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Sun W, Fleisher D, Timlin D, Ray C, Wang Z, Beegum S, Reddy V. Projected long-term climate trends reveal the critical role of vapor pressure deficit for soybean yields in the US Midwest. Sci Total Environ 2023; 878:162960. [PMID: 36958552 DOI: 10.1016/j.scitotenv.2023.162960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/23/2023] [Accepted: 03/16/2023] [Indexed: 05/13/2023]
Abstract
Extreme climate events including heat waves and droughts are projected to become more frequent under future climate change conditions. However, the mechanisms between soybean yields and climate factors, specifically involving variable rainfall and high heat episodes, are still unclear, particularly with respect to spatial trends in the United States (US) Midwest. A recently modified version of the model GLYCIM was used to evaluate rainfed soybean production across 12 states at a 10 km spatial resolution for three time periods (2011-2020, 2051-2060, 2091-2099) under Representative Concentration Pathway (RCP) scenarios 4.5 and 8.5. Results showed that except for the northernmost Midwest counties, most of the current rainfed cropping system in the Midwest would suffer a 24.6-47.4 % yield loss without considering the CO2 fertility effect. Incorporating the effect of elevated CO2 showed a smaller yield loss of 11.6-29.5 %. The increased frequency of extreme degree days (EDD) or accumulation of hourly temperatures above 30 °C associated with increased vapor pressure deficit (VPD) played a key role in contributing to water deficits and resultant crop losses under these future climate conditions. Although a relatively weak relationship between summer rainfall and crop yield was observed, decreased rainfall caused VPD to increase which induced crop water deficits. These findings suggest that it is crucial to consider VPD along with high temperature and low rainfall trends simultaneously for development of potential management or breeding-based adaptative strategies for soybean.
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Affiliation(s)
- Wenguang Sun
- Adaptive Cropping System Laboratory, USDA-ARS, Beltsville, MD 20705, USA; Nebraska Water Center, University of Nebraska Lincoln, Lincoln, NE 68588-6204, USA.
| | - David Fleisher
- Adaptive Cropping System Laboratory, USDA-ARS, Beltsville, MD 20705, USA.
| | - Dennis Timlin
- Adaptive Cropping System Laboratory, USDA-ARS, Beltsville, MD 20705, USA
| | - Chittaranjan Ray
- Adaptive Cropping System Laboratory, USDA-ARS, Beltsville, MD 20705, USA; Nebraska Water Center, University of Nebraska Lincoln, Lincoln, NE 68588-6204, USA
| | - Zhuangji Wang
- Adaptive Cropping System Laboratory, USDA-ARS, Beltsville, MD 20705, USA; Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD 20742, USA
| | - Sahila Beegum
- Adaptive Cropping System Laboratory, USDA-ARS, Beltsville, MD 20705, USA; Nebraska Water Center, University of Nebraska Lincoln, Lincoln, NE 68588-6204, USA
| | - Vangimalla Reddy
- Adaptive Cropping System Laboratory, USDA-ARS, Beltsville, MD 20705, USA
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Beegum S, Timlin D, Reddy KR, Reddy V, Sun W, Wang Z, Fleisher D, Ray C. Improving the cotton simulation model, GOSSYM, for soil, photosynthesis, and transpiration processes. Sci Rep 2023; 13:7314. [PMID: 37147386 PMCID: PMC10163017 DOI: 10.1038/s41598-023-34378-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 04/28/2023] [Indexed: 05/07/2023] Open
Abstract
GOSSYM, a mechanistic, process-level cotton crop simulation model, has a two-dimensional (2D) gridded soil model called Rhizos that simulates the below-ground processes daily. Water movement is based on gradients of water content and not hydraulic heads. In GOSSYM, photosynthesis is calculated using a daily empirical light response function that requires calibration for response to elevated carbon dioxide (CO2). This report discusses improvements made to the GOSSYM model for soil, photosynthesis, and transpiration processes. GOSSYM's predictions of below-ground processes using Rhizos are improved by replacing it with 2DSOIL, a mechanistic 2D finite element soil process model. The photosynthesis and transpiration model in GOSSYM is replaced with a Farquhar biochemical model and Ball-Berry leaf energy balance model. The newly developed model (modified GOSSYM) is evaluated using field-scale and experimental data from SPAR (soil-plant-atmosphere-research) chambers. Modified GOSSYM better predicted net photosynthesis (root mean square error (RMSE) 25.5 versus 45.2 g CO2 m-2 day-1; index of agreement (IA) 0.89 versus 0.76) and transpiration (RMSE 3.3 versus 13.7 L m-2 day-1; IA 0.92 versus 0.14) and improved the yield prediction by 6.0%. Modified GOSSYM improved the simulation of soil, photosynthesis, and transpiration processes, thereby improving the predictive ability of cotton crop growth and development.
