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Conversion of native pasturelands to cultivated land led to a decline in soil fertility resulting in low agricultural productivity. This study attempted to investigate the magnitude and rate of pastureland to cultivated land conversion and the associated impact on selected soil properties. The study was conducted in three villages of Ofla district, northern Ethiopia. Land-use conversion that happened between 1973 and 2015 was investigated using satellite images supplemented by field observation and key informant interview. Cultivated lands with different history of cultivation period (2, 10, 20, 30, 42 years) since conversion were identified. A total of 54 soil samples were collected from cultivated and pasture lands for soil physico-chemical analysis. Results showed that pastureland conversion to cultivated land increased at a medium rate of 17 ha year−1 and by 46% over the last 42 years. Over the same period, soil organic carbon, total nitrogen, available phosphorous, available potassium and electrical conductivity declined by 65%, 59%, 57%, 70% and 74%, respectively. The continued steady decline in soil quality with increasing period of cultivation shows that the current management practices are not sustainable and calls for urgent solution to reverse the negative scenario.
Girmay Gebresamuel; Berhanu Molla; Kassa Teka; Emnet Negash; Mitiku Haile; Chukwuebuka Christopher Okolo. Changes in soil organic carbon stock and nutrient status after conversion of pasture land to cultivated land in semi-arid areas of northern Ethiopia. Archives of Agronomy and Soil Science 2020, 1 -17.
AMA StyleGirmay Gebresamuel, Berhanu Molla, Kassa Teka, Emnet Negash, Mitiku Haile, Chukwuebuka Christopher Okolo. Changes in soil organic carbon stock and nutrient status after conversion of pasture land to cultivated land in semi-arid areas of northern Ethiopia. Archives of Agronomy and Soil Science. 2020; ():1-17.
Chicago/Turabian StyleGirmay Gebresamuel; Berhanu Molla; Kassa Teka; Emnet Negash; Mitiku Haile; Chukwuebuka Christopher Okolo. 2020. "Changes in soil organic carbon stock and nutrient status after conversion of pasture land to cultivated land in semi-arid areas of northern Ethiopia." Archives of Agronomy and Soil Science , no. : 1-17.
The consequences of prolonged precipitation-deficient periods are primarily substantial water deficit, with the spatial characteristics of drylands and various socioeconomic factors worsening its impacts and deepening poverty among agrarian communities, with attendant food security implications. This study utilizes a combination of climate, remote sensing and field survey data. These data were used to obtain a first-hand information on the impacts of recent (2015 and 2017) droughts on crop yield in southern Tigray, northern Ethiopia. Annual and seasonal rainfall, annual and seasonal NDVI and Dev-NDVI, and monthly SPI-1, SPI-3 and SPI-12 (for June to October) were considered as likely factors that could relate with yield and yield loss in the area. Correlation and multiple linear stepwise regression statistical techniques were used to determine drought-yield relationships, and identify more accurate predictors of yield and yield losses in each of the drought years. The area witnessed a more widespread precipitation deficit in 2015 than in 2017, where the lowland area recorded entire crop losses. Also, droughts manifested spatiotemporal variations and impacts across the 3 different agroecologies – primarily reduction in vegetation amounts, coinciding with the planting and maturing stages of crops. Crop failures therefore translated to food shortages and reduced income of smallholders, which denotes food insecurity in the time of droughts. Seasonal rainfall and June Dev-NDVI predicted 66.9% of 2015 yield loss, while NDVI predicted 2017 sorghum yield by 96%. Spate irrigation should be further popularized in the low-lying areas of Raya Azebo to augment for future deficiencies in the kiremt rainfall.
Emmanuel Eze; Atkilt Girma; Amanuel Zenebe; Chukwuebuka Christopher Okolo; Emnet Negash. Yield and yield-reduction in recent drought years in southern Tigray, northern Ethiopia: Implications on food security. 2020, 1 .
AMA StyleEmmanuel Eze, Atkilt Girma, Amanuel Zenebe, Chukwuebuka Christopher Okolo, Emnet Negash. Yield and yield-reduction in recent drought years in southern Tigray, northern Ethiopia: Implications on food security. . 2020; ():1.
