Influence of slope aspects on soil chemi
european journal of soil biology 44 (2008) 364–372
available at www.sciencedirect.com
journal homepage: http://www.elsevier.com/locate/ejsobi
Original article
Influence of slope aspects on soil chemical and biochemical
properties in a Pinus laricio forest ecosystem
of Aspromonte (Southern Italy)
Maria Sidaria, Giuliana Ronzelloa, Giuseppe Vecchiob, Adele Muscoloa,*
a
Department of Agricultural and Forest Systems Management, Faculty of Agriculture, University ‘‘Mediterranea’’ of Reggio Calabria,
Piazza San Francesco, 4-89061 Gallina di Reggio Calabria, Italy
b
Experimental Institute of Study and Defence of Soil. Department ‘‘Technologies of Soil’’,
via Cagliari, 15, 88063 Catanzaro Lido (Cz), Italy
article info
abstract
Article history:
The study assesses the influence of soil aspect on differences in soil chemical and bio-
Received 14 November 2007
chemical properties. We examined soils on contiguous south- and north-facing slopes of
Accepted 14 May 2008
the Aspromonte Mountains (Calabria, Southern Italy), influenced by the same climate,
Published online 9 June 2008
vegetation and parent material. In each of the two topographic aspects, six study sites
were described. The investigated variables were air temperature, soil temperature, soil
Keywords:
water content, photosynthetically active radiation, soil microbial biomass C, organic mat-
Chemical properties
ter content, total nitrogen, total water-soluble phenols, humic and fulvic acids. Fluorescein
Enzyme activity
diacetate hydrolytic activity, dehydrogenase, protease urease, alkaline and acid phospha-
Pinus laricio
tases, enzymes related to soil microbiological activity and hydrolysing coefficient, an
Organic matter
empiric indicator of soil quality, were analyzed and interpreted. Except in few cases, all
Slope aspect
considered soil properties and microclimate variables showed significant differences
Soil microbial biomass
between topographic aspects. In the soil on the north-facing slope, a lower content of
organic matter and microorganisms and a lower activity of the enzymes related to soil
microbiological activity were observed. The differences may be attributed to topographic
aspect-induced microclimatic differences, which causing differences in the biotic soil
component and organic matter trend, affect soil fertility.
ª 2008 Elsevier Masson SAS. All rights reserved.
1.
Introduction
The spatial variation of soil properties is significantly
influenced by some environmental factors such as climate,
landscape features, including landscape position, topography,
slope gradient and evolution, parent material, and vegetation
[1–3]. It is common knowledge that topography, in the forest
ecosystem, influences local microclimates by changing the
pattern of precipitation, temperature and relative humidity
[4,5] and significantly affects soil texture and soil organic
matter trend, which are acknowledged to be among the
most important soil physiochemical properties, influencing
* Corresponding author. Tel.: þ39 0965/689012; fax: þ39 0965/312827.
E-mail address: [email protected] (A. Muscolo).
1164-5563/$ – see front matter ª 2008 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejsobi.2008.05.001
european journal of soil biology 44 (2008) 364–372
microbial population activity, dynamic, and ecology of the soil
microbiota [6]. It is generally accepted that microbial population is positively related to organic matter content [7–9] and
its activity plays a central role in organic matter trend and
nutrient cycling in the forest ecosystem. Fluctuation in the
size and turnover of soil microbial biomass is very important
in controlling the turnover of carbon (C) [10] associated
nutrients nitrogen (N), phosphorous (P) and sulphur (S), which
in turn regulate plant availability of N, P, S [11].
Nutrient mineralization from fresh plant litter occurs via the
enzymatic activities of the microbial communities. Trend in soil
microbial biomass and enzyme activity varies with plant species
[12], and it is dependent on the combination of soil moisture,
temperature, root activity, and organic matter return to soils
via litter fall [13]. Each change in soil chemistry and litter quality
can result in different enzyme activities into the decomposing
litter, which in turn can result in increased rate of litter decomposition [14]. A considerable number of studies have been
conducted to relate organic matter decomposition to climate
conditions (temperature, moisture) or litter quality under Mediterranean climate [15,16]. In general, effects of topography on
litter quality and decomposition have received little attention.
