<p align="justify"> <span style="font-family:Verdana;"></span><span style="font-family:Verdana;"></span>Soil organic carbon (SOC) mineralization was carried ...<p align="justify"> <span style="font-family:Verdana;"></span><span style="font-family:Verdana;"></span>Soil organic carbon (SOC) mineralization was carried out on soil samples collected from two depths: 0 - 20 cm and 20 - 40 cm for all land use (LU) types (grasslands, croplands, natural forest/fallow lands, cocoa/palm plantations, and settlement/agro-forests). Microbiological analyses were carried out by measuring microbial activity in 40 g of dried soil samples wetted to 60% water holding capacity and incubated at 27 °C. Carbon dioxide (CO<sub>2</sub>) emission was measured for 10 weeks using a CO<sub>2</sub> trap. Descriptive and graphical analyses of CO<sub>2</sub> respiration were done using CO<sub>2 </sub>emission data. Models were developed to describe CO<sub>2</sub> respiration and the first order kinetic model provided best fit to C-mineralization. Potentially mineralizable carbon (C<sub>o</sub>) and C-mineralization rate were higher in grasslands than other LU types, indicating a higher rate of microbial activity and carbon cycling. Metabolic quotient was higher in forest/fallow lands and reflects greater stress of the microbial community and a high requirement of maintenance energy. Grasslands enhanced more SOC accumulation and decomposition, suggesting a better carbon sink than other land use and management systems (LUMS). Microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) varied across LU patterns with maximum values in grasslands and minimum values in natural forest/fallow lands insinuating better soil quality for grasslands. MBC and SOC positively correlated with C<sub>o</sub> and C-mineralization, which intimates that C-mineralization is influenced by availability of MBC and SOC. Metabolic quotient (qCO<sub>2</sub>) negatively correlated with microbial quotient (MBC:SOC), depicting that higher values of qCO<sub>2</sub> signify difficulties in using organic substrates during microbial activity as a result of low MBC:SOC. Changes in LUMS affected the mineralization kinetics of SOC in the study area. </p>展开更多
This work assessed the impact of land use and land cover (LULC) change on the socio-economic conditions of the inhabitants in the Mount Bambouto Caldera from 1980-2016. To achieve this, three time series satellite ima...This work assessed the impact of land use and land cover (LULC) change on the socio-economic conditions of the inhabitants in the Mount Bambouto Caldera from 1980-2016. To achieve this, three time series satellite images;Landsat Thematic Mapper (TM) (1980), Landsat Enhanced Thematic Mapper (ETM) (2001), and Landsat 8 Operational Land Imager (OLI) (2016) scenes were employed to investigate the changes in LULC. The use of satellite images was supplemented with individual interviews, discussions with focus groups and key informants, and direct field observations. Five categories of LULC classes were identified namely: thick woody vegetation (natural forest and oil palms), light vegetation (croplands), savannah (grasslands), buildings (settlements), and bare grounds. The results showed that between 1980 and 2016, croplands, buildings and bare lands increased by 4%, 0.43% and 5.7% respectively while savannah/grassland and natural forest decreased by 4.4% and 5.8% respectively. Household survey revealed soil fertility decline and lack of credit schemes to be major constraints to crop production. Many religious holidays contribute to seasonal food shortages and the community faces a host of socio-economic and institutional challenges. Consequently, majority of house-holds are destitute, live in abject poverty;which is an indication of the need for interventions by government and other development stakeholders to tackle the problems of soil fertility, land use change and food insecurity.展开更多
Mount Bambouto is a polygenic stratovolcano of the Cameroon Volcanic Line,built between 21 Ma and 4.5 Ma(Nkouathio et al.,2008).It is situated at about 200 km NE of mount Cameroon,at 09°55′and 10°15′East a...Mount Bambouto is a polygenic stratovolcano of the Cameroon Volcanic Line,built between 21 Ma and 4.5 Ma(Nkouathio et al.,2008).It is situated at about 200 km NE of mount Cameroon,at 09°55′and 10°15′East and,05°25′and 05°50′North.This volcano covers an area of 500 Km^2 and culminates at 2740 m at Meletan hill and bears a collapsed elliptical caldera at the summit(13×8 km).Mount展开更多
Mount Bambouto is a polygenic stratovolcano of the Cameroon Volcanic Line, built between 21 Ma and 4.5 Ma. It is situated approximately 200 km NE of Mount Cameroon, between 09° 55＇ and 10°15＇ longitude eas...Mount Bambouto is a polygenic stratovolcano of the Cameroon Volcanic Line, built between 21 Ma and 4.5 Ma. It is situated approximately 200 km NE of Mount Cameroon, between 09° 55＇ and 10°15＇ longitude east and, 05°25＇ and 05°50＇ latitude north. The volcano covers an area of 500 km^2 and culminates at 2740 m at Meletan dome and bears a collapsed caldera at the summit （13 × 8 km）. Mount Bambouto is characterized by several natural hazards of different origins： meteorological, such as landslides and rock falls; anthropogenic, such as bushfires, tribal wars and deforestation; and volcanological, such as volcanic eruption. The thematic map shows that 55-60% of the caldera has high probability of occurrence of mass movement. The caldera has a high population density （3000 inhabitants）, which increases the level of risk, evaluated at approximately $US3.8 million for patrimony, 3000 civilian deaths and destruction of biodiversity.展开更多