Chicago/Turabian StyleEmmanuel Eze; Atkilt Girma; Amanuel Zenebe; Chukwuebuka Christopher Okolo; Emnet Negash. 2020. "Yield and yield-reduction in recent drought years in southern Tigray, northern Ethiopia: Implications on food security." , no. : 1.
The consequences of prolonged precipitation-deficient periods are primarily substantial water deficit, with the spatial characteristics of a place being (semi)arid, and various socioeconomic factors worsening its impacts and deepening poverty among agrarian communities.This study utilizes a combination of climate, remote sensing and field survey data from farmers to obtain a first-hand information on the impacts of recent (2015 and 2017) droughts on crop yield in Raya Azebo and Endamehoni woredas in Ethiopia. Annual rainfall, kiremt rainfall, annual NDVI and Dev-NDVI, kiremt season Dev-NDVI, monthly Dev-NDVI (for June to October), and monthly SPI-1, SPI-3 and SPI-12 (for June to October) were considered as likely factors that could relate with yield and yield loss in the area. Correlation and multiple linear stepwise regression statistical techniques were used to determine drought-yield relationships, and identify more accurate predictors of yield and yield losses in each of the drought years.Results obtained show droughts as having spatiotemporal variations and impacts, with its primary and common reflection being reduced vegetation amount, translating to crop failures, food shortages and reduced income of smallholders.Spate irrigation should be further popularized in the low-lying areas of Raya Azebo to augment for future deficiencies in the kiremt rainfall.
Emmanuel Eze; Chukwuebuka Christopher Okolo; Emnet Negash. Yield and yield-reduction in recent drought years in southern Tigray, northern Ethiopia: Implications on food security. 2020, 1 .
AMA StyleEmmanuel Eze, Chukwuebuka Christopher Okolo, Emnet Negash. Yield and yield-reduction in recent drought years in southern Tigray, northern Ethiopia: Implications on food security. . 2020; ():1.
Chicago/Turabian StyleEmmanuel Eze; Chukwuebuka Christopher Okolo; Emnet Negash. 2020. "Yield and yield-reduction in recent drought years in southern Tigray, northern Ethiopia: Implications on food security." , no. : 1.
Agriculture remains the dominant source of food production and the livelihood foundation for majority of the rural poor in the sub-Saharan Africa, including Ethiopia. Access to agricultural-water is, however, a limitation hindering crop productivity and end food insecurity in the drylands. In rain-deficit lowlands such as in the Raya-valley, flood-based farming is a means of improving crop production. Such spate irrigation systems grow in importance; though the effects of headwater hydrological deficit on flood-farming systems are lacking evidence. The present work investigates the impacts of headwater hydrological deficit on spate-irrigated agriculture in Tsge’a spate systems. Canal length and area of spate-irrigated agriculture along Guguf river for the 1980s and 2010s were tracked using Global Positioning System; while runoff trend analysed using linear regression. Annual volume of flash-flood shrunk by 7.36x106 m3. This is mainly due to changing climate and increasing water retention by the soil and humans at the escarpment. As a result, length of canals and area of spate-based farms downstream declined by 1.37 km (35%) and 1540 ha (57.5%), respectively, only in three decades time. This corresponds to an average withdrawal of -44 ha yr-1. A 1x106 m3 decline in flash-flood caused a 366.4 ha decline in spate-based farms. Moreover, farm fields located next to the river course are less affected, as compared to farms on the tail of the scheme. If the current trend continues, there is likely a high risk that the remaining farms currently receiving flood may run out of spate systems. Therefore, flood management technologies are needed to optimize the efficiency of soil moisture in the spate system.
The abstract is based on Negash, E., Gebresamuel, G., Embaye, T., Nguvulu, A., Meaza, H., Gebrehiwot, M., Demisse, B., Gebreyohannes, T., Nyssen, J., & Zenebe, A. (2020). Impact of headwater hydrological deficit on the downstream flood-based farming system in northern Ethiopia. Irrigation and Drainage, In Press.