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Affiliation(s)
- Sahila Beegum
- Adaptive Cropping System Laboratory, USDA-ARS, Beltsville, MD, 20705, USA.
- Nebraska Water Center, Robert B. Daugherty Water for Food Global Institute, 2021 Transformation Drive, University of Nebraska, Lincoln, NE, 68588, USA.
| | - Dennis Timlin
- Adaptive Cropping System Laboratory, USDA-ARS, Beltsville, MD, 20705, USA
| | - Kambham Raja Reddy
- Department of Plant and Soil Sciences, Mississippi State University, Mississippi, MS, 39762, USA
| | - Vangimalla Reddy
- Adaptive Cropping System Laboratory, USDA-ARS, Beltsville, MD, 20705, USA
| | - Wenguang Sun
- Adaptive Cropping System Laboratory, USDA-ARS, Beltsville, MD, 20705, USA
- Nebraska Water Center, Robert B. Daugherty Water for Food Global Institute, 2021 Transformation Drive, University of Nebraska, Lincoln, NE, 68588, USA
| | - Zhuangji Wang
- Adaptive Cropping System Laboratory, USDA-ARS, Beltsville, MD, 20705, USA
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD, 20742, USA
| | - David Fleisher
- Adaptive Cropping System Laboratory, USDA-ARS, Beltsville, MD, 20705, USA
| | - Chittaranjan Ray
- Nebraska Water Center, Robert B. Daugherty Water for Food Global Institute, 2021 Transformation Drive, University of Nebraska, Lincoln, NE, 68588, USA
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Jaja N, Codling EE, Timlin D, Rutto LK, Reddy VR. Phytoremediation efficacy of native vegetation for nutrients and heavy metals on soils amended with poultry litter and fertilizer. Int J Phytoremediation 2023; 25:1423-1434. [PMID: 36644901 DOI: 10.1080/15226514.2022.2161466] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Poultry litter on agricultural lands could introduce nitrogen (N), phosphorus (P), heavy metals in soil and ground water. Native vegetations were identified to assess efficacy for phytoremediation of nutrients and metals from soil and water. Objective was to measure capability of multi-year native species to remove metals, nutrients, and prevent Nitrate-N leaching below the rooting zone. Treatments were distributed in four replicates with/without fertilization. Suction lysimeters were installed at 30, 60, and 90-cm depths in 3 of 4 replicates. Species were identified, recorded, five specified cuttings sampled. Plant, soil, water samples were prepared and analyzed by spectroscopy. Nitrate-N extraction, nitrates in water samples were determined using flow injection analysis. Fertilized plots (NVM) had 39% more biomass yield than unfertilized plots (NVN). In plants, nutrient and metal concentrations varied significantly with 14% increase in Zn, 36% and 26% in K and Mg over NVN for first and second year. Uneven between NVM and NVN, topsoil had higher values for most nutrients and metals. Largest P and (NO3-)-N in plant and water were observed from NVM. Cultivation of native vegetation appears to be an effective approach for remediation of excess nitrates-N, P, heavy metals from surface and sub-surface zones of the soil.
