Browsing by Author "Schmitter, Petra"
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Item 2nd stakeholder dialogue meeting report - Ghana(Feed the Future, 2020) Minh, Thai Thi; Schmitter, Petra; Cofie, Olufunke; IWMI; ILSSI; USAIDItem Assessing potential land suitable for surface irrigation using groundwater in Ethiopia(Applied Geography, 2017) Worqlul, Abeyou W.; Jeong, Jaehak; Dile, Yihun T.; Osorio, Javier; Schmitter, Petra; Gerik, Thomas; Srinivasan, R.; Clark, Neville; ElsevierAlthough Ethiopia has abundant land for irrigation, only a fraction of its potential land is being utilized.This study evaluates suitability of lands for irrigation using groundwater in Ethiopia using GIS-basedMulti-Criteria Evaluation (MCE) techniques in order to enhance the country's agricultural industry.Key factors that significantly affect irrigation suitability evaluated in this study include physical landfeatures (land use, soil, and slope), climate (rainfall and evapotranspiration), and market access (proximity to roads and access to market). These factors were weighted using a pair-wise comparison matrix,then reclassified and overlaid to identify suitable areas for groundwater irrigation using a 1-km grid.Groundwater data from the British Geological Survey were used to estimate the groundwater potential,which indicates the corresponding irrigation potential for major crops. Results indicated that more than6 million ha of land are suitable for irrigation in Ethiopia. A large portion of the irrigable land is located inthe Abbay, Rift Valley, Omo Ghibe, and Awash River basins. These basins have access to shallowgroundwater (i.e., depth of groundwater less than 20 m from the surface) making it easier to extract. Thecomparison between available groundwater and total crop water requirements indicate that groundwater alone may not be sufficient to supply all suitable land. The study estimates that only 8% of thesuitable land can be irrigated with the available shallow groundwater. However, groundwater is a viableoption for supplementing surface water resources for irrigation in several basins in the countryItem Business Model Scenarios and Suitability: Smallholder Solar Pump-based Irrigation in Ethiopia(IWMI, 2018) Otoo, Miriam; Lefore, Nicole; Schmitter, Petra; Barron, Jennie; Gebregziabher, GebrehaweriaThis report outlines a business model approach to assessing the feasibility and for encouraging investment in smallholder solar pump irrigation. It also proposes a new methodology for mapping the suitability of solar energy-based irrigation pumps. The proposed business model framework and the methodology for suitability mapping are applied to Ethiopia as a case study, based on data from existing case studies and reports. A brief analysis outlines the regulatory and institutional context for investment in solar pump irrigation, and the ways in which it both constrains and attempts to support investment. The report identifies and outlines three business model scenarios that present opportunities for investing in smallholder solar pump-based irrigation, which would contribute towards sustainable intensification for food and nutrition security. The business model scenarios are based on the value proposition of supplying water to smallholder farmers for irrigated agricultural production. Analysis of potential gains and benefits suggests that direct purchase of solar pumps by farmers is feasible, and that out-grower schemes and pump supplier options with bundled financing offer promising solutions. The potential constraints that different investors may face in up-scaling the business models are also discussed, particularly within institutional, regulatory and financial contexts. The report provides development actors and investors with evidence-based information on the suitability and sustainability of solar pump irrigation in Ethiopia, as well as suggestions for helping to enable smallholders to invest in individually-owned, smallholder photovoltaic (PV) solar pumps.Item Conservation Agriculture Saves Irrigation Water in the Dry Monsoon Phase in the Ethiopian Highlands(Water, 2019) Belay, Sisay A.; Schmitter, Petra; Worqlul, Abeyou W.; Steenhuis, Tammo S.; Reyes, Manuel R.; Tilahun, Seifu A.; MDPIWater resources in sub-Saharan Africa are more overstressed than in many other regions of the world. Experiments on commercial farms have shown that conservation agriculture (CA) can save water and improve the soil. Nevertheless, its benefits on smallholder irrigated farms have not been adequately investigated, particularly in dry monsoon phase in the Ethiopian highlands. We investigated the effect of conservation agriculture (grass mulch cover and no-tillage) on water-saving on smallholder farms in the Ethiopian highlands. Irrigated onion and garlic were grown on local farms. Two main factors were considered: the first factor was conservation agriculture versus conventional tillage, and the second factor was irrigation scheduling using reference evapotranspiration (ETo) versus irrigation scheduling managed by farmers. Results showed that for both onion and garlic, the yield and irrigation water use efficiency (IWUE) was