Soil degradation is a serious environmental problem in Ethiopia. However, little information is documented on indicators such as variations in soil properties across different landforms in a catchment. This study was ...Soil degradation is a serious environmental problem in Ethiopia. However, little information is documented on indicators such as variations in soil properties across different landforms in a catchment. This study was aimed to assess soil properties and their changes across sites with different erosion statuses, and identify landscape positions that require prior management attention in the Mai-Negus catchment, northern Ethiopia. Three types of erosion-status sites(stable, eroding and aggrading) were identified using reconnaissance surveys, and then the corresponding soil samples were collected and analyzed. The major soil properties were significantly varied(P ≤ 0.05) among the three erosion-status sites. The highest soil p H, organic carbon, total nitrogen, cation exchange capacity, iron and zinc were recorded from the aggrading sites in the reservoir and valley landforms of the study catchment. A higher bulk density was generally recorded in the eroding sites, whereas a lower value was observed in the aggrading sites. The highest sand content was observed in the eroding sites of the mountain followed by the central ridge landform. The paired mean difference and the correlation matrix of most soil properties between the different erosion statuses also showed significant differences. About 95% of the erosionstatus sites were correctly classified by the discriminant function, indicating that the field survey-based classification was acceptable for decision making. On the basis of this study, suitable interventions should thus be introduced to the prioritized landforms, which are the mountain and central ridge, and eroding sites with severely degraded soil properties across the catchment.展开更多
Soil-erosion-induced land degradation is a great challenge in the Ethiopian highlands. Consequently, the government has invested in soil and water conservation measures to tackle the problem where farmland terracing i...Soil-erosion-induced land degradation is a great challenge in the Ethiopian highlands. Consequently, the government has invested in soil and water conservation measures to tackle the problem where farmland terracing is one of the commonly implemented measures in the country. The purpose of this study was to analyze the role of farmland terracing in maintaining soil fertility and to evaluate its performance within a terrace, across terrace age and slope of terrain. The study was conducted in the Lake Maybar watershed in Wello, northern Ethiopia. Composite topsoil samples were collected from plots representing four slope categories across the terrain and three positions within a terrace. The samples were analyzed for selected soil physico-chemical properties and statistically tested using ANOVA （analysis of variance）. The study revealed that soil pH （△pH [H2O] = 0.6）, exchangeable K＋ （△K＋ = 0.33 cmol（＋）/kg） and clay （9%） content significantly increased towards the lower terrain position. Unlike other studies, all soil properties except bulk density （△ 0.40 g/cm3） showed non-significant differences within a terrace. Bench terrace formation reduced soil fertility gradients within a terrace for which it has been commented. Soil fertility also showed very slight change across terrace age, which indicates terracing reduced erosion-induced soil and nutrient loss. However, in order to optimize impact of farmland terracing on soil fertility maintenance, terracing should be complemented by fertility amendment considering site-specific conditions.展开更多
Identifying land management practices(LMPs)that enhance on-site sediment management and crop productivity is crucial for the prevention,reduction,and restoration of land degradation and contributing to achieving land ...Identifying land management practices(LMPs)that enhance on-site sediment management and crop productivity is crucial for the prevention,reduction,and restoration of land degradation and contributing to achieving land degradation neutrality(LDN).We reviewed studies in Ethiopia to assess the effects of LMPs on soil loss(84 studies)and crop productivity(34 studies)relative to control practice.Yield variability on conserved lands was assessed using 12,796 fixed plot data.Effects of LMP on soil loss were 0.5-55 t ha^(−1)y^(−1)compared to control practices yielding 50 to 140 t ha^(−1)y^(−1).More than 55%of soil loss records revealed soil loss less than the tolerable rate(10 t ha^(−1)).Area closure,perennial vegetation cover,agronomic practices,mechanical erosion control practices,annual cropland cover,and drainage groups of practices led to 74.0±18.3%,69.0±24.6%,66.2±30.5%,66.1±18.0%,63.5±20.0%,and 40±11,1%soil loss reduction,respectively.A yield increase of 25.2±15.0%,37.5±28.0%,and 75.4±85.0%was found from drainage,agronomy,and mechanical erosion control practices,respectively.The average yield loss by erosion on fields without appropriate land management practice and on conserved fields was 26.5±26.0%and 25±3.7%,respectively.The findings suggest that practices that entail a continuous presence of soil cover during the rainy season,perennial vegetation,retention of moisture,and barriers for sediment transport were most effective at decreasing soil loss and increasing productivity.This review provides evidence to identify the best LMP practices for wider adoption and inform decision-making on LMP investments towards achieving sustainable solutions to reverse land degradation.展开更多
