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Articles 1 - 30 of 63
Full-Text Articles in Botany
Duplicate Gene Expression In Allopolyploid Gossypium Reveals Two Temporally Distinct Phases Of Expression Evolution, Lex E. Flagel, Joshua A. Udall, Dan Nettleton, Jonathan F. Wendel
Duplicate Gene Expression In Allopolyploid Gossypium Reveals Two Temporally Distinct Phases Of Expression Evolution, Lex E. Flagel, Joshua A. Udall, Dan Nettleton, Jonathan F. Wendel
Dan Nettleton
Polyploidy has played a prominent role in shaping the genomic architecture of the angiosperms. Through allopolyploidization, several modern Gossypium (cotton) species contain two divergent, although largely redundant genomes. Owing to this redundancy, these genomes can play host to an array of evolutionary processes that act on duplicate genes. We compared homoeolog (genes duplicated by polyploidy) contributions to the transcriptome of a natural allopolyploid and a synthetic interspecific F1 hybrid, both derived from a merger between diploid species from the Gossypium A-genome and D-genome groups. Relative levels of A- and D-genome contributions to the petal transcriptome were determined for 1,383 gene …
Floristic Response To Urbanization: Filtering Of The Bioregional Flora In Indianapolis, Indiana, Usa, Rebecca W. Dolan, Myla F.J. Aronson, Andrew L. Hipp
Floristic Response To Urbanization: Filtering Of The Bioregional Flora In Indianapolis, Indiana, Usa, Rebecca W. Dolan, Myla F.J. Aronson, Andrew L. Hipp
Rebecca W. Dolan
PREMISE OF THE STUDY: Globally, urban plant populations are becoming increasingly important, as these plants play a vital role in ameliorating effects of ecosystem disturbance and climate change. Urban environments act as filters to bioregional flora, presenting survival challenges to spontaneous plants. Yet, because of the paucity of inventory data on plants in landscapes both before and after urbanization, few studies have directly investigated this effect of urbanization. METHODS: We used historical, contemporary, and regional plant species inventories for Indianapolis, Indiana USA to evaluate how urbanization filters the bioregional flora based on species diversity, functional traits, and phylogenetic community structure. …
Invasive Species In An Urban Flora: History And Current Status In Indianapolis, Indiana, Rebecca W. Dolan
Invasive Species In An Urban Flora: History And Current Status In Indianapolis, Indiana, Rebecca W. Dolan
Rebecca W. Dolan
Invasive plant species are widely appreciated to cause significant ecologic and economic damage in agricultural fields and in natural areas. The presence and impact of invasives in cities is less well documented. This paper characterizes invasive plants in Indianapolis, Indiana. Based on historical records and contemporary accounts, 69 of the 120 species on the official Indiana state list are reported for the city. Most of these plants are native to Asia or Eurasia, with escape from cultivation as the most common mode of introduction. Most have been in the flora of Indianapolis for some time. Eighty percent of Indianapolis’ invasive …
Bacon's Swamp- Ghost Of A Central Indiana Natural Area Past, Rebecca W. Dolan
Bacon's Swamp- Ghost Of A Central Indiana Natural Area Past, Rebecca W. Dolan
Rebecca W. Dolan
Bacon’s Swamp was identified in the 1920s as a ca. 12 ha glacial kettle lake bog system at the southernmost limits of these habitats in Indiana. Located just 9.6 km from the center of Indianapolis, the site was all but destroyed in the mid-20th century by urban expansion. Prior to habitat conversion at the site, Bacon’s Swamp was a frequent location for Butler University ecology class field trips and student research projects. Herbarium specimens and published inventory records allow for analysis of the historical vegetation of Bacon’s Swamp using modern techniques. Floristic Quality Assessment applied to these historical records reveals …