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Affiliation(s)
- Ngowari Jaja
- Adaptive Cropping Systems Laboratory, USDA-ARS, Beltsville, MD, USA
| | - Eton E Codling
- Adaptive Cropping Systems Laboratory, USDA-ARS, Beltsville, MD, USA
| | - Dennis Timlin
- Adaptive Cropping Systems Laboratory, USDA-ARS, Beltsville, MD, USA
| | - Laban K Rutto
- Agriculture Research Station, College of Agriculture, Virginia State University, Petersburg, VA, USA
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Devi MJ, Reddy VR, Timlin D. Drought-Induced Responses in Maize under Different Vapor Pressure Deficit Conditions. Plants (Basel) 2022; 11:2771. [PMID: 36297794 PMCID: PMC9611867 DOI: 10.3390/plants11202771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 10/12/2022] [Accepted: 10/18/2022] [Indexed: 06/16/2023]
Abstract
Water stress in plants depends on the soil water level and the evaporative demand. In this study, the physiological, biochemical, and molecular response of maize were examined under three evaporative demand conditions (low—1.00 kPa, medium—2.2 kPa, and high—4.00 kPa Vapor pressure deficit (VPD)) at three different soil water content (SWC); well-watered, 45%, and 35% SWC. Plants grown at 35% SWC under high VPD had significant (p < 0.01) lower leaf weight, leaf area, and leaf number than low VPD. Plants under low, medium, and high VPD with drought stress (45% and 35% SWC) showed a 30 to 60% reduction in their leaf area compared to well-watered plants. Gas exchange parameters including photosynthesis, stomatal conductance, and water use efficiency exhibited significant differences (p < 0.01) between treatments, with the highest reduction occuring at 35% SWC and high VPD. Both drought and VPD significantly (p < 0.01) increased C4 enzyme levels and some transcription factors with increased stress levels. Transcription factors primarily related to Abssisic Acid (ABA) synthesis were upregulated under drought, which might be related to high ABA levels. In summary, severe drought levels coupled with high VPD had shown a significant decrease in plant development by modifying enzymes, ABA, and transcription factors.
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Affiliation(s)
- Mura Jyostna Devi
- USDA-ARS, Adaptive Cropping Systems Laboratory, Beltsville, MD 20705, USA
- USDA-ARS, Vegetable Crops Research Unit, Madison, WI 53706, USA
- Department of Horticulture, University of Wisconsin-Madison, Madison, WI 53706, USA
| | | | - Dennis Timlin
- USDA-ARS, Adaptive Cropping Systems Laboratory, Beltsville, MD 20705, USA
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Yun K, Timlin D, Kim SH. Coupled Gas-Exchange Model for C 4 Leaves Comparing Stomatal Conductance Models. Plants (Basel) 2020; 9:plants9101358. [PMID: 33066493 PMCID: PMC7602149 DOI: 10.3390/plants9101358] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/30/2020] [Accepted: 10/04/2020] [Indexed: 11/25/2022]
Abstract
Plant simulation models are abstractions of plant physiological processes that are useful for investigating the responses of plants to changes in the environment. Because photosynthesis and transpiration are fundamental processes that drive plant growth and water relations, a leaf gas-exchange model that couples their interdependent relationship through stomatal control is a prerequisite for explanatory plant simulation models. Here, we present a coupled gas-exchange model for C4 leaves incorporating two widely used stomatal conductance submodels: Ball–Berry and Medlyn models. The output variables of the model includes steady-state values of CO2 assimilation rate, transpiration rate, stomatal conductance, leaf temperature, internal CO2 concentrations, and other leaf gas-exchange attributes in response to light, temperature, CO2, humidity, leaf nitrogen, and leaf water status. We test the model behavior and sensitivity, and discuss its applications and limitations. The model was implemented in Julia programming language using a novel modeling framework. Our testing and analyses indicate that the model behavior is reasonably sensitive and reliable in a wide range of environmental conditions. The behavior of the two model variants differing in stomatal conductance submodels deviated substantially from each other in low humidity conditions. The model was capable of replicating the behavior of transgenic C4 leaves under moderate temperatures as found in the literature. The coupled model, however, underestimated stomatal conductance in very high temperatures. This is likely an inherent limitation of the coupling approaches using Ball–Berry type models in which photosynthesis and stomatal conductance are recursively linked as an input of the other.