The promotion of land,soil and water conservation measures has been a widespread development in sub-Saharan Africa in a bid to tackle degradation and improve productivity.As a result,several gov-ernments have launched...The promotion of land,soil and water conservation measures has been a widespread development in sub-Saharan Africa in a bid to tackle degradation and improve productivity.As a result,several gov-ernments have launched various campaigns on soil,land and water conservation measures.The aim of this study is to determine some of the factors that influence farmers'awareness(knowledge)and adoption of land,soil and water conservation practices.Data for this study was collected from 312 households using a questionnaire survey in the Chinyanja Triangle of Southern Africa.The study sites.were sampled from Tete province of Mozambique,central and southern regions of Malawi and eastern Province of Zambia.We used t-tests to classify adopters and non-adopters of soil,land and water con-servation measures and binomial logit models to identify the factors that infuence farmers'knowledge of conservation measures and adoption of land productivity practices.The results show that the household head's age,education,agricultural advice reception and farmer group membership are critical in raising awareness.While the household head's age,education,agricultural advice reception,farmer group membership,pieces of land owned or used in production and land-to-man ratio influenced adoption decisions.The study,therefore,concludes that in order to improve land productivity in the Chinyanja Triangle,there is a need to consider farmers'heterogeneity in terms of household head's age,level of education,extension services outreach,and socio-economic char acteristics.This suggests that governments'policies in the region should be aimed at improving farmers'level of education,extension delivery that will target the elderly and the youth,land ownership,credit access,and social capital such as group formation.展开更多
Soil erosion is a very critical form of land degradation resulting in the loss of soil nutrients and downstream sedimentation of water storages in the highlands of Ethiopia.As it is technically and financially impossi...Soil erosion is a very critical form of land degradation resulting in the loss of soil nutrients and downstream sedimentation of water storages in the highlands of Ethiopia.As it is technically and financially impossible to conserve all landscapes affected by erosion,identification of priority areas of intervention is necessary.Spatially distributed erosion models can help map landscape susceptibility to erosion and identify high erosion risk areas.Integration of erosion models with geographic information systems(GIS)enables assessing evaluate the spatial variability of soil erosion and plan implementing conservation measures at landscape levels.In this study,the Revised Universal Soil Loss Equation adjusted for sediment delivery ratio was used in a GIS system to assess landscape sensitivity to erosion and identify hotspots.The approach was applied in three catchments with size being 10–20 km^(2) and results were compared against quantitative and semi-quantitative data.The model estimated mean soil loss rates of about 45 t ha^(−1) y^(−1) with an average variability of 30%between catchments.The estimated soil loss rate is above the tolerable limit of 10 t ha^(−1) y^(−1).The model predicted high soil loss rates at steep slopes and shoulder positions as well as along gullies.The results of the study demonstrate that knowledge of spatial patterns of high soil loss risk areas can help deploy site-specific conservation measures.展开更多
Background:Grazing by livestock and cultivation have been considered as two important causes of soil erosion and nutrient export.However,there has been limited evidence that grazing or cultivation matters to soil eros...Background:Grazing by livestock and cultivation have been considered as two important causes of soil erosion and nutrient export.However,there has been limited evidence that grazing or cultivation matters to soil erosion and nutrient export in Ethiopia.Hence,this study was conducted in the Galesa watershed in Ethiopia to examine the effects of grazing and cultivation on runoff,soil loss,and nutrient export.Daily values of runoff,soil erosion,and nutrient outflow were measured for three consecutive years following standard procedures.Independent t test was performed to check if the means of runoff,soil loss,and nutrient loss from grazing and cultivated lands were significantly different.Moreover,repeated analysis of variance(ANOVA)was used to test if mean values of runoff,soil loss,and nutrient export varied significantly