Climate Smart Agriculture

Assessment of Woody Species Diversity and Carbon Stock Estimation along Altitudinal Gradient of Kulkal Ber Natural Forest in Maksegnet District, Northwestern Ethiopia

Wed, 01 Jan 2025 00:00:00 GMT

Assessment of Woody Species Diversity and Carbon Stock Estimation along Altitudinal Gradient of Kulkal Ber Natural Forest in Maksegnet District, Northwestern Ethiopia Belayneh (PhD.), Anteneh; Toru (PhD, Tessema Forest ecosystems play a vital role in mitigating climate change and conserving biodiversity. Assessing their woody species diversity and carbon stocks along altitudinal gradient is essential for informing forest management strategies that enhance carbon sequestration in both vegetation and soil. This study aimed to establish baseline data on woody species diversity, structural attributes, and carbon stock potential along altitudinal gradient of the Kulkal Ber Natural Forest in Maksegnet District, Northwestern Ethiopia. Data collection was conducted using a stratified systematic sampling approach. Six transects, spaced 500 m apart along the altitudinal gradient, were established. A total of 60 plots (20 m × 20 m) were systematically placed at 200 m intervals along the transect lines. Additionally, five 5 m × 5 m subplots (positioned at the corners and center of the main plot) were used for sampling shrubs. Within each 5 m × 5 m subplot, a single 1 m × 1 m nested subplot was used to collect ground herbaceous layer (GHL) and soil samples. Woody species diversity was assessed using the Shannon-Wiener diversity index (H'), while hierarchical cluster analysis was performed to classify plant community types. Above and belowground biomass was estimated using general allometric models, and soil organic carbon (SOC) and grass, herb, and litter (GHL) carbon content were determined through laboratory analysis. A total of 36 woody species belonging to 26 families and 31 genera were identified. The overall Shannon-Wiener diversity index (H') was 1.801, with an evenness value of 0.48. The six most abundant species, in descending order of density, were Dodonaea angustifolia, Combretum molle, Rhus glutinosa, Millettia ferruginea, Rhus vulgaris, and Cordia africana. The forest’s basal area was 6.53 m² ha⁻¹. ANOVA results indicated that altitudinal variation had no significant effect on species diversity. However, species composition, evenness value, and structural attributes highlighted the dominance of few species, with low importance value indices. Hierarchical cluster analysis identified three distinct plant community types, such as Ficus thonningii–Dodonaea viscosa, Olea europaea–Clausena anisata, and Myrsine africana–Euphorbia tirucalli. The total mean carbon stock of the forest was 150.76 t C ha⁻¹, with aboveground carbon (AGC) of 57.29 t C ha⁻¹, belowground carbon (BGC) of 15.47 t C ha⁻¹, grass, herb and litter (GHL) carbon of 3.21 t C ha⁻¹, deadwood carbon (DWC) of 2.86 t C ha⁻¹, and soil organic carbon (SOC) of 71.93 t C ha⁻¹. While AGC, BGC, and SOC showed no significant variation with altitude, GHL carbon was significantly higher at lower altitudes, suggesting that altitude influences ground herbaceous layer carbon accumulation. The forest’s population structure exhibited a reversed J-shaped height class distribution in the two altitudinal gradients, dominated by small trees and shrubs, indicating good regeneration potential. These findings emphasize the importance of conservation measures and sustainable management strategies to safeguard the genetic resources and carbon sequestration capacity of Kulkal Ber Natural Forest 85

PLANT DIVERSITY AND DETERMINANT OF FARMER PREFERENCE OF SPECIES IN SMALLHOLDER HOMEGARDEN AGROFORESTRY: THE CASE OF HABRO DISTRICT OF WEST HARARGHE ZONE, OROMIA REGIONAL STATE, ETHIOPIA

