Basic HTML Version
Comparison of Soil macro fauna biodiversity in broad leaf and Needle leaf Afforested stands
22
adjacent broadleaved natural forest located in
compartment 1 of Shast Kalate (Bahram Nia) training
forest, at the Gorgan University of Agricultural
Sciences and Natural Resources (Figure 7). It is
located in northern Iran (36° 41’ to 36° 45’ northern
latitudes and 54° 20’ to 54° 24’ eastern longitudes)
with an average annual precipitation of about 650 mm
and an altitude ranging from 700 to 730 m a.s.l. The
area is on flat and uniform terrain with low slope
(3%~5%). The forest is established on brown forest
soil with mostly sandstone as bedrock Clay-loam-silty
texture and worn stones are spread around the region.
Thickness of A horizon is 5 cm to 10 cm dark brown
full of organic matter and grain with high permeability
capacity, B horizon is reached to 50 cm depth and its
color is brick with dense texture (Moghimian et al.,
2013). The investigated treatments in this research
consisted of 20-year-old plantations with species of
Alder (
Alnus subcordata
C. A. Mey.), Poplar (
Populus
deltoids
Marsh.), Maple (
Acer velutinum
Bioss.),
Cypress (
Cupressus sempervirens
L. var. horizontalis)
and the adjacent mixed natural forest. Tree spacing
within the plantations was 5 m × 5 m and the stands
were never fertilized. The tree species in the natural
forest consisted of Beech, Hornbeam, Maple, Alder
and other broad -leaved species.
Figure 7 Geographical position of the study site in the north of
Iran
3.2 Sampling of soil macrofauna
Five soil samples were randomly collected from each
afforested type and also adjacent mixed natural forest.
Whole of soil macrofauna were collected using core
soil sampler with 81 cm
2
cross section from 0~10 cm
and 10~20 cm depths. The samples transferred to lab
then the earthworms in them were manually separated
(Rahmani and Zare Maivan, 2004; Mohammad Nejad
Kiasari et al., 2011). Soil macro-fauna biomass was
weighed by a scale with 0.01 g accurateness.
3.3 Soil sampling and analysis
Soil samples were kept simultaneously with
macrofauna sampling and then conveyed to laboratory
due to physico-chemical analysis. Soils were air-dried
and passed through 2-mm sieve (aggregates were
broken to pass through a 2 mm sieve). Bulk density is
a measure of a soils mass per unit volume of soil. It is
used as a measure of soil wetness, volumetric water
content, and porosity. Factors that influence the
measurement include; organic matter content, the
porosity of the soil, and the soil structure these factors
will intern control hydraulic conductivity. Bulk
density was measured by Plaster method (clod
method). Soil moisture was measured by drying soil
samples at 105
℃
for 24 hours. Soil pH was
determined using a pH meter in a 1:2.5, soil: water
solution. Soil organic carbon was determined using
the Walkey-Black technique (Allison, 1975). The total
nitrogen was measured using a semi Micro-Kjeldhal
technique (Bremner and Mulvaney, 1982).
3.4 Diversity measures
There are various ways of measuring diversity of soil
fauna. In current research, the formulas of Shannon -
Wiener (diversity), Simpson (evenness) and Margalef
(richness) indices were used as follows (Moghiman et
al., 2013):
1- Shannon-Wiener diversity
Where
H'
is Shannon-Wiener index;
S
is
invertebrate's group's number;
Pi
is average
abundance of per invertebrates groups;
Ln
is natural
logarithm.
2- Simpson evenness
) ln (
'
1
s
i
i
i
P P
H
s
i
i
p
D
1
2
Molecular Soil Biolgy