over the study years.Results:Although the average annual runoff depth was 7.8%higher in grazing land(GL),soil erosion was significantly lower(39%)in GL as compared to cultivated land(CL).Similarly,sediment and runoff-associated annual losses of total nitrogen(N),available phosphorus(P),exchangeable potassium(K),and organic carbon(OC)were low in the GL treatments.Lowest losses of total N(9.30 kg ha^(−1) year^(−1)),available P(0.83 kg ha^(−1) year^(−1)),and exchangeable K(1.84 kg ha^(−1) year^(−1))were recorded in GL treatment.Likewise,lowest losses of sediment-associated total N(32.8 kg ha^(−1) year^(−1)),available P(0.39 kg ha^(−1) year^(−1)),exchangeable K(0.23 kg ha^(−1) year^(−1)),and soil organic carbon(630 kg ha^(−1) year^(−1))were recorded from GL over the 3 years of experimentation.Conclusion:Our results indicate that cultivation increased soil erosion as compared to grazing.Although there were significant reductions in soil erosion and nutrient export from grazing lands compared with cultivated lands,the absolute losses were still high.This implies the need for grazing land management using appropriate physical and biological erosion control measures to increase productivity and reduce soil erosion as well as nutrient export.展开更多
Background:Sustainable land management interventions were introduced in Geda watershed in 2012 to reduce soil erosion,improve water infiltration,and increase plant-carbon inputs into the soil.This study explored the i...Background:Sustainable land management interventions were introduced in Geda watershed in 2012 to reduce soil erosion,improve water infiltration,and increase plant-carbon inputs into the soil.This study explored the impact of the interventions on biomass production,carbon stock,and carbon sequestration.Stratified sampling was employed in the main and the dry seasons in the treated and untreated sub-watersheds that are found adjacent to each other.Above-and below-ground plant biomass,soil bulk density and organic carbon in 0-15-and 15-30-cm depths,and soil moisture content in 0-20-and 20-40-cm depths were collected from the crop,grazing,and tree lucerne plots.All analyses were performed based on standard procedures.Results:Plant biomass production,carbon stock,and carbon sequestration varied highly significantly(P≤0.001)among sub-watersheds,landscape positions,and land uses.Higher mean values were observed for treated subwatershed,lower landscape position,and tree lucerne plot.The higher mean values in the lower landscape position of the treated sub-watershed were due to tree lucerne plantation.Similarly,topsoil(0-15 cm)carbon stock was statistically higher(P≤0.001)in the treated sub-watershed and at tree lucerne plot(P≤0.05).In addition,carbon stock by sub-surface soil(15-30 cm)was significantly higher(P≤0.001)in the treated sub-watershed under crop and grazing lands but the higher value was in cropland and in the upper position.This could be due to the decomposition of organic materials from biomasses of crops and biological supporting measures(tree lucerne and Phalaris)facilitated by tillage.Six years of sustainable land management interventions led to the sequestration of 12.25,7.77,and 13.5 Mg C ha^(−1) under cropland,tree lucerne,and grazing plots,respectively.Conclusion:Sustainable land management interventions revealed auspicious ecological impacts in Geda watershed in terms of improving plant biomass production,carbon stock,and correspondingly capturing higher carbon dioxide equivalent taking untreated sub-watershed as a baseline.Prohibition of free grazing was the key element of the intervention to reduce biomass export and increase carbon sequestration in the treated sub-watershed.Thus,sustaining tree lucerne plants as a conservation measure and the prohibition of free grazing practices are principally essential.展开更多
Background:Land degradation through soil erosion by water is severe in the highlands of Ethiopia.In order to curb this problem,the government initiated sustainable land management interventions in different parts of t...Background:Land degradation through soil erosion by water is severe in the highlands of Ethiopia.In order to curb this problem,the government initiated sustainable land management interventions in different parts of the country since 2008,and in Geda watershed since 2012.However,the impacts of the interventions on soil properties were not assessed so far.Thus,this study investigated the impacts of sustainable land management interventions on selected soil properties in Geda watershed.Soil samples were collected from treated and untreated subwatersheds at the upper and lower landscape positions,from cropland and grazing lands at two soil depths(0-15 cm and 15-30 cm).Selected soil physicochemical properties were assessed with respect to landscape position,land-use type,and soil depth in both treated and untreated sub-watersheds.Results:Generally,most of the soil physicochemical properties differed greatly across sub-watersheds,land-use types,and soil depths.Clay,electrical conductivity,total N,available P,exchangeable K,and organic carbon were higher in the treated sub-watershed,whereas sand,silt,bulk density,and