over 40% greater for CA than conventional tillage (CT). The soil moisture after irrigation was higher in CA compared with CT treatment while CA used 49 mm less irrigation water. In addition, we found that ETo-based irrigation was superior to the farmers’ irrigation practices for both crops. IWUE was lower in farmers irrigation practices due to lower onion and garlic yield responses to overirrigation and greater water application variability.Item Deep Tillage Improves Degraded Soils in the (Sub) Humid Ethiopian Highlands(Land, 2019) Abidela Hussein, Misbah; Muche, Habtamu; Schmitter, Petra; Nakawuka, Prossie; Tilahun, Seifu A.; Langan, Simon; Barron, Jennie; Steenhuis, Tammo S.; MDPIIntensification of rainfed agriculture in the Ethiopian highlands has resulted in soil degradation and hardpan formation, which has reduced rooting depth, decreased deep percolation, and increased direct runoff and sediment transport. The main objective of this study was to assess the potential impact of subsoiling on surface runoff, sediment loss, soil water content, infiltration rate, and maize yield. Three tillage treatments were replicated at five locations: (i) no tillage (zero tillage), (ii) conventional tillage (ox-driven Maresha plow, up to a depth of 15 cm), and (iii) manual deep ripping of the soil’s restrictive layers down to a depth of 60 cm (deep till). Results show that the posttreatment bulk density and penetration resistance of deep tillage was significantly less than in the traditional tillage and zero-tillage systems. In addition, the posttreatment infiltration rate for deep tillage was significantly greater, which resulted in significantly smaller runoff and sedimentation rates compared to conventional tillage and zero tillage. Maize yields were improved by 6% under deep tillage compared to conventional tillage and by 29% compared to no tillage. Overall, our findings show that deep tillage can be effective in overcoming some of the detrimental effects of hardpans in degraded soils.Item Endosulfan Pesticide Dissipation and Residue Levels in Khat and Onion in a Sub-humid Region of Ethiopia(Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, 2020) Sishu, Feleke K.; Thegaye, Elisabeth K.; Schmitter, Petra; Habtu, Nigus G.; Tilahun, Seifu A.; Steenhuis, Tammo S.; SpringerEndosulfan, a mixture of α- and β-isomers, is used by farmers in the wet and dry season for khat and onion production. Khat leaf samples were collected in farmer fields at intervals of 1 h; 1, 5, 9 and 14 d after application. The dissipation rate of α- and β-isomers and residue level in khat were compared with residue levels in onion. The extraction was done by using Quick Easy Cheap Effective Rugged and Safe (QuEChERS) method and analyzed by Gas Chromatography – Electron Capture Detector (GC-ECD). Greater residue α- and β-isomer endosulfan levels were found in khat compared to onion as khat leaves are sprayed repeatedly in two week. Residue levels of khat exceeded the tolerable EU limit of 0.05 mg.kg−1 for leafy vegetables and herbs. For both raw and processed onion sample α- and β-endosulfan residues level were below the tolerable of limit EU regulation for bulb vegetables (i.e. 0. 1 mg.kg−1). The mean half-life for the α-isomer of endosulfan was 3.4 d in the wet season and 3.6 d in the dry season whilst that for the β-isomer was 5.0 d and 5.4 d respectively. Both isomers dissipated fastest in the wet season under conditions of high humidity and precipitation. The β-isomer persisted longer and had a lower dissipation rate from plants surface compared to the α-isomer.Item Establishing irrigation potential of a hillside aquifer in the African highlands(Hydrological Processes,, 2020) Tilahun, Seifu A.; Yilak, Debebe L.; Schmitter, Petra; Zimale, Fasikaw A.; Langan, Simon; Barron, Jennie; Parlange, Jean-Yves; Steenhuis, Tammo S.; WileyFeeding 9 billion people in 2050 will require sustainable development of all water resources, both surface and subsurface. Yet, little is known about the irrigation potential of hillside shallow aquifers in many highland settings in sub‐Saharan Africa that are being considered for providing irrigation water during the dry monsoon phase for smallholder farmers. Information on the shallow groundwater being available in space and time on sloping lands might aid in increasing food production in the dry monsoon phase. Therefore, the research objective of this work is to estimate potential groundwater storage as a potential source of irrigation water for hillside aquifers where lateral subsurface flow is dominant. The research was carried out in the Robit Bata experimental watershed in the Lake Tana basin which is typical of many undulating watersheds in the Ethiopian highlands. Farmers have excavated more than 300 hand dug wells for irrigation. We used 42 of these wells to monitor water table fluctuation from April 16, 2014 to December 2015. Precipitation and runoff data were recorded for the same period. The temporal groundwater storage was estimated using two methods: one based on the water balance with rainfall as input and baseflow and evaporative losses leaving the watershed as outputs; the second based on