ground (9 0.1 mm). Seedling survi-

val was also determined.

Data analysis

Analysis of variance (anova) and Tukey’s test were

used to analyse the differences between the growing

media for each variable (except for height growth) in

the nursery and the root-egress test. The growing

medium was a fixed factor and the tray a random

factor in the analysis, which also included their

interaction. The difference in height growth during

nursery cultivation was analysed using a linear mixed

model, repeated anova with growing medium, mea-

surement time and their interaction as the fixed

factors, and tray as a random factor. The significance

of the difference (pB0.05) between treatments was

determined by the Bonferroni test. The homogeneity

of variances was tested with Levene’s test and

normality with Shapiro and Wilk’s W test. Survival

rates after nursery cultivation were arcsin�x trans-

formed before analysis. After outplanting, the differ-

ence in height growth between treatments was

analysed using a linear mixed model, repeated anova

with growing medium, year and their interaction as

the fixed factors, and block and the interaction of

block and plot as random factors. The interaction of

planting height and year was used as a covariate. The

significance of the difference (pB0.05) between

treatments was determined using the Bonferroni

test. The data for survival after outplanting were

analysed by the non-parametric Kruskall�Wallis test.

392 A.-M. Veijalainen et al.

Dow

nloa

ded

by [

Uni

vers

ity o

f G

uelp

h] a

t 09:

48 0

7 D

ecem

ber

2014

Results

Nursery cultivation

Compost additions to the peat growing media

decreased the height growth of the seedlings in the

nursery (Figure 1). During the first 12 weeks,

seedlings grown in 100C in particular grew at a

significantly slower rate than seedlings grown in

100P. After that, there were no significant differ-

ences between the growing media in the height

growth. However, the final height of the seedlings

was lower the greater the proportion of compost in

the medium (pB0.05). The compost additions also

decreased diameter, needle and stem dry masses

(Table II). The root dry mass of seedlings grown in

75P25C was, however, the same as that of seedlings

grown in 100P. The root:shoot ratio was higher the

greater the proportion of compost in the medium.

Seedling survival was significantly lower (8597%) in

100C than in the other growing media (9693%,

9892% and 9991% for 50P50C, 75P25C and

100P, respectively). Most of the seedlings (70%)

died within 5 weeks after sowing. The most common

microbes isolated from the dead seedlings in all the

growing media were Pythium spp.

After the first growing season, all of the foliar

nutrient concentrations, except for Mg, were within

the ranges suitable for Norway spruce (Rikala, 2002)

in all growing media (Table III). The mean Mg

concentration was lower in the other growing media

than in 100P, although not below the deficiency limit

(0.8 g kg�1) and, as a result, no visual deficiency

symptoms were observed. Although the foliar N

concentration was higher the greater the proportion

of compost in the medium (Table III), the foliar N

content decreased with increasing compost propor-

tion (pB0.05), being 8.690.7, 7.290.9, 6.690.2

and 5.290.4 mg in 100P, 75P25C, 50P50C and

100C, respectively.

The amounts of plant-available N, P and K (mg

root plug�1) were significantly higher in spring in

the growing media containing compost (Table IV).

The initial amounts of Ca and Mg were not affected

by the compost additions. The amounts of N, Ca

and Mg decreased in the growing media containing

compost and the amount of K increased in all the

growing media during seedling growth.

The mean water content was near optimal, 40�55% of total porosity, in all growing media during

the first growing season (Figure 2). However,

according to visual observations, the water was

retained in the upper part of those growing media

that contained compost. The root growth was clearly

restricted to the upper part of the root plug in pure

compost, and therefore the incomplete root system

was not able to keep the root plug together during

handling. In the root-egress test, however, the dry

mass of new roots did not differ significantly between

the seedlings grown in 100P (47917 mg) and in the

other growing media (5396, 3795 and 40911 mg

in 75P25C, 50P50C and 100C, respectively). The

root egress was significantly different only between

75P25C and 50P50C.

Outplanting

Only during the first season at the forest site did the

seedlings grown in peat gain more height than

seedlings grown in the other growing media (pB

0.01) (Table V). Thereafter, the seedlings grew at a

similar rate in all treatments. After three growing

seasons, the final height was significantly lower in

50P50C and 100C than in 100P. However, the

difference was not significant between 100P and

75P25C. The final diameter was significantly differ-

ent only between 100P and 100C. The survival rate

of the outplanted seedlings was over 94% in all

treatments. The most important reason for mortality

was night frost in May 2004.

