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Agronomic Responses Of Corn Hybrids From Different Eras To Deficit And Adequate Levels Of Water And Nitrogen, Patrick M. O'Neill, J.F. Shanahan, James S. Schepers, Bob Caldwell Dec 2004

Agronomic Responses Of Corn Hybrids From Different Eras To Deficit And Adequate Levels Of Water And Nitrogen, Patrick M. O'Neill, J.F. Shanahan, James S. Schepers, Bob Caldwell

Agronomy & Horticulture -- Faculty Publications

Maintaining current high yields of corn (Zea mays L.) grown in the USA poses an environmental threat due to continued overuse of water and N inputs. To reduce overreliance on inputs, future corn breeding efforts should focus on improving tolerance of corn to water and N stresses, utilizing appropriate tolerance mechanisms. The objective of this study was to identify appropriate mechanisms by characterizing agronomic responses of 12 hybrids from three different eras (‘B73 x Mo17’ from 1970s and three early 1990s and eight late 1990s Pioneer brand hybrids) to varying water and N supply. This was done by growing the ...


Sources Of Plant Materials For Land Rehabilitation, Heidi Howard, John A. Guretzky, Brandy Koch, Shannon Mcdowell, Steven Warren, Gwyn L. Howard Dec 2004

Sources Of Plant Materials For Land Rehabilitation, Heidi Howard, John A. Guretzky, Brandy Koch, Shannon Mcdowell, Steven Warren, Gwyn L. Howard

Agronomy & Horticulture -- Faculty Publications

Military training often results in environmental degradation that has negative impacts on future training missions. The U.S. Army Construction Engineering Research Laboratory (CERL) conceptualized the Army’s Integrated Training Area Management (ITAM) program in response to the concerns expressed by military land managers and trainers over the declining condition of training and testing lands. ITAM has evolved to include land condition and trend analysis (LCTA), environmental awareness (EA), training requirements integration (TRI), and land rehabilitation and maintenance (LRAM). The need for LRAM has increased dramatically over the past decade. Among the many difficulties faced in planning and implementing a ...


Land Rehabilitation And Maintenance Equipment Sources, Heidi Howard, Shannon Mcdowell, Amanda Breon, John A. Guretzky, Bradley Tadlock Dec 2004

Land Rehabilitation And Maintenance Equipment Sources, Heidi Howard, Shannon Mcdowell, Amanda Breon, John A. Guretzky, Bradley Tadlock

Agronomy & Horticulture -- Faculty Publications

Military training can often be destructive to the environment. Environmental impacts associated with heavy training include soil compaction, soil erosion, siltation of waterways and wetlands, increased threat of flooding, loss of wildlife habitat, declining biodiversity, and invasion by noxious weeds. Planning and implementing land rehabilitation projects generally involves some soil movement, establishment of vegetation, stabilization and hardening of sites, etc. Procurement of appropriate heavy equipment and other specialized equipment is sometimes a difficult task that involves obtaining multiple vendors, especially when procuring equipment for rental, lease, or purchase. This report and associated database were created to help land managers easily ...


Interactions Among Western Ragweed And Other Sandhills Species After Drought, Patrick E. Reece, Joe E. Brummer, Brian K. Northup, Ann E. Koehler, Lowell E. Moser Nov 2004

Interactions Among Western Ragweed And Other Sandhills Species After Drought, Patrick E. Reece, Joe E. Brummer, Brian K. Northup, Ann E. Koehler, Lowell E. Moser

Agronomy & Horticulture -- Faculty Publications

Interannual differences in yield and species composition of herbaceous vegetation on semiarid rangelands are common and often related to variations in precipitation regime. Interspecific interactions that occur after drought-induced population fluxes of western ragweed (Ambrosia psilostachya D.C.) were evaluated by removing western ragweed or associated species from 1-m2 quadrats at weekly intervals beginning in early May, June, or July 1991 or 1992 on high-seral sandhills prairie in Nebraska. The composite of peak standing crops for ragweed and each group of associated species was 77% greater during May–October 1991 (2 252 kg•ha-1) compared with 1992 (1 ...


