Life Sciences Commons^™

Crop And Soil Productivity Response To Corn Residue Removal: A Literature Review, Wallace Wilhelm, J.M.F. Johnson, J. L. Hatfield, W.B. Voorhees, D.R. Linden

Department of Agronomy and Horticulture: Faculty Publications

Society is facing three related issues: over-reliance on imported fuel, increasing levels of greenhouse gases in the atmosphere, and producing sufficient food for a growing world population. The U.S. Department of Energy and private enterprise are developing technology necessary to use high-cellulose feedstock, such as crop residues, for ethanol production. Corn (Zea mays L.) residue can provide about 1.7 times more C than barley (Hordeum vulgare L.), oat (Avena sativa L.), sorghum [Sorghum bicolor (L.) Moench], soybean [Glycine max L.) Merr.], sunflower (Helianthus annuus L.), and wheat (Triticum aestivum L.) residues based on …

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

Department of Agronomy and 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

Department of Agronomy and 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 …

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

Department of Agronomy and 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.

Emergence And Survival Of Legumes Seeded Into Pastures Varying In Landscape Position, John A. Guretzky, Kenneth J. Moore, Allen D. Knapp, E. Charles Brummer

Department of Agronomy and Horticulture: Faculty Publications

Landscape position affects legume establishment in pastures. We conducted this study to (i) determine the role of emergence and survival on establishment of legumes on summit and backslope positions and (ii) examine how competition, as influenced by sward-cutting height and N fertilization, affects legume emergence and survival across these positions. We no-till drilled a mixture composed of red clover (Trifolium pratense L.), alfalfa (Medicago sativa L.), and birdsfoot trefoil (Lotus corniculatus L.) into an existing cool-season grass pasture at Rhodes, IA, in 1998 and 1999. Treatments consisted of landscape positions (summit and backslope), N fertilizer rates (0, …

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

Department of Agronomy and 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 (EC_a) mapping are inexpensive alternatives to de- scribing field conditions. Our objective was to examine the relationships of DEM-derived slope, soil EC_a, and legume distribution in pastures.We examined these relationships across four 1.4-ha pastures. Each pasture was divided into …

Registration Of Npm-4, A Dwarf White Grain Pearl Millet Germplasm, J.F. Rajewski, D.J. Andrews, Ismail M. Dweikat

Department of Agronomy and Horticulture: Faculty Publications

Dwarf grain pearl millet [Pennisetum glucum (L.) R. Br.] germplasm NPM-4 (Reg. no. GP-37, PI 634545) was released in September 2003 by the Institute of Agriculture and Natural Resources, University of Nebraska, Lincoln, NE.

NPM-4 was derived from open-pollinated outcrosses of white grain inbred line 57028R1w grown in a 1998 Puerto Vallarta winter nursery. The source of the outcross pollen was from primarily genetically diverse, dwarf, early maturing, gray seeded lines being developed as parents for grain yield. Line 57028R₁w was derived from 89C57028R₁/3*90PV0121. Line 89C57028R₁ is gray-seeded, and line 90PV0121 has white seed. …

Genotypic And Environmental Modification Of Asian Noodle Quality Of Hard Winter Wheats, Robert A. Graybosch, N. Ames, P. Stephen Baenziger, C. J. Peterson

Department of Agronomy and Horticulture: Faculty Publications

The relative effects of environment, genotype, and their interactions on the modification of Asian noodle quality attributes were assessed using 38 winter wheat (Triticum aestivum L.) cultivars and breeding lines grown in replicated trials at three Nebraska locations in harvest year 2000. Noodle color was determined in both white salted and yellow alkaline procedures, and noodle textural features were investigated by producing white salted noodles. Significant environmental, genotypic, and genotype-by-environment variation was observed for nearly all initial and 24-hr noodle color traits in both types of noodles. Significant genotypic effects were observed for several textural traits, while significant environmental …

Implementation Of A Mitochondrial Mutator, Sally Mackenzie, Ricardo Vilela Abdelnoor

Department of Agronomy and Horticulture: Faculty Publications

Plant MSH1 polynucleotides and polypeptides are described. Also described are methods for the use and modulation of such MSH1 polynucleotides and polypeptides.