Sariyildiz and Anderson [17] and Sariyildiz et al. [18] showed
that aspect and slope position within an ecosystem affect the
soil chemistry, litter quality and nutrient cycling. Boerner and
Le Blanc [19] and Sariyildiz et al. [18] showed that slope position
exerted greater effects on soil chemical properties and organic N
turnover than does bedrock type. Topography, which generally
is considered an ultimate control of many biotic and physical
factors, seldom can operate as the mechanism directly responsible for such processes as humification.
Studies on topographic characteristics, on slope aspect in
particular, have produced contrasting results; foresters have
traditionally viewed south aspects as less productive than
north aspects, yet there is substantial evidence that the
assumption of lower site productivity on south aspects may
be incorrect [20]. Therefore, the study reported here was
conducted to evaluate the influence of south or north aspect
on soil biochemical properties and organic matter trend within
a naturally regenerated 80 years old Pinus laricio Poiret population forest of Aspromonte Mountains, in Calabria (Southern
Italy). We hypothesise that soil aspect could be of relative
importance in controlling variability in soil chemical and biochemical properties which in turn influence soil productivity.
The microbial activity and the organic matter trend, considered early and sensitive indicators of environmental changes,
were evaluated by determining the microbial biomass C and
organic matter content. In this paper, we decided to measure
urease, alkaline and acid phosphatases, dehydrogenase, FDA
hydrolysis, and protease enzyme activities, because they are
related to soil microbiological activities and thus may be used
as indicators of soil ecosystem functioning [21].
2.
Materials and methods
2.1.
Study area
The study area was located in the Peripoli Mountain (San
Lorenzo) of Aspromonte Mountains (Calabria, Southern Italy),
365
1270 m above sea level. Coordinates: Lat. 38 030 0000 N, Long.
15 510 0400 E. The climate in this area is predominantly
Mediterranean, with dry hot summers and cold winters. The
annual mean temperature is 12 C, with a mean rainfall of
about 1250 mm. Rainfall in the study region is typically highest during the winter (1100) and autumn (1500) compared to
spring (900) and summer (600). Snow usually contributes little
(
available at www.sciencedirect.com
journal homepage: http://www.elsevier.com/locate/ejsobi
Original article
Influence of slope aspects on soil chemical and biochemical
properties in a Pinus laricio forest ecosystem
of Aspromonte (Southern Italy)
Maria Sidaria, Giuliana Ronzelloa, Giuseppe Vecchiob, Adele Muscoloa,*
a
Department of Agricultural and Forest Systems Management, Faculty of Agriculture, University ‘‘Mediterranea’’ of Reggio Calabria,
Piazza San Francesco, 4-89061 Gallina di Reggio Calabria, Italy
b
Experimental Institute of Study and Defence of Soil. Department ‘‘Technologies of Soil’’,
via Cagliari, 15, 88063 Catanzaro Lido (Cz), Italy
article info
abstract
Article history:
The study assesses the influence of soil aspect on differences in soil chemical and bio-
Received 14 November 2007
chemical properties. We examined soils on contiguous south- and north-facing slopes of
Accepted 14 May 2008
the Aspromonte Mountains (Calabria, Southern Italy), influenced by the same climate,
Published online 9 June 2008
vegetation and parent material. In each of the two topographic aspects, six study sites
were described. The investigated variables were air temperature, soil temperature, soil
Keywords:
water content, photosynthetically active radiation, soil microbial biomass C, organic mat-
Chemical properties
ter content, total nitrogen, total water-soluble phenols, humic and fulvic acids. Fluorescein
Enzyme activity
diacetate hydrolytic activity, dehydrogenase, protease urease, alkaline and acid phospha-
Pinus laricio
tases, enzymes related to soil microbiological activity and hydrolysing coefficient, an
Organic matter
empiric indicator of soil quality, were analyzed and interpreted. Except in few cases, all
Slope aspect
considered soil properties and microclimate variables showed significant differences
Soil microbial biomass
between topographic aspects. In the soil on the north-facing slope, a lower content of
organic matter and microorganisms and a lower activity of the enzymes related to soil
microbiological activity were observed. The differences may be attributed to topographic
aspect-induced microclimatic differences, which causing differences in the biotic soil
component and organic matter trend, affect soil fertility.