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Affiliation(s)
- Kyungdahm Yun
- School of Environmental and Forest Sciences, College of the Environment, University of Washington, Seattle, WA 98195, USA;
| | - Dennis Timlin
- Adaptive Cropping Systems Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD 20705, USA;
| | - Soo-Hyung Kim
- School of Environmental and Forest Sciences, College of the Environment, University of Washington, Seattle, WA 98195, USA;
- Correspondence:
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Falconnier GN, Corbeels M, Boote KJ, Affholder F, Adam M, MacCarthy DS, Ruane AC, Nendel C, Whitbread AM, Justes É, Ahuja LR, Akinseye FM, Alou IN, Amouzou KA, Anapalli SS, Baron C, Basso B, Baudron F, Bertuzzi P, Challinor AJ, Chen Y, Deryng D, Elsayed ML, Faye B, Gaiser T, Galdos M, Gayler S, Gerardeaux E, Giner M, Grant B, Hoogenboom G, Ibrahim ES, Kamali B, Kersebaum KC, Kim SH, van der Laan M, Leroux L, Lizaso JI, Maestrini B, Meier EA, Mequanint F, Ndoli A, Porter CH, Priesack E, Ripoche D, Sida TS, Singh U, Smith WN, Srivastava A, Sinha S, Tao F, Thorburn PJ, Timlin D, Traore B, Twine T, Webber H. Modelling climate change impacts on maize yields under low nitrogen input conditions in sub-Saharan Africa. Glob Chang Biol 2020; 26:5942-5964. [PMID: 32628332 DOI: 10.1111/gcb.15261] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 05/19/2020] [Accepted: 06/22/2020] [Indexed: 06/11/2023]
Abstract
Smallholder farmers in sub-Saharan Africa (SSA) currently grow rainfed maize with limited inputs including fertilizer. Climate change may exacerbate current production constraints. Crop models can help quantify the potential impact of climate change on maize yields, but a comprehensive multimodel assessment of simulation accuracy and uncertainty in these low-input systems is currently lacking. We evaluated the impact of varying [CO2 ], temperature and rainfall conditions on maize yield, for different nitrogen (N) inputs (0, 80, 160 kg N/ha) for five environments in SSA, including cool subhumid Ethiopia, cool semi-arid Rwanda, hot subhumid Ghana and hot semi-arid Mali and Benin using an ensemble of 25 maize models. Models were calibrated with measured grain yield, plant biomass, plant N, leaf area index, harvest index and in-season soil water content from 2-year experiments in each country to assess their ability to simulate observed yield. Simulated responses to climate change factors were explored and compared between models. Calibrated models reproduced measured grain yield variations well with average relative root mean square error of 26%, although uncertainty in model prediction was substantial (CV = 28%). Model ensembles gave greater accuracy than any model taken at random. Nitrogen fertilization controlled the response to variations in [CO2 ], temperature and rainfall. Without N fertilizer input, maize (a) benefited less from an increase in atmospheric [CO2 ]; (b) was less affected by higher temperature or decreasing rainfall; and (c) was more affected by increased rainfall because N leaching was more critical. The model intercomparison revealed that simulation of daily soil N supply and N leaching plays a crucial role in simulating climate change impacts for low-input systems. Climate change and N input interactions have strong implications for the design of robust adaptation approaches across SSA, because the impact of climate change in low input systems will be modified if farmers intensify maize production with balanced nutrient management.
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Affiliation(s)
| | - Marc Corbeels
- AIDA, Univ Montpellier, CIRAD, Montpellier, France
- CIMMYT, Nairobi, Kenya
| | | | | | - Myriam Adam
- CIRAD, UMR AGAP, Bobo-Dioulasso, Burkina Faso
- AGAP, Univ Montpellier, CIRAD, INRA, Montpellier SupAgro, Montpellier, France
| | - Dilys S MacCarthy
- Soil and Irrigation Research Centre, School of Agriculture, College of Basic and Applied Science, University of Ghana, Accra, Ghana
| | - Alex C Ruane
- Climate Impacts Group, National Aeronautics and Space Administration Goddard Institute for Space Studies, New York, NY, USA
| | - Claas Nendel
- Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Anthony M Whitbread
- International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Dar es Salaam, Tanzania
| | - Éric Justes
- PERSYST, Univ Montpellier, CIRAD, Montpellier, France
| | | | - Folorunso M Akinseye
- International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Kano, Nigeria
| | - Isaac N Alou
- Department of Plant and Soil Sciences, University of Pretoria, Pretoria, South Africa
| | - Kokou A Amouzou
- West Africa Program, African Plant Nutrition Institute (APNI), Yamoussoukro, Cote d'Ivoire
| | | | - Christian Baron
- CIRAD, UMR TETIS, Montpellier, France
- TETIS, Univ Montpellier, AgroParisTech, CIRAD, CNRS, IRSTEA, Montpellier, France
| | - Bruno Basso
- Department of Earth and Environmental Sciences, Michigan State University, East Lansing, MI, USA
| | | | | | - Andrew J Challinor
- Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds, UK
| | - Yi Chen
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Delphine Deryng
