The aim of this study was to quantify the current soil organic carbon stock under different types of savannah agrosystems in the Sudano-Sahelian zone of Cameroon in the context of greenhouse gas emissions and land degradation. It is so crucial for combating climate change and improving ecological restoration. Random field sampling was carried out on 0-10, 10-20 and 20-30 cm depth, then were collected in four types of savannah agrosystems. Soil bulk density, pH, moisture content, CEC, exchangeable bases, particle size distribution and soil organic carbon were determined using standard laboratory procedures and calculations. The results of the study did not reveal a significant difference in soil organic carbon stock between different types of savannah agrosystems (P>0.05). Soils of Tamarindus indica savannah agrosystems in recorded higher values SCOS (36.03 ± 3.31 tC/ha), Prosopis africana (33.40 ± 3.27 tC/ha), Haematostaphis barterii (31.83 ± 3.21 tC/ha) and Detarium microcarpum (31.19 ± 3.19 tC/ha) savannah agrosystems. Similarly, SCOS decreased with soil depth in all types of savannah agrosystems. Results showed a positive and significant (P<0.05) correlation between soil organic carbon stock with basal area, biovolume, bulk density, moisture content, C/N ratio, Ca 2+ , Mg 2+ , OM; negative and significant (P<0.05) with Soil pH, Total Nitrogen, Na + but negative and non-significant (P>0.05) with Density, K + , CEC, Sand %, Silt %, Clay %, Silt + Clay %. The results show the potential contribution of savannah agrosystems to improve soil organic carbon sequestration and environmental protection.

The vegetation and the afforestation of agricultural land non-forest represent a potential increase in carbon stocks which could, under certain conditions and within certain limits, compensate part of the emissions resulting from the use of fossil fuels and deforestations. Quantification of stocks of biomass and carbon dioxide contained in agroforestry systems has become an international priority within the framework of the implementation of REDD+ mechanism. Estimates of stocks of carbon in woody biomass, dead organic matter, belowground biomass, litter, herbaceous and lianas plant biomass were incorporated in allometric equation based on non-destructive method. The total carbon stock evaluated in the parkland of Tectona grandis was 207.34 ton/3ha out of which woody biomass accounted for 130.19 ton/3ha belowground biomass (40.4 ton/3ha), dead organic matter (22.85 ton/3ha), litter (9.09 ton/3ha), herbaceous plant biomass (2.28 ton/3ha) and lianas (2.53 ton/3ha). The aboveground biomass therefore contributed approximately 62.80 % of the total stock of carbon assessed. This show the considerable contribution of Tectona grandis parkland to climate change mitigation in Cameroon.

The aim of this study was to quantify the current soil organic carbon stock under different age ranges of cashew agroecosystems in the Sudano-Sahelian zone of Cameroon in the context of greenhouse gas emissions and land degradation. It is so crucial for combating climate change and improving ecological restoration. Random field sampling was carried out on 0-10, 10-20 and 20-30 cm depths were collected in three age groups (0-10; 10-20; over 20 years old) of Cashew agroecosystems. Soil bulk density, Soil reaction (pH), moisture content, total nitrogen, C/N ratio, particle size distribution and soil organic carbon were determined using standard laboratory procedures and calculations. The results of the study did not reveal a significant difference in soil organic carbon stock across the different age groups of the cashew agroecosystems (P>0.05). The highest values of soil organic carbon stocks were observed in the 0-10 cm depth. Soils under plots with over 20 cashew agroecosystems in Bénoué subdivisions recorded higher SOCS values (36.30±2.92 tC/ha). Similarly, the SOCS decreased with soil depth in all three age groups of Cashew agroecosystems. The mean SOC concentrations (%) ranged from 0.20±0.02-0.41±0.10%. Soil organic carbon stock ranged from 16.45±0.73-37.04±2.32 tC/ha depending on depth between the three age ranges of Cashew agroecosystems studied in the four subdivisions. The Cashew agroecosystems soils with high C stock are those with sandy loamy texture (25.79±2.29 tC/ha). Results showed a positive and significant (P<0.05) correlation between soil organic C stock with bulk density, moisture content, C/N ratio, SOC; negative and significant (P<0.05) with Soil reaction (pH), Total Nitrogen, but negative and non-significant (P>0.05) with % Sand, % Silt, % Clay, % Silt + Clay. The results show the potential contribution of Cashew agroecosystems to improve soil organic carbon sequestration and environmental protection. This information will be necessary for developing appropriate technological and political solutions to increase agricultural sustainability and combat environmental degradation in the Sudano-Sahelian zone of Cameroon.