the observed rise and fall of water levels in wells. We found that maximum groundwater storage was at the end of the rain phase in September after which it decreased linearly until the middle of December due to short groundwater retention times. In the remaining part of the dry season period, only wells located close to faults contained water. Thus, without additional water sources, sloping lands can only be used for significant irrigation inputs during the first 3 months out of the 8 months long dry season.Item Helping farmers in irrigation scheduling and irrigated small holder farms increasing water productivity(IWMI, [2005?]) Appoh, Richard; Schmitter, PetraItem Insights From a Multi-Method Recharge: Estimation Comparison Study(Groundwater, 2018) Walker, David; Parkin, Geoff; Schmitter, Petra; Gowing, John; Tilahun, Seifu A.; Haile, Alemseged T.; Yimam, Abdu Y.; NGWAAlthough most recharge estimation studies apply multiple methods to identify the possible range in recharge values, many donot distinguish clearly enough between inherent uncertainty of the methods and other factors affecting the results. We investigatedthe additional value that can be gained from multi-method recharge studies through insights into hydrogeological understanding, inaddition to characterizing uncertainty. Nine separate groundwater recharge estimation methods, with a total of 17 variations, wereapplied at a shallow aquifer in northwest Ethiopia in the context of the potential for shallow groundwater resource development.These gave a wide range of recharge values from 45 to 814 mm/a. Critical assessment indicated that the results depended on whatthe recharge represents (actual, potential, minimum recharge or change in aquifer storage), and spatial and temporal scales, aswell as uncertainties from application of each method. Important insights into the hydrogeological system were gained from thisdetailed analysis, which also confirmed that the range of values for actual recharge was reduced to around 280-430 mm/a. Thisstudy demonstrates that even when assumptions behind methods are violated, as they often are to some degree especially whendata are limited, valuable insights into the hydrogeological system can be gained from application of multiple methodsItem Irrigated Fodder Opportunities for Small Scale Irrigators(International Livestock Research Institute;International Water Management Institute, [2017?]) Schmitter, Petra; Blummel, Michael; Lefore, NicoleItem A multi-stakeholder dialogue on farmer-led irrigation in Ethiopia: Engaging with Stakeholders from the Agricultural Water Management Task Force(Feed the Future, 2020) Minh, Thai Thi; Schmitter, Petra; Ludi, Eva; USAID; ILSSI; IWMIItem Predicting Shallow Groundwater Tables for Sloping Highland Aquifers(Water Resources Research, 2019) Alemie, Tilashwork C.; Tilahun, Seifu, A.; Ochoa-Tocachi, Boris F.; Schmitter, Petra; Buytaert, Wouter; Parlange, J-Yves; Steenhuis, Tammo S.; AGU 100While hydrological science has made great strides forward during the last 50 years with the advance of computing power and availability of satellite images, much is unknown about the sustainable development of water for irrigation, domestic use, and livestock consumption for millions of households in the developing world. Specifically, quantification of shallow underground water resources for irrigation in highland regions remains challenging. The objective is to better understand the hydrology of highland watersheds with sloping hillside aquifers. Therefore, we present a subsurface flow model for hillside aquifers with recharge that varied from day to day. Recharge to the aquifer was estimated by the Thornthwaite Mather procedure. A characteristic time was identified for travel time of water flowing from the upper part of the hillside to the river or well. Using the method of characteristics, we found that the height of shallow groundwater level can be predicted by determining the total recharge over the characteristic time divided by drainable porosity. We apply the model to farmer‐dug wells in the Ethiopian highlands using observed rainfall, potential evaporation, and a fitted travel time. We find that the model performs well with maximum water table heights being determined by the soil surface and minimum heights by the presence or absence of volcanic dikes downhill. Our application shows that unless the water is ponded behind a natural or artificial barrier, hillslope aquifers are unable to provide a continuous source of water during the long, dry season. This clearly limits any irrigation development in the highlands from shallow sloping groundwater.Item A review of trends, constraints and opportunities of smallholder irrigation in East Africa(Global Food Security, 2018) Nakawuka, Prossie; Langan, Simon; Schmitter, Petra; Barron, Jennie; ElsevierSmallholder irrigation expansion would significantly increase agricultural production, and reduce food insecurity and poverty levels in East Africa. This paper reviews literature on trends, constraints and opportunities of smallholder irrigation in four East African countries: Ethiopia, Kenya, Tanzania and Uganda. Irrigation development has