Sun, 01 Sep 2024 00:00:00 GMT

PLANT DIVERSITY AND DETERMINANT OF FARMER PREFERENCE OF SPECIES IN SMALLHOLDER HOMEGARDEN AGROFORESTRY: THE CASE OF HABRO DISTRICT OF WEST HARARGHE ZONE, OROMIA REGIONAL STATE, ETHIOPIA Abdela Mohammed; (PhD) Tessema Toru; (Assist. Prof.) Dargo Kebede Homegarden agroforestry (HGAF) has the potential to support diverse multipurpose plant species; however, the diversity of plant species and the factors influencing farmers' their preferences in smallholder homegardens are poorly understood. This study investigated plant diversity and the determinants of farmer preference for species in smallholder HGAF in Habro District. A total 149 households were selected following specify for the household survey. All trees, shrubs, and herbaceous plants were counted and recorded in 10mx10m, 5mx2m, and 1mx1m size quadrats, respectively. For Household survey a questionnaire usedand focus group discussion. The recorded data were organized and analyzed using Statistical Package for Social Sciences (SPSS) version 20 employing descriptive statistics and econometric models, specifically Multinomial logistic regression models. A total of 1,286 individual plants belonging to 60 species and 33 families, with 30% trees and 28% shrubs, were recorded. There was Significant differences (P < 0.05) in woody and herbaceous plant species richness and abundance observed among the study sites. Accordingly, Melka Balo kebele had the highest values and Gadisa kebele with the lowest. There were also significant differences in the mean Shannon index (H'), Simpson index, and evenness (E) of woody species between Melka Bello and the other two sites (Gadisa and Lugo), were the highest values in Melka Bello. The mean H'and Simpson index of herbaceous species showed significant differences (P < 0.05) only between Gadisa and the other two sites (Melka Bello and Lugo), with lower values observed in Gadisa. Mean evenness of herbaceous species showed a significant difference between Melka Bello and the other two sites (Lugo and Gadisa), with the lower value in Melka Bello. Catha edulis was the most frequent species, followed by M. paradisiaca, C. arabica, and Casimiroa edulis. The analysis of the IVI of woody species shows the dominance of only a few species in the HG. Farmers most preferred four plant species in order of Catha edulis > C. arabica > Casimiroa edulis > M. paradisiaca. Household wealth class, education, and age have a significant positive influence (p < 0.1) on farmers preference of species. Household wealth class, education, and age had a significant positive influence on the preference for planting C. edulis to C. arabica. Household wealth class and education level had a significant positive influence on the preference for Casimiroa edulis. Education had a significant positive influence on M. paradisiaca preference, while agroecology and Household experience had a significant negative influence. Promoting them while considering socio-economic factors and enhancing agro-ecological knowledge is crucial 102p.

MODELING THE IMPACT OF LAND USE/COVER, CLIMATE CHANGE, AND SOIL MANAGEMENT PRACTICE’S ON SOIL ORGANIC CARBON STOCK IN NORTHWEST AND CENTRAL RIFT VALLEY OF ETHIOPIA

Sun, 01 Dec 2024 00:00:00 GMT

MODELING THE IMPACT OF LAND USE/COVER, CLIMATE CHANGE, AND SOIL MANAGEMENT PRACTICE’S ON SOIL ORGANIC CARBON STOCK IN NORTHWEST AND CENTRAL RIFT VALLEY OF ETHIOPIA Bethel Geremew Shefine; Prof. Tsegaye Tadesse (PhD); D.rBobe Bedadi (PhD) The stock of soil organic carbon (SOC) has been impacted by changes in land use and land cover (LULC), climate change (CC), and soil management (SM) practices. Soil organic carbon loss increases when forest converted to agricultural land, and likewise SM practice like crop rotation increase SOC while tillage decrease, but the impact of CC on SOC stock is not direct. To monitor and predict the dynamics of SOC stock at various scales, soil carbon models (SCM) are essential. In Ethiopia, SCM were not validated well due to lack of skill and adequate data to use the model. In other word, SCM were not explicitly utilized in the context of CC, LULC changes, and SM practices. Thus, the objective of this study is Evaluate the likely impacts of LULCC, changing Climate, and Soil Management Practices on SOC stock of Anjeni Watershed using a modeling approach. RothC and CQESTR models were used for this study. to assess the impact of CC, LULC change, slope gradient, and the RothC model performance on SOC stock of Anjeni watershed (AW) i.e., northwest Ethiopia as well as evaluate the CQESTR model for estimating SOC response to tillage and residue removal in Melkasa agricultural research center (MARC) i.e., in central rift valley. Current and historical soil carbon, bulk density, clay content, land use, crop yield, crop residue and climate data were used as inputs to evaluate the performance of RothC and CQESTR models. The RothC model was calibrated using long-term SOC, land management, and climatic data from the AW, while CQESTR used tillage and crop residue management data from MARC. The RothC correlation coefficient between simulated and observed SOC in 1997 and 2021 were 0.77 and 0.86, respectively, whereas CQESTR model was able to simulate SOC change with correlation coefficient value of 0.89 and mean square deviation of 0.008, indicating that both models effectively characterized the SOC. The RothC model simulated higher current and projected SOC for grass/fallow land as compared to the cultivated land. The RothC model predicted/simulated slightly different SOC stock under different slope gradients, with values ranging from 4.15 ton/ha, in the lower slope gradient to 2.1 ton/ha in the upper slope gradient. xx xx The projected temperature for the year (2022-2052) indicated rising that result in increasing of SOC from the baseline for e.g., in upper slope gradient of GFDL by 0.64 and 2.1 ton/ha using IPSL (SSP5-8.5) and MPI (SSP5-2.6), respectively. The CQESTR model result in MARC indicated a declining trend of SOC under CP both in topsoil layer (0-15) and lower layer (15-30) cm soil depths, which is due to practices of tillage and crop residue removal from cultivated land in maize bean intercropping. Variations in SOC concentration was noted in the lower layer soil depths under CA, while the topsoil layer SOC for CA increased over time. The predicted SOC under CP decrease to less than 1% by 2030 from about 1.25% in the 2000s. Overall, improved SM practices including CA, soil water conservation, and the expansion of fallow lands are responsible for the anticipated SOC stock increase in both locations, which is beneficial for increasing agricultural productivity. The models tested simulated the SOC under different land use, climate scenario and soil management practices reasonably well, and hence can be used as decision support tools under Ethiopia context. However, calibration and validation of other models would be crucial and more has to be done to resolve critical shortage of long-term data across locations in the country. Without such data, the use of such decision-support tools can’t be possible. 137

