Your search found 8 records
1 Saleth, Rathinasamy Maria; Inocencio, Arlene; Noble, Andrew D.; Ruaysoongnern, S. 2009. Economic gains of improving soil fertility and water holding capacity with clay application: the impact of soil remediation research in northeast Thailand. Colombo, Sri Lanka: International Water Management Institute (IWMI). 30p. (IWMI Research Report 130) [doi: https://doi.org/10.3910/2009.130]
Soil improvement ; Impact assessment ; Research projects ; Soil fertility ; Sandy soils ; Water holding capacity ; Clay soils ; Soil water relations ; Soil management ; Farming systems ; Crop yield ; Vegetable crops ; Rice ; Sorghum ; Models ; Statistical methods ; Cost benefit analysis ; Economic analysis ; Economic aspects / Thailand
(Location: IWMI HQ Call no: IWMI 631.422 G750 SAL Record No: H042267)
(427 KB)
Declining productivity of agricultural soils in Northeast Thailand is a challenge facing land managers and farmers. A program was initiated in 2002 to investigate the potential role of incorporating clay-based materials into degraded soils as a means of enhancing productivity. This research report attempts to provide an ex-post assessment of the field level impact and economic viability of this approach, using the empirically derived estimates of the average income impacts that the application of bentonite or clay technology has generated among farm communities in Northeast Thailand. From an exclusive IWMI perspective, the impact evaluation suggests that the program has a net present value (NPV) of US$0.41 million with a benefit-cost ratio (BCR) of 2.44 for the sample, and a NPV of US$21 million with a BCR of 75 for the region.
2 Saleth, Rathinasamy Maria; Inocencio, A.; Noble, Andrew D.; Ruaysoongnern, S. 2009. Economic gains of improving soil fertility and water holding capacity with clay application: the impact of soil remediation research in northeast Thailand. Journal of Development Effectiveness, 1(3):336-352. [doi: https://doi.org/10.1080/19439340903105022]
Bentonite ; Clay soils ; Farming systems ; Impact assessment ; Water holding capacity ; Soil water relations ; Soil management ; Crop yield ; Vegetable crops ; Rice ; Sorghum ; Models ; Statistical methods ; Cost benefit analysis ; Economic analysis / Thailand
(Location: IWMI HQ Call no: e-copy only Record No: H034809)
(0.42 MB)
Using survey data collected from 250 farmers, this paper evaluates the impact of the Soil Remediation Research Project (SRRP) undertaken by International Water Management Institute (IWMI) in Northeast Thailand during 2002–2005. SRRP has demonstrated and promoted the application of clay as a quick and low-cost means for improving the fertility and water holding capacity of sandy soils. The impact evaluation suggests that the SRRP has a net present value (NPV) of US$0.7 million with a benefit–cost ratio (BCR) of 3.1 for the sample context and an NPVof US$99.5 million with a BCR of 317.7 for the larger context of the region.
3 Nikiema, Josiane; Cofie, Olufunke; Asante-Bekoe, Barbara; Otoo, Miriam; Adamtey, N. 2014. Potential of locally available products for use as binders in producing fecal compost pellets in Ghana. Environmental Progress and Sustainable Energy, 33(2):504-511. [doi: https://doi.org/10.1002/ep.11790]
Faeces ; Composts ; Fertilizers ; Binders ; Crops ; Cassava ; Soil fertility ; Costs ; Pelleting ; Clay ; Beeswax ; Classification ; Water holding capacity ; Environmental effects ; Risks / Ghana
(Location: IWMI HQ Call no: e-copy only Record No: H046137)
(1.81 MB)
Market studies in Ghana have revealed a potential for composted or cocomposted fecal matter as nutrient source inputs for agricultural production. To increase the marketability of such products, high nutrient value and easier handling/transporting options are among the significant factors which drive demand. Pelletization is seen as a potentially interesting option to address these challenges. To preserve form stability of the pellet products, the addition of a binding material during the pelletization process is crucial. In Ghana, water, beeswax, clay, and cassava starch have been identified as locally available binding materials. A comparative assessment of these materials as a premier binder suitable for pelletization was performed based on predefined criteria. Quantitative criteria considered included the total amounts available, the seasonal variation during the year and cost. Qualitative criteria such as handling and storage conditions, ease of use during pelletization, and the binding ability were also evaluated. Based on this assessment, clay and cassava-based starch were selected as the most promising binding agents. Currently, clay is abundant in Ghana and this may suggest a guarantee for consistent and stable supply over coming years. However, from the perspective of cassava-based starch, this situation depicts limited production of starch and competition on the local markets.