Changes In Plant Species Composition And Structure In Two Peri-Urban Nature Preserves Over 10 Years, Rebecca W. Dolan, Jessica D. Stepens, Marcia E. Moore
Changes In Plant Species Composition And Structure In Two Peri-Urban Nature Preserves Over 10 Years, Rebecca W. Dolan, Jessica D. Stepens, Marcia E. Moore
Rebecca W. Dolan
Peri-urban natural areas, at the boundaries of cities and adjacent agricultural/rural land, are subject to ecological threats endemic to both land use types. We used permanent plots to document changes in habitat quality by monitoring herbaceous-layer plant species presence and cover over a decade (1996/97 and 2007) in two peri-urban nature preserves in central Indiana, U.S.A. The preserves are comprised of different forest community types: wet-mesic depressional forest and mesic upland forest. Habitat characteristics, based on Floristic Quality Assessment parameters, showed only a single change for either preserve between survey years: wetness values were lower in the wet-mesic depressional site …
Next-Generation Field Guides, Elizabeth J. Farnsworth, Miyoko Chu, W. John Kress, Amanda K. Neill, Jason H. Best, John Pickering, Robert D. Stevenson, Gregory W. Courtney, John K. Vandyk, Aaron M. Ellison
Next-Generation Field Guides, Elizabeth J. Farnsworth, Miyoko Chu, W. John Kress, Amanda K. Neill, Jason H. Best, John Pickering, Robert D. Stevenson, Gregory W. Courtney, John K. Vandyk, Aaron M. Ellison
John K. VanDyk
To conserve species, we must first identify them. Field researchers, land managers, educators, and citizen scientists need up-to-date and accessible tools to identify organisms, organize data, and share observations. Emerging technologies complement traditional, book-form field guides by providing users with a wealth of multimedia data. We review technical innovations of next-generation field guides, including Web-based and stand-alone applications, interactive multiple-access keys, visual-recognition software adapted to identify organisms, species checklists that can be customized to particular sites, online communities in which people share species observations, and the use of crowdsourced data to refine machine-based identification algorithms. Next-generation field guides are user …
Weed Seed Germplasm Collection 1964-2014 Of The Weed Biology Laboratory, Jack Dekker
Weed Seed Germplasm Collection 1964-2014 Of The Weed Biology Laboratory, Jack Dekker
Jack Dekker
J. Dekker weed seed germplasm collection; including: Lots 1-3974: 1964-2014; main seed library listed by lot numbers. Lots 649-1457: 1989 all-Iowa Setaria transect study. Lots 1762-1812: 1981; Diane Manthey, North Dakota St. Univ., Setaria collection at Bob Anderson's (USDA, Univ. of Minn) 1960's wild oat study sites. Lots 2389-2595: 1992 north temperate world collection (Japan, Russia, Europe) by J. Dekker. Lots 3270-3685: 1993 Brent Reschly transect study of eastern Iowa conventional and Amish farmers. Lots 3786-3962: 2000 J. Dekker 2000 salt-tolerant Setaria of southern Japan collection. All seed in all these collections belong, and were collected and archived by Jack …
A Global Analysis Of The Impacts Of Urbanization On Bird And Plant Diversity Reveals Key Anthropogenic Drivers, Myla F.J. Aronson, Frank A. La Sorte, Charles H. Nilon, Madhusudan Katti, Mark A. Goddard, Christopher A. Lepczyk, Paige S. Warren, Nicholas S.G. Williams, Sarel Cilliers, Bruce Clarkson, Cynnamon Dobbs, Rebecca W. Dolan, Marcus Hedblom, Stefan Klotz, Jip Louwe Kooijmans, Ingolf Kühn, Ian Macgregor-Fors, Mark Mcdonnell, Ulla Mörtberg, Petr Pyšek, Stefan Siebert, Jessica Sushinsky, Peter Werner, Marten Winter
A Global Analysis Of The Impacts Of Urbanization On Bird And Plant Diversity Reveals Key Anthropogenic Drivers, Myla F.J. Aronson, Frank A. La Sorte, Charles H. Nilon, Madhusudan Katti, Mark A. Goddard, Christopher A. Lepczyk, Paige S. Warren, Nicholas S.G. Williams, Sarel Cilliers, Bruce Clarkson, Cynnamon Dobbs, Rebecca W. Dolan, Marcus Hedblom, Stefan Klotz, Jip Louwe Kooijmans, Ingolf Kühn, Ian Macgregor-Fors, Mark Mcdonnell, Ulla Mörtberg, Petr Pyšek, Stefan Siebert, Jessica Sushinsky, Peter Werner, Marten Winter