文摘<p align="justify"> <span style="font-family:Verdana;"></span><span style="font-family:Verdana;"></span>Soil organic carbon (SOC) mineralization was carried out on soil samples collected from two depths: 0 - 20 cm and 20 - 40 cm for all land use (LU) types (grasslands, croplands, natural forest/fallow lands, cocoa/palm plantations, and settlement/agro-forests). Microbiological analyses were carried out by measuring microbial activity in 40 g of dried soil samples wetted to 60% water holding capacity and incubated at 27 °C. Carbon dioxide (CO<sub>2</sub>) emission was measured for 10 weeks using a CO<sub>2</sub> trap. Descriptive and graphical analyses of CO<sub>2</sub> respiration were done using CO<sub>2 </sub>emission data. Models were developed to describe CO<sub>2</sub> respiration and the first order kinetic model provided best fit to C-mineralization. Potentially mineralizable carbon (C<sub>o</sub>) and C-mineralization rate were higher in grasslands than other LU types, indicating a higher rate of microbial activity and carbon cycling. Metabolic quotient was higher in forest/fallow lands and reflects greater stress of the microbial community and a high requirement of maintenance energy. Grasslands enhanced more SOC accumulation and decomposition, suggesting a better carbon sink than other land use and management systems (LUMS). Microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) varied across LU patterns with maximum values in grasslands and minimum values in natural forest/fallow lands insinuating better soil quality for grasslands. MBC and SOC positively correlated with C<sub>o</sub> and C-mineralization, which intimates that C-mineralization is influenced by availability of MBC and SOC. Metabolic quotient (qCO<sub>2</sub>) negatively correlated with microbial quotient (MBC:SOC), depicting that higher values of qCO<sub>2</sub> signify difficulties in using organic substrates during microbial activity as a result of low MBC:SOC. Changes in LUMS affected the mineralization kinetics of SOC in the study area. </p>
文摘This work assessed the impact of land use and land cover (LULC) change on the socio-economic conditions of the inhabitants in the Mount Bambouto Caldera from 1980-2016. To achieve this, three time series satellite images;Landsat Thematic Mapper (TM) (1980), Landsat Enhanced Thematic Mapper (ETM) (2001), and Landsat 8 Operational Land Imager (OLI) (2016) scenes were employed to investigate the changes in LULC. The use of satellite images was supplemented with individual interviews, discussions with focus groups and key informants, and direct field observations. Five categories of LULC classes were identified namely: thick woody vegetation (natural forest and oil palms), light vegetation (croplands), savannah (grasslands), buildings (settlements), and bare grounds. The results showed that between 1980 and 2016, croplands, buildings and bare lands increased by 4%, 0.43% and 5.7% respectively while savannah/grassland and natural forest decreased by 4.4% and 5.8% respectively. Household survey revealed soil fertility decline and lack of credit schemes to be major constraints to crop production. Many religious holidays contribute to seasonal food shortages and the community faces a host of socio-economic and institutional challenges. Consequently, majority of house-holds are destitute, live in abject poverty;which is an indication of the need for interventions by government and other development stakeholders to tackle the problems of soil fertility, land use change and food insecurity.
文摘Mount Bambouto is a polygenic stratovolcano of the Cameroon Volcanic Line,built between 21 Ma and 4.5 Ma(Nkouathio et al.,2008).It is situated at about 200 km NE of mount Cameroon,at 09°55′and 10°15′East and,05°25′and 05°50′North.This volcano covers an area of 500 Km^2 and culminates at 2740 m at Meletan hill and bears a collapsed elliptical caldera at the summit(13×8 km).Mount
文摘Mount Bambouto is a polygenic stratovolcano of the Cameroon Volcanic Line, built between 21 Ma and 4.5 Ma. It is situated approximately 200 km NE of Mount Cameroon, between 09° 55＇ and 10°15＇ longitude east and, 05°25＇ and 05°50＇ latitude north. The volcano covers an area of 500 km^2 and culminates at 2740 m at Meletan dome and bears a collapsed caldera at the summit （13 × 8 km）. Mount Bambouto is characterized by several natural hazards of different origins： meteorological, such as landslides and rock falls; anthropogenic, such as bushfires, tribal wars and deforestation; and volcanological, such as volcanic eruption. The thematic map shows that 55-60% of the caldera has high probability of occurrence of mass movement. The caldera has a high population density （3000 inhabitants）, which increases the level of risk, evaluated at approximately $US3.8 million for patrimony, 3000 civilian deaths and destruction of biodiversity.