Emnet Negash; Jan Nyssen; Girmay Gebresamuel; Tesfa-Alem Embaye; Alick Nguvulu; Hailemariam Meaza; Misgina Gebrehiwot; Biadglign Demisse; Tesfaalem Gebreyohannes; Amanuel Zenebe. Flood-based Farming as Affected by Hydrological Deficit in the Semiarid Lowlands of Northern Ethiopia. 2020, 1 .
AMA StyleEmnet Negash, Jan Nyssen, Girmay Gebresamuel, Tesfa-Alem Embaye, Alick Nguvulu, Hailemariam Meaza, Misgina Gebrehiwot, Biadglign Demisse, Tesfaalem Gebreyohannes, Amanuel Zenebe. Flood-based Farming as Affected by Hydrological Deficit in the Semiarid Lowlands of Northern Ethiopia. . 2020; ():1.
Chicago/Turabian StyleEmnet Negash; Jan Nyssen; Girmay Gebresamuel; Tesfa-Alem Embaye; Alick Nguvulu; Hailemariam Meaza; Misgina Gebrehiwot; Biadglign Demisse; Tesfaalem Gebreyohannes; Amanuel Zenebe. 2020. "Flood-based Farming as Affected by Hydrological Deficit in the Semiarid Lowlands of Northern Ethiopia." , no. : 1.
Land use and the associated ecosystem service functions vary with changes in agroecological conditions. This study analyzed the distribution of ecosystem service values along the agroecological gradient in Borena landscape. Land-cover information was extracted from Landsat satellite images; and ecosystem service values were estimated using established global and local databases. Land-cover types were constrained in one or two agroecological zones with varying proportions. Cultivated land covering 53.7% of the total landscape area, plantation forest (32.3%) and grassland (9.4%) land-cover types exist in all agroecological zones, with the highest proportion in the humid highland. The highest long-term average ecosystem service value was observed along the humid highland accounting for about 21.8–33.11 million $US. The sub-humid highland consisted 5.67–8.88 million $US. Ecosystem service value showed a decreasing trend between 1973 and 2001 along all agroecological zones and increased in 2016. Moreover, the highest depletion was found along the humid highland (7.27–18.93 million $US) and least depletion was observed along the cold highland (1.79–4.40). Occurrence of the highest depletion along the most inhabited zone, i.e., humid highland, revealed that many of the impacts are human induced. Agroecological gradient substantially determines the amount and distribution of ecosystem service values. Sustainable land management efforts and proper land-use planning are required with special attention to susceptible zones to conserve and increase ecosystem service values.
Emnet Negash; Tesfaye Getachew; Emiru Birhane; Hailemariam Gebrewahed. Ecosystem Service Value Distribution Along the Agroecological Gradient in North-Central Ethiopia. Earth Systems and Environment 2020, 4, 107 -116.
AMA StyleEmnet Negash, Tesfaye Getachew, Emiru Birhane, Hailemariam Gebrewahed. Ecosystem Service Value Distribution Along the Agroecological Gradient in North-Central Ethiopia. Earth Systems and Environment. 2020; 4 (1):107-116.
Chicago/Turabian StyleEmnet Negash; Tesfaye Getachew; Emiru Birhane; Hailemariam Gebrewahed. 2020. "Ecosystem Service Value Distribution Along the Agroecological Gradient in North-Central Ethiopia." Earth Systems and Environment 4, no. 1: 107-116.
Flood‐based farming is a means of improving crop production in rain‐deficit lowlands. Such spate irrigation systems are growing in importance, although the effects of headwater hydrological deficit on downstream flood farming are lacking evidence. This study investigates the impacts of headwater hydrological deficit on the extent of spate‐irrigated agriculture in the Guguf spate system. The length of canals and area of spate‐irrigated agriculture to the right and left of the Guguf River for the 1980s and 2010s were tracked using a global positioning system and mapped in a geographic information system interface, while climate data were collected from National Meteorological Agency. Trends of selected hydroclimatic variables were analysed using linear regression and the Pettitt test. The flash floods have shrunk by 7.36 × 106 m3, as a result of which the length of canals and area of spate‐based farms declined by 1.37 km and 1540 ha, i.e. 35 and 57.5%, respectively, in only three decades. This corresponds to an average withdrawal of −44.0 ha yr‾¹. A single 1 million m3 decline in flash floods caused a 366.4 ha decline in spate‐based farms. Moreover, farm fields located next to the river course are less affected, compared to those at the tail of the scheme. If the current trend continues, there is a high risk that the remaining farms currently receiving floods may find themselves outside of the spate systems. Therefore, we suggest that flood management technologies are needed to optimize the efficiency of soil moisture in the spate system. © 2020 John Wiley & Sons, Ltd.