- Integrative Research Institute on Transformations of Human-Environment Systems (IRI THESys), Humboldt-Universität zu Berlin, Berlin, Germany
- NewClimate Institute, Berlin, Germany
| | - Maha L Elsayed
- MALR-ARC, Central Laboratory for Agricultural Climate (CLAC), Giza, Egypt
| | - Babacar Faye
- Crop Science Group, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Bonn, Germany
| | - Thomas Gaiser
- Crop Science Group, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Bonn, Germany
| | - Marcelo Galdos
- Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds, UK
| | - Sebastian Gayler
- Institute of Soil Science and Land Evaluation, Biogeophysics, University of Hohenheim, Stuttgart, Germany
| | | | - Michel Giner
- AIDA, Univ Montpellier, CIRAD, Montpellier, France
| | - Brian Grant
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, ON, Canada
| | | | - Esther S Ibrahim
- Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Bahareh Kamali
- Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | | | - Soo-Hyung Kim
- School of Environmental and Forest Sciences, University of Washington, Seattle, USA
| | - Michael van der Laan
- Department of Plant and Soil Sciences, University of Pretoria, Pretoria, South Africa
| | - Louise Leroux
- AIDA, Univ Montpellier, CIRAD, Montpellier, France
- CIRAD, UPR AIDA, Dakar, Senegal
| | - Jon I Lizaso
- CEIGRAM-Universidad Politécnica de Madrid, ETSIAAB, Madrid, Spain
| | - Bernardo Maestrini
- Department of Earth and Environmental Sciences, Michigan State University, East Lansing, MI, USA
| | - Elizabeth A Meier
- CSIRO Agriculture and Food, Queensland Bioscience Precinct, St Lucia, Qld, Australia
| | - Fasil Mequanint
- Institute of Soil Science and Land Evaluation, Biogeophysics, University of Hohenheim, Stuttgart, Germany
| | | | | | - Eckart Priesack
- Institute of Biochemical Plant Pathology, Helmholtz Center Munich, Neuherberg, Germany
| | | | | | - Upendra Singh
- International Center for Soil Fertility and Agricultural Development, Muscle Shoals, AL, USA
| | - Ward N Smith
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, ON, Canada
| | - Amit Srivastava
- Crop Science Group, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Bonn, Germany
| | - Sumit Sinha
- Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds, UK
| | - Fulu Tao
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
- Natural Resources Institute Finland (Luke), Helsinki, Finland
| | - Peter J Thorburn
- CSIRO Agriculture and Food, Queensland Bioscience Precinct, St Lucia, Qld, Australia
| | - Dennis Timlin
- Crop Systems and Global Change Research Unit, USDA-ARS, Beltsville, MD, USA
| | | | - Tracy Twine
- Department of Soil, Water, and Climate, University of Minnesota, St. Paul, MN, USA
| | - Heidi Webber
- Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
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Bassu S, Brisson N, Durand JL, Boote K, Lizaso J, Jones JW, Rosenzweig C, Ruane AC, Adam M, Baron C, Basso B, Biernath C, Boogaard H, Conijn S, Corbeels M, Deryng D, De Sanctis G, Gayler S, Grassini P, Hatfield J, Hoek S, Izaurralde C, Jongschaap R, Kemanian AR, Kersebaum KC, Kim SH, Kumar NS, Makowski D, Müller C, Nendel C, Priesack E, Pravia MV, Sau F, Shcherbak I, Tao F, Teixeira E, Timlin D, Waha K. How do various maize crop models vary in their responses to climate change factors? Glob Chang Biol 2014; 20:2301-20. [PMID: 24395589 DOI: 10.1111/gcb.12520] [Citation(s) in RCA: 149] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 12/02/2013] [Indexed: 05/18/2023]
Abstract
Potential consequences of climate change on crop production can be studied using mechanistic crop simulation models. While a broad variety of maize simulation models exist, it is not known whether different models diverge on grain yield responses to changes in climatic factors, or whether they agree in their general trends related to phenology, growth, and yield. With the goal of analyzing the sensitivity of simulated yields to changes in temperature and atmospheric carbon dioxide concentrations [CO2 ], we present the largest maize crop model intercomparison to date, including 23 different models. These models were evaluated for four locations representing a wide range of maize production conditions in the world: Lusignan (France), Ames (USA), Rio Verde (Brazil) and Morogoro (Tanzania). While individual models differed considerably in absolute yield simulation at the four sites, an ensemble of a minimum number of models was able to simulate absolute yields accurately at the four sites even with low data for calibration, thus suggesting that using an ensemble of models has merit. Temperature increase had strong negative influence on modeled yield response of roughly -0.5 Mg ha(-1) per °C. Doubling [CO2 ] from 360 to 720 μmol mol(-1) increased grain yield by 7.5% on average across models and the sites. That would therefore make temperature the main factor altering maize yields at the end of this century. Furthermore, there was a large uncertainty in the yield response to [CO2 ] among models. Model responses to temperature and [CO2 ] did not differ whether models were simulated with low calibration information or, simulated with high level of calibration information.