The present study investigated the floristic structure and ecological role of Rourea afzelii stands insavannah, forest galleries and swampy areas to Cameroon. An 80 m x 50 m transect method wasundertaken to measure floristic diversity using Shannon index, Pielou equitability, Simpson’s indexand the importance value index. The structure of Rourea afzelii stands is determined by density,basal area and biovolume. The results of this study show that Rourea afzelii stands are morediversified in savannah with a Shannon diversity index (ISH =4 ± 0.03bit). The highest log stabilityof Rourea afzelii stands is observed in the savannah (EQ=0.75 ± 0.008). The Simpson index of theRourea afzelii stands is larger in the forest gallery (D=0.088 ± 0.0022). Rourea afzelii Stands aredenser in savannah (113 ± 2.54 individuals/ha). The basal area and biovolume of Rourea afzeliistands are very high in swamp area (St=15.75 ± 0.02 m2/ha, Biov=9.08 ± 0.12 m3/ha). The diametricstructure has an asymmetrical “L” shaped appearance, indicating a strong regeneration of Roureaafzelii Stands in the three sites studied. Rourea afzelii Stands in forest galleries sequestered morecarbon (26.41 ± 0.0015 ton C/ha) than those in savannahs and swampy areas. This valuecorresponds to sequestration of carbon dioxide of 96.92 ± 0.82 ton CO2/ha. Economically, thiscorresponds to the CDM carbon price (290.77± 3.332 Euros/ha), a Voluntary Market Carbon Priceof 455.54 ± 1.908 Euros/ha, a REDD + carbon price of 9692 ± 8.152 Euros/ha. In conclusion, theresults of this study can be used in the context of protection and conservation as well as thedomestication of such a species.

The present work has been done to provide basic data for a better conservation and valorization ofKhaya senegalensis stands in Sudano-Sahelian zone of Cameroon. A 100 m x 50 m transectmethod was undertaken to measure floristic diversity through the use of species richness,Shannon index, Pielou equitability, Simpson index, importance value index and importance valuefamily. The vegetation structure is determined by density, basal area and biovolume. Theinventory included trees with a dbh ?10 cm on an area of 1 ha per plot. A total of 6743individuals distributed in 24 families, 33 genera and 54 species were inventoried in all Khayasenegalensis stands studied. Statistical analysis showed significant differences, Shannon index,Simpson index, Pielou equitability, density, basal area, biovolume, species richness, heights class,diameters class, circumferences class but does not certify a significant difference of importancevalue index among in the villages. The undergrowth of Khaya senegalensis stands is more diverseat Bamé with a Shannon diversity index (ISH=5.87 ± 0.12 bit). The greatest of Pielou equitabilityis observed at Bamé (EQ=0.80 ± 0.01). The largest of Simpson index is recorded at Bamé(D=0.098 ± 0.001). Khaya senegalensis Stands are denser at Bamé (194 ± 3.12 individuals/ha).The basal area and biovolume of Khaya senegalensis stands are very high at Bamé (BA=25.87 ±0.06 m2/ha and Biovolume =15.32 ± 0.012 m3/ha). The species importance value is maximal in allthe studied villages (SIV=300 ± 71.45). The importance value index of species revealed a cleardominance in the undergrowth of Khaya senegalensis stands are Combretum adenogonium;Acacia senegal; Terminalia laxiflora; Guiera senegalensis; Acacia nilotica; Entada Africana.The vertical structure has three aspects, like the L (Dbh), asymmetric (height) and dissymmetrical(circumference) structures attesting to a strong regeneration of the understory ligneous woods ofKhaya senegalensis stands studied.