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Roles of climate and agricultural practices in discharge changes in an agricultural watershed in Iowa Texte intégral
2014
Villarini, Gabriele | Strong, Aaron
River discharge represents a vital resource for many human activities. The improved understanding of the physical processes controlling its regime can lead to large economic and societal benefits, such as improved flood warning and mitigation, and improved water management during droughts. This is particularly true for the agricultural U.S. Midwest and Iowa more specifically. Iowa is relentlessly plagued by catastrophic flooding, with the spring and summer river floods of 1993, 2008, and 2013 and the drought of 2012 being the most recent widespread events affecting the state. These natural disasters also come with a very large price tag, both in terms of economic damage and fatalities.During the 20th and 21st centuries, discharge over this area has been changing on a number of temporal scales, from annual to decadal. An outstanding question is related to the contribution of changes in the climate system and in land use/land cover and agricultural practices in explaining changes in discharge. We address this question by developing statistical models to describe the changes in different parts of the discharge distribution. We use rainfall and harvested corn and soybean acreage to explain the observed stream flow variability. We focus on the Raccoon River at Van Meter, which is a 9000-km2 watershed with daily discharge measurements covering most of the 20th century up to the present. Our results indicate that rainfall variability is responsible for the majority of the changes observed in the discharge record, with changes in cultivated area affecting the discharge responses in different ways, depending on which part of the discharge distribution is considered. In particular, land use change exacerbates high discharge during heavy precipitation and low discharge during low precipitation.
Afficher plus [+] Moins [-]Agricultural R&D in Senegal: An Assessment of the Senegalese Agricultural Research Institute
2014
Gaye, Lamine | Sène, Louis | Stads, Gert-Jan
Agricultural R&D in Togo: An Assessment of the Togolese Agricultural Research Institute
2014
Adabe, Kokou Edoh | Stads, Gert-Jan
The Agricultural Science and Technology Indicators (ASTI) initiative of the International Food Policy Research Institute (IFPRI) and the West African Council for Agricultural Research and Development (CORAF/WECARD) conducted an in-depth study of critical issues relating to human, financial, and institutional agricultural R&D capacities in Burkina Faso and five other West African countries (Benin, Ghana, Senegal, Sierra Leone, and Togo). As part of this study, detailed quantitative and qualitative data were collected at an institutional level. This included a staff motivation survey targeting a representative group of research and managerial staff in terms of position, qualification, gender, seniority, and physical location.
Afficher plus [+] Moins [-]Phosphorus and Water Budgets in an Agricultural Basin Texte intégral
2014
Faridmarandi, Sayena | Naja, Ghinwa M.
Water and phosphorus (P) budgets of a large agricultural basin located in South Florida (Everglades Agricultural Area, EAA) were computed from 2005 to 2012. The annual surface outflow P loading from the EAA averaged 157.2 mtons originating from Lake Okeechobee (16.4 mtons, 10.4%), farms (131.0 mtons, 83.4%), and surrounding basins (9.8 mtons, 6.2%) after attenuation. Farms, urban areas, and the adjacent C-139 basin contributed 186.1, 15.6, and 3.8 mtons/yr P to the canals, respectively. The average annual soil P retention was estimated at 412.5 mtons. Water and P budgets showed seasonal variations with high correlation between rainfall and P load in drainage and surface outflows. Moreover, results indicated that the canals acted as a P sink storing 64.8 mtons/yr. To assess the P loading impact of farm drainage on the canals and on the outflow, dimensionless impact factors were developed. Sixty-two farms were identified with a high and a medium impact factor I₁ level contributing 44.5% of the total drainage P load to the canals, while their collective area represented less than 23% of the EAA area (172 farms). Optimizing the best management practice (BMP) strategies on these farms could minimize the environmental impacts on the downstream sensitive wetlands areas.