Rebecca W. Dolan
Urbanization contributes to the loss of the world's biodiversity and the homogenization of its biota. However, comparative studies of urban biodiversity leading to robust generalities of the status and drivers of biodiversity in cities at the global scale are lacking. Here, we compiled the largest global dataset to date of two diverse taxa in cities: birds (54 cities) and plants (110 cities). We found that the majority of urban bird and plant species are native in the world's cities. Few plants and birds are cosmopolitan, the most common beingColumba livia and Poa annua. The density of bird and plant species …
Resolution Of Deep Nodes Yields An Improved Backbone Phylogeny And A New Basal Lineage To Study Early Evolution Of Asteraceae, Jose L. Panero, Susana E. Freire, Luis Ariza Espinar, Bonnie S. Crozier, Gloria E. Barboza, Juan J. Cantero
Resolution Of Deep Nodes Yields An Improved Backbone Phylogeny And A New Basal Lineage To Study Early Evolution Of Asteraceae, Jose L. Panero, Susana E. Freire, Luis Ariza Espinar, Bonnie S. Crozier, Gloria E. Barboza, Juan J. Cantero
Jose L. Panero
A backbone phylogeny that fully resolves all subfamily and deeper nodes of Asteraceae was constructed using 14 chloroplast DNA loci. The recently named genus Famatinanthus was found to be sister to the Mutisioideae–Asteroideae clade that represents more than 99% of Asteraceae and was found to have the two chloroplast inversions present in all Asteraceae except the nine genera of Barnadesioideae. A monotypic subfamily Famatinanthoideae and tribe Famatinantheae are named herein as new. Relation- ships among the basal lineages of the family were resolved with strong support in the Bayesian analysis as (Barnadesioideae (Famatinanthoideae (Mutisioideae (Stifftioideae (Wunderlichioideae– Asteroideae))))). Ancestral state reconstruction …
The Role Of Olfactory Cues In The Sequential Radiation Of A Gall-Boring Beetle, Mordellistena Convicta, Bradley Rhodes, Catherine Blair, Mizuki Takahashi, Warren Abrahamson
The Role Of Olfactory Cues In The Sequential Radiation Of A Gall-Boring Beetle, Mordellistena Convicta, Bradley Rhodes, Catherine Blair, Mizuki Takahashi, Warren Abrahamson
Warren G. Abrahamson, II
1. Herbivorous insects often have close associations with specific host plants, and their preferences for mating and ovipositing on a specific host-plant species can reproductively isolate populations, facilitating ecological speciation. Volatile emissions from host plants can play a major role in assisting herbivores to locate their natal host plants and thus facilitate assortative mating and host-specific oviposition. 2. The present study investigated the role of host-plant volatiles in host fidelity and oviposition preference of the gall-boring, inquiline beetle, Mordellistena convicta, using Y-tube olfactometers. Previous studies suggest that the gall-boring beetle is undergoing sequential host-associated divergence by utilizing the resources that …
Maize Radiation Use Efficiency Under Optimal Growth Conditions, John L. Lindquist, Timothy J. Arkebauer, Daniel T. Walters, Kenneth G. Cassman, Achim Dobermann
Maize Radiation Use Efficiency Under Optimal Growth Conditions, John L. Lindquist, Timothy J. Arkebauer, Daniel T. Walters, Kenneth G. Cassman, Achim Dobermann
John L. Lindquist
Accurate measurement of crop growth and radiation use efficiency (RUE) under optimal growth conditions is required to predict plant dry matter accumulation and grain yield near the genetic growth potential. Research was conducted to quantify the biomass and leaf area index (LAI) accumulation, extinction coefficient, and RUE of maize (Zea mays L.) under conditions of optimal growth. Maize was grown in two environments over five growing seasons (1998–2002). Total aboveground biomass at maturity ranged from 2257 g m-2 in 1998 to 2916 g m-2 in 2001; values that are considerably greater than the biomass achieved in most previous studies on …