been slow in these countries, and has been mainly through traditional schemes. Recently, individual irrigation technologies such as small motorized pumps, drip kits, treadle pumps, rope and washer pumps are being promoted. Adoption of these technologies and expansion of smallholder irrigation however face a number of challenges including land tenure issues; lack of access to appropriate irrigation technologies, improved agricultural inputs, reliable markets, finance and credit services, and research support; poor transport and communication infrastructures; poor irrigation water management; poor extension systems; and the over dependence on national governments, NGOs and donors for support. Despite these challenges, opportunities exist for smallholder irrigation expansion in East Africa. Such opportunities include: high untapped irrigation potential; rainwater harvesting to improve water availability; high commitment of national governments, NGOs and donors to smallholder irrigation expansion; low cost irrigation technologies adaptable to local conditions; traditional schemes rehabilitation; growing urbanization; and increased use of mobile phones that can be used to disseminate information.Item Suitability mapping framework for solar photovoltaic pumps for smallholder farmers in sub-Saharan Africa(Applied Geography, 2018) Schmitter, Petra; Kibret, Kefyalew S.; Lefore, Nicole; Barron, Jennie; ElsevierAs solar panels become more affordable, solar photovoltaic (PV) pumps have been identified as a high potential water-lifting technology to meet the growing irrigation demand in sub-Saharan Africa (SSA). However, little is known about the geo-spatial potential of solar-based PV pumping for irrigation taking into account not only solar radiation but also the availability of water resources and linkage to markets. This study developed a suitability framework using multi-criteria analysis in an open source geographic information system (GIS) environment and tested it in the case of Ethiopia. The accessibility of water resources was the driving factor for different scenarios. Suitability results following the groundwater scenarios showed good agreement with the available referenced well depth data. Comparing the suitability maps with available land use data showed that on average 9% (96 103 ha) of Ethiopian irrigated and 18% (3,739 103 ha) of rainfed land would be suitable for solar PV pump irrigation. Furthermore, small solar PV pumps could be an alternative water-lifting technology for 11% of the current and future small motorized hydrocarbon fuel pumps on smallholder farms (2,166 103 ha). Depending on the technical pump capacity, between 155 103 ha and 204 103 ha of land would be suitable for solar PV pumps and provide smallholder farmers with the option to either pump from small reservoirs or shallow groundwater. With the ongoing interest in development for smallholder irrigation, the application of this model will help to upscale solar PV pumps for smallholder farmers in SSA as a climate-smart technology in an integrated manner.Item Suitability of Watershed Models to Predict Distributed Hydrologic Response in the Awramba Watershed in Lake Tana Basin(Land Degradation & Development, 2016) Moges, Mamaru A.; Schmitter, Petra; Tilahun, Seifu A.; Langan, Simon; Dagnew, Dessalegn C.; Akale, Adugnaw T.; Steenhuis, Tammo S.; John Wiley & Sons, Ltd.Planning effective landscape interventions is an important tool to fight against land degradation and requires knowledge on spatial distribution of runoff. The objective of this paper was to test models that predict temporal and spatial distribution of runoff. The selected models were parameter‐efficient semi‐distributed watershed model (PED‐WM), Hydrologiska Byrans Vattenbalansavdelning integrated hydrological modeling system (HBV‐IHMS), and Soil and Water Assessment Tool (SWAT). We choose 7‐km2 Awramba watershed in the Lake Tana basin with detailed hydrological information for testing these models. Discharge at the outlet, rainfall, and distributed information on infiltration rates, water table, and extent of the saturated area were collected from 2013 to 2015. The maximum saturated area was 6·5% of the watershed. Infiltration rates exceeded rainfall intensities 91% of the time. Hence, saturation excess runoff was the main runoff mechanism. Models were calibrated for the rainy seasons in 2013 and 2014 and validated for 2015. For daily flow validation, the PED‐WM model (Nash–Sutcliff efficiency, NSE = 0·61) outperformed HBV‐IHMS (NSE = 0·51) and SWAT (NSE = 0·48). Performance on monthly time step was similar. Difference in model behavior depended on runoff mechanism. In PED‐WM, saturation excess is the main direct runoff process and could predict the maximum extent of the saturated area closely at 6·9%. HBV‐IHMS model runoff simulation depended on soil moisture status and evapotranspiration, and hence was able to simulate saturation excess flow but not the extent of the saturated area. SWAT, where infiltration excess is the main runoff mechanism, could only predict the monthly discharges well. This study shows that prevailing runoff mechanisms and distribution of