Agroforestry,as a platform for harmonizing agriculture and forestry is a win-win approach for the farming community and environmental sustainability.However,its potential is not well studied and quantified in Northwes...Agroforestry,as a platform for harmonizing agriculture and forestry is a win-win approach for the farming community and environmental sustainability.However,its potential is not well studied and quantified in Northwestern highland.Thus,this study aimed to investigate the woody species diversity,and carbon stock potential of traditional agroforestry practices in Northwestern Highlands(NWH)of Ethiopia.A total of 120 households were selected using stratified sampling for household(HH)surveys,and vegetation inventory was conducted in the winter season of 2023 on systematically laid 400 m2 sample quadrats.Shannon-Weiner diversity index(H’),Simpson’s diversity index(1-D)and Shannon evenness(E)were calculated to estimate woody species diversity.Variation in species diversity and carbon stock within and between agroforestry practices was assessed by 1-way ANOVA and rank differences were separated by post-hoc,Tukey HSD multiple comparison test.The result showed that four different agroforestry practices were identified,consisting of 44 woody species belonging to 23 families.Homegarden was the richest in terms of woody species composition(30),followed by boundary planting(25),while parkland agroforestry had the poorest species composition(12).The total carbon stock of the agroforestry practices in the study ranged from 92.51±29.21 to 143.52±47.83 Mg/ha),with soil organic carbon accounting for about 57.66%,followed by aboveground biomass carbon with 32.1%.Homegardens agroforestry had contributed more to the total carbon stocks than the other agroforestry practices.The total CO_(2)sequestration by above and below ground biomass of woody species in the traditional agroforestry practices of the NWH was estimated to be 519.97 and 104.01 Mg/ha,respectively.The study confirmed that the traditional agroforestry practices of the NWH of Ethiopia maintain a high diversity of woody species and are remarkably important for biodiversity conservation and climate change mitigation.展开更多
An efficient and reliable automated model that can map physical Soil and Water Conservation（SWC） structures on cultivated land was developed using very high spatial resolution imagery obtained from Google Earth and ...An efficient and reliable automated model that can map physical Soil and Water Conservation（SWC） structures on cultivated land was developed using very high spatial resolution imagery obtained from Google Earth and Arc GIS？ERDAS IMAGINE？and SDC Morphology Toolbox for MATLAB and statistical techniques. The model was developed using the following procedures：（1） a high-pass spatial filter algorithm was applied to detect linear features,（2） morphological processing was used to remove unwanted linear features,（3） the raster format was vectorized,（4） the vectorized linear features were split per hectare（ha） and each line was then classified according to its compass directionand（5） the sum of all vector lengths per class of direction per ha was calculated. Finallythe direction class with the greatest length was selected from each ha to predict the physical SWC structures. The model was calibrated and validated on the Ethiopian Highlands. The model correctly mapped 80% of the existing structures. The developed model was then tested at different sites with different topography. The results show that the developed model is feasible for automated mapping of physical SWC structures. Thereforethe model is useful for predicting and mapping physical SWC structures areas across diverse areas.展开更多
Analysis of the nexus between vegetation dynamics and climatic parameters like surface temperature is essential in environmental and ecological studies and for monitoring of the natural resources. This study explored ...Analysis of the nexus between vegetation dynamics and climatic parameters like surface temperature is essential in environmental and ecological studies and for monitoring of the natural resources. This study explored the spatio-temporal distribution of land surface temperature(LST) and Normalized Difference Vegetation Index(NDVI) and the relationship between them in the Andassa watershed from 1986 to 2016 periods using Landsat data. Monthly average air temperature data of three meteorological sites were used for validating the results. The findings of the study showed that the LST of the Andassa watershed has increased during the study periods. Overall, average LST has been rising with an increasing rate of 0.081?C per year. Other results of this study also showed that there has been a dynamic change in vegetation cover of the watershed in all seasons. There was also a negative correlation between LST and NDVI in all the studied years. From this study we can understand that there has been degradation of vegetation and intensification of LST from 1986 to 2016.展开更多
