Environmental Engineering Reference
In-Depth Information
Analyses of Pedological Factors
Pedological factors like soil temperature, soil pH, free soil water salinity, soil organic
carbon, organic matter, soil texture (% sand, % silt & % clay), moisture, field water capacity,
bulk density, particle density, porosity, exchangeable Ca, Mg & K, total nitrogen (TN) and
available phosphorous (AP) of soil of saltmarsh bed were analyzed by using following
methods:
Temperature
Soil temperature was recorded by penetrating a standard mercury filled centigrade
thermometer in the soil to depth of 10cm in each sampling station.
pH
Soil pH was detected
in situ
using a soil pH meter (DEMETRA, Mo-36, E. M. System
Soil Tester, Tokyo, Japan).
Salinity
Free soil water salinity was measured by a refractometer (0-100‰, OSK, Japan) after the
collection of intertitial water of soil by pressing the soil with umbrella cloth.
Soil Organic Carbon
Soil organic carbon (SOC) was determined by Walkey and Black wet oxidation method
modified by Huq and Alam (2005). Thus the amount of carbon expressed as percent, oxidized
by 1N K
2
Cr
2
O
7
solution was calculated as follows:
(
B
T
)
f
0
003
1
100
Percentage of organic carbon =
W
Where,
B = Amount in ml of N FeSO4 solution required in blank experiment.
T = Amount in ml of N FeSO4 solution required in experiment with soil.
f = Strength of N FeSO4 solution (from blank experiment).
W= Weight of oven dry soil.
Soil Organic Matter
For the estimation of soil organic matter (SOM) of the study area a known weight of soil
was dried in an oven at 105ºC to constant weight. Then the oven dried soil was ignited at
500ºC for 6 hours and cooled in desiccators. The loss in dry weight was measured and
organic matter content was expressed as a percentage (Parsons et al.
,
1984) using the
following formula:
ASI
100
%Organic matter=
AOS
Where ASI= Amount of soil after ignition at 500ºC
AOS= Amount of oven dried soil at 105ºC