runoff source areas should be used for proper model selection. Copyright © 2016 John Wiley & Sons, Ltd.Item Water resource assessment, gaps, and constraints of vegetable production in Robit and Dangishta watersheds, Upper Blue Nile Basin, Ethiopia(Agricultural Water Management, 2019) Worqlul, Abeyou W.; Dile, Yihun T.; Schmitter, Petra; Jeong, Jaehak; Meki, Manyowa N.; Gerik, Thomas J.; Srinivasan, Raghavan; Lefore, Nicole; Clarke, Neville; ElsevierThe vast majority of farmers in sub-Saharan Africa depend on rainfed agriculture for food production and livelihood. Various factors including but not limited to rainfall variability, land degradation, and low soil fertility constrain agricultural productivity in the region. The objectives of this study were to 1) estimate the water resources potential to sustain small-scale irrigation (SSI) in Ethiopia during the dry season so as to expand food supply by growing vegetables, and 2) understand the gaps and constraints of vegetable production. The case studies were conducted in the Robit and Dangishta watersheds of the Upper Blue Nile Basin, Ethiopia. To document farmers’ cropping practices, field-level data were collected from 36 households who had been cultivating tomato (Solanum lycopersicum L.) and onion (Allium cepa L.) during the dry season (November – April). Two components of the Integrated Decision Support System (IDSS) - the Soil and Water Assessment Tool (SWAT) and Agricultural Policy Environmental eXtender (APEX) – were respectively used to assess impacts of SSI at the watershed and field-scale levels. Results suggest that there is a substantial amount of surface runoff and shallow groundwater recharge at the watershed scale. The field-scale analysis in the Robit watershed indicated that optimal tomato yield could be obtained with 500 mm of water and 200 to 250 kg/ha of urea applied with 50 kg/ha of diammonium phosphate (DAP). In Dangishta, optimum onion yield can be obtained with 400 mm of water and 120 to 180 kg/ha of urea applied with 50 kg/ha of DAP. The field-scale simulation indicated that the average shallow groundwater recharge (after accounting for other groundwater users such as household and livestock use) was not sufficient to meet tomato and onion water demand in the dry season (October to April). The field-scale analysis also indicated that soil evaporation attributed a significant proportion of evapotranspiration (60% for onion and 40% for tomato). Use of mulching or other soil and water conservation interventions could optimize irrigation water for vegetable production by reducing soil evaporation and thereby increasing water availability in the crop root zone.Item Watershed modeling for reducing future non-point source sediment and phosphorus load in the Lake Tana Basin, Ethiopia(Journal of Soils and Sediments, 2018) Moges, Mamaru A.; Schmitter, Petra; Tilahun, Seifu A.; Steenhuis, Tammo S.Agricultural intensification to meet the food needs of the rapidly growing population in developing countries affects water quality. In regions such as the Lake Tana basin, knowledge is lacking on measures to reduce non-point source pollutants in humid tropical monsoon climates. The aim of this paper was, therefore, to develop a non-point model that can predict the placement of practices to reduce the transport of sediment and phosphorus (P) in a (sub) humid watershed. Materials and methods In order to achieve the objective, hydrometeorological, sediment, and P data were collected in the watershed since 2014. The parameter efficient semi-distributed watershed model (PED-WM) was calibrated and validated in the Ethiopian highlands to simulate runoff and associated sediments generated through saturation excess. The P module added to PED-WM was used to predict dissolved (DP) and particulate P (PP) loads aside from discharge and sediment loads of the 700 ha of the Awramba watershed of Lake Tana basin. The PED-WM modules were evaluated using the statistical model performance measuring techniques. The model parameter based prediction of source areas for the non-point source sediment and P was also evaluated spatially and compared with the Topographic Wetness Index (TWI) of the watershed. Results and discussion The water balance component of the non-point source model performed well in predicting discharge, sediment, DP, and PP with NSE of 0.7, 0.65, 0.65, and 0.63, respectively. In addition, the predicted discharge followed the hydrograph with insignificant deviation from its pattern due to seasonality. The model predicted a sediment yield of 28.2 t ha−1 year−1 and P yield of 9.2 kg ha−1 year−1 from Awrmaba. Furthermore, non-point source areas contributed to 2.7 kg ha−1 year−1 (29%) of DP at the outlet. The main runoff and sediment source areas identified using PED-WM were the periodically saturated runoff areas. These saturated areas were also the main source for DP and PP transport in the catchment. Conclusions Using the PED-WM with the P module enables the identification of the source areas as well as the prediction of P and sediment loading which yields valuable information for watershed management and placement of best management practices.