Background:Soil erosion is one of the major threats in the Ethiopian highlands.In this study,soil erosion in the Muga watershed of the Upper Blue Nile Basin(Abay)under historical and future climate and land use/land c...Background:Soil erosion is one of the major threats in the Ethiopian highlands.In this study,soil erosion in the Muga watershed of the Upper Blue Nile Basin(Abay)under historical and future climate and land use/land cover(LULC)change was assessed.Future LULC was predicted based on LULC map of 1985,2002,and 2017.LULC maps of the historical periods were delineated from Landsat images,and future LULC was predicted using the CA–Markov chain model.Precipitation for the future period was projected from six regional circulation models.The RUSLE model was used to estimate the current and future soil erosion rate in Muga watershed.Results:The average annual rate of soil erosion in the study area was increased from about 15 t ha^(−1) year^(−1) in 1985 to 19 t ha^(−1) year^(−1) in 2002,and 19.7 t ha^(−1) year^(−1) in 2017.Expansion of crop cultivation and loss of vegetation caused an increase in soil erosion.Unless proper measure is taken against the LULC changes,the rate of soil loss is expected to increase and reach about 20.7 t ha^(−1) year^(−1) in 2033.In the 2050s,soil loss is projected to increase by 9.6%and 11.3%under RCP4.5 and RCP8.5,respectively,compared with the baseline period.Thus,the soil loss rate is expected to increase under both scenarios due to the higher erosive power of the future intense rainfall.When both LULC and climate changes act together,the mean annual soil loss rate shows a rise of 13.2%and 15.7%in the future under RCP4.5 and RCP8.5,respectively,which is due to synergistic efects.Conclusions:The results of this study can be useful for formulating proper land use planning and investments to mitigate the adverse efect of LULC on soil loss.Furthermore,climate change will exacerbate the existing soil erosion problem and would need for vigorous proper conservation policies and investments to mitigate the negative impacts of climate change on soil loss.展开更多
Soil erosion is a serious environmental problem arising from agricultural intensification and landscape changes.Improper land management coupled with intense rainfall has intricated the problem in most parts of the Et...Soil erosion is a serious environmental problem arising from agricultural intensification and landscape changes.Improper land management coupled with intense rainfall has intricated the problem in most parts of the Ethiopian highlands.Soil loss costs a profound amount of the national GDP.Thus,quantifying soil loss and prioritizing areas for conservation is imperative for proper planning and resource conser-vation.Therefore,this study has modeled the mean soil loss and annual sediment yield of the Gumara watershed.Landsat 5 TM,Landsat 7ETM+,and Landsat 8 OLI were used for land use land cover(LULC)change analysis.Besides these,other datasets related to rainfall,digital soil map,Digital Elevation Model,reference land use,and cover(LULC)ground truth points were used to generate parameters for modeling soil loss.The watershed was classified into five major land-use classes(water body,cultivated land,grazing land,built-up and forest and plantation)using a maximum likelihood algorithm covering a period of the last 30 years(1988-2019).The mean annual soil loss and sediment yield were quantified using RUSLE,Sediment delivery ratio(SDR),and Sediment Yields models(SY).The analysis result unveils that within the past 30 years,the watershed has undergone significant LULC changes from forest&plantation(46.33%)and grazing land to cultivated land(31.59%)with the rate of-1.42km^(2)yr^(-1) and-2.80km^(2)yr^(-1) respectively.In the same vein,the built-up area has expanded to cultivated and grazing land.Subsequently,nearly 15%(207 km2)of the watershed suffered from moderate to very severe soil loss.On average,the watershed losses 24.2t ha^(-1) yr^(-1) of soil and yields 2807.02t ha^(-1) yr^(-1) sediment.Annually,the watershed losses 385,157t ha^(-1)yr^(-1) soil from the whole study area.Among the admir-ative districts,Farta(Askuma,Giribi,Mahidere Mariam and Arigo kebeles),Fogera(Gazen Aridafofota and Gura Amba kebeles),East Este(Witimera kebele),and Dera(Gedame Eyesus and Deriana Wechit kebeles)districts which cover 50%of the watershed were found severely affected by soil erosion.Thus,to curve back this scenario,soil and water conservation practices should prioritize in the aforementioned districts of the watersheds.展开更多
基金financed by Debre Markose University Burie Campus.