Soil Organic Carbon Content And Composition Of 130-Year Crop, Pasture And Forest Land-Use Managements, Dean A. Martens, Thomas E. Reedy, David T. Lewis (Retired)

Department of Agronomy and Horticulture: Faculty Publications

Conversion of former agricultural land to grassland and forest ecosystems is a suggested option for mitigation of increased atmospheric CO₂. A Sharpsburg prairie loess soil (fine, smectitic, mesic Typic Argiudoll) provided treatments to study the impact of long-term land use on soil organic carbon (SOC) content and composition for a 130-year-old cropped, pasture and forest comparison. The forest and pasture land use significantly retained more SOC, 46% and 25%, respectively, compared with cropped land use, and forest land use increased soil C content by 29% compared with the pasture. Organic C retained in the soils was a function …

Meeting Cereal Demand While Protecting Natural Resources And Improving Environmental Quality, Kenneth G. Cassman, Achim R. Dobermann, Daniel T. Walters, Haishun Yang

Department of Agronomy and Horticulture: Faculty Publications

Agriculture is a resource-intensive enterprise. The manner in which food production systems utilize resources has a large influence on environmental quality. To evaluate prospects for conserving natural resources while meeting increased demand for cereals, we interpret recent trends and future trajectories in crop yields, land and nitrogen fertilizer use, carbon sequestration, and greenhouse gas emissions to identify key issues and challenges. Based on this assessment, we conclude that avoiding expansion of cultivation into natural ecosystems, increased nitrogen use efficiency, and improved soil quality are pivotal components of a sustainable agriculture that meets human needs and protects natural resources. To achieve …

Soybean Nitrogen Contribution To Corn And Sorghum In Western Corn Belt Rotations, Gary E. Varvel, Wallace Wilhelm

Department of Agronomy and Horticulture: Faculty Publications

Increased N availability is often associated with the beneficial effects of rotating grain and legume crops. Our objective was to utilizeyield response data from two long-term studies to determine the amount of N supplied by soybean [Glycine max (L.) Merr.] for subsequent nonlegume crops in 2-yr rotations. The experiments were located in eastern Nebraska (Mead) (rainfed) and central Nebraska (Shelton) (irrigated). Continuous corn (Zea mays L.) and soybean–corn cropping systems were present in both experiments while continuous sorghum [Sorghum bicolor (L.) Moench] and soybean–sorghum cropping systems were present at Mead only. Three N fertilizer rates were used …

Grazing Management: Summer Grazing Strategies Following Early-Season Grazing Of Big Bluestem, Eric M. Mousel, Walter H. Schacht, Lowell E. Moser

Department of Agronomy and Horticulture: Faculty Publications

Big bluestem (Andropogon gerardii Vitman) has a rapid growth phase that begins in early to mid-June in eastern Nebraska. During this rapid growth phase, rate of biomass accumulation exceeds intake rate of grazing livestock, resulting in low levels of harvest efficiency. To delay the rapid growth phase, big bluestem pasture can be grazed in mid- to late May without affecting herbage yields for the remainder of the growing season. A pasture experiment was conducted in 1999, 2000, and 2001 near Mead, NE. The objective was to determine the effect of timing and frequency of grazing big bluestem pasture, …

Evaluating Shootgro 4.0 As A Potential Winter Wheat Management Tool In The Czech Republic, Z. Zalud, G.S. Mcmaster, Wallace Wilhelm

Department of Agronomy and Horticulture: Faculty Publications

Improving current cultural practices often involves more precise timing of the management activity based on crop development. Using crop simulation models to predict crop development and phenology has several problems. First, most existing models do not simulate sufficient developmental and phenological detail required to optimize selected management practices. Second, crop models normally emphasize the cultivars and conditions for the region in which they were developed, and may not generate satisfactory results when applied in new regions. Lastly, when users apply these models to new regions they often lack the specific data and knowledge of the model to adequately determine the …