Emnet Negash; Girmay Gebresamuel; Tesfa‐Alem Embaye; Alick Nguvulu; Hailemariam Meaza; Misgina Gebrehiwot; Biadgilgn Demissie; Tesfaalem Gebreyohannes; Jan Nyssen; Amanuel Zenebe. IMPACT OF HEADWATER HYDROLOGICAL DEFICIT ON THE DOWNSTREAM FLOOD‐BASED FARMING SYSTEM IN NORTHERN ETHIOPIA. Irrigation and Drainage 2020, 69, 342 -351.
AMA StyleEmnet Negash, Girmay Gebresamuel, Tesfa‐Alem Embaye, Alick Nguvulu, Hailemariam Meaza, Misgina Gebrehiwot, Biadgilgn Demissie, Tesfaalem Gebreyohannes, Jan Nyssen, Amanuel Zenebe. IMPACT OF HEADWATER HYDROLOGICAL DEFICIT ON THE DOWNSTREAM FLOOD‐BASED FARMING SYSTEM IN NORTHERN ETHIOPIA. Irrigation and Drainage. 2020; 69 (3):342-351.
Chicago/Turabian StyleEmnet Negash; Girmay Gebresamuel; Tesfa‐Alem Embaye; Alick Nguvulu; Hailemariam Meaza; Misgina Gebrehiwot; Biadgilgn Demissie; Tesfaalem Gebreyohannes; Jan Nyssen; Amanuel Zenebe. 2020. "IMPACT OF HEADWATER HYDROLOGICAL DEFICIT ON THE DOWNSTREAM FLOOD‐BASED FARMING SYSTEM IN NORTHERN ETHIOPIA." Irrigation and Drainage 69, no. 3: 342-351.
This study analyzes the impact of land use/land cover (LULC) changes on the hydrology of the dry Afromontane forest landscape in northern Ethiopia. Landsat satellite images of thematic mapper (TM) (1986), TM (2001), and Operational Land Imager (OLI) (2018) were employed to assess LULC. All of the images were classified while using the maximum likelihood image classification technique, and the changes were assessed by post-classification comparison. Seven LULC classes were defined with an overall accuracy 83–90% and a Kappa coefficient of 0.82–0.92. The classification result for 1986 revealed dominance of shrublands (48.5%), followed by cultivated land (42%). Between 1986 and 2018, cultivated land became the dominant (39.6%) LULC type, accompanied by a decrease in shrubland to 32.2%, as well as increases in forestland (from 4.8% to 21.4%) and bare land (from 0% to 0.96%). The soil conservation systems curve number model (SCS-CN) was consequently employed to simulate forest hydrological response to climatic variations and land-cover changes during three selected years. The observed changes in direct surface runoff, the runoff coefficient, and storage capacity of the soil were partially linked to the changes in LULC that were associated with expanding bare land and built-up areas. This change in land use aggravates the runoff potential of the study area by 31.6 mm per year on average. Runoff coefficients ranged from 25.3% to 47.2% with varied storm rainfall intensities of 26.1–45.4 mm/ha. The temporal variability of climate change and potential evapotranspiration increased by 1% during 1981–2018. The observed rainfall and modelled runoff showed a strong positive correlation (R2 = 0.78; p < 0.001). Regression analysis between runoff and rainfall intensity indicates their high and significant correlation (R2 = 0.89; p < 0.0001). Changes were also common along the slope gradient and agro-ecological zones at varying proportions. The observed changes in land degradation and surface runoff are highly linked to the change in LULC. Further study is suggested on climate scenario-based modeling of hydrological processes that are related to land use changes to understand the hydrological variability of the dry Afromontane forest ecosystems.