文摘Agroforestry,as a platform for harmonizing agriculture and forestry is a win-win approach for the farming community and environmental sustainability.However,its potential is not well studied and quantified in Northwestern highland.Thus,this study aimed to investigate the woody species diversity,and carbon stock potential of traditional agroforestry practices in Northwestern Highlands(NWH)of Ethiopia.A total of 120 households were selected using stratified sampling for household(HH)surveys,and vegetation inventory was conducted in the winter season of 2023 on systematically laid 400 m2 sample quadrats.Shannon-Weiner diversity index(H’),Simpson’s diversity index(1-D)and Shannon evenness(E)were calculated to estimate woody species diversity.Variation in species diversity and carbon stock within and between agroforestry practices was assessed by 1-way ANOVA and rank differences were separated by post-hoc,Tukey HSD multiple comparison test.The result showed that four different agroforestry practices were identified,consisting of 44 woody species belonging to 23 families.Homegarden was the richest in terms of woody species composition(30),followed by boundary planting(25),while parkland agroforestry had the poorest species composition(12).The total carbon stock of the agroforestry practices in the study ranged from 92.51±29.21 to 143.52±47.83 Mg/ha),with soil organic carbon accounting for about 57.66%,followed by aboveground biomass carbon with 32.1%.Homegardens agroforestry had contributed more to the total carbon stocks than the other agroforestry practices.The total CO_(2)sequestration by above and below ground biomass of woody species in the traditional agroforestry practices of the NWH was estimated to be 519.97 and 104.01 Mg/ha,respectively.The study confirmed that the traditional agroforestry practices of the NWH of Ethiopia maintain a high diversity of woody species and are remarkably important for biodiversity conservation and climate change mitigation.
基金covered by the Swiss National Centre of Competence in Research North-South (NCCR North-South) program
文摘An efficient and reliable automated model that can map physical Soil and Water Conservation（SWC） structures on cultivated land was developed using very high spatial resolution imagery obtained from Google Earth and Arc GIS？ERDAS IMAGINE？and SDC Morphology Toolbox for MATLAB and statistical techniques. The model was developed using the following procedures：（1） a high-pass spatial filter algorithm was applied to detect linear features,（2） morphological processing was used to remove unwanted linear features,（3） the raster format was vectorized,（4） the vectorized linear features were split per hectare（ha） and each line was then classified according to its compass directionand（5） the sum of all vector lengths per class of direction per ha was calculated. Finallythe direction class with the greatest length was selected from each ha to predict the physical SWC structures. The model was calibrated and validated on the Ethiopian Highlands. The model correctly mapped 80% of the existing structures. The developed model was then tested at different sites with different topography. The results show that the developed model is feasible for automated mapping of physical SWC structures. Thereforethe model is useful for predicting and mapping physical SWC structures areas across diverse areas.
文摘Analysis of the nexus between vegetation dynamics and climatic parameters like surface temperature is essential in environmental and ecological studies and for monitoring of the natural resources. This study explored the spatio-temporal distribution of land surface temperature(LST) and Normalized Difference Vegetation Index(NDVI) and the relationship between them in the Andassa watershed from 1986 to 2016 periods using Landsat data. Monthly average air temperature data of three meteorological sites were used for validating the results. The findings of the study showed that the LST of the Andassa watershed has increased during the study periods. Overall, average LST has been rising with an increasing rate of 0.081?C per year. Other results of this study also showed that there has been a dynamic change in vegetation cover of the watershed in all seasons. There was also a negative correlation between LST and NDVI in all the studied years. From this study we can understand that there has been degradation of vegetation and intensification of LST from 1986 to 2016.
