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Full-Text Articles in Physical Sciences and Mathematics

Evaluating A Satellite-Based Seasonal Evapotranspiration Product And Identifying Its Relationship With Other Satellite-Derived Products And Crop Yield: A Case Study For Ethiopia, Tsegaye Tadesse, Gabriel B. Senay, Getachew Berhan, Teshome Regassa, Shimelis Beyene Jan 2015

Evaluating A Satellite-Based Seasonal Evapotranspiration Product And Identifying Its Relationship With Other Satellite-Derived Products And Crop Yield: A Case Study For Ethiopia, Tsegaye Tadesse, Gabriel B. Senay, Getachew Berhan, Teshome Regassa, Shimelis Beyene

Department of Agronomy and Horticulture: Faculty Publications

Satellite-derived evapotranspiration anomalies and normalized difference vegetation index (NDVI) products from Moderate Resolution Imaging Spectroradiometer (MODIS) data are currently used for African agricultural drought monitoring and food security status assessment. In this study, a process to evaluate satellite-derived evapotranspiration (ETa) products with a geospatial statistical exploratory technique that uses NDVI, satellite-derived rainfall estimate (RFE), and crop yield data has been developed. The main goal of this study was to evaluate the ETa using the NDVI and RFE, and identify a relationship between the ETa and Ethiopia’s cereal crop (i.e., teff, sorghum, corn/maize, barley, and wheat) yields during the main rainy …


Response Of Stomatal Density And Bound Gas Exchange In Leaves Of Maize To Soil Water Deficit, Wensai Zhao, Yonglin Sun, Roger Kjelgren, Xiping Liu Jan 2015

Response Of Stomatal Density And Bound Gas Exchange In Leaves Of Maize To Soil Water Deficit, Wensai Zhao, Yonglin Sun, Roger Kjelgren, Xiping Liu

Plants, Soils, and Climate Faculty Publications

Stomatal behavior in response to drought has been the focus of intensive research, but less attention has been paid to stomatal density. In this study, 5-week-old maize seedlings were exposed to different soil water contents. Stomatal density and size as well as leaf gas exchange were investigated after 2-, 4- and 6-weeks of treatment, which corresponded to the jointing, trumpeting, and filling stages of maize development. Results showed that new stomata were generated continually during leaf growth. Reduced soil water content significantly stimulated stomatal generation, resulting in a significant increase in stomatal density but a decrease in stomatal size and …


On Underestimation Of Global Vulnerability To Tree Mortality And Forest Die-Off From Hotter Drought In The Anthropocene, Craig D. Allen, David D. Breshears, Nate G. Mcdowell Jan 2015

On Underestimation Of Global Vulnerability To Tree Mortality And Forest Die-Off From Hotter Drought In The Anthropocene, Craig D. Allen, David D. Breshears, Nate G. Mcdowell

United States Geological Survey: Staff Publications

Patterns, mechanisms, projections, and consequences of tree mortality and associated broadscale forest die-off due to drought accompanied by warmer temperatures—‘‘hotter drought’’, an emerging characteristic of the Anthropocene—are the focus of rapidly expanding literature. Despite recent observational, experimental, and modeling studies suggesting increased vulnerability of trees to hotter drought and associated pests and pathogens, substantial debate remains among research, management and policy-making communities regarding future tree mortality risks. We summarize key mortalityrelevant findings, differentiating between those implying lesser versus greater levels of vulnerability. Evidence suggesting lesser vulnerability includes forest benefits of elevated [CO2] and increased water-use efficiency; observed and modeled increases …


Climate-Smart Brachiaria For Improving Livestock Production In East Africa: Emerging Opportunities, Sita R. Ghimire, Donald M. G. Njarui, Mupenzi Mutimura, Juan A. Cardoso, Linda Johnson, Elias M. Gichangi, Suliana Teasdale, Kennedy Odokonyero, John Caradus, Idupulapati M. Rao, Appolinaire Djikeng Jan 2015

Climate-Smart Brachiaria For Improving Livestock Production In East Africa: Emerging Opportunities, Sita R. Ghimire, Donald M. G. Njarui, Mupenzi Mutimura, Juan A. Cardoso, Linda Johnson, Elias M. Gichangi, Suliana Teasdale, Kennedy Odokonyero, John Caradus, Idupulapati M. Rao, Appolinaire Djikeng

IGC Proceedings (1997-2023)

Brachiaria grass is an important tropical forage of African origin with desirable attributes of agricultural and environmental significance. Brachiaria has been extensively cultivated as a pasture across the tropics except in its endemic provenance of Africa. In 2013, a collaborative research program was initiated in Kenya and Rwanda with the aim of improving the availability of quality livestock feeds adapted to drought and low fertility soils using Brachiaria. The outcomes sought were increased livestock productivity leading to improved farmer income and the development of seed production opportunities. The program has identified five preferred cultivars, and four of them are currently …