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Affiliation(s)
- Simona Bassu
- Unité d'Agronomie, INRA-AgroParisTech, BP 01, Thiverval-Grignon, 78850, France
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Sicher RC, Timlin D, Bailey B. Responses of growth and primary metabolism of water-stressed barley roots to rehydration. J Plant Physiol 2012; 169:686-95. [PMID: 22285575 DOI: 10.1016/j.jplph.2012.01.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 01/09/2012] [Accepted: 01/10/2012] [Indexed: 05/02/2023]
Abstract
Barley seedlings were grown in pots in controlled environment chambers and progressive drought treatments were imposed 11 d after sowing. Soil water content decreased from 92 to 10% following 14 d without watering. Increases of biomass in shoots and roots slowed after 4 and 9 d of water stress, respectively. Thirty barley root metabolites were monitored in this study and 85% were significantly altered by drought. Sucrose, raffinose, glucose, fructose, maltose, malate, asparagine and proline increased and myo-inositol, glycerate, alanine, serine, glycine and glutamate decreased during drought. Primary metabolism was likely involved in various crucial processes during water stress including, osmotic adjustment, nitrogen sequestration and ammonia detoxification. Rates of photosynthesis and stomatal conductance recovered in 2 d and shoot growth commenced the 3rd day after rehydration. Root growth also exhibited a lag after rehydration but this was attributed to high nutrient concentrations during water stress. Malate and proline recovered within 1 d but serine was only partially reversed 6 d after rehydration. Malate, aspartate and raffinose decreased below well-watered, control levels following rehydration. Variation in the magnitude and time necessary for individual compounds to fully recover after rehydration suggested the complexity of metabolic processes initiated by re-watering.
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Affiliation(s)
- Richard C Sicher
- Crop Systems and Global Change Laboratory, USDA-ARS, Room 342, Building 001, BARC-West, 10300 Baltimore Avenue, Beltsville, MD 20705, USA.
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Chun JA, Cooke RA, Kang MS, Choi M, Timlin D, Park SW. Runoff losses of suspended sediment, nitrogen, and phosphorus from a small watershed in Korea. J Environ Qual 2010; 39:981-990. [PMID: 20400593 DOI: 10.2134/jeq2009.0226] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Nutrients and sediments in runoff lead to the degradation of water quality of lakes and streams. The development of schemes to mitigate such degradation requires a characterization of the underlying transport processes. The objectives of this study were to develop annual and seasonal load-discharge relationships for suspended sediment (SS), total nitrogen (TN), and total phosphorus (TP) losses from a small mixed land use watershed and to use these relationships to explicate the annual and monthly patterns of losses of these species. Data from 1996 to 2004 were used to develop load-discharge relationships for SS, TN, and TP at the HP#6 watershed, a subwatershed of the Balhan reservoir watershed located in Bongdam-myun and Paltan-myun, Gyeonggi-do, Korea. Standard least squares curve fitting and S-estimation procedures were used to fit power functions to the data collected over this time period. The fitted load-discharge relationships are indicative of seasonal variations in SS and TN and of TP losses from HP#6. The exponents of the fitted power functions for TN and TP in the fall, for TP in summer season, and for SS in all seasons are >1, indicating that the concentrations of these species increase as flow rate increases. Most of the SS, TN, and TP transported in runoff left the watershed between April and September; thus, cost-efficient strategies can be established by focusing on this period. Further study of the seasonal variations is required for a better characterization of seasonal losses of SS, TN, and TP in runoff from the HP#6 watershed.
