Environmental Engineering Reference
In-Depth Information
7.60
7.40
7.20
7.00
6.80
6.60
6.40
6.20
6.00
Figure 13. Seasonal variation of soil pH of salt marsh bed of Fauzderhat area of Chittagong coast.
A distinct seasonal variation of free soil water salinity was found in the present study
(Figure 14). Free soil water salinity values recorded in different seasons were ranged from
10.52±4.52 to 21.06±2.69ppt. Minimum value (5.33ppt) for free soil water salinity was
recorded during monsoon while the maximum value (24ppt) was found during winter
(Appendix A). Soil water salinity gradually increased from monsoon that was peaked in
winter throughout the study (Figure 14). Significant variations (p<0.05) in free soil water
salinity between monsoon, postmonsoon, winter and premonsoon were observed during the
study period (Table 1). Significantly (p<0.05) higher value in winter and lower value in
monsoon was recorded. The free soil water salinity was positively correlated with water
salinity, water transparency, water table depth, soil organic carbon, organic matter, percentage
of clay, soil moisture, field water capacity and negatively correlated with dissolved oxygen,
total suspended solids, tidal height, inundation period, percentage of sand, bulk density,
particle density, exchangeable Ca& Mg, total N and total P of soil at the significant level of
p<0.01. Soil salinity negatively influenced by soil temperature at a significant level of p<0.05
also (Appendix B).
Organic carbon measured from the soil of salt marsh plant,
P. coarctata
bed was
fluctuated among seasons that were ranged from 1.76±0.20 to 3.42±0.08 (%) throughout the
study period. Minimum value (1.58%) for soil organic carbon was found during monsoon and
the maximum value (4.57%) was found during winter (Appendix A, Figure 15). The recorded
values of soil organic carbon fluctuated in different seasons at a significant level (p<0.05,
Table 1). Significantly (p<0.05) higher value in winter and lower value in monsoon was
recorded. Soil organic carbon showed a positive correlation with water salinity, water
transparency, soil salinity, organic matter, water table depth, percentage of clay, moisture,
field water capacity of soil and negatively correlated with water temperature, dissolved
oxygen, total suspended solids, tidal height, inundation period, soil temperature, percentage of
sand, bulk density, particle density, exchangeable Ca& Mg, total N and available P at 1%
level of significance (Appendix B).
The average values of organic matter determined from the soil of salt marsh plant,
P.
coarctata
bed were changed in different seasons that were ranged from 3.03±0.35 to