Temporal Origin Of Nitrogen In The Grain Of Irrigated Rice In The Dry Season: The Outcome Of Uptake, Cycling, Senescence And Competition Studied Using A 15N-Point Placement Technique, J. E. Sheehy, M. Mnzava, Kenneth G. Cassman, P. L. Mitchell, P. Pablico, R. P. Robles, H. P. Samonte, J. S. Lales, A. B. Ferrer Oct 2004

Temporal Origin Of Nitrogen In The Grain Of Irrigated Rice In The Dry Season: The Outcome Of Uptake, Cycling, Senescence And Competition Studied Using A 15N-Point Placement Technique, J. E. Sheehy, M. Mnzava, Kenneth G. Cassman, P. L. Mitchell, P. Pablico, R. P. Robles, H. P. Samonte, J. S. Lales, A. B. Ferrer

Agronomy & Horticulture -- Faculty Publications

It is often suggested that nitrogen absorbed in the vegetative stage of growth acts as a “reservoir” to supply the shortfall in demand during grain filling. The main objective of the work described in this paper was to investigate how effectively nitrogen absorbed at different stages of the growing season was retained and used for grain growth. The total nitrogen in the grain is the integral of the product of the total nitrogen absorbed at any instant and the eventual allocation of a fraction of that nitrogen to the grain. A point-placement technique was used to deliver small amounts of ...


Growth And Yield Of Snap Beans As Affected By Wind Protection And Microclimate Changes Due To Shelterbelts And Planting Dates, Laurie Hodges, Mohd Nazip Suratman, James R. Brandle, Kenneth G. Hubbard Aug 2004

Growth And Yield Of Snap Beans As Affected By Wind Protection And Microclimate Changes Due To Shelterbelts And Planting Dates, Laurie Hodges, Mohd Nazip Suratman, James R. Brandle, Kenneth G. Hubbard

Agronomy & Horticulture -- Faculty Publications

The effects of wind protection on growth and total and marketahle yields of snap bean (Phaseolus vulgaris L.) planted at 2-week intervals through the 1994 and 1995 growing seasons were examined. Research was conducted under nonirrigated conditions at the Shelterbelt Research Area, Univ, of Nebraska Agricultural Research and Development Center (ARDC) near Mead. 'Strike' (white-seeded) and 'Rushmore' (dark-seeded) were planted in locations sheltered from wind stress hy tree windbreaks (shelterbelts) and in locations exposed to normal winds using a randomized complete-block design with a split-split plot arrangement of treatments. Air temperature, soil temperature, humidity, wind speed, and wind direction were ...


Rice Yields Decline With Higher Night Temperature From Global Warming, Shaobing Peng, Jianliang Huang, John Sheehy, Rebecca C. Laza, Romeo M. Visperas, Xuhua Zhong, Grace S. Centeno, Gurdev S. Khush, Kenneth G. Cassman Jul 2004

Rice Yields Decline With Higher Night Temperature From Global Warming, Shaobing Peng, Jianliang Huang, John Sheehy, Rebecca C. Laza, Romeo M. Visperas, Xuhua Zhong, Grace S. Centeno, Gurdev S. Khush, Kenneth G. Cassman

Agronomy & Horticulture -- Faculty Publications

The impact of projected global warming on crop yields has been evaluated by indirect methods using simulation models. Direct studies on the effects of observed climate change on crop growth and yield could provide more accurate information for assessing the impact of climate change on crop production. We analyzed weather data at the International Rice Research Institute Farm from 1979 to 2003 to examine temperature trends and the relationship between rice yield and temperature by using data from irrigated field experiments conducted at the International Rice Research Institute Farm from 1992 to 2003. Here we report that annual mean maximum ...


Characterization Of Humic Acid Fractions Improves Estimates Of Nitrogen Mineralization Kinetics For Lowland Rice Soils, Nguyen Bao Ve, D. C. Olk, Kenneth G. Cassman Jul 2004

Characterization Of Humic Acid Fractions Improves Estimates Of Nitrogen Mineralization Kinetics For Lowland Rice Soils, Nguyen Bao Ve, D. C. Olk, Kenneth G. Cassman

Agronomy & Horticulture -- Faculty Publications

Nitrogen mineralization in irrigated lowland rice (Oryza sativa L.) soils is poorly predicted by total soil C and N. To improve its prediction, two humic acid fractions were extracted with NaOH from lowland rice soils of Vietnam and the Philippines to evaluate their influence on N mineralization kinetics during 84-d anaerobic incubations. Indicative of young organic matter, the mobile humic acid (MHA) fraction had a smaller C/N ratio and optical density at 465 nm (E4) than did the calcium humate (CaHA) fraction, which was extracted after removal of polyvalent cations from the soil. Nitrogen contents of both fractions ...