Divergent Selection For Seedling Tiller Number In Big Bluestem And Switchgrass, Alexander J. Smart, Kenneth P. Vogel, Lowell E. Moser, Walter W. Stroup

Department of Agronomy and Horticulture: Faculty Publications

Selection at the seedling stage in forage grass breeding would be extremely useful if seedling traits are highly heritable and correlated to desired agronomic traits. Objectives of this study were to determine the response to selection for high shoot weight and divergent selection or seedling tiller number in big bluestem (Andropogon gerardii Vitman) and switchgrass (Panicum virgatum L.) seedlings and obtain estimates of realized heritability for these traits. Base populations were breeding populations of ‘Pawnee’ big bluestem and ‘Pathfinder’ switchgrass. Divergent selection for single or multiple (three or more) tiller(s) 6 to 8 wk after planting in a …

Establishment And Seedling Growth Of Big Bluestem And Switchgrass Populations Divergently Selected For Seedling Tiller Number, Alexander J. Smart, Lowell E. Moser, Kenneth P. Vogel

Department of Agronomy and Horticulture: Faculty Publications

Selection at the seedling stage in grass breeding would be extremely useful if seedling traits are correlated to desired agronomic traits. The objective of this study was to evaluate seedling morphological development, plant growth, and field establishment of big bluestem (Andropogon gerardii Vitman) and switchgrass (Panicum virgatum L.) populations that were developed by divergent selection for seed- ling tiller number while selecting for high shoot weight. Six populations were evaluated: (i) ‘Pawnee’ big bluestem base, (ii) ‘Pathfinder’ switchgrass base, (iii) big bluestem multiple tiller, (iv) big bluestem single tiller, (v) switchgrass multiple tiller, and (vi) switchgrass single tiller. …

Spatial And Temporal Variability Of Soil Nitrate And Corn Yield: Multifractal Analysis, Bahman Eghball, James S. Schepers, Mehrdad Negahban, Michael R. Schlemmer

Department of Agronomy and Horticulture: Faculty Publications

High levels of residual soil NO ₃–N can contaminate ground water by leaching through the soil. Our objective was to reduce the level and spatial variability of residual soil NO ₃–N while maintaining optimum corn (Zea mays L. ) production by variable rate N fertilizer application. The experiment was located on a 60-ha sprinkler-irrigated corn field in central Nebraska and included four N management practices: uniform rate, variable rate (VRAT), variable rate at 75% of recommended amount (VRAT + 75%), and variable rate plus 10% (VRAT + 10%). VRAT + 75% decreased the amount of residual NO …

Identification Of Qtls And Environmental Interactions Associated With Agronomic Traits On Chromosome 3a Of Wheat, B. T. Campbell, P. Stephen Baenziger, K. S. Gill, Kent M. Eskridge, H. Budak, M. Erayman, Ismail M. Dweikat, Y. Yen

Department of Agronomy and Horticulture: Faculty Publications

Genetic analyses of complex traits in wheat (Triticum aestivum L.) are facilitated by the availability of unique genetic tools such as chromosome substitution lines and recombinant inbred chromosome lines (RICLs) which allow the effects of genes on a single chromosomes to be studied individually. Chromosome 3A of ‘Wichita’ is known to contain alleles at quantitative trait loci (QTLs) that influence variation in grain yield and agronomic performance traits relative to alleles of ‘Cheyenne.’ To determine the number, location, and environmental interactions of genes related to agronomic performance on chromosome 3A, QTL and QTL x environment analyses of 98 RICLs-3A …

Tagging And Mapping Of Genes And Qtl And Molecular Marker-Assisted Selection For Traits Of Economic Importance In Bean And Cowpea, J. D. Kelly, P. Gepts, P. N. Miklas, D. P. Coyne

Department of Agronomy and Horticulture: Faculty Publications

Bean/Cowpea Collaborative Research Support Program (B/C CRSP) scientists have successfully developed integrated consensus maps of the 11 linkage groups (LGs) in both bean (Phaseolus vulgaris L.) and cowpea (Vigna unguiculata L. Walp). The bean map is approximately 1200 cM with some 500 markers and an additional 500 markers shared with other bean maps. The cowpea map spans 2670 cM with over 400 markers. In addition to molecular markers, both maps include map locations of defense genes and phenotypic traits for disease and insect resistance, seed size, color and storage proteins, pod color and those traits associated with the …