Comparative Ecophysiology Of Grain Sorghum And Abutilon Theophrasti In Monoculture And In Mixture, Samba Traoré, John L. Lindquist, Stephen Mason, Alex Martin, D. A. Mortensen
Comparative Ecophysiology Of Grain Sorghum And Abutilon Theophrasti In Monoculture And In Mixture, Samba Traoré, John L. Lindquist, Stephen Mason, Alex Martin, D. A. Mortensen
John L. Lindquist
Selection of crop genotypes that are more competitive with weeds for light interception may improve crop yield stability in the presence of weeds. The effects of interference on ecophysiological characteristics of Abutilon theophrasti Medic. and three morphologically diverse grain sorghum hybrids was evaluated to determine the relative tolerance and suppressive ability of the three hybrids and specific traits that may contribute to those differences. A tall hybrid was more tolerant to A. theophrasti interference than two medium stature hybrids. Early leaf area growth of two medium-stature sorghum hybrids was reduced by A. theophrasti interference, whereas early growth of a tall …
Common Lambsquarters (Chenopodium Album) Interference With Corn Across The North-Central United States, David W. Fischer, R. Gordon Harvey, Thomas T. Bauman, Sam Phillips, Stephen E. Hart, Gregg A. Johnson, James J. Kells, Philip Westra, John L. Lindquist
Common Lambsquarters (Chenopodium Album) Interference With Corn Across The North-Central United States, David W. Fischer, R. Gordon Harvey, Thomas T. Bauman, Sam Phillips, Stephen E. Hart, Gregg A. Johnson, James J. Kells, Philip Westra, John L. Lindquist
John L. Lindquist
Variation in crop–weed interference relationships has been shown for a number of crop–weed mixtures and may have an important influence on weed management decision-making. Field experiments were conducted at seven locations over 2 yr to evaluate variation in common lambsquarters interference in field corn and whether a single set of model parameters could be used to estimate corn grain yield loss throughout the north-central United States.
Influence Of Nitrogen And Duration Of Weed Interference On Corn Growth And Development, Sean P. Evans, Stevan Z. Knezevic, John L. Lindquist, Charles A. Shapiro
Influence Of Nitrogen And Duration Of Weed Interference On Corn Growth And Development, Sean P. Evans, Stevan Z. Knezevic, John L. Lindquist, Charles A. Shapiro
John L. Lindquist
An improved understanding of the effects of nitrogen (N) on crop–weed interactions is needed for the development of integrated weed management systems where responsible use of N fertilizers is considered. Field experiments conducted in 1999 and 2000 at two locations in eastern Nebraska quantify the effects of N and increasing duration of weed interference on corn growth and development. A naturally occurring population of weeds was allowed to compete with the corn crop for increasing lengths of time and at three rates of N application (0, 60, and 120 kg N ha-1). Weed interference and withholding applied N increased the …
Simulated Insect Defoliation And Duration Of Weed Interference Affected Soybean Growth, Travis C. Gustafson, Stevan Z. Knezevic, Thomas E. Hunt, John L. Lindquist
Simulated Insect Defoliation And Duration Of Weed Interference Affected Soybean Growth, Travis C. Gustafson, Stevan Z. Knezevic, Thomas E. Hunt, John L. Lindquist
John L. Lindquist