Nitrogen Mineralization From Humic Acid Fractions In Rice Soils Depends On Degree Of Humification, Bao Ve Nguyen, D. C. Olk, Kenneth G. Cassman Jul 2004

Nitrogen Mineralization From Humic Acid Fractions In Rice Soils Depends On Degree Of Humification, Bao Ve Nguyen, D. C. Olk, Kenneth G. Cassman

Agronomy & Horticulture -- Faculty Publications

Although the chemical nature of soil organic matter (SOM) is thought to affect the mineralization rate of N bound in SOM, little direct evidence exists for such effects. To test the hypothesis that the N mineralization rate is affected by the degree of SOM humification, we added equivalent amounts of humic acid (HA) N as either the labile mobile humic acid (MHA) fraction or the more humified cal- cium humate (CaHA) fraction to two lowland rice (Oryza sativa L.) soils, which were subsequently incubated under anaerobic conditions for 6 wk. The HA fractions had been chemically extracted from seven irrigated ...


A New Integrated Genetic Linkage Map Of The Soybean, Q.J. Song, L.F. Marek, R.C. Shoemaker, K.G. Lark, V.C. Concibido, X. Delannay, James E. Specht, P.B. Cregan Jun 2004

A New Integrated Genetic Linkage Map Of The Soybean, Q.J. Song, L.F. Marek, R.C. Shoemaker, K.G. Lark, V.C. Concibido, X. Delannay, James E. Specht, P.B. Cregan

Agronomy & Horticulture -- Faculty Publications

A total of 391 simple sequence repeat (SSR) markers designed from genomic DNA libraries, 24 derived from existing GenBank genes or ESTs, and five derived from bacterial artificial chromosome (BAC) end sequences were developed. In contrast to SSRs derived from EST sequences, those derived from genomic libraries were a superior source of polymorphic markers, given that the mean number of tandem repeats in the former was significantly less than that of the latter (P<0.01). The 420 newly developed SSRs were mapped in one or more of five soybean mapping populations: ‘Minsoy’ × ‘Noir 1’, ‘Minsoy’ × ‘Archer’, ‘Archer’ × ‘Noir 1’, ‘Clark’ × ‘Harosoy’, and A81-356022 × PI468916. The JoinMap software package was used to combine the five maps into an integrated genetic map spanning 2,523.6 cM of Kosambi map distance across 20 linkage groups that contained 1,849 markers, including 1,015 SSRs, 709 RFLPs, 73 RAPDs, 24 classical traits, six AFLPs, ten isozymes, and 12 others. The number of new SSR markers added to each linkage group ranged from 12 to 29. In the integrated map, the ratio of SSR marker number to linkage group map distance did not differ among 18 of the 20 linkage groups; however, the SSRs were not uniformly spaced over a linkage group, clusters of SSRs with very limited recombination were frequently present. These clusters of SSRs may be indicative of gene-rich regions of soybean, as has been suggested by a number of recent studies, indicating the significant association of genes and SSRs. Development of SSR markers from map-referenced BAC clones was a very effective means of targeting markers to marker-scarce positions in the genome.


Stability Of The Allergenic Soybean Kunitz Trypsin Inhibitor, Robin Roychaudhuri, Gautam Sarath, Michael G. Zeece, John P. Markwell May 2004

Stability Of The Allergenic Soybean Kunitz Trypsin Inhibitor, Robin Roychaudhuri, Gautam Sarath, Michael G. Zeece, John P. Markwell

Agronomy & Horticulture -- Faculty Publications

The soybean Kunitz trypsin inhibitor (SKTI) is a 21.5 kDa allergenic protein that belongs to the family of all antiparallel h-sheet proteins that are highly resistant to thermal and chemical denaturation. Spectroscopic and biochemical techniques such as circular dichroism (CD), ANS fluorescence and proteolysis were used to study its molecular structure under denaturing conditions such as acid and heat to which these allergens are commonly exposed during food processing. Reduction of native SKTI leads to its complete and rapid proteolysis by pepsin in simulated gastric fluid (SGF). Limited proteolysis with chymotrypsin during renaturation after heating showed that the native ...