Discussion

After nursery cultivation, the seedling survival,

growth and biomass production were found to be

better, the greater the proportion of peat in the

growing medium. Thus, light sphagnum peat was a

better growing medium than composted forest-

nursery waste or peat�compost mixtures. However,

there were no longer any differences in seedling

survival between the treatments 3 years after out-

planting. The difference in seedling size before

outplanting was still detectable after 3 years,

although the final height and diameter were not

significantly different between seedlings grown in

100P and 75P25C. Therefore, the results of this

0

2

4

6

8

10

12

14

16

100P 75P25C 50P50C 100C

mc,thgieH

1816141210

8

weeks after

sowing

a

b a a

ab

c b ab

b a b

a

Figure 1. Height growth (mean9SD, cm) of the seedlings grown

in the mixtures of peat (P) and compost (C) (% by volume) during

the first growing season in the nursery. Different letters indicate

significant difference (n�6) and columns without letters indicate

no significant difference (mixed-model repeated anova and

Bonferroni pairwise comparisons, pB0.05).

Growing P. abies in peat�compost mixtures 393

Dow

nloa

ded

by [

Uni

vers

ity o

f G

uelp

h] a

t 09:

48 0

7 D

ecem

ber

2014

experiment suggest that viable seedlings for forest

plantations can be produced at least in containers

filled with 75P25C. However, it cannot be con-

cluded that 75P25C is a better growing medium

than the other compost media, because the final

height and diameter in this treatment did not differ

significantly from other compost treatments after the

early growth on the forest site.

In the nursery, the reduced seedling growth in the

growing media containing compost was clearly due

to the unfavourable physical conditions. In previous

laboratory studies, pure compost was found to have

a higher density than peat (0.5 and 0.1 g cm�3,

respectively) and finer texture than peat (proportion

of particles B 1 mm was 85% and 44%, respec-

tively) (Veijalainen et al., 2007a). In addition, the

total and air-filled porosities were the lower the

greater the proportion of compost in the growing

medium (as shown in Figure 2). From visual

observations, most of the irrigation water, which

was given frequently with small doses, was retained

in the upper part of the compost medium, which

kept the lowest part of the root plug dry. This has

also been reported in pure peat, when the container

medium is irrigated similarly (Heiskanen, 1995).

Thus, the irrigation, which ensures that the whole

root plug gets wet, needs to be applied for compost

media.

In the lowest part of the compost-containing

media, the root growth was restricted owing to

increased density, dryness and possible water repel-

lence, as reported previously (Heiskanen & Rikala,

1998; Singh & Sainju, 1998). The poorly grown root

system was thus not able to supply the shoot system

with sufficient water and mineral nutrients, although

the amount of plant-available nutrients was high in

the compost medium. The ability of soil amend-

ments to influence root growth has also been found

in bareroot nurseries. For example, Tworkorski et al.

(1983) reported reduced root growth of white oak

(Quercus alba L.) as the bulk density of the nursery

soil increased.

In the upper part of the root plug, a high water

content and subsequent low air-filled porosity may

have caused localized oxygen deficiency in the com-

post-containing media (Bunt, 1988). The lower

germination in pure compost (76%) than in the

other mixtures (� 90%), as well as the poor root

growth, may thus be a consequence of oxygen

deficiency (Dasberg & Mendel, 1971; Singh &

Sainju, 1998; Kaila, 2007). The moist surface also

favoured the growth of Pythium species (Lilja et al.,

1998) and mosses (Cronberg, 1991), which caused

Table II. Morphological characteristics (mean9SD) of seedlings grown in the mixtures of peat (P) and compost (C) (% by volume) for one

growing season.

Dry mass (g DM)

Root to shoot ratio Root collar diameter

Growing medium Needles Stem Roots (g/g) (mm)

100P 0.5190.04a 0.3390.02a 0.3690.02a 0.4490.02c 2.390.1a

75P25C 0.4190.05b 0.2590.03b 0.3690.03a 0.5590.03b 2.090.1b

50P50C 0.3390.01c 0.2090.02c 0.3190.02b 0.6090.03ab 1.990.1b

100C 0.2590.02d 0.1590.03d 0.2690.02c 0.6590.03a 1.790.1c

p B0.001 B0.001 B0.001 B0.001 B0.001

Note: DM�dry matter.

p-Values are from anova (n�6). Different letters indicate significant difference between treatments (Tukey’s HSD test).

