Determinants of tillage frequency among smallholder farmers in two semi-arid areas in Ethiopia

Temesgen, Melesse; Rockström, Johan; Savenije, Hubert; Hoogmoed, W.B.; Alemu, Dawit

doi:10.1016/j.pce.2007.04.012

Cited by 71 publications

(58 citation statements)

References 7 publications

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“…Teff (Eragrostis tef), a widely cultivated and highly nutritional crop native to Ethiopia, was planted in the beginning of July and harvested in the beginning of December with several tillage operations preceding planting. Tillage operations were adapted to the usage of the traditional Ethiopian plough called Maresha according to Temesgen et al (2008), with a tillage depth of 20 cm and a mixing efficiency of 0.3.…”

Section: Swat Model Setupmentioning

confidence: 99%

Comparing CFSR and conventional weather data for discharge and soil loss modelling with SWAT in small catchments in the Ethiopian Highlands

Roth

Lemann

2016

Hydrol. Earth Syst. Sci.

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Abstract. Accurate rainfall data are the key input parameter for modelling river discharge and soil loss. Remote areas of Ethiopia often lack adequate precipitation data and where these data are available, there might be substantial temporal or spatial gaps. To counter this challenge, the Climate Forecast System Reanalysis (CFSR) of the National Centers for Environmental Prediction (NCEP) readily provides weather data for any geographic location on earth between 1979 and 2014. This study assesses the applicability of CFSR weather data to three watersheds in the Blue Nile Basin in Ethiopia. To this end, the Soil and Water Assessment Tool (SWAT) was set up to simulate discharge and soil loss, using CFSR and conventional weather data, in three small-scale watersheds ranging from 112 to 477 ha. Calibrated simulation results were compared to observed river discharge and observed soil loss over a period of 32 years. The conventional weather data resulted in very good discharge outputs for all three watersheds, while the CFSR weather data resulted in unsatisfactory discharge outputs for all of the three gauging stations. Soil loss simulation with conventional weather inputs yielded satisfactory outputs for two of three watersheds, while the CFSR weather input resulted in three unsatisfactory results. Overall, the simulations with the conventional data resulted in far better results for discharge and soil loss than simulations with CFSR data. The simulations with CFSR data were unable to adequately represent the specific regional climate for the three watersheds, performing even worse in climatic areas with two rainy seasons. Hence, CFSR data should not be used lightly in remote areas with no conventional weather data where no prior analysis is possible.

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Section: Swat Model Setupmentioning

confidence: 99%

Comparing CFSR and conventional weather data for discharge and soil loss modelling with SWAT in small catchments in the Ethiopian Highlands

Roth

Lemann

2016

Hydrol. Earth Syst. Sci.

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“…For this reason tillage power optimization is still one of the main research fields (Collins et al, 1978;Bloome et al, 1983;Singh et al, 1991;Owend & Eward, 1996). Some studies have already started this optimization either by reducing the tillage frequency (number of operations during the production cycle) (Temesgen et al, 2008) or by using strip tillage (limiting the surface of tillage) (Mullins et al, 1998;Licht & Al-Kaisi, 2005;Temesgen et al, 2012;Celik et al, 2013;Trevini et al, 2013). However, these techniques are acceptable in very few conditions and cannot be generalized especially with hard environmental conditions (scarcity of water and arid climate).…”

Section: Introductionmentioning

confidence: 99%

Soil-blade orientation effect on tillage forces determined by 3D finite element models

Ibrahmi

Bentaher

Maalej

2014

Span. j. agric. res.

