EQA (Sep 2018)
SPATIAL DISTRIBUTION, DYNAMICS AND MAPPING OF THE SOIL ORGANIC CARBON AND TOTAL NITROGEN DENSITY ESTIMATES IN LAGOS LAGOON WETLANDS
Abstract
Accurate estimation of wetland carbon densities is a prerequisite for wetland conservation and implementation of carbon sink enhancement plans. This study was designed to investigate spatial distribution in Soil Organic Carbon (SOC) and Total Nitrogen (TN), and Soil Organic Carbon density (SOCD) and Total Nitrogen density (TND) stocks in Lagos lagoon wetlands and the influence of other soil physicochemical. The SOC content generally exhibited high seasonal variations for all the sampling points in the wetlands. During wet season it ranges from 12.71±0.15 - 164.995±1.65 g/kg with a coefficient of variation of 40.99%, and dry season ranged from 132.02±3.520 - 383.570±8.43 g/kg with a coefficient of variation of 34.45%. The soil carbon content in the wet season was much lower than the dry season. The total nitrogen content in the wet season ranged from 4.53 – 16.58 g/kg with a COV of 27.96%, while the dry season ranged between 10.16 and 40.31 g/kg with a coefficient of variation of 29.39%.The SOC density of Lagos lagoon wetlands for tops soils ranged from 10.53 to 37.89 kgm−2 with an arithmetic mean of 26.70±1.41 kgm−2 and TND ranged from 0.61 to 2.37 kgm−2 with an arithmetic mean of 1.96±0.09 kgm−2. Pearson correlation reveal a positive correlation between SOC and TN (r=0.643), bulk density and SOC (r=0.344), TN and bulk density (r=0.478) and soil moisture and pH (r=0.085). In the present study, a negative correlation was observed in SOC and pH, and TN and pH. The results suggest that nitrogen content, moisture content and bulk density, which are significantly influenced by vegetation, seasons and topography, are some of the factors affecting their accumulation and seasonal variation. Thus, density of nitrogen and carbon in wetlands are important for soil quality. They also influence the carbon and nitrogen sequestration potential as well as reducing atmospheric CO₂ and mitigating the threat of global warming.Background: Soil organic carbon and total nitrogen are important components of wetland soils; they can greatly influence the wetland ecosystem fertility, quality and productivity. Accurate estimation of wetland carbon densities and pools is aprerequisite for wetland resource conservation and implementation of carbon sink enhancement plans. This study was designed to investigate the dynamics and spatial distribution in Soil Organic Carbon (SOC) and total nitrogen (TN), and SOC and TN density stocks in Lagos lagoon wetlands and the influence of other soil physicochemical parameters on them.Results: The SOC content generally exhibited high seasonal variations for all the sampling points in the wetlands. For wet season it ranges from 12.71±0.15 - 164.995±1.65 g/kg with a coefficient of variation of 40.99%, and dry season ranged from 132.02±3.520 - 383.570±8.43 g/kg with a coefficient of variation of 34.45%. The soil carbon content in the wet season was much lower than the dry season. The total nitrogen content in the wet season ranged from 4.53 – 16.58 g/kg with a coefficient of variation of 27.96%, while the dry season ranged between 10.16 and 40.31 g/kg with a coefficient of variation of 29.39%.The SOC density of Lagos lagoon wetlands for tops soils ranged from 10.53 to 37.89 kgm−2 with an arithmetic mean of 26.70±1.41 kgm−2 and TND ranged from 0.61 to 2.37 kgm−2 with an arithmetic mean of 1.96±0.09 kgm−2. Pearson correlation reveal a positive correlation between SOC and TN concentrations (r=0.643), bulk density was positively correlated also with SOC (r=0.344), TN and bulk density (r=0.478) and soil moisture content and pH (r=0.085) were also positively correlated. In the present study, a negative correlation was observed in SOC and pH, and TN and pH. The results suggest that nitrogen content, moisture content and bulk density, which are significantly influenced by vegetation cover and types, seasons and topography, are some of the factors affecting soil organic carbon and nitrogen accumulation and seasonal variation.Conclusion: This study provided an insight in the understanding of the seasonal and spatial distribution of SOC and TN density in the Lagos lagoon wetland. In conclusion, the estimation of the density and storage of nitrogen and organic carbon in the wetlands are important for knowing and maintaining the quality of the soils, and they also influence the carbon and nitrogen sequestration potential of the wetlands as well as reducing atmospheric CO₂ and mitigating the threat of global warming.
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