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Maize And Soybean Root Front Velocity And Maximum Depth In Iowa, Usa, Raziel A. Ordóñez, Michael J. Castellano, J. L. Hatfield, M. J. Helmers, Mark A. Licht, Matt Liebman, Ranae Dietzel, Rafael Martinez-Feria, Javed Iqbal, Laila A. Puntel, S. Carolina Córdova, Kaitlin Togliatti, Emily E. Wright, Sotirios V. Archontoulis
Maize And Soybean Root Front Velocity And Maximum Depth In Iowa, Usa, Raziel A. Ordóñez, Michael J. Castellano, J. L. Hatfield, M. J. Helmers, Mark A. Licht, Matt Liebman, Ranae Dietzel, Rafael Martinez-Feria, Javed Iqbal, Laila A. Puntel, S. Carolina Córdova, Kaitlin Togliatti, Emily E. Wright, Sotirios V. Archontoulis
Department of Agronomy and Horticulture: Faculty Publications
Quantitative measurements of root traits can improve our understanding of how crops respond to soil and weather conditions, but such data are rare. Our objective was to quantify maximum root depth and root front velocity (RFV) for maize (Zea mays) and soybean (Glycine max) crops across a range of growing conditions in the Midwest USA. Two sets of root measurements were taken every 10–15 days: in the crop row (in-row) and between two crop rows (center-row) across six Iowa sites having different management practices such as planting dates and drainage systems, totaling 20 replicated experimental treatments. …
Yield Gap Analysis Of Us Rice Production Systems Shows Opportunities For Improvement, Matthew B. Espe, Kenneth Cassman, Haishun Yang, Nicolas Guilpart, Patricio Grassini, Justin Van Wart, Merle Anders, Donn Beighley, Dustin Harrell, Steve Linscombe, Kent Mckenzie, Randall Mutters, Lloyd T. Wilson, Bruce A. Linquist
Yield Gap Analysis Of Us Rice Production Systems Shows Opportunities For Improvement, Matthew B. Espe, Kenneth Cassman, Haishun Yang, Nicolas Guilpart, Patricio Grassini, Justin Van Wart, Merle Anders, Donn Beighley, Dustin Harrell, Steve Linscombe, Kent Mckenzie, Randall Mutters, Lloyd T. Wilson, Bruce A. Linquist
Department of Agronomy and Horticulture: Faculty Publications
Many assessments of crop yield gaps based on comparisons to actual yields suggest grain yields in highly intensified agricultural systems are at or near the maximum yield attainable. However, these estimates can be biased in situations where yields are below full yield potential. Rice yields in the US continue to increase annually, suggesting that rice yields are not near the potential. In the interest of directing future efforts towards areas where improvement is most easily achieved, we estimated yield potential and yield gaps in US rice production systems, which are amongst the highest yielding rice systems globally. Zones around fourteen …
How Do Various Maize Crop Models Vary In Their Responses To Climate Change Factors?, Simon Bassu, Nadine Brisson, Jean-Louis Durand, Kenneth J. Boote, Jon Lizaso, James Jones, Cynthia Rosenzweig, Alex Ruane, Myriam Adam, Christian Baron, Bruno Basso, Christian Biernath, Hendrick Boogaard, Sjaak Conijn, Marc Corbeels, Delphine Deryng, Giacomo De Sanctis, Sebastian Gayler, Patricio Grassini, Jerry Hatfield, Steven Hoek, Cesar Izaurralde, Raymond Jongschaap, Armen Kemanian, Christian Kersebaum, Soo-Hyung Kim, Naresh Kumar, David Makowski, Christoph Muller, Claas Nendel, Eckart Priesack, Maria Virinia Pravia, Federico Sau, Iurii Shcherbak, Fulu Tao, Edmar Teixeira, Dennis Timlin, Katharina Waha