pH were higher in the untreated subwatershed.The higher sand,silt,and bulk density could be attributed to erosion,while the higher pH could be due to the higher exchangeable Na in the untreated sub-watershed.Most of the selected soil chemical properties were not affected by landscape position,but land-use type affected available P and organic carbon with higher mean values at croplands than at grazing lands,which could be ascribed to the conservation structure and tillage of the soils in that conservation structures trap and accumulate transported organic materials from the upper slope,while tillage facilitates aeration and decomposition processes.Conclusion:Sustainable land management interventions improved soil physicochemical properties and brought a positive restoration of the soil ecosystem.Maintaining the soil conservation measures and enhancing community awareness about the benefits,coupled with management of livestock grazing are required to sustain best practices.展开更多
Introduction:Ethiopia has made efforts to tackle the challenges of low crop and livestock productivity and degradation of land resources through various rural development strategies.However,increasing demands for food...Introduction:Ethiopia has made efforts to tackle the challenges of low crop and livestock productivity and degradation of land resources through various rural development strategies.However,increasing demands for food,animal feed,fuel,and income-generating activities are putting pressure on the land.In this paper,we describe the production pressure and competition between crop and livestock production,quantify rates of land-use/cover(LULC)changes,and examine driving forces and consequences of land conversion.Methods:The study was conducted in Gudo Beret watershed,North Shewa Zone of Amhara region,Ethiopia.It used a combination of methods including remote sensing,household interviews,field observations,focus group discussions,and key informant interviews.Supervised and unsupervised image classification methods were employed to map LULC classes for 31 years(1984–2016).Results:The results of satellite remote sensing revealed that 51%of the land in the study area was subject to accelerated land conversions.The household survey results indicated that feed resources and grain production pressures were 1.43 and 1.34 t ha^(−1) respectively.The observed annual changes in plantation and settlement areas were 2.6%and 2.9%.This was mainly at the expense of bushland and grazing land systems.Cropland increased(0.4%year^(−1))while grazing land reduced(3.5%year^(−1))under contrasting dynamics and competitive changes.An increase in human and livestock populations and farm expansion were major drivers of land conversion that adversely affected household livelihoods and the natural ecosystem.The consequences of these pressures resulted in a lack of animal feed,low crop-livestock productivity,and a reduction in natural vegetation coverage.Conclusions:We suggest that sustainable land resource management,more integrated crop-livestock production,and the use of productivity-enhancing technologies could play a role in managing competition for land resources.展开更多
Rainfall variability coupled with poor land and water management is contributing to food insecurity in many sub-Saharan African countries such as Ethiopia.To address such challenges,various efforts have been implement...Rainfall variability coupled with poor land and water management is contributing to food insecurity in many sub-Saharan African countries such as Ethiopia.To address such challenges,various efforts have been implemented in Ethiopia.The objective of this study was to evaluate the long-term impacts of different soil and water conservation and water harvesting interventions on groundwater and drought resilience of the Gule watershed,northern Ethiopia.The study involved:(i)documentation of the ap-proaches followed and the technologies implemented in Gule since the 1990s,(ii)monitoring the hy-drological effects of the interventions for ten years,and(iii)evaluation of the effects of the interventions on groundwater(level and quality),spring discharge and suspended sediment concentration(SSC)in runoff.Results showed that interventions were implemented at different stages and scales.As a result of the interventions,the watershed was transformed into a landscape resilient to rainfall variability:(a)dry shallow groundwater wells have become productive and the level of water in wells has raised,(b)the groundwater quality has improved,(c)SSC in high floods has reduced by up to 65%,(d)discharge of existing springs has increased by up to 73%and new springs have started to emerge.Due to improved water availability,irrigated land has increased from less than 3.5 ha before 2002 to 166 ha in 2019.Communities have remained water-secure during an extreme drought in 2015/2016.Implementation of watershed management practices has transformed the landscape to be resilient to rainfall variability in a semi-arid environment:a lesson for adaptation to climate variability and change in similar environments.展开更多