Development Of A Procedure For Sustainable In Situ Aquifer Denitrification, Imtiyaz A. Khan, Roy F. Spalding

Department of Agronomy and Horticulture: Faculty Publications

Denitrification experiments have provided data showing the pitfalls and successes in developing a sustainable injection/extraction system in a sand and gravel aquifer. Experiments increase in complexity from continuous injection at one well to automated-pulsed eight well injections. In both continuous and pulsed injection of organic carbon, 40 mg NO_3-N l^–1 was reduced below the detection limit of < 0.1 mg NO_3-N l^–1 in the denitrification zones. Under continuous injection, accumulation of bacterial exudates in the vicinity of the injection well resulted in injection well clogging within ten days. Periodic cleaning of the injection well and the adjacent …

An Evaluation Of Four Crop : Weed Competition Models Using A Common Data Set, W. Deen, R. Cousens, J. Warringa, L. Bastiaans, P. Carberrys, K. Rebel, S. Riha, C. Murphy, L. R. Benjamin, C. Cloughley, J. Cussans, F. Forcella, T. Hunt, P. Jamieson, John Lindquist, E. Wangs

Department of Agronomy and Horticulture: Faculty Publications

To date, several crop : weed competition models have been developed. Developers of the various models were invited to compare model performance using a common data set. The data set consisted of wheat and Lolium rigidum grown in monoculture and mixtures under dryland and irrigated conditions. Results from four crop : weed competition models are presented: ALMANAC, APSIM, CROPSIM and INTERCOM. For all models, deviations between observed and predicted values for monoculture wheat were only slightly lower than for wheat grown in competition with L. rigidum, even though the workshop participants had access to monoculture data while parameterizing models. …

Spatial And Temporal Variability Of Soil Nitrate And Corn Yield: Multifractal Analysis, Bahman Eghball, James S. Schepers, Mehrdad Negahban, Michael R. Schlemmer

Department of Agronomy and Horticulture: Faculty Publications

High levels of residual soil NO₃–N can contaminate ground water by leaching through the soil. Our objective was to reduce the level and spatial variability of residual soil NO₃–N while maintaining optimum corn (Zea mays L.) production by variable rate N fertilizer application. The experiment was located on a 60-ha sprinkler-irrigated corn field in central Nebraska and included four N management prac- tices: uniform rate, variable rate (VRAT), variable rate at 75% of recommended amount (VRAT @ 75%), and variable rate plus 10% (VRAT + 10%). VRAT @ 75% decreased the amount of residual NO …

Mapping The Fas Locus Controlling Stearic Acid Content In Soybean, M. M. Spencer, V. R. Pantalone, E. J. Meyer, D. Landau-Ellis, D. L. Hyten Jr.

Department of Agronomy and Horticulture: Faculty Publications

Increasing the stearic acid content to improve soybean [Glycine max (L) Merr] oil quality is a desirable breeding objective for food-processing applications. Although a saturated fatty acid, stearic acid has been shown to reduce total levels of blood cholesterol and offers the potential for the production of solid fat products (such as margarine) without hydrogenation. This would result in the reduction of the level of trans fat in food products and alleviate some current health concerns. A segregating F₂ population was developed from the cross between Dare, a normal stearic acid content cultivar, and FAM94-41, a high stearic …

Registration Of Rn582 Sorghum Germplasm Line, J. F. Pedersen, J. J. Toy

Department of Agronomy and Horticulture: Faculty Publications

RN582 sorghum [Sorghum bicolor (L.)Moench] germplasm line (Reg. no. GP-591, PI 628277) was developed jointly by the USDA-ARS and the Agricultural Research Division, Institute of Agriculture and Natural Resources, University of Nebraska, and was released in September 2001.