Belay Manjur Gebru; Woo-Kyun Lee; Asia Khamzina; Sle-Gee Lee; Emnet Negash. Hydrological Response of Dry Afromontane Forest to Changes in Land Use and Land Cover in Northern Ethiopia. Remote Sensing 2019, 11, 1905 .
AMA StyleBelay Manjur Gebru, Woo-Kyun Lee, Asia Khamzina, Sle-Gee Lee, Emnet Negash. Hydrological Response of Dry Afromontane Forest to Changes in Land Use and Land Cover in Northern Ethiopia. Remote Sensing. 2019; 11 (16):1905.
Chicago/Turabian StyleBelay Manjur Gebru; Woo-Kyun Lee; Asia Khamzina; Sle-Gee Lee; Emnet Negash. 2019. "Hydrological Response of Dry Afromontane Forest to Changes in Land Use and Land Cover in Northern Ethiopia." Remote Sensing 11, no. 16: 1905.
Kassa Gebremeskel; Kassa Teka; Emiru Birhane; Emnet Negash. The role of integrated watershed management on soil-health in northern Ethiopia. Acta Agriculturae Scandinavica, Section B — Soil & Plant Science 2019, 69, 667 -673.
AMA StyleKassa Gebremeskel, Kassa Teka, Emiru Birhane, Emnet Negash. The role of integrated watershed management on soil-health in northern Ethiopia. Acta Agriculturae Scandinavica, Section B — Soil & Plant Science. 2019; 69 (8):667-673.
Chicago/Turabian StyleKassa Gebremeskel; Kassa Teka; Emiru Birhane; Emnet Negash. 2019. "The role of integrated watershed management on soil-health in northern Ethiopia." Acta Agriculturae Scandinavica, Section B — Soil & Plant Science 69, no. 8: 667-673.
Irrigated agriculture in the rainfall‐deficit semi‐arid lowlands of the Raya valley rely on spate systems to produce food crops. Climate and land‐cover dynamics upstream are, however, threatening runoff response reaching these spate systems. The objective of this study was thus to analyse the hydrological response of dryland catchments to changing climate and land cover in Guguf spate systems. Thirty‐six years of climate data were analysed using Mann–Kendall, Pettitt's test and linear regression methods, and time‐series land‐cover information extracted from Landsat satellite images in a remote‐sensing interface. The Soil Conservation Systems curve number method was then employed to formulate the likely impact of climate and land‐cover changes on runoff response, and trends analysed. Results showed that temperature, evapotranspiration and rainfall varied at least by 0.11°C, 15.2 mm and −5.1 mm yr−1 respectively, intensifying moisture stress. Moreover, improving vegetation cover in the highlands enhanced the water‐abstraction capacity of the soil, impeding the runoff curve number by 9.2%. Thus, the combined effects of climate induced moisture stress and land cover led water abstraction upstream has threatened runoff response at a rate of 0.23 × 106 m3 yr−1. In other words, the runoff response reaching Guguf spate systems degenerated by 7.96 × 106 m3 over 36 years. Such unusual highland–lowland hydrological linkage has therefore endangered the availability of surplus water to irrigate spate‐based farms downstream. Appropriate policies and strategies would therefore be desirable to address conflicting interests in scarce water resources in the face of climate change. © 2019 John Wiley & Sons, Ltd.
Emnet Negash; Girmay Gebresamuel; Tesfa‐Alem G. Embaye; Amanuel Zenebe. The effect of climate and land‐cover changes on runoff response in Guguf spate systems, northern Ethiopia. Irrigation and Drainage 2019, 68, 399 -408.
AMA StyleEmnet Negash, Girmay Gebresamuel, Tesfa‐Alem G. Embaye, Amanuel Zenebe. The effect of climate and land‐cover changes on runoff response in Guguf spate systems, northern Ethiopia. Irrigation and Drainage. 2019; 68 (3):399-408.
Chicago/Turabian StyleEmnet Negash; Girmay Gebresamuel; Tesfa‐Alem G. Embaye; Amanuel Zenebe. 2019. "The effect of climate and land‐cover changes on runoff response in Guguf spate systems, northern Ethiopia." Irrigation and Drainage 68, no. 3: 399-408.