Table III. Foliar nutrient concentrations (mean9SD, g kg�1 DM) of seedlings grown in the mixtures of peat (P) and compost (C) (% by

volume) for one growing season.

Foliar nutrient concentration (g kg�1 DM)

Growing medium N P Ka Ca Mg

100P 1791b 2.890.2b 12.390.6a 4.090.4ab 1.2790.88a

75P25C 1892b 2.890.3b 10.090.7b 3.990.3b 1.0090.91b

50P50C 2091a 3.290.2a 11.490.4a 4.590.3a 0.9790.04b

100C 2191a 3.190.2ab 11.490.9ab 4.390.3ab 0.9790.48b

Ref. valueb 16�23 1.4�3.0 7.0�12.0 2.5�5.0 1.2�2.0

p B0.0001 0.004 B0.0001 0.012 B0.0001

Note: DM�dry matter; N�nitrogen; P�phosphorus; K�potassium; Ca�calcium; Mg�magnesium.

p-Values are from one-way anova (n�6). Different letters indicate significant difference between treatments (Tukey’s HSD test).a Significant difference determined by Dunnett’s T3 test; b reference value (Rikala, 2002).

394 A.-M. Veijalainen et al.

Dow

nloa

ded

by [

Uni

vers

ity o

f G

uelp

h] a

t 09:

48 0

7 D

ecem

ber

2014

damping-off in the newly germinated seedlings

and restricted aeration in the compost medium,

respectively.

In this study, the root-egress potential tested

before planting was not affected by the growing

medium used, indicating no differences for the

outplanting performance potential (Burdett, 1987).

Although no differences were found in seedling

survival, the compost additions reduced seedling

growth during the first year after outplanting. It is

likely that the higher foliar N content of the seedlings

grown originally in peat promoted the growth after

outplanting, because the retranslocation of stored

nutrients is known to support new growth in

transplanted seedlings (Kaakinen et al., 2004).

Moreover, the initially larger seedlings with higher

nutrient reserves grown in peat were better able to

compete with the ground vegetation after outplant-

ing (Malik & Timmer, 1996). However, after the

first growing season, the original growing medium

no longer affected the seedling growth, which

suggests even development of all the seedlings later

on in this forest site, although the seedlings grown in

compost were still shorter than those grown in peat

3 years after outplanting.

In conclusion, light sphagnum peat is a better

growing medium than composted forest-nursery

waste or peat�compost mixtures if Norway spruce

container seedlings are grown according to the

nursery-culture practices used in this study. The

quality of seedlings, height and diameter growth,

biomass production and foliar N content decreased

with increasing level of compost during nursery

cultivation, although the differences in height and

stem diameter decreased during the early growth on

the forest site. In particular, growing medium that

contained mainly compost was unfavourable for

seedling growth owing to the increased bulk density

and the problems associated with aeration, wettabil-

ity and water availability under the nursery-culture

practices used. Therefore, the possibility of improv-

ing the physical conditions in the compost media by

mixing a coarse constituent, such as vermiculite or

other materials, into these container media must be

examined. More research is also needed into the

management of compost-based growing media dur-

ing nursery cultivation, such as irrigation

and fertilization practices. Furthermore, the produc-

tion of high-quality seedlings presupposes that the

Table IV. Amount of plant-available nutrients (mean9SD, mg root plug�1) in the mixtures of peat (P) and compost (C) (% by volume)

at the beginning and end of the first growing season.

Nutrient (mg root plug�1) 100P 75P25C 50P50C 100C p

N

Spring 1.390.5d 2.690.2c 3.990.4b 5.590.4a B 0.001

Autumn 1.790.3a 1.490.4a 1.690.3a 1.890.2a 0.192

P

Spring 0.490.1b 1.590.1a 1.690.1a 1.490.2a B 0.001

Autumn 0.990.1c 1.290.2b 1.590.2ab 1.690.1a B 0.001

K

Spring 1.290.1d 7.290.4c 12.390.7b 20.792.0a B 0.001

Autumn 10.591.2c 16.291.8b 23.792.3a 24.290.5a B 0.001

Ca

Spring 5291b 6092a 5594ab 5696ab 0.016

Autumna 4991a 4396a 5196a 4792a 0.026

Mg

Spring 1591b 1891a 1791ab 1892a 0.001

Autumna 1591a 1392a 1692a 1491a 0.038

Note: root plug volume�85 cm3.