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 May 2004

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

Agronomy & Horticulture -- Faculty Publications

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 parameters ...


Feasibility Of Site-Specific Management Of Corn Hybrids And Plant Densities In The Great Plains, J.F. Shanahan, Thomas A. Doerge, Jerry J. Johnson, Merle F. Vigil Apr 2004

Feasibility Of Site-Specific Management Of Corn Hybrids And Plant Densities In The Great Plains, J.F. Shanahan, Thomas A. Doerge, Jerry J. Johnson, Merle F. Vigil

Agronomy & Horticulture -- Faculty Publications

The goal of this research was to determine the potential for use of site-specific management of corn hybrids and plant densities in dryland landscapes of the Great Plains by determining (1) within-field yield variation, (2) yield response of different hybrids and plant densities to variability, and (3) landscape attributes associated with yield variation. This work was conducted on three adjacent fields in eastern Colorado during the 1997, -98, and -99 seasons. Treatments consisted of a combination of two hybrids (early and late maturity) and four plant densities (24,692, 37,037, 49,382 and 61,727 plants ha-1) seeded ...


Agronomic Ufos, Thomas R. Sinclair, Kenneth G. Cassman Apr 2004

Agronomic Ufos, Thomas R. Sinclair, Kenneth G. Cassman

Agronomy & Horticulture -- Faculty Publications

Science is challenged from time-to-time by claims that are completely outside the usual boundaries of observation and experience. Reports of flying saucers (unidentified flying objects) and creationism’s counter to evolution are two examples that fall into this category. Credentialed scientists can themselves become the victims of such phenomena when their research results are not evaluated through anonymous peer review as part of publication. The cold fusion debacle of a few years ago is an example of such a bypass of peer evaluation.

Unfortunately, agronomic science is not immune to such problems, particularly as they relate to claims of miraculously ...


Appropriateness Of Management Zones For Characterizing Spatial Variability Of Soil Properties And Irrigated Corn Yields Across Years, Aaron R. Schepers, J.F. Shanahan, Mark A. Liebig, James S. Schepers, Sven Johnson, Ariovaldo Luchiari Jr. Feb 2004

Appropriateness Of Management Zones For Characterizing Spatial Variability Of Soil Properties And Irrigated Corn Yields Across Years, Aaron R. Schepers, J.F. Shanahan, Mark A. Liebig, James S. Schepers, Sven Johnson, Ariovaldo Luchiari Jr.

Agronomy & Horticulture -- Faculty Publications

Recent precision-agriculture research has focused on use of management zones (MZ) as a method for variable application of inputs like N. The objectives of this study were to determine (i) if landscape attributes could be aggregated into MZthat characterize spatial varia- tion in soil chemical properties and corn yields and (ii) if temporal variability affects expression of yield spatial variability. This work was conducted on an irrigated cornfield near Gibbon, NE. Five landscape attributes, including a soil brightness image (red, green, and blue bands), elevation, and apparent electrical conductivity, were acquired for the field.Ageoreferenced soil-sampling scheme was used to ...


Prediction Of Leaf/Stem Ratio Using Near-Infrared Reflectance Spectroscopy (Nirs): A Technical Note, Alexander J. Smart, Walter H. Schacht, Lowell E. Moser, Jerry D. Volesky Feb 2004

Prediction Of Leaf/Stem Ratio Using Near-Infrared Reflectance Spectroscopy (Nirs): A Technical Note, Alexander J. Smart, Walter H. Schacht, Lowell E. Moser, Jerry D. Volesky

Agronomy & Horticulture -- Faculty Publications

Leaf/stem ratio of grass stands is an important factor affecting diet selection, quality, and forage intake. Determination of leaf/stem ratio involves a labor-intensive process of hand separating leaf and stem fractions. Our objectives in this study were to evaluate leaf/stem ratio prediction using near-infrared reflectance spectroscopy (NIRS) in monocultures of big bluestem (Andropogon gerardii Vitman), switch- grass (Panicum virgatum L.), intermediate wheatgrass [Thinopyrum intermedian (Host) Barkw. & D.R. Dewey], and smooth bromegrass (Bromus inermis Leyss.). Samples of each species were hand-clipped from monocultures at four locations throughout Nebraska in the 1997 and 1998 growing seasons. Ground samples ...