4 Bodian, A.; Dezetter, A.; Dacosta, H. 2016. Rainfall-runoff modelling of water resources in the upper Senegal River Basin. International Journal of Water Resources Development, 32(1):89-101. [doi: https://doi.org/10.1080/07900627.2015.1026435]
Water resources ; Rainfall-runoff relationships ; Hydrology ; Models ; Calibration ; Performance evaluation ; Soils ; Water holding capacity ; River basins ; Discharges ; Precipitation ; Evapotranspiration / Guinea / Mali / Senegal River Basin
(Location: IWMI HQ Call no: e-copy only Record No: H047648)
(1.58 MB)
The streamflow series for the upstream basin of the Senegal River is marked by considerable gaps. The objective of this article is to simulate and extend hydrological data, using the GR2M rainfall-runoff model. A sensitivity analysis of the model to rainfall and water holding capacity input data was performed. This analysis was performed after calculating catchment rainfall, mean potential evapotranspiration, and maximum, minimum and mean water holding capacity. The best combination of input data was chosen by catchment based on the Nash-Sutcliffe criterion. Then cross calibration-validation tests were performed, using the selected input data to choose model parameter sets.
5 Allam, M. M.; Figueroa, A. J.; McLaughlin, D. B.; Eltahir, E. A. B. 2016. Estimation of evaporation over the Upper Blue Nile Basin by combining observations from satellites and river flow gauges. Water Resources Research, 52(2):644-659. [doi: https://doi.org/10.1002/2015WR017251]
Evapotranspiration ; Water resources ; River basins ; Soil moisture ; Water budget ; Models ; Satellite observation ; Water storage ; Water holding capacity ; Hydrology ; Stream flow ; Runoff ; Precipitation ; Estimation ; Farmland / Ethiopia / Upper Blue Nile Basin
(Location: IWMI HQ Call no: e-copy only Record No: H047776)
(2.28 MB)
Reliable estimates of regional evapotranspiration are necessary to improve water resources management and planning. However, direct measurements of evaporation are expensive and difficult to obtain. Some of the difficulties are illustrated in a comparison of several satellite-based estimates of evapotranspiration for the Upper Blue Nile (UBN) basin in Ethiopia. These estimates disagree both temporally and spatially. All the available data products underestimate evapotranspiration leading to basin-scale mass balance errors on the order of 35 percent of the mean annual rainfall. This paper presents a methodology that combines satellite observations of rainfall, terrestrial water storage as well as river-flow gauge measurements to estimate actual evapotranspiration over the UBN basin. The estimates derived from these inputs are constrained using a one-layer soil water balance and routing model. Our results describe physically consistent long-term spatial and temporal distributions of key hydrologic variables, including rainfall, evapotranspiration, and river-flow. We estimate an annual evapotranspiration over the UBN basin of about 2.55 mm per day. Spatial and temporal evapotranspiration trends are revealed by dividing the basin into smaller subbasins. The methodology described here is applicable to other basins with limited observational coverage that are facing similar future challenges of water scarcity and climate change.
6 Finley, S. 2016. Sustainable water management in smallholder farming: theory and practice. Wallingford, UK: CABI. 198p.
