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Microarray Analysis Of Late-Season Velvetleaf (Abutilon Theophrasti) Effect On Corn, David P. Horvath, Robert Gulden, Sharon A. Clay
Microarray Analysis Of Late-Season Velvetleaf (Abutilon Theophrasti) Effect On Corn, David P. Horvath, Robert Gulden, Sharon A. Clay
Agronomy, Horticulture and Plant Science Faculty Publications
Microarray analysis was used to identify changes in gene expression in corn leaves collected from plants at the V11–14 growth stage that resulted from competition with velvetleaf. The plants were grown in field plots under adequate N (addition of 220 kg N ha1) and irrigation to minimize N and water stress. Consequently, only differences resulting from competition for micronutrients, light, and perhaps allelopathic stress were anticipated. Genes involved in carbon and nitrogen utilization, photosynthesis, growth and development, oxidative stress, signal transduction, responses to auxin and ethylene, and zinc transport were repressed in corn growing in competition with velvetleaf. …
Spatial Distribution, Temporal Stability, And Yield Loss Estimates For Annual Grasses And Common Ragweed (Ambrosia Artimisiifolia) In A Corn/Soybean Production Field Over Nine Years, Sharon A. Clay, Bruce Kreutner, David E. Clay, Cheryl Reese, Jonathan Kleinjan, Frank Forcella
Spatial Distribution, Temporal Stability, And Yield Loss Estimates For Annual Grasses And Common Ragweed (Ambrosia Artimisiifolia) In A Corn/Soybean Production Field Over Nine Years, Sharon A. Clay, Bruce Kreutner, David E. Clay, Cheryl Reese, Jonathan Kleinjan, Frank Forcella
Agronomy, Horticulture and Plant Science Faculty Publications
Weeds generally occur in patches in production fields. Are these patches spatially and temporally stable? Do management recommendations change on the basis of these data? The population density and location of annual grass weeds and common ragweed were examined in a 65-ha corn/soybean production field from 1995 to 2004. Yearly treatment recommendations were developed from field means, medians, and kriging grid cell densities, using the hyperbolic yield loss (YL) equation and published incremental YL values (I ), maximum YL values (A), and YL limits of 5, 10, or 15%. Mean plant densities ranged from 12 to 131 annual grasses m22 …
Sorption-Desorption Of Imidacloprid And Its Metabolites In Soil And Vadose Zone Materials, Sharon V. Papiernik, William C. Koskinen, Lucia Cox, Pamela J. Rice, Sharon A. Clay, Nancy R. Werdin-Pfisterer, Kristen A. Norberg
Sorption-Desorption Of Imidacloprid And Its Metabolites In Soil And Vadose Zone Materials, Sharon V. Papiernik, William C. Koskinen, Lucia Cox, Pamela J. Rice, Sharon A. Clay, Nancy R. Werdin-Pfisterer, Kristen A. Norberg
Agronomy, Horticulture and Plant Science Faculty Publications
Sorption-desorption is one of the most important processes affecting the leaching of pesticides through soil because it controls the amount of pesticide available for transport. Subsurface soil properties can significantly affect pesticide transport and the potential for groundwater contamination. This research characterized the sorption-desorption of imidacloprid (1-[(6-chloro-3-pyridinyl)-methyl]-Nnitro-2-imidazolidinimine) and three of its metabolites, 1-[(6-chloro-3-pyridinyl)methyl]-2-imidazolidinone (imidacloprid-urea), 1-[(6-chloro-3-pyridinyl)methyl]-4,5-dihydro-1H-imidazol-2-amine (imidaclopridguanidine), and 1-[(6-chloro-3-pyridinyl)methyl]-1H-imidazol-2-amine (imidacloprid-guanidine-olefin), as a function of changing soil properties with depth in two profiles extending from the surface to a depth of 1.8 or 8 m. Sorption of each compound was highly variable and hysteretic in all cases. Normalizing the sorption coefficients (Kf) …
Theoretical Derivation Of Stable And Nonisotopic Approaches For Assessing Soil Organic Carbon Turnover, D. E. Clay, C. G. Carlson, S. A. Clay, C. Reese, Z. Liu, J. Chang, M. M. Ellsbury
Theoretical Derivation Of Stable And Nonisotopic Approaches For Assessing Soil Organic Carbon Turnover, D. E. Clay, C. G. Carlson, S. A. Clay, C. Reese, Z. Liu, J. Chang, M. M. Ellsbury
Agronomy, Horticulture and Plant Science Faculty Publications
Techniques for measuring soil organic C (SOC) turnover in production fields are needed. The objectives of this study were to propose and test nonisotopic and 13 C stable isotopic techniques for assessing SOC turnover. Based on SOC equilibrium and mass balance relationships, an equation was derived: NHC/SOC initial=[1/(SOC× k NHC)](dSOC/dt)+ k SOC/k NHC, where dSOC/dt is the annual change in SOC, NHC is nonharvested C returned to soil, k SOC is the annual mineralization rate of SOC, and k NHC is the annual mineralization rate of NHC. This equation was used to calculate maintenance rates. An isotopic approach based on …