N�nitrogen; P�phosphorus; K�potassium; Ca�calcium; Mg�magnesium.

p-Values are from one-way anova (n�6). Different letters indicate significant difference between treatments (Tukey’s HSD test).a Significant difference determined by Dunnett’s T3 test.

PTf

o%0

4

PTf

o%0

5

PTf

o%2

4

PTf

o%9

4

PTf

o% 0

4

PTf

o%8

4

PTf

o%5

4

PT f

o%5

5

0

20

40

60

80

100

before after before after before after before after

100P 75P25C 50P50C 100C

emulovlatotfo

%

Air

Water

Mineral

Organic

Figure 2. Mean (�SD) air, water and solid (organic and mineral)

content (% of total volume) in the growing-medium mixtures of

peat (P) and compost (C) (% by volume) before and after daily

watering in the nursery. Water content (% of total porosity, TP) is

indicated inside the bar.

Growing P. abies in peat�compost mixtures 395

Dow

nloa

ded

by [

Uni

vers

ity o

f G

uelp

h] a

t 09:

48 0

7 D

ecem

ber

2014

compost is well matured and free of weed seeds and

pathogens.

Acknowledgements

We thank the staff of the Suonenjoki Research Unit

and Nursery for their help, and the Central Labora-

tory of the Finnish Forest Research Institute for the

chemical analyses. Special thanks to A. Heikkila,

MSc, Ms S. Kolehmainen, Mr J. Laitinen, Mr E.

Molkanen, Ms R. Vanhanen and Mr M. Udd for

technical assistance, and to Dr J. Heinonen and Dr J.

Lappi for statistical advice. We also thank Dr R.

Rikala from FFRI and Dr H. Heinonen-Tanski from

the University of Kuopio for comments on the

manuscript, and Dr J. Derome for revision of the

English. Financial support from the Foundation for

Research of Natural Resources in Finland and the

Finnish Cultural Foundation is gratefully acknowl-

edged.

References

Bunt, A. C. (1988). Media and mixes for container-grown plants.

London: Unwin Hyman.

Burdett, A. N. (1987). Understanding root growth capacity:

Theoretical considerations in assessing planting stock quality

by means of root growth tests. Canadian Journal of Forest

Research, 17, 768�775.

Cajander, A. K. (1949). Forest types and their significance. Acta

Forestalia Fennica, 56, 1�71.

Carlile, W. R. (2005, September). The use of composted materials in

growing media. Paper presented at the meeting of Interna-

tional Symposium on Growing Media, Angers, France.

Cronberg, N. (1991). Atgarder for kontroll av lungmossa i

plantskolemiljo [Controlling the growth of mosses in the

nurseries]. Plantnytt, 6, 1�4. (In Swedish.)

Dasberg, S. & Mendel, K. (1971). The effect of soil water and

aeration on seed germination. Journal of Experimental Botany,

22, 992�998.

Davis, A. S., Jacobs, D. F., Wightman, K. E. & Birge, Z. K. D.

(2006). Organic matter added to bareroot nursery beds

influences soil properties and morphology of Fraxinus

pennsylvanica and Quercus rubra seedlings. New Forests,

31, 293�303.

Halonen, O., Tulkki, H. & Derome, J. (1983). Nutrient analysis

methods. Finnish Forest Research Institute Research Papers

121. (In Finnish.)

Heiskanen, J. (1995). Water status of sphagnum peat and a peat�perlite mixture in containers subjected to irrigation regimes.

HortScience, 30, 281�284.

Heiskanen, J. & Rikala, R. (1998). Influence of different container

media on rooting of Scots pine and silver birch seedling after

transplanting. New Forests, 16, 27�42.

Hillel, D. (1980). Introduction to soil physics. London: Academic

Press.

Holopainen, P., Airaksinen, S., Heinonen-Tanski, H. & Heiska-

nen, M.-L. (2002). Utilization of composted horse manure

with peat bedding in greenhouse and field cultivation. In G.

Schmilewski, & L. Rochefort (Eds.), Peat in horticulture*Quality and environmental challenges. Proceedings of Interna-

tional Peat Symposium (pp. 154�160). Saarijarvi: Interna-

tional Peat Society.