Water management ; Sustainability ; Smallholders ; Rainfed farming ; Conservation agriculture ; Water resources ; Water availability ; Water productivity ; Water use efficiency ; Rainwater ; Water harvesting ; Water quality ; Soil water content ; Water holding capacity ; Plant water relations ; Crop management ; Water requirements ; Evapotranspiration ; Climate change ; Irrigation water ; Water distribution ; Water storage ; Irrigation methods ; Irrigation scheduling ; Irrigation efficiency ; Strategies ; Land degradation
(Location: IWMI HQ Call no: 631.7 G000 FIN Record No: H047765)
(0.44 MB)
7 Sreelash, K.; Buis, S.; Sekhar, M.; Ruiz, L.; Tomer, S. K.; Guerif, M. 2017. Estimation of available water capacity components of two-layered soils using crop model inversion: effect of crop type and water regime. Journal of Hydrology, 546:166-178. [doi: https://doi.org/10.1016/j.jhydrol.2016.12.049]
Water holding capacity ; Water availability ; Estimation ; Soil water content ; Soil hydraulic properties ; Layered soils ; Soil moisture ; Field capacity ; Wilting point ; Water stress ; Crop management ; Models ; Sensitivity analysis ; Leaf Area Index ; Maize ; Sorghum ; Sunflowers ; Turmeric ; Remote sensing ; Catchment areas / South India / Berambadi Catchment
(Location: IWMI HQ Call no: e-copy only Record No: H048041)
(1.43 MB)
Characterization of the soil water reservoir is critical for understanding the interactions between crops and their environment and the impacts of land use and environmental changes on the hydrology of agricultural catchments especially in tropical context. Recent studies have shown that inversion of crop models is a powerful tool for retrieving information on root zone properties. Increasing availability of remotely sensed soil and vegetation observations makes it well suited for large scale applications. The potential of this methodology has however never been properly evaluated on extensive experimental datasets and previous studies suggested that the quality of estimation of soil hydraulic properties may vary depending on agro-environmental situations. The objective of this study was to evaluate this approach on an extensive field experiment. The dataset covered four crops (sunflower, sorghum, turmeric, maize) grown on different soils and several years in South India. The components of AWC (available water capacity) namely soil water content at field capacity and wilting point, and soil depth of two-layered soils were estimated by inversion of the crop model STICS with the GLUE (generalized likelihood uncertainty estimation) approach using observations of surface soil moisture (SSM; typically from 0 to 10 cm deep) and leaf area index (LAI), which are attainable from radar remote sensing in tropical regions with frequent cloudy conditions. The results showed that the quality of parameter estimation largely depends on the hydric regime and its interaction with crop type. A mean relative absolute error of 5% for field capacity of surface layer, 10% for field capacity of root zone, 15% for wilting point of surface layer and root zone, and 20% for soil depth can be obtained in favorable conditions. A few observations of SSM (during wet and dry soil moisture periods) and LAI (within water stress periods) were sufficient to significantly improve the estimation of AWC components. These results show the potential of crop model inversion for estimating the AWC components of two-layered soils and may guide the sampling of representative years and fields to use this technique for mapping soil properties that are relevant for distributed hydrological modelling.
8 Trnka, M.; Vizina, A.; Hanel, M.; Balek, J.; Fischer, M.; Hlavinka, P.; Semeradova, D.; Stepanek, P.; Zahradnicek, P.; Skalak, P.; Eitzinger, J.; Dubrovsky, M.; Maca, P.; Belinova, M.; Zeman, E.; Brazdil, R. 2022. Increasing available water capacity as a factor for increasing drought resilience or potential conflict over water resources under present and future climate conditions. Agricultural Water Management, 264:107460. (Online first) [doi: https://doi.org/10.1016/j.agwat.2022.107460]
Water availability ; Water resources ; Drought ; Resilience ; Climate change ; Water balance ; Soil water retention ; Soil moisture ; Water holding capacity ; Precipitation ; Trends ; River basins ; Hydrological modelling ; Land use / Czechia
(Location: IWMI HQ Call no: e-copy only Record No: H050925)
(16.00 MB)
The close relationship between the onset and severity of agricultural and hydrological drought is considered self-evident, yet relatively few studies have addressed the effects of applying agricultural drought adaptation to hydrological drought characteristics. The present study applies a model cascade capable of simultaneously considering the interactions between agricultural and hydrological droughts. The study area covers all river basins in the Czech Republic and includes the periods of 1956–2015 (baseline) and 2021–2080 (future). The model cascade was shown to explain 91% of the variability in the seasonal and annual accumulated runoff and allows for the analysis of increasing/maintaining/decreasing available water capacity (AWC) across the 133 defined basins with a total area of c. 78,000 km2. The study reports that the probability and extent of agricultural drought increased over the entire period with higher AWC scenario showing slower pace of such increase especially from April to June. The trends in the extent or severity of hydrological droughts were of low magnitude. The future climate has been projected through the use of ensembles of five global (CMIP5) and five regional (EURO-CORDEX) climate models. The results showed a significant increase in the duration of agricultural drought stress and in the area affected throughout the year, particularly in July–September. The hydrological drought response showed a marked difference between areas with a negative and positive climatic water balance, i.e., areas where long-term reference evapotranspiration exceeds long-term precipitation (negative climatic water balance) and where it does not (positive climatic water balance). The overall results indicate that increasing soil AWC would decrease the frequency and likely also impact of future agricultural droughts, especially during spring. This result would be especially true if the wetter winters predicted by some of the models materialized. Hydrological droughts at the country level are estimated to become more pronounced with increasing AWC, particularly in catchments with a negative climatic water balance.
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