Forage & Grazing Lands: Morphological Characteristics Of Big Bluestem And Switchgrass Plants Divergently Selected For Seedling Tiller Number, Alexander J. Smart, Lowell E. Moser, Kenneth P. Vogel Jan 2004

Forage & Grazing Lands: Morphological Characteristics Of Big Bluestem And Switchgrass Plants Divergently Selected For Seedling Tiller Number, Alexander J. Smart, Lowell E. Moser, Kenneth P. Vogel

Agronomy & Horticulture -- Faculty Publications

Selection at the seedling stage in grass breeding would be useful if seedling traits were correlated to desired agronomic traits of mature plants. Objectives of this study were to determine if seedlings from big bluestem (Andropogon gerardii Vitman) and switchgrass (Panicumvirgatum L.) populations that differ genetically in seedling tiller num- ber differ in mature plant (i) morphological characteristics, (ii) forage yield managed by a three-cut harvest system or a single end-of-season harvest, and (iii) leaf elongation rate. Field experiments were conducted on a Kennebec silt loam soil (fine-silty, mixed, superactive, mesic Cumulic Hapludolls). In addition, greenhouse studies were con-ducted in ...


Seed Quality Qtl In A Prominent Soybean Population, D. L. Hyten Jr., V. R. Pantalone, C. E. Sams, A. M. Saxon, D. Landau-Ellis, T. R. Stefaniak, M. E. Schmidt Jan 2004

Seed Quality Qtl In A Prominent Soybean Population, D. L. Hyten Jr., V. R. Pantalone, C. E. Sams, A. M. Saxon, D. Landau-Ellis, T. R. Stefaniak, M. E. Schmidt

Agronomy & Horticulture -- Faculty Publications

Soybean [Glycine max (L.) Merr.] is a versatile crop due to its multitude of uses as a high protein meal and vegetable oil. Soybean seed traits such as seed protein and oil concentration and seed size are important quantitative traits. The objective of this study was to identify representative protein, oil, and seed size quantitative trait loci (QTL) in soybean. A recombinant inbred line (RIL) population consisting of 131 F6-derived lines was created from two prominent ancestors of North American soy-beans (‘Essex’ and ‘Williams’) and the RILs were grown in six environments. One hundred simple sequence repeat (SSR) markers spaced ...


Resource Allocation In A Breeding Program For Phosphorus Concentration In Maize Grain, Brandon M. Wardyn, W. Ken Russell Jan 2004

Resource Allocation In A Breeding Program For Phosphorus Concentration In Maize Grain, Brandon M. Wardyn, W. Ken Russell

Agronomy & Horticulture -- Faculty Publications

When beef cattle (Bos taurus) are fed grain of maize (Zea mays L.) in which the concentration of phosphorus (P) exceeds the animal’s need for this element, the excess P is excreted in the feces. Spreading this manure on cropland increases the potential for P pollution of surface waters by run-off. Experiments were undertaken to determine the relative magnitudes of genotypic and nongenotypic variances of P concentration in maize grain (P-Gr) to assess the ability to select maize genotypes in which this trait more closely matches the dietary need of beef cattle. Genetic variability was found in a population ...


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 Jan 2004

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

Agronomy & Horticulture -- Faculty Publications

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.


Plant Population And Fertilization Impacts On Irrigated Corn In Nebraska, Daniel T. Walters, Achim R. Dobermann Jan 2004

Plant Population And Fertilization Impacts On Irrigated Corn In Nebraska, Daniel T. Walters, Achim R. Dobermann

Agronomy & Horticulture -- Faculty Publications

Since 1999, a team of researchers at the University of Nebraska has been conducting studies to understand the yield potential of corn and soybeans and how management affects it. The crop model discussed in the previous article was a product of this team. The research compares continuous corn to a corn-soybean rotation and evaluates how plant population and nutrient management impact yield. In addition to determining productivity, the research involves an integrated assessment of profitability, input use efficiency, energy balance, and environmental consequences.


Predicting Phenological Development In Winter Wheat, Qingwu Xue, Albert Weiss, P. Stephen Baenziger Jan 2004

Predicting Phenological Development In Winter Wheat, Qingwu Xue, Albert Weiss, P. Stephen Baenziger

Agronomy & 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 product ...