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Affiliation(s)
- Jong A Chun
- USDA-ARS Crop Systems and Global Change Lab, Beltsville, MD 20705, USA
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Jonathan N, Melliar-Smith C, Okuda S, Slater D, Timlin D. Initial vibrational energy level distributions determined by infra-red chemiluminescence. Mol Phys 2006. [DOI: 10.1080/00268977100102831] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Walthall CL, Gish TJ, Daughtry CS, Dulaney WP, Kung KJ, McCarty G, Timlin D, Angier JT, Buss P, Houser PR. An innovative approach for locating and evaluating subsurface pathways for nitrogen loss. ScientificWorldJournal 2001; 1 Suppl 2:223-9. [PMID: 12805741 PMCID: PMC6083929 DOI: 10.1100/tsw.2001.286] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Fundamental watershed-scale processes governing chemical flux to neighboring ecosystems are so poorly understood that effective strategies for mitigating chemical contamination cannot be formulated. Characterization of evapotranspiration, surface runoff, plant uptake, subsurface preferential flow, behavior of the chemicals in neighboring ecosystems, and an understanding of how crop management practices influence these processes are needed. Adequate characterization of subsurface flow has been especially difficult because conventional sampling methods are ineffective for measuring preferential flow of water and solutes. A sampling strategy based on ground-penetrating radar (GPR) mapping of subsurface structures coupled with near real-time soil moisture data, surface topography, remotely sensed imagery, and a geographic information system (GIS) appears to offer a means of accurately identifying subsurface preferential flow pathways. Four small adjacent watersheds draining into a riparian wetland and first-order stream at the USDA-ARS Beltsville Agricultural Research Center, Beltsville, MD are being studied with this protocol. The spatial location of some preferential flow pathways for chemicals exiting these agricultural watersheds to the neighboring ecosystems have been identified. Confirmation of the pathways is via examination of patterns in yield monitor data and remote sensing imagery.
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Affiliation(s)
- C L Walthall
- USDA-ARS Hydrology and Remote Sensing Lab, Beltsville, MD 20705, USA.
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Taplin SH, Mandelson MT, Anderman C, White E, Thompson RS, Timlin D, Wagner EH. Mammography diffusion and trends in late-stage breast cancer: evaluating outcomes in a population. Cancer Epidemiol Biomarkers Prev 1997; 6:625-31. [PMID: 9264276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The purpose of this study was to assess mammography diffusion in a population offered an organized breast cancer screening program, using intervals of 1-3 years, and to evaluate its effect on the late-stage cancer (tumors > or = 3 cm2) rates compared to rates in the surrounding community. We measured "ever-use" of mammography (1986-1992) among women enrollees of a consumer-controlled health care organization (n > or = 60,000/year; ages > or = 40), Group Health Cooperative of Puget Sound (GHC). Among these same women and the surrounding community (n = > or = 745,000/year), we measured late-stage cancer rates. Using unconditional logistic regression, we compared annual rates of ever-use among GHC women ages 40-49 and > or = 50 (1986-1992) and late-stage breast cancer (1983/84-1991/92) among all women. Among all GHC women ages 40 to 49, and 50 years of age and older, 67.4 and 82.8%, respectively, ever-used mammography by 1992. By 1992, approximately one-third of the mammograms among GHC women occurred in each of the three previous years. The rate of late-stage tumors declined significantly in the GHC and non-GHC populations among women 50 years of age and older (P < 0.001) but not among women ages 40 to 49. In conclusion, implementing a system of automated reminders was not sufficient to maximize mammography use in a population. Reductions in late-stage disease occurred among women ages > or = 50, even when regular" was not synonymous with "annual."