Juntunen, M.-L. & Rikala, R. (2001). Fertilization practice in

Finnish forest nurseries from the standpoint of environmen-

tal impact. New Forests, 21, 141�158.

Kaakinen, S., Jolkkonen, A., Iivonen, S. & Vapaavuori, E. (2004).

Growth, allocation and tissue chemistry of Picea abies

seedlings affected by nutrient supply during the second

growing season. Tree physiology, 24, 707�719.

Kaila, A. (2007). Kuusen siementen hapenkulutuksen mittaaminen

happielektrodimenetelmalla -esitutkimus [Monitoring oxygen

consumption of germinating Picea abies seeds by O2 electrode

method]. Master’s thesis, University of Helsinki. (In Fin-

nish.)

Lilja, A., Heiskanen, J. & Heinonen, R. (1998). Effects of

irrigation on uninucleate Rhizoctonia on nursery seedlings

of Pinus sylvestris and Picea abies growth in peat growth

medium. Scandinavian Journal of Forest Research, 13, 184�188.

Malik, V. & Timmer, V. R. (1996). Growth, nutrient dynamics,

and interspecific competition of nutrient-loaded black spruce

seedlings on a boreal mixedwood site. Canadian Journal of

Forest Research, 26, 1651�1659.

Puustjarvi, V. (1977). Peat and its use in horticulture. Helsinki:

Liikekirjapaino.

Raviv, M. (2005). Production of high-quality composts for

horticultural purposes: A mini-review. HortTechnology, 15,

52�57.

Rikala, R. (2002). Metsataimiopas*Taimien valinta ja kasittely

tarhalta uudistusalalle [Forest tree seedlings*Selection and

Table V. Height growth (mean9SD, cm, n�6) of seedlings after outplanting, and final height and stem diameter after three growing

seasons.

Height growth (cm)

Final height Final stem

Growing medium 1st year 2nd year 3rd year (cm) diameter (mm)

100P 13.291.4 a 18.291.9 19.291.9 59.693.2 a 8.591.9 a

75P25C 11.391.3 b 17.491.8 17.891.8 55.493.0 ab 7.691.5 ab

50P50C 10.691.3 b 16.691.8 18.491.8 54.392.9 b 7.191.5 ab

100C 10.091.4 b 16.392.0 17.392.0 51.493.3 b 6.691.3 b

Note: the seedlings were grown in mixtures of sphagnum peat (P) and compost (C) (% by volume) for one growing season before

outplanting. Different letters indicate significant difference in height growth based on the estimated marginal means used in the mixed

model repeated anova and Bonferroni pairwise comparison (pB0.05).

396 A.-M. Veijalainen et al.

Dow

nloa

ded

by [

Uni

vers

ity o

f G

uelp

h] a

t 09:

48 0

7 D

ecem

ber

2014

handling practices from nursery to planting site]. Finnish

Forest Research Institute Research Papers 881. (In Finnish.)

Singh, B. P & Sainju, U. M. (1998). Soil physical and morpho-

logical properties and root growth. HortScience, 33, 966�971.

Tworkorski, T. J., Burger, J. A. & Smith, D. W. (1983). Soil

texture and bulk density affect early growth of white oak

seedlings. Tree Planters’ Notes, 34, 22�25.

Veijalainen, A.-M., Lilja, A. & Juntunen, M.-L. (2005). Survival

of uninucleate Rhizoctonia species during composting of

forest nursery waste. Scandinavian Journal of Forest Research,

20, 206�212.

Veijalainen, A.-M., Heiskanen, J., Juntunen, M.-L. & Lilja, A.

(2007a). Tree-seedling compost as a component in sphag-

num peat-based growing media for conifer seedlings: Physi-

cal and chemical properties. Acta Horticulturae, 450, in press.

Veijalainen, A.-M., Juntunen, M.-L., Lilja, A., Heinonen-Tanski,

H. & Tervo, L. (2007b). Forest nursery waste composting in

windrows with or without horse manure or urea*The

composting process and nutrient leaching. Silva Fennica,

41, 13�27.

Wilson, S. B., Stoffella, P. J. & Graetz, D. A. (2002). Development

of compost-based media for containerized perennials. Scien-

tia Horticulturae, 93, 311�320.

Growing P. abies in peat�compost mixtures 397

Dow

nloa

ded

by [

Uni

vers

ity o

f G

uelp

h] a

t 09:

48 0

7 D

ecem

ber

2014