THE EFFECT OF SEASONAL RAINFALL VARIABILITY ON WATER QUALITY IN LAKE MUTANDA CATCHMENT, SOUTHWESTERN UGANDA

Thu, 01 Jun 2023 00:00:00 GMT

THE EFFECT OF SEASONAL RAINFALL VARIABILITY ON WATER QUALITY IN LAKE MUTANDA CATCHMENT, SOUTHWESTERN UGANDA Turyasingura Benson; Dr. Deribachew Bekana; Dr. Charles B. Niwagaba Despite the vital importance of reliable data sets on the current effect of seasonal rainfall variability on water resources in Lake Mutanda catchment of southwestern Uganda, little is known about the status of this phenomenon. Lake Mutanda and its catchment provide water for domestic use, and irrigation. This study was aimed to assess the effects of seasonal rainfall variability on physicochemical and bacteriological water quality of Lake Mutanda and its catchments, and to suggest the water management strategies for local farmers in response to rainfall variability. Physicochemical quality parameter such as turbidity, temperature, calcium, electrical conductivity, pH, chemical oxygen demand, and nitrate was analyzed using standard method. A mixed research designs utilizing both qualitative and quantitative data collection methods was used regarding agricultural water management practices. A total of 397 respondents were selected to participate in the study using simple random and multistage sampling techniques. Survey questionnaires and key informant interview methods of data collection was also used. In terms of physicochemical quality, nitrates (7.50±0.71 mg/L), calcium (70.50±0.71 mg/L), pH (7.33±0.04), electrical conductivity (188.00±5.66 uS/cm), chemical oxygen demand (4.50±0.71 mg/L) were within the WHO guidelines during wet and dry seasons. However, turbidity (38.0±2.940 NTU), temperature was (19.20±0.14 °C), magnesium (138.5±6.36 mg/L), phosphates (9.00±0.00 mg/L), and dissolved oxygen (5.85±0.64 mg/L) were above the permissible limits (WHO, 2017) in both seasons. The study revealed that water samples from all the sampling sites contains high level of fecal coliforms (4.00±0.07 CFU/100 mL), total coliforms (16.00±1.41 CFU/100 mL), and total bacterial account (16.00±1.41 CFU/100 mL), and were not within the acceptable WHO permissible level (0/100 mL). The obtained results show poor lake water management but people use it untreated. However, there is moderate understanding of agricultural practices as reported by farmers: Mulching (38%), terracing (20%), and contour farming (15%) which would be imperative in the conservation of water quality in Lake Mutanda. Therefore, there is need for considering continuous public training, protection of water catchment areas, monitoring of water quality and treatment of water in Lake Mutanda by policy makers before the water is supplied to the public for domestic use 107