In-Season Prediction Of Attainable Maize Yield Using The Hybrid-Maize Model, Achim R. Dobermann, Haishun Yang, Kenneth G. Cassman, Daniel T. Walters Jan 2004

In-Season Prediction Of Attainable Maize Yield Using The Hybrid-Maize Model, Achim R. Dobermann, Haishun Yang, Kenneth G. Cassman, Daniel T. Walters

Agronomy & Horticulture -- Faculty Publications

The Hybrid-Maize Model

Real-time Simulation and Yield Forecasting

Case Study 1: Irrigated Maize, Lincoln, Nebraska

Case Study 2: Rainfed Maize, Oliveros, Argentina

Case Study 3: Rainfed Maize, Mead, Nebraska

Conclusions

References


Test Of The Hybrid-Maize Model For Simulation Of Soil Moisture Dynamics And Maize Response To Water Deficit, Haishun S. Yang, Achim R. Dobermann, Kenneth G. Cassman, Kenneth G. Hubbard, Timothy J. Arkebauer, Shashi Verma, Daniel T. Walters Jan 2004

Test Of The Hybrid-Maize Model For Simulation Of Soil Moisture Dynamics And Maize Response To Water Deficit, Haishun S. Yang, Achim R. Dobermann, Kenneth G. Cassman, Kenneth G. Hubbard, Timothy J. Arkebauer, Shashi Verma, Daniel T. Walters

Agronomy & Horticulture -- Faculty Publications

The Hybrid-Maize model (Yang et al, 2004), which has been validated under optimal water conditions, was evaluated for its ability to simulate soil moisture dynamics in the root zone and effects of water deficits on maize development and final yields (Fig. 1). The experimental data for this evaluation were obtained from ongoing field studies of the Carbon Sequestration Program (CSP) at the University of Nebraska. The studies include three cropping systems, each located in a quarter-section field (57 ha), two of which are irrigated by central-pivots and the third is rainfed. One irrigated field is in continuous maize and the ...


Expression Of A Putative Flavonoid 3'-Hydroxylase In Sorghum Mesocotyls Synthesizing 3-Deoxyanthocyanidin Phytoalexins, Jayanand Boddu, Catherine Svabek, Rajandeep Sekhon, Amanda Gevens, Ralph L. Nicholson, A. Daniel Jones, Jeffrey F. Pedersen, David L. Gustine, Surinder Chopra Jan 2004

Expression Of A Putative Flavonoid 3'-Hydroxylase In Sorghum Mesocotyls Synthesizing 3-Deoxyanthocyanidin Phytoalexins, Jayanand Boddu, Catherine Svabek, Rajandeep Sekhon, Amanda Gevens, Ralph L. Nicholson, A. Daniel Jones, Jeffrey F. Pedersen, David L. Gustine, Surinder Chopra

Agronomy & Horticulture -- Faculty Publications

In sorghum, ingress of Cochliobolus heterostrophus stimulates the synthesis of 3-deoxyanthocyanidins that act as phytoalexins. Apigeninidin and luteolinidin are two major phytoalexins induced in the first 24 h after infection. In an attempt to understand genetic regulation of the biosynthesis of sorghum phytoalexins, we isolated a differentially expressed partial cDNA. Characterization and comparison showed that this cDNA sequence corresponds to a putative flavonoid 3-hydroxylase. Full length sequence characterization allowed us to establish that the sorghum putative f3h cDNA encodes a peptide of 517 amino acids that has domains conserved among cytochrome P450 proteins functioning in the flavonoid biosynthetic ...


Using Multi-Spectral Imagery To Evaluate Corn Grown Under Nitrogen And Drought Stressed Conditions, Shannon L. Osborne, James S. Schepers, Mike R. Schlemmer Jan 2004

Using Multi-Spectral Imagery To Evaluate Corn Grown Under Nitrogen And Drought Stressed Conditions, Shannon L. Osborne, James S. Schepers, Mike R. Schlemmer

Agronomy & Horticulture -- Faculty Publications

The in-season estimation of crop stresses which have the potential of adversely affecting crop yield and/or quality could allow producers to make in-season management decisions to correct for the particular stress. A field study was conducted to evaluate the use of multispectral imagery for estimating corn (Zea mays L.) grain yield, in-season biomass and nitrogen (N) concentration under varying N and drought stresses. The experiment was a split-plot design with three replications using a factorial arrangement of treatments. Three irrigation (whole-plot) treatments included dry land, irrigation based on 0.5, and full evapotranspiration (ET). Sub-plot treatments included five ...