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This paper investigated the effect of the cutting parameters of a blade on the tillage force components using finite element modeling. A three-dimensional model was carried out with Abaqus Explicit in order to study the interaction between the tool and soil. The soil was modeled with linear forms of the Drucker-Pager model, while the tool was considered as a rigid body with a reference point taken at its tip. The effect of tillage depth and the width of a vertical blade were studied. It was found that the amounts of the draught and vertical forces increase linearly with a slope of 0.037 and 0.0143 respectively when the width increases. The narrow tool (width < 60mm) has a greater effect on the specific draught force than a larger tool. Draught and specific draught force increase with polynomial and linear curve respectively versus the depth. However, this effect was reduced for the vertical force. These results were in a good agreement with previously published works. The second part of this paper is focused on the oblique position of the blade to evaluate the effect of the attack angles on both the tillage forces (draught, lateral and vertical) and the cutting process of the soil during and after its failure. For all considered angles, the draught force presents the highest values compared to the vertical and lateral forces. Results showed that working with small cutting and an average rake angles (30°to 60°and 45°respectively) can produce a good soil inversion.Additional key words: FEM; oblique blade; force; attack angles.* Corresponding author: ayadi.ibrahmi@yahoo.fr; ayadiibrahmi@hotmail.fr Received: 16-02-14. Accepted: 10-10-14.Abbreviations used: CFD (computational fluid dynamics); DEM (discrete element method); FEM (finite element method); RF (reaction force); RF2 (vertical force); RF3 (draught force); α (cutting angle); θ (rake angle).

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“…In addition, the traditional Ethiopian ploughing tool called Maresha was added to the ArcSWAT management database. The Maresha was assigned a tillage depth of 20 cm and mixing efficiency of 0.3 (Temesgen et al, 2008;Dile and Srinivasan, 2014).…”

Section: Model Parametrizationmentioning

confidence: 99%

Model parameter transfer for streamflow and sediment loss prediction with SWAT in a tropical watershed

2016

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Distributed hydrologic models are increasingly used to describe the spatiotemporal dynamics of water and sediment fluxes within basins. In data-scarce regions like Ethiopia, oftentimes, discharge or sediment load data are not readily available and therefore researchers have to rely on input data from global models with lower resolution and accuracy. In this study we evaluated a model parameter transfer from a 100 hectare (ha) large subwatershed (Minchet) to a 4800 ha catchment in the highlands of Ethiopia using the Soil and Water Assessment Tool (SWAT). The Minchet catchment has long-lasting time series on discharge and sediment load dating back to 1984, which were used to calibrate the subcatchment before (a) validating the Minchet subcatchment and (b) through parameter transfer validating the entire Gerda watershed without prior calibration. Uncertainty analysis was carried out with the Sequential Uncertainty Fitting-2 (SUFI-2) with SWATCup and ArcSWAT2012. We used a similarity approach, where the complete set of model parameters is transposed from a donor catchment that is very similar regarding physiographic attributes (in terms of landuse , soils, geology and rainfall patterns). For calibration and validation the Nash-Sutcliff model efficiency, the Root Mean Square Error-observations Standard Deviation Ratio (RSR) and the Percent Bias (PBIAS) indicator for model performance ratings during calibration and validation periods were applied. Goodness of fit and the degree to which the calibrated model accounted for the uncertainties were assessed with the P-factor and the R-factor of the SUFI-2 algorithm. Results show that calibration and validation for streamflow performed very good for the subcatchment as well as for the entire catchment using model parameter transfer. For sediment loads, calibration performed better than validation and parameter transfer yielded satisfactory results, which suggests that the SWAT model can be used to adequately simulate monthly streamflow and sediment load in the Gerda catchment through model parameter transfer only. Vincent

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Determinants of tillage frequency among smallholder farmers in two semi-arid areas in Ethiopia

Cited by 71 publications

References 7 publications

Comparing CFSR and conventional weather data for discharge and soil loss modelling with SWAT in small catchments in the Ethiopian Highlands

Comparing CFSR and conventional weather data for discharge and soil loss modelling with SWAT in small catchments in the Ethiopian Highlands

Soil-blade orientation effect on tillage forces determined by 3D finite element models

Model parameter transfer for streamflow and sediment loss prediction with SWAT in a tropical watershed

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