基金the financial support by Deutscher Akademischer Austausch Dienst (DAAD)/Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) (Germany) through the Centre for Development Research (ZEF), University of Bonn (Germany)the support of Aksum University (Ethiopia) for the first author’s field work
文摘Soil degradation is a serious environmental problem in Ethiopia. However, little information is documented on indicators such as variations in soil properties across different landforms in a catchment. This study was aimed to assess soil properties and their changes across sites with different erosion statuses, and identify landscape positions that require prior management attention in the Mai-Negus catchment, northern Ethiopia. Three types of erosion-status sites(stable, eroding and aggrading) were identified using reconnaissance surveys, and then the corresponding soil samples were collected and analyzed. The major soil properties were significantly varied(P ≤ 0.05) among the three erosion-status sites. The highest soil p H, organic carbon, total nitrogen, cation exchange capacity, iron and zinc were recorded from the aggrading sites in the reservoir and valley landforms of the study catchment. A higher bulk density was generally recorded in the eroding sites, whereas a lower value was observed in the aggrading sites. The highest sand content was observed in the eroding sites of the mountain followed by the central ridge landform. The paired mean difference and the correlation matrix of most soil properties between the different erosion statuses also showed significant differences. About 95% of the erosionstatus sites were correctly classified by the discriminant function, indicating that the field survey-based classification was acceptable for decision making. On the basis of this study, suitable interventions should thus be introduced to the prioritized landforms, which are the mountain and central ridge, and eroding sites with severely degraded soil properties across the catchment.
文摘Soil-erosion-induced land degradation is a great challenge in the Ethiopian highlands. Consequently, the government has invested in soil and water conservation measures to tackle the problem where farmland terracing is one of the commonly implemented measures in the country. The purpose of this study was to analyze the role of farmland terracing in maintaining soil fertility and to evaluate its performance within a terrace, across terrace age and slope of terrain. The study was conducted in the Lake Maybar watershed in Wello, northern Ethiopia. Composite topsoil samples were collected from plots representing four slope categories across the terrain and three positions within a terrace. The samples were analyzed for selected soil physico-chemical properties and statistically tested using ANOVA （analysis of variance）. The study revealed that soil pH （△pH [H2O] = 0.6）, exchangeable K＋ （△K＋ = 0.33 cmol（＋）/kg） and clay （9%） content significantly increased towards the lower terrain position. Unlike other studies, all soil properties except bulk density （△ 0.40 g/cm3） showed non-significant differences within a terrace. Bench terrace formation reduced soil fertility gradients within a terrace for which it has been commented. Soil fertility also showed very slight change across terrace age, which indicates terracing reduced erosion-induced soil and nutrient loss. However, in order to optimize impact of farmland terracing on soil fertility maintenance, terracing should be complemented by fertility amendment considering site-specific conditions.
文摘Identifying land management practices(LMPs)that enhance on-site sediment management and crop productivity is crucial for the prevention,reduction,and restoration of land degradation and contributing to achieving land degradation neutrality(LDN).We reviewed studies in Ethiopia to assess the effects of LMPs on soil loss(84 studies)and crop productivity(34 studies)relative to control practice.Yield variability on conserved lands was assessed using 12,796 fixed plot data.Effects of LMP on soil loss were 0.5-55 t ha^(−1)y^(−1)compared to control practices yielding 50 to 140 t ha^(−1)y^(−1).More than 55%of soil loss records revealed soil loss less than the tolerable rate(10 t ha^(−1)).Area closure,perennial vegetation cover,agronomic practices,mechanical erosion control practices,annual cropland cover,and drainage groups of practices led to 74.0±18.3%,69.0±24.6%,66.2±30.5%,66.1±18.0%,63.5±20.0%,and 40±11,1%soil loss reduction,respectively.A yield increase of 25.2±15.0%,37.5±28.0%,and 75.4±85.0%was found from drainage,agronomy,and mechanical erosion control practices,respectively.The average yield loss by erosion on fields without appropriate land management practice and on conserved fields was 26.5±26.0%and 25±3.7%,respectively.The findings suggest that practices that entail a continuous presence of soil cover during the rainy season,perennial vegetation,retention of moisture,and barriers for sediment transport were most effective at decreasing soil loss and increasing productivity.This review provides evidence to identify the best LMP practices for wider adoption and inform decision-making on LMP investments towards achieving sustainable solutions to reverse land degradation.