An improved understanding of crop stress from multiple pests is needed for better implementation of integrated pest management (IPM) strategies. Field studies were conducted in 2003 and 2004 at two locations in eastern Nebraska to describe the effects of simulated early-season insect defoliation of soybean and duration of weed interference on soybean growth. Three levels of simulated defoliation (undefoliated, 30, and 60%) and seven durations of weed interference (weedy and weed free; weed removal at V2, V4, V6, R3, and R5) were evaluated in a split-plot design. Defoliation significantly reduced soybean leaf-area index (LAI), total dry matter (TDM), and crop …
Light-Saturated Co2 Assimilation Rates Of Corn And Velvetleaf In Response To Leaf Nitrogen And Development Stage, John L. Lindquist
Light-Saturated Co2 Assimilation Rates Of Corn And Velvetleaf In Response To Leaf Nitrogen And Development Stage, John L. Lindquist
John L. Lindquist
Single-leaf CO2 assimilation rate under saturating light (CA) varies as a function of leaf nitrogen content per unit leaf area (NL). Measured CA for many crop species also declines with developmental stage. Because these relationships may have strong implications for crop–weed competition, a field experiment was conducted to quantify corn and velvetleaf CA as influenced by leaf NL and stage of development. Crop and weed CA were measured on the most recent fully expanded leaves of plants grown in four nitrogen (N) application treatments. Both corn and velvetleaf CA increased …
Hybrid-Maize—A Maize Simulation Model That Combines Two Crop Modeling Approaches, H. S. Yang, A. Dobermann, John L. Lindquist, Daniel T. Walters, Timothy J. Arkebauer, Kenneth G. Cassman
Hybrid-Maize—A Maize Simulation Model That Combines Two Crop Modeling Approaches, H. S. Yang, A. Dobermann, John L. Lindquist, Daniel T. Walters, Timothy J. Arkebauer, Kenneth G. Cassman
John L. Lindquist
A new maize (Zea mays L.) simulation model, Hybrid-Maize, was developed by combining the strengths of two modeling approaches: the growth and development functions in maize-specific models represented by CERES- Maize, and the mechanistic formulation of photosynthesis and respiration in generic crop models such as INTERCOM and WOFOST. It features temperature-driven maize phenological development, vertical canopy integration of photosynthesis, organ-specific growth respiration, and temperature-sensitive maintenance respiration. The inclusion of gross assimilation, growth respiration and maintenance respiration makes the Hybrid- Maize model potentially more responsive to changes in environmental conditions than models such as CERES-Maize. Hybrid-Maize also requires fewer genotype-specific …
A Simulation Approach For Evaluating Maize Yield Potential In Different Environments, Haishun S. Yang, Achim R. Dobermann, Kenneth G. Cassman, Daniel T. Walters, John L. Lindquist
A Simulation Approach For Evaluating Maize Yield Potential In Different Environments, Haishun S. Yang, Achim R. Dobermann, Kenneth G. Cassman, Daniel T. Walters, John L. Lindquist
John L. Lindquist
What is yield potential? To achieve yield potential of an environment: Why yield potential important? Objectives: Nebraska (NE): To estimate yield potential across NE requires: How to estimate yield potential across NE? Choice of model: Hybrid-Maize Simulation of best yields under current practices Current practices: best yields Current practices: variation of best yields To achieving full yield potential: Optimal management: gain in season length Optimal management: gain in yield Optimal management: temporal (mean=14 y) variation of yields Conclusions
Performance Of Weedsoft For Predicting Soybean Yield Loss, Shawn M. Hock, Stevan Z. Knezevic, Alex Martin, John L. Lindquist
Performance Of Weedsoft For Predicting Soybean Yield Loss, Shawn M. Hock, Stevan Z. Knezevic, Alex Martin, John L. Lindquist
John L. Lindquist