基金The International Foundation for Science had funded this research(IFS)(Grant No.W_6250-1,January 2019)and Bahir Dar University。
文摘Background:Soil erosion is one of the major threats in the Ethiopian highlands.In this study,soil erosion in the Muga watershed of the Upper Blue Nile Basin(Abay)under historical and future climate and land use/land cover(LULC)change was assessed.Future LULC was predicted based on LULC map of 1985,2002,and 2017.LULC maps of the historical periods were delineated from Landsat images,and future LULC was predicted using the CA–Markov chain model.Precipitation for the future period was projected from six regional circulation models.The RUSLE model was used to estimate the current and future soil erosion rate in Muga watershed.Results:The average annual rate of soil erosion in the study area was increased from about 15 t ha^(−1) year^(−1) in 1985 to 19 t ha^(−1) year^(−1) in 2002,and 19.7 t ha^(−1) year^(−1) in 2017.Expansion of crop cultivation and loss of vegetation caused an increase in soil erosion.Unless proper measure is taken against the LULC changes,the rate of soil loss is expected to increase and reach about 20.7 t ha^(−1) year^(−1) in 2033.In the 2050s,soil loss is projected to increase by 9.6%and 11.3%under RCP4.5 and RCP8.5,respectively,compared with the baseline period.Thus,the soil loss rate is expected to increase under both scenarios due to the higher erosive power of the future intense rainfall.When both LULC and climate changes act together,the mean annual soil loss rate shows a rise of 13.2%and 15.7%in the future under RCP4.5 and RCP8.5,respectively,which is due to synergistic efects.Conclusions:The results of this study can be useful for formulating proper land use planning and investments to mitigate the adverse efect of LULC on soil loss.Furthermore,climate change will exacerbate the existing soil erosion problem and would need for vigorous proper conservation policies and investments to mitigate the negative impacts of climate change on soil loss.
文摘Soil erosion is a serious environmental problem arising from agricultural intensification and landscape changes.Improper land management coupled with intense rainfall has intricated the problem in most parts of the Ethiopian highlands.Soil loss costs a profound amount of the national GDP.Thus,quantifying soil loss and prioritizing areas for conservation is imperative for proper planning and resource conser-vation.Therefore,this study has modeled the mean soil loss and annual sediment yield of the Gumara watershed.Landsat 5 TM,Landsat 7ETM+,and Landsat 8 OLI were used for land use land cover(LULC)change analysis.Besides these,other datasets related to rainfall,digital soil map,Digital Elevation Model,reference land use,and cover(LULC)ground truth points were used to generate parameters for modeling soil loss.The watershed was classified into five major land-use classes(water body,cultivated land,grazing land,built-up and forest and plantation)using a maximum likelihood algorithm covering a period of the last 30 years(1988-2019).The mean annual soil loss and sediment yield were quantified using RUSLE,Sediment delivery ratio(SDR),and Sediment Yields models(SY).The analysis result unveils that within the past 30 years,the watershed has undergone significant LULC changes from forest&plantation(46.33%)and grazing land to cultivated land(31.59%)with the rate of-1.42km^(2)yr^(-1) and-2.80km^(2)yr^(-1) respectively.In the same vein,the built-up area has expanded to cultivated and grazing land.Subsequently,nearly 15%(207 km2)of the watershed suffered from moderate to very severe soil loss.On average,the watershed losses 24.2t ha^(-1) yr^(-1) of soil and yields 2807.02t ha^(-1) yr^(-1) sediment.Annually,the watershed losses 385,157t ha^(-1)yr^(-1) soil from the whole study area.Among the admir-ative districts,Farta(Askuma,Giribi,Mahidere Mariam and Arigo kebeles),Fogera(Gazen Aridafofota and Gura Amba kebeles),East Este(Witimera kebele),and Dera(Gedame Eyesus and Deriana Wechit kebeles)districts which cover 50%of the watershed were found severely affected by soil erosion.Thus,to curve back this scenario,soil and water conservation practices should prioritize in the aforementioned districts of the watersheds.