ª 2008 Elsevier Masson SAS. All rights reserved.
1.
Introduction
The spatial variation of soil properties is significantly
influenced by some environmental factors such as climate,
landscape features, including landscape position, topography,
slope gradient and evolution, parent material, and vegetation
[1–3]. It is common knowledge that topography, in the forest
ecosystem, influences local microclimates by changing the
pattern of precipitation, temperature and relative humidity
[4,5] and significantly affects soil texture and soil organic
matter trend, which are acknowledged to be among the
most important soil physiochemical properties, influencing
* Corresponding author. Tel.: þ39 0965/689012; fax: þ39 0965/312827.
E-mail address: [email protected] (A. Muscolo).
1164-5563/$ – see front matter ª 2008 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejsobi.2008.05.001
european journal of soil biology 44 (2008) 364–372
microbial population activity, dynamic, and ecology of the soil
microbiota [6]. It is generally accepted that microbial population is positively related to organic matter content [7–9] and
its activity plays a central role in organic matter trend and
nutrient cycling in the forest ecosystem. Fluctuation in the
size and turnover of soil microbial biomass is very important
in controlling the turnover of carbon (C) [10] associated
nutrients nitrogen (N), phosphorous (P) and sulphur (S), which
in turn regulate plant availability of N, P, S [11].
Nutrient mineralization from fresh plant litter occurs via the
enzymatic activities of the microbial communities. Trend in soil
microbial biomass and enzyme activity varies with plant species
[12], and it is dependent on the combination of soil moisture,
temperature, root activity, and organic matter return to soils
via litter fall [13]. Each change in soil chemistry and litter quality
can result in different enzyme activities into the decomposing
litter, which in turn can result in increased rate of litter decomposition [14]. A considerable number of studies have been
conducted to relate organic matter decomposition to climate
conditions (temperature, moisture) or litter quality under Mediterranean climate [15,16]. In general, effects of topography on
litter quality and decomposition have received little attention.
Sariyildiz and Anderson [17] and Sariyildiz et al. [18] showed
that aspect and slope position within an ecosystem affect the
soil chemistry, litter quality and nutrient cycling. Boerner and
Le Blanc [19] and Sariyildiz et al. [18] showed that slope position
exerted greater effects on soil chemical properties and organic N
turnover than does bedrock type. Topography, which generally
is considered an ultimate control of many biotic and physical
factors, seldom can operate as the mechanism directly responsible for such processes as humification.
Studies on topographic characteristics, on slope aspect in
particular, have produced contrasting results; foresters have
traditionally viewed south aspects as less productive than
north aspects, yet there is substantial evidence that the
assumption of lower site productivity on south aspects may
be incorrect [20]. Therefore, the study reported here was
conducted to evaluate the influence of south or north aspect
on soil biochemical properties and organic matter trend within
a naturally regenerated 80 years old Pinus laricio Poiret population forest of Aspromonte Mountains, in Calabria (Southern
Italy). We hypothesise that soil aspect could be of relative
importance in controlling variability in soil chemical and biochemical properties which in turn influence soil productivity.
The microbial activity and the organic matter trend, considered early and sensitive indicators of environmental changes,
were evaluated by determining the microbial biomass C and
organic matter content. In this paper, we decided to measure
urease, alkaline and acid phosphatases, dehydrogenase, FDA
hydrolysis, and protease enzyme activities, because they are
related to soil microbiological activities and thus may be used
as indicators of soil ecosystem functioning [21].
2.
Materials and methods
2.1.
Study area
The study area was located in the Peripoli Mountain (San
Lorenzo) of Aspromonte Mountains (Calabria, Southern Italy),
365
1270 m above sea level. Coordinates: Lat. 38 030 0000 N, Long.
15 510 0400 E. The climate in this area is predominantly
Mediterranean, with dry hot summers and cold winters. The
annual mean temperature is 12 C, with a mean rainfall of
about 1250 mm. Rainfall in the study region is typically highest during the winter (1100) and autumn (1500) compared to
spring (900) and summer (600). Snow usually contributes little
(