Decision support systems (DSSs) have been developed to assist producers and consultants with weed management decisions. WeedSOFT is a DSS currently used in several states in the northcentral region of the United States. Accurate estimates of crop yield loss due to weed interference are required for cost-effective weed management recommendations. WeedSOFT uses competitive indices (CIs) to predict crop yield loss under multiple weed species, weed densities, and relative times of weed emergence. Performance of several WeedSOFT versions to predict soybean yield loss from weed competition was evaluated using CI values in WeedSOFT version 9.0 compared to new CI values calculated …
The Influence Of Plant Population Spatial Arrangement On Individual Plant Yield, John L. Lindquist, D. Rhode, K. J. Puettmann, B. D. Maxwell
The Influence Of Plant Population Spatial Arrangement On Individual Plant Yield, John L. Lindquist, D. Rhode, K. J. Puettmann, B. D. Maxwell
John L. Lindquist
Two greenhouse experiments were conducted to evaluate the performance of individual oat (Avena sativa) target plants as influenced by neighbor oat plants with different spatial arrangements. Crop spatial arrangement was separated into three com- ponents: (I) population density, (2) distance between plants (distance dispersion, DD), and (3) angular arrangement of plants about one another (angular dispersion, AD). Distance dispersion was quantified using a weighted mean distance from a target individual to its neighbors. Angular dispersion of neighbors around the target was quantified using a measure of circular variance. DD and AD were combined to create a dispersion index (DI). At …
Critical Period For Weed Control: The Concept And Data Analysis, Stevan Z. Knezevic, Sean P. Evans, Erin E. Blankenship, Rene C. Van Acker, John L. Lindquist
Critical Period For Weed Control: The Concept And Data Analysis, Stevan Z. Knezevic, Sean P. Evans, Erin E. Blankenship, Rene C. Van Acker, John L. Lindquist
John L. Lindquist
The critical period for weed control (CPWC) is a period in the crop growth cycle during which weeds must be controlled to prevent yield losses. Knowing the CPWC is useful in making decisions on the need for and timing of weed control and in achieving efficient herbicide use from both biological and economic perspectives. An increase in the use of herbicide-tolerant crops, especially soybean resistant to glyphosate, has stimulated interest in the concept of CPWC. Recently, several studies examined this concept in glyphosate-resistant corn and soybean across the midwestern United States. However, these studies presented various methods for data analysis …
Influence Of Planting Date And Weed Interference On Sweet Corn Growth And Development, Martin M. Williams Ii, John L. Lindquist
Influence Of Planting Date And Weed Interference On Sweet Corn Growth And Development, Martin M. Williams Ii, John L. Lindquist
John L. Lindquist
Crop planting date and canopy density influence interactions between weeds and sweet corn (Zea mays L.); however, little is known about sweet corn growth response to weed interference. Field studies were conducted in 2004 and 2005 near Urbana, IL, to quantify the influence of planting date and weed interference on growth of sweet corn height, leaf area, aboveground biomass, and phenological development. Crop growth response to weed interference (presence or absence) was determined for sweet corn planted early May (EARLY) and late June (LATE). Dominant weed species included barnyard-grass [Echinochloa crus-galli (L.) Beauv.], common lambsquarters (Chenopodium album L.), common purslane …
Comparison And Hybridization Of Two Approaches For Maize Simulation, Haishun Yang, Kenneth G. Cassman, Achim R. Dobermann, Daniel T. Walters, John L.. Lindquist, Timothy J. Arkebauer
Comparison And Hybridization Of Two Approaches For Maize Simulation, Haishun Yang, Kenneth G. Cassman, Achim R. Dobermann, Daniel T. Walters, John L.. Lindquist, Timothy J. Arkebauer
John L. Lindquist