Afficher plus [+] Moins [-]Agricultural R&D in Togo: An Assessment of the Togolese Agricultural Research Institute
2014
Adabe, Kokou Edoh; Stads, Gert-Jan
Agricultural R&D in Togo: An Assessment of the Togolese Agricultural Research Institute
2014
Adabe, Kokou Edoh; Stads, Gert-Jan
CGIAR Research Program on Policies, Institutions, and Markets (PIM) | IFPRI1; ASTI; CRP2 | The Agricultural Science and Technology Indicators (ASTI) initiative of the International Food Policy Research Institute (IFPRI) and the West African Council for Agricultural Research and Development (CORAF/WECARD) conducted an in-depth study of critical issues relating to human, financial, and institutional agricultural R&D capacities in Burkina Faso and five other West African countries (Benin, Ghana, Senegal, Sierra Leone, and Togo). As part of this study, detailed quantitative and qualitative data were collected at an institutional level. This included a staff motivation survey targeting a representative group of research and managerial staff in terms of position, qualification, gender, seniority, and physical location. | EPTD; PIM | Non-PR | Project paper
Afficher plus [+] Moins [-]Agricultural R&D in Senegal: An Assessment of the Senegalese Agricultural Research Institute
2014
Gaye, Lamine; Sène, Louis; Stads, Gert-Jan
Agricultural R&D in Senegal: An Assessment of the Senegalese Agricultural Research Institute
2014
Gaye, Lamine; Sène, Louis; Stads, Gert-Jan
CGIAR Research Program on Policies, Institutions, and Markets (PIM) | IFPRI1; ASTI; CRP2 | EPTD; PIM | Non-PR | Project paper
Afficher plus [+] Moins [-]Food web structure in an agricultural drainage channel through an urbanized zone in Japan Texte intégral
2014
Hiramatsu, Ken | Yonebayashi, Koyo | Ichion, Eiji | Nishimura, Shinichi | Onishi, Takeo
Channels and streams flowing through urbanized areas are often modified by lining the channel bed with concrete to prevent flooding caused by land-use changes in the catchment area. Even when eco-friendly works, such as fish pools and fish habitat blocks, are incorporated into the modification to accommodate aquatic ecosystems, there will be impacts on the food web and, consequently, the amount of food available for fish. In this study, the food web structure of the Ooe drainage channel, a small concrete-lined stream through an urban area, was investigated using stable isotope ratios of carbon and nitrogen. We compared the characteristics of the Ooe channel to those of several other aquatic systems. We found a single trophic transfer line, from particulate organic matter (POM) to benthic fish (Rhinogobius sp.) and crustaceans (Palaemon paucidens) via swimming fish (Squalidus chankaensis and Pseudorasbora. parva). However, the highest trophic level (benthic fish) was only 2.6–2.8 because few planktonic arthropods occurred in the web between POM and fish, unlike in more natural bodies of water. In addition, neither terrestrial plants nor periphyton were major sources of POM. Instead, organic matter from domestic wastewater appeared to be the major source of POM in the Ooe channel. Thus, the food web structure of this concrete-lined stream flowing through an urbanized zone proved to be strongly affected by its non-natural surroundings and extremely vulnerable to changes in those surroundings.
Afficher plus [+] Moins [-]Agricultural R&D in Sierra Leone: An Assessment of the Sierra Leone Agricultural Research Institute
2014
Momoh, John | Beintema, Nienke M.
Despite increasing availability of household water treatment products, demand in developing countries remains low. Willingness to pay for water treatment products and factors that affect demand are not well understood. In this study, we estimate willingness to pay for WaterGuard, a dilute chlorine solution for point-of-use water treatment, using actual purchase decisions at randomly assigned prices. Secondly, we identify household characteristics that are correlated with the purchase decision. Among a sample of 854 respondents from 107 villages in rural Kenya, we find that mean willingness to pay is approximately 80% of the market price. Although only 35% of sample households purchased WaterGuard at the market price, 67% of those offered a 50% discount purchased the product. A marketing message emphasizing child health did not have a significant effect on purchase behavior, overall or among the subset of households with children under five. These findings suggest that rural Kenyans are willing to pay for WaterGuard at low prices but are very sensitive to increasing price. Households with young children that could benefit the most from use of WaterGuard do not appear to be more likely to purchase the product, and a marketing message designed to target this population was ineffective.
Afficher plus [+] Moins [-]Agricultural R&D in Sierra Leone: An Assessment of the Sierra Leone Agricultural Research Institute
2014
Momoh, John; Beintema, Nienke M.
Agricultural R&D in Sierra Leone: An Assessment of the Sierra Leone Agricultural Research Institute
2014
Momoh, John; Beintema, Nienke M.
CGIAR Research Program on Policies, Institutions, and Markets (PIM) | IFPRI1; ASTI; CRP2 | EPTD; PIM | Non-PR | Project paper
Afficher plus [+] Moins [-]Modeling a phosphorus credit trading program in an agricultural watershed Texte intégral
2014
Corrales, Juliana | Naja, G Melodie | Bhat, Mahadev G. | Miralles-Wilhelm, Fernando
Water quality and economic models were linked to assess the economic and environmental benefits of implementing a phosphorus credit trading program in an agricultural sub-basin of Lake Okeechobee watershed, Florida, United States. The water quality model determined the effects of rainfall, land use type, and agricultural management practices on the amount of total phosphorus (TP) discharged. TP loadings generated at the farm level, reaching the nearby streams, and attenuated to the sub-basin outlet from all sources within the sub-basin, were estimated at 106.4, 91, and 85 mtons yr−1, respectively. Almost 95% of the TP loadings reaching the nearby streams were attributed to agriculture sources, and only 1.2% originated from urban areas, accounting for a combined TP load of 87.9 mtons yr−1. In order to compare a Least-Cost Abatement approach to a Command-and-Control approach, the most cost effective cap of 30% TP reduction was selected, and the individual allocation was set at a TP load target of 1.6 kg ha−1 yr−1 (at the nearby stream level). The Least-Cost Abatement approach generated a potential cost savings of 27% ($1.3 million per year), based on an optimal credit price of $179. Dairies (major buyer), ornamentals, row crops, and sod farms were identified as potential credit buyers, whereas citrus, improved pastures (major seller), and urban areas were identified as potential credit sellers. Almost 81% of the TP credits available for trading were exchanged. The methodology presented here can be adapted to deal with different forms of trading sources, contaminants, or other technologies and management practices.
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