Molecular Mapping And Identification Of Soybean Fatty Acid Modifier Quantitative Trait Loci, D. L. Hyten Jr., Vincent R. Pantalone, Arnold M. Saxton, Michael E. Schmidt, Carl E. Sams Jan 2004

Molecular Mapping And Identification Of Soybean Fatty Acid Modifier Quantitative Trait Loci, D. L. Hyten Jr., Vincent R. Pantalone, Arnold M. Saxton, Michael E. Schmidt, Carl E. Sams

Agronomy & Horticulture -- Faculty Publications

Altering FA content in soybean [Glycine max (L.) Merr.] oil for improved functionality is a research goal of many soybean breeders. Several of the genes that alter palmitic, stearic, oleic, linoleic, and linolenic acids are modifier genes with small effects, causing these FA traits to act as quantitative traits. The objective of this study was to identify modifier FA quantitative trait loci (QTL) in soybean. A recombinant inbred line population was created from two prominent ancestors of currently avail-able U.S. cultivars (Essex and Williams) and grown in five environments. One hundred simple se-quence repeat markers spaced throughout the genome ...


Old-Field Grassland Successional Dynamics Following Cessation Of Chronic Disturbance, Susan Tunnell, David Engle, Eric Jorgensen Jan 2004

Old-Field Grassland Successional Dynamics Following Cessation Of Chronic Disturbance, Susan Tunnell, David Engle, Eric Jorgensen

Agronomy & Horticulture -- Faculty Publications

Question: Does increasing i>Festuca canopy cover reduce plant species richness and, therefore, alter plant community composition and the relationship of litter to species richness in old-field grassland?
Location: Southeastern Oklahoma, USA.
Methods: Canopy cover by species, species richness, and litter mass were collected within an old-field grassland site on 16, 40 m x &#;40 m plots. Our study was conducted during the first three years of a long-term study that investigated the effects of low-level nitrogen enrichment and small mammal herbivory manipulations.
Results: Succession was altered by an increase in abundance of Festuca over the 3-yr study period. Species ...


Windbreaks In North American Agricultural Systems, James R. Brandle, Laurie Hodges, Xinhua H. Zhou Jan 2004

Windbreaks In North American Agricultural Systems, James R. Brandle, Laurie Hodges, Xinhua H. Zhou

Agronomy & Horticulture -- Faculty Publications

Windbreaks are a major component of successful agricultural systems throughout the world. The focus of this chapter is on temperate-zone, commercial, agricultural systems in North America, where windbreaks contribute to both producer profitability and environmental quality by increasing crop production while simultaneously reducing the level of off-farm inputs. They help control erosion and blowing snow, improve animal health and survival under winter conditions, reduce energy consumption of the farmstead unit, and enhance habitat diversity, providing refuges for predatory birds and insects. On a larger landscape scale windbreaks provide habitat for various types of wildlife and have the potential to contribute ...


Distribution Of Legumes Along Gradients Of Slope And Soil Electrical Conductivity In Pastures, John A. Guretzky, Kenneth J. Moore, C. Lee Burras, E. Charles Brummer Jan 2004

Distribution Of Legumes Along Gradients Of Slope And Soil Electrical Conductivity In Pastures, John A. Guretzky, Kenneth J. Moore, C. Lee Burras, E. Charles Brummer

Agronomy & Horticulture -- Faculty Publications

Legumes establish and persist on backslope landscape positions but fail on summits and toeslopes in southeastern Iowa pastures, suggesting that these pastures be managed site specifically. Visual delineation of landscape positions, however, can be difficult, and char- acterization of spatial variability through soil sampling is expensive. Creation of digital elevation models (DEM) and apparent soil electrical conductivity (ECa) mapping are inexpensive alternatives to de- scribing field conditions. Our objective was to examine the relationships of DEM-derived slope, soil ECa, and legume distribution in pastures.We examined these relationships across four 1.4-ha pastures. Each pasture was divided into ...