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Affiliation(s)
- S H Taplin
- Department of Preventive Care, Center for Health Studies, Group Health Cooperative of Puget Sound, Seattle, Washington 98101-1448, USA
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Stuart ME, Handley MA, Thompson RS, Conger M, Timlin D. Clinical practice and new technology: prostate-specific antigen (PSA). HMO Pract 1992; 6:5-11. [PMID: 10123759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
In response to a marked increase in the use of an available test, Group Health Cooperative of Puget Sound (GHC) evaluated the use of prostatic specific antigen (PSA) as a screening test for prostate cancer. A project team reviewed the literature and determined that PSA did not meet GHC's criteria for screening. An implementation team then developed a comprehensive program to educate staff, facilitate practice change, measure outcomes and provide continuing feedback to physicians. These efforts are described and preliminary reports reported.
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Affiliation(s)
- M E Stuart
- Group Health Cooperative of Puget Sound, Seattle, WA 98112
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Kasp-Grochowska E, Beck J, Holmes RC, Black MM, Timlin D. The role of circulating immune complexes in the aetiology of polymorphic eruption of pregnancy. Arch Dermatol Res 1984; 276:71-3. [PMID: 6232902 DOI: 10.1007/bf00511057] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Circulating immune complexes were measured in 35 patients with polymorphic eruption of pregnancy employing three different techniques. No significant abnormalities were detected by the C1q solid phase binding assay and polyethylene glycol precipitation of immunoglobulin G. However, using a solid phase polyclonal rheumatoid factor binding assay, which detects small immune complexes, we demonstrated a significant reduction in the level of circulating immune complexes during the acute stage of the eruption. We suggest that the leakage of small immune complexes through dilated upper dermal vessels may play a role in the aetiology of polymorphic eruption of pregnancy.
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Abstract
In a study of twenty-five patients with herpes gestationis we found that 80% possessed the HLA antigen DR3, which confers increased immune responsiveness and a predisposition to 'auto-immune disease'. In five patients the development of herpes gestationis coincided with a change in sexual partner, suggesting that the development of herpes gestationis may depend on exposure to an antigen derived from the father. This might share determinants with a component of the basement membrane zone of skin. Although anti-basement membrane zone antibodies are present in HG it is not clear whether they play a pathogenic role. The infrequency of neonatal involvement and the lack of correlation between immunofluorescence findings and clinical activity in our patients suggested that the antibodies might be a result of tissue damage rather than its cause. Two patients in our study were exceptional in that episodes of herpes gestationis were followed by normal pregnancies. In these patients the relationship of their DR antigens to those of the fetus may have been important in determining whether or not the pregnancy would be affected by herpes gestationis.
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Corney G, Thompson B, Campbell DM, MacGillivray I, Seedburgh D, Timlin D. The effect of zygosity on the birth weight of twins in Aberdeen and northeast Scotland. Acta Genet Med Gemellol (Roma) 1979; 28:353-60. [PMID: 555206 DOI: 10.1017/s0001566000008916] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Birth weight data for 356 pairs of newborn twins of known zygosity and placentation are presented. The combined weights of dizygotic twins are heavier than those of monozygotic twins. The significance of this finding is discussed in relation to the association between increased maternal height and dizygotic twinning.
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Abstract
Data on maternal height are presented for 307 pairs of newborn twins of known zygosity from Oxford and 267 pairs from Aberdeen and north-east Scotland. The results support the hypothesis that mothers of DZ twins are taller than those of MZ twins. Mothers of MZ twins resemble mothers of singletons in height, whereas mothers of DZ twins are taller.
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Abstract
When lichen planus strikes families, a very rare happening, it is likely to afflict younger members, to erupt more acutely, extensively, and gravely, attacking also nails and mucous membranes, and to recur. Ten patients with familial lichen planus, two each from five distinct Caucasian families, the parents of whom were unrelated by birth, were found to be carrying HLA-B7 statistically more frequently than in the normal population or in those with the characteristic forms of lichen planus. We hint that their genotype might have rendered them susceptible to a pathogen that precipitated their disease.
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Jonathan N, Melliar-Smith CM, Timlin D, Slater DH. Analysis of hydrogen fluoride infrared chemiluminescence from simple atom-molecule reactions. Appl Opt 1971; 10:1821-1826. [PMID: 20111214 DOI: 10.1364/ao.10.001821] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The various gas-phase atom-molecule reactions which have been shown to give hydrogen fluoride infrared chemiluminescence are reviewed and the wide range of information made available by high resolution spectroscopic studies is discussed.
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