基金the Dryland Systems Consultative Research Programme(CRP11).
文摘The promotion of land,soil and water conservation measures has been a widespread development in sub-Saharan Africa in a bid to tackle degradation and improve productivity.As a result,several gov-ernments have launched various campaigns on soil,land and water conservation measures.The aim of this study is to determine some of the factors that influence farmers'awareness(knowledge)and adoption of land,soil and water conservation practices.Data for this study was collected from 312 households using a questionnaire survey in the Chinyanja Triangle of Southern Africa.The study sites.were sampled from Tete province of Mozambique,central and southern regions of Malawi and eastern Province of Zambia.We used t-tests to classify adopters and non-adopters of soil,land and water con-servation measures and binomial logit models to identify the factors that infuence farmers'knowledge of conservation measures and adoption of land productivity practices.The results show that the household head's age,education,agricultural advice reception and farmer group membership are critical in raising awareness.While the household head's age,education,agricultural advice reception,farmer group membership,pieces of land owned or used in production and land-to-man ratio influenced adoption decisions.The study,therefore,concludes that in order to improve land productivity in the Chinyanja Triangle,there is a need to consider farmers'heterogeneity in terms of household head's age,level of education,extension services outreach,and socio-economic char acteristics.This suggests that governments'policies in the region should be aimed at improving farmers'level of education,extension delivery that will target the elderly and the youth,land ownership,credit access,and social capital such as group formation.
基金The study benefited financial support by the Centre for Development Research(ZEF),DAAD(Germany)fieldwork support by Mekelle University(Ethiopia).
文摘Soil erosion is a very critical form of land degradation resulting in the loss of soil nutrients and downstream sedimentation of water storages in the highlands of Ethiopia.As it is technically and financially impossible to conserve all landscapes affected by erosion,identification of priority areas of intervention is necessary.Spatially distributed erosion models can help map landscape susceptibility to erosion and identify high erosion risk areas.Integration of erosion models with geographic information systems(GIS)enables assessing evaluate the spatial variability of soil erosion and plan implementing conservation measures at landscape levels.In this study,the Revised Universal Soil Loss Equation adjusted for sediment delivery ratio was used in a GIS system to assess landscape sensitivity to erosion and identify hotspots.The approach was applied in three catchments with size being 10–20 km^(2) and results were compared against quantitative and semi-quantitative data.The model estimated mean soil loss rates of about 45 t ha^(−1) y^(−1) with an average variability of 30%between catchments.The estimated soil loss rate is above the tolerable limit of 10 t ha^(−1) y^(−1).The model predicted high soil loss rates at steep slopes and shoulder positions as well as along gullies.The results of the study demonstrate that knowledge of spatial patterns of high soil loss risk areas can help deploy site-specific conservation measures.