Two approaches dominate simulation modeling of maize growth: (1) a generic approach, represented by the family of crop models developed by Dutch scientists at the Wageningen University, e.g. SUCROS (Spitters et al, 1989), WOFOST (Diepen et al, 1989) and INTERCOM (Kropff and van Laar, 1993), and (2) a maize-specific approach, represented by CERES-Maize (Jones and Kiniry, 1986) and its derivatives such as the maize module in DSSAT, and the MSB model developed by Muchow et al. (Muchow et al, 1990). These two approaches differ in three aspects. First, maize development in generic models is driven primarily by availability of assimilate …
Effect Of Cultivation And Within-Field Differences In Soil Conditions On Feral Helianthus Annuus Growth In Ridge-Tillage Maize, Michael G. Burton, David A. Mortensen, John L. Lindquist
Effect Of Cultivation And Within-Field Differences In Soil Conditions On Feral Helianthus Annuus Growth In Ridge-Tillage Maize, Michael G. Burton, David A. Mortensen, John L. Lindquist
John L. Lindquist
Differences in weed population dynamics with respect to within-field heterogeneity are not well documented despite increasing interest in site-specific management of agro-ecosystems. The focus of this study was to determine if mechanical weed management (cultivation) and/or soil factors help to explain observed within-field distributions of feral common sunflower ( Helianthus annuus L.). The ridges and furrows created by the ridge–tillage system adds additional microsites to existing spatial heterogeneity for soil characteristics such as soil organic carbon (SOC) concentration. Experimental areas were selected on the basis of naturally high or low SOC concentration. Cultivation resulted in 100% mortality of H. annuus …
Soybean Row Spacing And Weed Emergence Time Influence Weed Competitiveness And Competitive Indices, Shawn M. Hock, Stevan Z. Knezevic, Alex Martin, John L. Lindquist
Soybean Row Spacing And Weed Emergence Time Influence Weed Competitiveness And Competitive Indices, Shawn M. Hock, Stevan Z. Knezevic, Alex Martin, John L. Lindquist
John L. Lindquist
Weed competitiveness can be quantified with the concept of competitive index (CI), a relative scale of weed competitiveness. Field studies were conducted in 2002 and 2003 in northeastern and southeastern Nebraska to evaluate the influence of soybean row spacing and relative weed emergence time on the competitiveness of major weed species in soybean. Ten weed species were seeded in soybean spaced 19 and 76 cm apart at the planting, emergence, and first trifoliate leaf stages of soybean. Total weed dry matter (TDM), weed plant volume, and percent soybean yield loss were arbitrarily selected as a base for determining the CI …
Effect Of Nitrogen Addition And Weed Interference On Soil Nitrogen And Corn Nitrogen Nutrition, John L. Lindquist, Sean P. Evans, Charles A. Shapiro, Stevan Z. Knezevic
Effect Of Nitrogen Addition And Weed Interference On Soil Nitrogen And Corn Nitrogen Nutrition, John L. Lindquist, Sean P. Evans, Charles A. Shapiro, Stevan Z. Knezevic
John L. Lindquist
Weeds cause crop loss indirectly by reducing the quantity of resources available for growth. Quantifying the effects of weed interference on nitrogen (N) supply, crop growth, and N nutrition may assist in making both N and weed management decisions. Experiments were conducted to quantify the effect of N addition and weed interference on soil nitrate-N (NO3- N) over time and the dependence of corn growth on NO3-N availability, determine the corn N nutrition index (NNI) at anthesis, and evaluate if relative chlorophyll content can be utilized as a reliable predictor of NNI. Urea was applied at 0, 60, …
Effect Of Nitrogen Addition On The Comparative Productivity Of Corn And Velvetleaf (Abutilon Theophrasti), Darren C. Barker, Stevan Z. Knezevic, Alex R. Martin, Daniel T. Walters, John L. Lindquist
Effect Of Nitrogen Addition On The Comparative Productivity Of Corn And Velvetleaf (Abutilon Theophrasti), Darren C. Barker, Stevan Z. Knezevic, Alex R. Martin, Daniel T. Walters, John L. Lindquist
John L. Lindquist