RN582 is an S₆ selection from the cross (RTx430 ms₃ms₃X E 35-1) X E 35-1. RTx430 was developed and released by the Texas Agricultural Experiment Station (Miller, 1984) and was provided to this project containing the nuclear male sterility gene ms₃ by A.B. Maunder in 1988. E 35-1 is an Ethiopian land race with white …

Reduction Of High Soil Test Phosphorus By Corn And Soybean Varieties, Bahman Eghball, J.F. Shanahan, Gary E. Varvel, John Gilley

Department of Agronomy and Horticulture: Faculty Publications

Soils with high levels of P can contribute to excess P in runoff and subsequently pollute the surface water. Excess P in the soil can be removed from the system by harvesting crops. The objectives of this study were to evaluate corn (Zea mays L.) P removal effects on soil P reduction, and to evaluate various corn hybrids and soybean [Glycine max (L.) Merr.] varieties for differences in grain P concentration and P removal. Soil with varying P levels as a result of annual or biennial beef cattle (Bos taurus) feedlot manure or compost appli- enough …

Single-Nucleotide Polymorphisms In Soybean, Y. L. Zhu, Q. J. Song, D. L. Hyten, C. P. Van Tassel, L. K. Matukumalli, D. R. Grimm, S. M. Hyatt, E. W. Fickus, N. D. Young, P. B. Cregan

Department of Agronomy and Horticulture: Faculty Publications

Single-nucleotide polymorphisms (SNPs) provide an abundant source of DNA polymorphisms in a number of eukaryotic species. Information on the frequency, nature, and distribution of SNPs in plant genomes is limited. Thus, our objectives were (1) to determine SNP frequency in coding and noncoding soybean (Glycine max L. Merr.) DNA sequence amplified from genomic DNA using PCR primers designed to complete genes, cDNAs, and random genomic sequence; (2) to characterize haplotype variation in these sequences; and (3) to provide initial estimates of linkage disequilibrium (LD) in soybean. Approximately 28.7 kbp of coding sequence, 37.9 kbp of noncoding perigenic DNA, and …

Understanding Corn Yield Potential In Different Environments, Achim R. Dobermann, Timothy J. Arkebauer, Kenneth G. Cassman, Rhae A. Drijber, J. Lindquist, James E. Specht, Daniel T. Walters, Haishun Yang, D. Miller, Darren L. Binder, Gregory Teichmeier, Richard B. Ferguson, Charles S. Wortmann

Department of Agronomy and Horticulture: Faculty Publications

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 …

Effects Of Western Corn Belt Cropping Systems On Agroecosystem Functions, Mark Liebig, Gary E. Varvel

Department of Agronomy and Horticulture: Faculty Publications

Agricultural sustainability is enhanced by management practices that optimize the performance of multiple agroecosystem functions. The performance of western Corn Belt cropping systems was evaluated based on four agroecosystem functions: food production, raw materials production, nutrient cycling, and greenhouse gas regulation. A simple multiattribute ranking procedure was used to quantify agroecosystem performance using data from a long-term cropping systems experiment near Mead, NE. Treatments included in the procedure were continuous corn (Zea mays L.) (CC), corn–soybean [Glycine max (L.) Merr.] (C–SB), corn–oat (Avena sativa L.) _ clover [80% sweet clover (Melilotus officinalis L.) and 20% red …

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

Department of Agronomy and Horticulture: Faculty Publications

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 …

Nitrogen Application Influences The Critical Period For Weed Control In Corn, Sean P. Evans, Stevan Z. Knezevic, John L. Lindquist, Charles A. Shapiro, Erin E. Blankenship

Department of Agronomy and Horticulture: Faculty Publications

The critical period for weed control (CPWC) is the period in the crop growth cycle during which weeds must be controlled to prevent unacceptable yield losses. Field studies were conducted in 1999 and 2000 in eastern Nebraska to evaluate the influence of nitrogen application on the CPWC in dryland corn in competition with a naturally occurring weed population. Nitrogen fertilizer was applied at rates equivalent to 0, 60, and 120 kg N ha^-1. A quantitative series of treatments of both increasing duration of weed interference and length of weed-free period were imposed within each nitrogen main plot. The …