文摘Background:Grazing by livestock and cultivation have been considered as two important causes of soil erosion and nutrient export.However,there has been limited evidence that grazing or cultivation matters to soil erosion and nutrient export in Ethiopia.Hence,this study was conducted in the Galesa watershed in Ethiopia to examine the effects of grazing and cultivation on runoff,soil loss,and nutrient export.Daily values of runoff,soil erosion,and nutrient outflow were measured for three consecutive years following standard procedures.Independent t test was performed to check if the means of runoff,soil loss,and nutrient loss from grazing and cultivated lands were significantly different.Moreover,repeated analysis of variance(ANOVA)was used to test if mean values of runoff,soil loss,and nutrient export varied significantly over the study years.Results:Although the average annual runoff depth was 7.8%higher in grazing land(GL),soil erosion was significantly lower(39%)in GL as compared to cultivated land(CL).Similarly,sediment and runoff-associated annual losses of total nitrogen(N),available phosphorus(P),exchangeable potassium(K),and organic carbon(OC)were low in the GL treatments.Lowest losses of total N(9.30 kg ha^(−1) year^(−1)),available P(0.83 kg ha^(−1) year^(−1)),and exchangeable K(1.84 kg ha^(−1) year^(−1))were recorded in GL treatment.Likewise,lowest losses of sediment-associated total N(32.8 kg ha^(−1) year^(−1)),available P(0.39 kg ha^(−1) year^(−1)),exchangeable K(0.23 kg ha^(−1) year^(−1)),and soil organic carbon(630 kg ha^(−1) year^(−1))were recorded from GL over the 3 years of experimentation.Conclusion:Our results indicate that cultivation increased soil erosion as compared to grazing.Although there were significant reductions in soil erosion and nutrient export from grazing lands compared with cultivated lands,the absolute losses were still high.This implies the need for grazing land management using appropriate physical and biological erosion control measures to increase productivity and reduce soil erosion as well as nutrient export.
基金This research was done by the financial support from the post graduate offices of Addis Ababa University and Debre Berhan University,and Africa RISINGa program financed by the United States Agency for International Development(USAID)as part of the United States Government’s Feed the Future Initiative.
文摘Background:Sustainable land management interventions were introduced in Geda watershed in 2012 to reduce soil erosion,improve water infiltration,and increase plant-carbon inputs into the soil.This study explored the impact of the interventions on biomass production,carbon stock,and carbon sequestration.Stratified sampling was employed in the main and the dry seasons in the treated and untreated sub-watersheds that are found adjacent to each other.Above-and below-ground plant biomass,soil bulk density and organic carbon in 0-15-and 15-30-cm depths,and soil moisture content in 0-20-and 20-40-cm depths were collected from the crop,grazing,and tree lucerne plots.All analyses were performed based on standard procedures.Results:Plant biomass production,carbon stock,and carbon sequestration varied highly significantly(P≤0.001)among sub-watersheds,landscape positions,and land uses.Higher mean values were observed for treated subwatershed,lower landscape position,and tree lucerne plot.The higher mean values in the lower landscape position of the treated sub-watershed were due to tree lucerne plantation.Similarly,topsoil(0-15 cm)carbon stock was statistically higher(P≤0.001)in the treated sub-watershed and at tree lucerne plot(P≤0.05).In addition,carbon stock by sub-surface soil(15-30 cm)was significantly higher(P≤0.001)in the treated sub-watershed under crop and grazing lands but the higher value was in cropland and in the upper position.This could be due to the decomposition of organic materials from biomasses of crops and biological supporting measures(tree lucerne and Phalaris)facilitated by tillage.Six years of sustainable land management interventions led to the sequestration of 12.25,7.77,and 13.5 Mg C ha^(−1) under cropland,tree lucerne,and grazing plots,respectively.Conclusion:Sustainable land management interventions revealed auspicious ecological impacts in Geda watershed in terms of improving plant biomass production,carbon stock,and correspondingly capturing higher carbon dioxide equivalent taking untreated sub-watershed as a baseline.Prohibition of free grazing was the key element of the intervention to reduce biomass export and increase carbon sequestration in the treated sub-watershed.Thus,sustaining tree lucerne plants as a conservation measure and the prohibition of free grazing practices are principally essential.
基金This research was undertaken with support from Africa RISING,a program financed by the United States Agency for International Development(USAID)as part of the United States Government’s Feed the Future Initiative.