Weeds that respond more to nitrogen fertilizer than crops may be more competitive under high nitrogen (N) conditions. Therefore, understanding the effects of nitrogen on crop and weed growth and competition is critical. Field experiments were conducted at two locations in 1999 and 2000 to determine the influence of varying levels of N addition on corn and velvetleaf height, leaf area, biomass accumulation, and yield. Nitrogen addition increased corn and velvetleaf height by a maximum of 15 and 68%, respectively. N addition increased corn and velvetleaf maximum leaf area index (LAI) by up to 51 and 90%. Corn and velvetleaf …
Understanding Corn Yield Potential In Different Environments, Achim R. Dobermann, Timothy J. Arkebauer, Kenneth G. Cassman, Rhae A. Drijber, John L. Lindquist, James E. Specht, Daniel T. Walters, Haishun Yang, Daniel N. Miller, Darren L. Binder, Gregory J. Teichmeier, Richard B. Ferguson, Charles S. Wortmann
Understanding Corn Yield Potential In Different Environments, Achim R. Dobermann, Timothy J. Arkebauer, Kenneth G. Cassman, Rhae A. Drijber, John L. Lindquist, James E. Specht, Daniel T. Walters, Haishun Yang, Daniel N. Miller, Darren L. Binder, Gregory J. Teichmeier, Richard B. Ferguson, Charles S. Wortmann
John L. Lindquist
The UNL research program on Ecological intensification of irrigated maize-based cropping systems aims to (i) improve understanding of the yield potential of corn and soybean and how it is affected by management, (ii) develop a scientific basis for evaluating yield potential at different locations, (iii) develop practical technologies for managing intensive cropping systems at 70-80% of the yield potential, and (iv) conduct integrated assessment of productivity, profitability, input use efficiency, soil carbon sequestration, energy and carbon budgets, and trace gas emissions. Results of this work have been reported earlier (Arkebauer et al., 2001; Dobermann et al., 2002). In this paper …
Influence Of Soybean Row Width And Velvetleaf Emergence Time On Velvetleaf (Abutilon Theophrasti), Shawn M. Hock, Stevan Z. Knezevic, Alex R. Martin, John L. Lindquist
Influence Of Soybean Row Width And Velvetleaf Emergence Time On Velvetleaf (Abutilon Theophrasti), Shawn M. Hock, Stevan Z. Knezevic, Alex R. Martin, John L. Lindquist
John L. Lindquist
Row spacing and the relative time of velvetleaf emergence affects the time of soybean canopy closure relative to velvetleaf, influencing the growth and development of velvetleaf. Field studies were conducted in northeastern Nebraska in 2002 and 2003 to describe velvetleaf growth as influenced by soybean presence or absence (velvetleaf grown with soybean or in monoculture), soybean row spacing (19 and 76 cm), and relative time of velvetleaf emergence. Velvetleaf seed production, leaf area (LA), and total dry matter (TDM) were greater in 76-cm- than in 19-cm-wide soybean rows. LA, TDM, and seed production of velvetleaf were reduced with later emergence …
Corn–Velvetleaf (Abutilon Theophrasti ) Interference Is Affected By Sublethal Doses Of Postemergence Herbicides, Brescia R. M. Terra, Alexander R. Martin, John L. Lindquist
Corn–Velvetleaf (Abutilon Theophrasti ) Interference Is Affected By Sublethal Doses Of Postemergence Herbicides, Brescia R. M. Terra, Alexander R. Martin, John L. Lindquist
John L. Lindquist
Injury to weeds from sublethal doses of POST herbicides may reduce the effect of weed interference on crop yield. Information on how herbicide dose influences weed mortality, growth, and seed production is needed to assess the potential benefit of applying reduced herbicide doses. Field experiments were conducted at Mead, NE, in 2001 and 2002 to quantify velvetleaf mortality, growth, and corn–velvetleaf interference in response to varying doses of three POST herbicides. Untreated velvetleaf at six densities (0, 1, 3, 6, 12, and 20 plants m-1 corn row) was grown in mixture with corn to establish a baseline corn–velvetleaf interference relationship. …