How Do Various Maize Crop Models Vary In Their Responses To Climate Change Factors?, Simon Bassu, Nadine Brisson, Jean-Louis Durand, Kenneth J. Boote, Jon Lizaso, James Jones, Cynthia Rosenzweig, Alex Ruane, Myriam Adam, Christian Baron, Bruno Basso, Christian Biernath, Hendrick Boogaard, Sjaak Conijn, Marc Corbeels, Delphine Deryng, Giacomo De Sanctis, Sebastian Gayler, Patricio Grassini, Jerry Hatfield, Steven Hoek, Cesar Izaurralde, Raymond Jongschaap, Armen Kemanian, Christian Kersebaum, Soo-Hyung Kim, Naresh Kumar, David Makowski, Christoph Muller, Claas Nendel, Eckart Priesack, Maria Virinia Pravia, Federico Sau, Iurii Shcherbak, Fulu Tao, Edmar Teixeira, Dennis Timlin, Katharina Waha
Department of Agronomy and Horticulture: Faculty Publications
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 …
A Comparison Of Cumulative-Germination Response Of Cheatgrass (Bromus Tectorum L.) And Five Perennial Bunchgrass Species To Simulated Field-Temperature Regimes, Stuart P. Hardegree, Corey A. Moffet, Bruce A. Roundy, Thomas A. Jones, Stephen J. Novak, Patrick E. Clark, Frederick B. Pierson, Gerald N. Flerchinger
A Comparison Of Cumulative-Germination Response Of Cheatgrass (Bromus Tectorum L.) And Five Perennial Bunchgrass Species To Simulated Field-Temperature Regimes, Stuart P. Hardegree, Corey A. Moffet, Bruce A. Roundy, Thomas A. Jones, Stephen J. Novak, Patrick E. Clark, Frederick B. Pierson, Gerald N. Flerchinger
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
Cheatgrass (Bromus tectorum L.) has come to dominate millions of hectares of rangeland in the Intermountain western United States. Previous studies have hypothesized that one mechanism conferring a competitive advantage to this species is the ability to germinate rapidly at low temperatures in the fall, winter and spring and, therefore, initiate growth and establishment more rapidly than more desirable perennial bunchgrass species. In this experiment, we developed thermal-germination-response models for multiple seedlots of cheatgrass and five perennial grass species. We conducted sensitivity analysis on potential-cumulative-germination response to a 38-year simulation of field-variable conditions of seedbed temperature and moisture. Cheatgrass …
Initial Response Of Evapotranspiration From Tallgrass Prairie Vegetation To Co2 At Subambient To Elevated Concentrations, H. W. Polley, H. B. Johnson, P. A. Fay, J. Sanabria
Initial Response Of Evapotranspiration From Tallgrass Prairie Vegetation To Co2 At Subambient To Elevated Concentrations, H. W. Polley, H. B. Johnson, P. A. Fay, J. Sanabria
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
A series of weighing lysimeters in which tallgrass prairie species had been planted were exposed to a subambient to elevated gradient in CO2 in a field chamber. Lysimeters with intact monoliths of three soil types were represented along the CO2 gradient. We used regression analysis to determine how CO2 effects on evapotranspiration per unit of soil surface area (ETsoil) and per unit of leaf area (ETla) depended on variation in leaf area index (LAI) and diurnal changes in environmental variables during the initial 6 weeks of CO2 treatment.