文摘Background:Land degradation through soil erosion by water is severe in the highlands of Ethiopia.In order to curb this problem,the government initiated sustainable land management interventions in different parts of the country since 2008,and in Geda watershed since 2012.However,the impacts of the interventions on soil properties were not assessed so far.Thus,this study investigated the impacts of sustainable land management interventions on selected soil properties in Geda watershed.Soil samples were collected from treated and untreated subwatersheds at the upper and lower landscape positions,from cropland and grazing lands at two soil depths(0-15 cm and 15-30 cm).Selected soil physicochemical properties were assessed with respect to landscape position,land-use type,and soil depth in both treated and untreated sub-watersheds.Results:Generally,most of the soil physicochemical properties differed greatly across sub-watersheds,land-use types,and soil depths.Clay,electrical conductivity,total N,available P,exchangeable K,and organic carbon were higher in the treated sub-watershed,whereas sand,silt,bulk density,and pH were higher in the untreated subwatershed.The higher sand,silt,and bulk density could be attributed to erosion,while the higher pH could be due to the higher exchangeable Na in the untreated sub-watershed.Most of the selected soil chemical properties were not affected by landscape position,but land-use type affected available P and organic carbon with higher mean values at croplands than at grazing lands,which could be ascribed to the conservation structure and tillage of the soils in that conservation structures trap and accumulate transported organic materials from the upper slope,while tillage facilitates aeration and decomposition processes.Conclusion:Sustainable land management interventions improved soil physicochemical properties and brought a positive restoration of the soil ecosystem.Maintaining the soil conservation measures and enhancing community awareness about the benefits,coupled with management of livestock grazing are required to sustain best practices.
基金This study was financially supported by the United States Agency for International Development(USAID)through Africa RISING research program.
文摘Introduction:Ethiopia has made efforts to tackle the challenges of low crop and livestock productivity and degradation of land resources through various rural development strategies.However,increasing demands for food,animal feed,fuel,and income-generating activities are putting pressure on the land.In this paper,we describe the production pressure and competition between crop and livestock production,quantify rates of land-use/cover(LULC)changes,and examine driving forces and consequences of land conversion.Methods:The study was conducted in Gudo Beret watershed,North Shewa Zone of Amhara region,Ethiopia.It used a combination of methods including remote sensing,household interviews,field observations,focus group discussions,and key informant interviews.Supervised and unsupervised image classification methods were employed to map LULC classes for 31 years(1984–2016).Results:The results of satellite remote sensing revealed that 51%of the land in the study area was subject to accelerated land conversions.The household survey results indicated that feed resources and grain production pressures were 1.43 and 1.34 t ha^(−1) respectively.The observed annual changes in plantation and settlement areas were 2.6%and 2.9%.This was mainly at the expense of bushland and grazing land systems.Cropland increased(0.4%year^(−1))while grazing land reduced(3.5%year^(−1))under contrasting dynamics and competitive changes.An increase in human and livestock populations and farm expansion were major drivers of land conversion that adversely affected household livelihoods and the natural ecosystem.The consequences of these pressures resulted in a lack of animal feed,low crop-livestock productivity,and a reduction in natural vegetation coverage.Conclusions:We suggest that sustainable land resource management,more integrated crop-livestock production,and the use of productivity-enhancing technologies could play a role in managing competition for land resources.
文摘Rainfall variability coupled with poor land and water management is contributing to food insecurity in many sub-Saharan African countries such as Ethiopia.To address such challenges,various efforts have been implemented in Ethiopia.The objective of this study was to evaluate the long-term impacts of different soil and water conservation and water harvesting interventions on groundwater and drought resilience of the Gule watershed,northern Ethiopia.The study involved:(i)documentation of the ap-proaches followed and the technologies implemented in Gule since the 1990s,(ii)monitoring the hy-drological effects of the interventions for ten years,and(iii)evaluation of the effects of the interventions on groundwater(level and quality),spring discharge and suspended sediment concentration(SSC)in runoff.Results showed that interventions were implemented at different stages and scales.As a result of the interventions,the watershed was transformed into a landscape resilient to rainfall variability:(a)dry shallow groundwater wells have become productive and the level of water in wells has raised,(b)the groundwater quality has improved,(c)SSC in high floods has reduced by up to 65%,(d)discharge of existing springs has increased by up to 73%and new springs have started to emerge.Due to improved water availability,irrigated land has increased from less than 3.5 ha before 2002 to 166 ha in 2019.Communities have remained water-secure during an extreme drought in 2015/2016.Implementation of watershed management practices has transformed the landscape to be resilient to rainfall variability in a semi-arid environment:a lesson for adaptation to climate variability and change in similar environments.