High Water Regime Can Reduce Ammonia Volatilization From Soils Under Potato Production, Guodong Liu, Yuncong Li, A. K. Alva
High Water Regime Can Reduce Ammonia Volatilization From Soils Under Potato Production, Guodong Liu, Yuncong Li, A. K. Alva
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
This research was conducted with Biscayne marl soil and Krome gravelly loam from Florida and Quincy fine sand and Warden silt loam from Washington to determine ammonia (NH3) volatilization at various temperature and soil water regimes. Potassium nitrate (KNO3), ammonium nitrate (NH4NO3), ammonium sulfate [(NH4)2SO4], or urea were applied to the soil at a rate of 75 kg N ha-1. Soil water regime was maintained at either 20% or 80% of field capacity (FC) and incubated at 11, 20, or 29 °C, which represented …
Increasing Co2 From Subambient To Elevated Concentrations Increases Grassland Respiration Per Unit Of Net Carbon Fixation, H. Wayne Polley, Patricia C. Meilnick, William A. Dugas, Hyrum B. Johnson, Joaquin Sanabria
Increasing Co2 From Subambient To Elevated Concentrations Increases Grassland Respiration Per Unit Of Net Carbon Fixation, H. Wayne Polley, Patricia C. Meilnick, William A. Dugas, Hyrum B. Johnson, Joaquin Sanabria
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
Respiration (carbon efflux) by terrestrial ecosystems is a major component of the global carbon (C) cycle, but the response of C efflux to atmospheric CO2 enrichment remains uncertain. Respiration may respond directly to an increase in the availability of C substrates at high CO2, but also may be affected indirectly by a CO2-mediated alteration in the amount by which respiration changes per unit of change in temperature or C uptake (sensitivity of respiration to temperature or C uptake).
Temperature Effects On Bradyrhizobium Spp. Growth And Symbiotic Effectiveness With Pigeonpea And Cowpea, Lurline E. Marsh, Raymond Baptiste, Dyremple B. Marsh, David Trinklein, Robert J. Kremer
Temperature Effects On Bradyrhizobium Spp. Growth And Symbiotic Effectiveness With Pigeonpea And Cowpea, Lurline E. Marsh, Raymond Baptiste, Dyremple B. Marsh, David Trinklein, Robert J. Kremer
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
Temperature is a limiting factor on legume-Bradyrhizobium symbiosis of subtropical plants in the temperate region. Twelve strains of Bradyrhizobium spp. that nodulate pigeonpea [Cajanus cajan (L.) Millsp], and cowpea [Vigna unguiculata (L.) Walp], were evaluated for tolerance to three temperature regimes (20 °C/10 °C, 30 °C/20 °C, and 38 °C/25 °C day/night temperature) by determining their growth following exposure to the regimes. The five most temperature-tolerant strains were further evaluated for symbiotic effectiveness with pigeonpea and cowpea under controlled temperatures. These strains were USDA 3278, USDA 3362, USDA 3364, USDA 3458, and USDA 3472. Plant heights of …
Effects Of Substrate And Temperature On Growth Of Aspergillus Flavus In Peanuts From Georgia, Premila Achar, Andres Sachez
Effects Of Substrate And Temperature On Growth Of Aspergillus Flavus In Peanuts From Georgia, Premila Achar, Andres Sachez
Faculty and Research Publications
We investigated the effects of different substrates (potato dextrose agar [PDA], nutrient agar [NA], and corn meal agar [CMA]) and temperatures on growth and aflatoxin production in Aspergillus flavus. Contaminated peanuts from retailers at different locations in Georgia were used throughout the experiment and 200 seeds were selected from each sample. PDA, NA, and CMA served as the substrate to express the mold from the contaminated seeds. Seeds were plated equidistantly on each of the media and incubated at 10° C, 27° C, 30° C, and 37° C, respectively. Seeds incubated on moist filter paper served as control. Neither growth …
Predicting Phenological Development In Winter Wheat, Qingwu Xue, Albert Weiss, P. Stephen Baenziger
Predicting Phenological Development In Winter Wheat, Qingwu Xue, Albert Weiss, P. Stephen Baenziger
Department of Agronomy and Horticulture: Faculty Publications
Accurate prediction of phenological development is important in the winter wheat Triticum aestivum agroecosystem. From a practical perspective, applications of pesticides and fertilizers are carried out at specific phenological stages. In crop-simulation modeling, the prediction of yield components (kernel number and kernel weight) and wheat-grain yield relies on accurate prediction of phenology. In this study, a nonlinear multiplicative model by Wang & Engel (WE) for predicting phenological development in differing winter wheat cultivars was evaluated using data from a 3 yr field experiment. In the vegetative phase (emergence to anthesis) the daily development rate (r) was simulated based on the …