Agricultural Science Commons^™

Review And Interpretation: Nitrogen Management Strategies To Reduce Nitrate Leaching In Tile-Drained Midwestern Soils, Dana L. Dinnes, Douglas L. Karlen, Dan B. Jaynes, Thomas C. Kaspar, Jerry L. Hatfield, Thomas S. Colvin, Cynthia A. Cambardella

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Balancing the amount of N needed for optimum plant growth while minimizing the NO₃ that is transported to ground and surface waters remains a major challenge for everyone attempting to understand and improve agricultural nutrient use efficiency. Our objectives for this review are to examine how changes in agricultural management practices during the past century have affected N in Midwestern soils and to identify the types of research and management practices needed to reduce the potential for nonpoint NO₃ leakage into water resources. Inherent soil characteristics and management practices contributing to nonpoint NO₃ loss from Midwestern soils, …

Molecular Cloning, Functional Characterization, And Subcellular Localization Of Soybean Nodule Dihydrolipoamide Reductase, Jose F. Moran, Zhaohui Sun, Gautam Sarath, Raul Arredondo-Peter, Euan K. James, Manuel Becana, Robert V. Klucas

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Nodule ferric leghemoglobin reductase (FLbR) and leaf dihydrolipoamide reductase (DLDH) belong to the same family of pyridine nucleotide-disulfide oxidoreductases. We report here the cloning, expression, and characterization of a second protein with FLbR activity, FLbR-2, from soybean (Glycine max) nodules. The cDNA is 1,779 bp in length and codes for a precursor protein comprising a 30-residue mitochondrial transit peptide and a 470-residue mature protein of 50 kD. The derived protein has considerable homology with soybean nodule FLbR-1 (93% identity) and pea (Pisum sativum) leaf mitochondria DLDH (89% identity). The cDNA encoding the mature protein was overexpressed …

Continuous Production Of Extracellular Antioxidants In Suspension Cells Attenuates The Oxidative Burst Detected In Plant Microbe Interactions, C. Jacyn Baker, Nichole R. O'Neil, Kenneth Deahl, John Lydon

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Suspension cells of Solanacearum tuberosum and Nicotiana tabacum placed in fresh buffer rapidly produce and maintain significant pools of extracellular antioxidants. The extracellular antioxidant was detected by first adding a known amount of exogenous H₂O₂ to samples and then immediately measuring the remaining H₂O₂. The difference between the amount added and amount remaining was used to determine the antioxidant capacity of the sample. This extracellular antioxidant pool attenuates levels of hydrogen peroxide produced during plant–bacterial interactions. When tobacco cells were inoculated with an isolate Pseudomonas syringae pv. syringae that causes a hypersensitive response …

Effect Of Habitat Depth On Host Location By Five Species Of Parasitoids (Hymenoptera: Pteromalidae, Chalcididae) Of House Flies (Diptera: Muscidae) In Three Types Of Substrates, Christopher Geden

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Four species of pteromalid parasitoids [Muscidifurax raptor Girault & Sanders, Spalangia cameroni Perkins, Spalangia endius Walker, Spalangia gemina Boucek, and the chalcidid Dirhinus himalayanus (Masi)] were evaluated for their ability to locate house fly pupae at various depths in poultry manure (41% moisture), fly rearing medium (43% moisture), and sandy soil (4% moisture) from a dairy farm. Searching activity in manure was largely confined to the surface (M. raptor, D. himalayanus, and S. gemina) or to depths of up to 2 cm below the surface (S. endius, S. cameroni). S. cameroni was the …

Strategies For Controlling House Fly Populations Resistant To Cyromazine, Diana C. Crespo, Roberto E. Lecuona, Jerome Hogsette

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The objectives of this study were to compare, from both biological and economic viewpoints, the impact of various control strategies and evaluate their effect on cyromazine-resistant Musca domestica L., and beneficial house fly pupal parasitoids on caged-layer farms (240,000 hens) in Argentina. The strategies evaluated were: chemical, chemical + cultural, and chemical + cultural + biological (integrated management). The products used were: cyromazine 1% and 50%, DDVP, azamethiphos with and without z-9-tricosene, lime, and the parasitoids Spalangia endius Walker and Muscidifurax raptor Girault & Sanders. In the absence of control measures, fly density increased quickly and the average parasitism rate …

An Innovative Soil Test For Predicting Nitrogen Mineralization, F. M. Hons, R. L. Haney, A J. Franzluebbers

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

A routine soil testing procedure for soil N mineralization is needed that is rapid and precise. Not accounting for N mineralization can result in over application of N, especially in soils with a history of manure application. Our objectives were to compare results from a recently proposed rapid lab procedure with i) long-term N mineralization under standard laboratory conditions, ii) actual forage N uptake from soil receiving dairy cattle (Bas taurus) manure in a two-year field study and iii) yields of various crops throughout Texas and Oklahoma. The rapid procedure is based on the quantity of CO_{2 …}

Soil Carbon, Nitrogen Use, And Water Use Affected By Rotation In The Northern Corn Belt, Joseph L. Pikul Jr., Thomas E. Schumacher, Merle Vigil, Walter E. Riedell

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Diversified crop rotation may improve production efficiency, reduce fertilizer nitrogen (N) requirements for com (Zea mays L.) and increase soil carbon (C) storage. Objectives were to determine effect of rotation and fertilizer N on soil C sequestration, water use, and N use. An experiment was started in 1990 on a Barnes clay loam (fine-loamy, mixed, superactive, frigid Calcic Hapludoll) near Brookings, South Dakota. Primary tillage on all rotations was with a chisel plow. Rotations were continuous com (CC), com-soybean [Glycine max (L.) Merr.] (CS) and a 4-year rotation of corn-soybean-wheat (Triticum aestivum L.) companion seeded with alfalfa …

Stomatal Acclimation Over A Subambient To Elevated Co2 Gradient In A C3/C4 Grassland, H. Maherali, C. D. Reid, H. W. Polley, H. B. Johnson, R. B. Jackson

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

An investigation to determine whether stomatal acclimation to [CO₂] occurred in C₃/C₄ grassland plants grown across a range of [CO₂] (200–550 μmol mol⁻¹) in the field was carried out.

Woody Invasion Of Grasslands: Evidence That Co2 Enrichment Indirectly Promotes Establishment Of Prosopis Glandulosa, H. Wayne Polley, Hyrum B. Johnson, Charles R. Tischler

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Grasslands worldwide have been invaded by woody species during the last 200 years. Atmospheric CO₂ enrichment may indirectly have facilitated invasion by reducing soil water depletion by grasses.

Soil Health And Global Sustainability: Translating Science Into Practice, John W. Doran

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Interest in the quality and health of soil has been stimulated by recent awareness that soil is vital to both production of food and fiber and global ecosystems function. Soil health, or quality, can be broadly defined as the capacity of a living soil to function, within natural or managed ecosystem boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality, and promote plant and animal health. Soil quality and health change over time due to natural events or human impacts. They are enhanced by management and land-use decisions that weigh the multiple functions of soil …

Soil Health As An Indicator Of Sustainable Management, John W. Doran, Stamatis Stamatiadis, John Haberern

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Population growth, a widening gap between the rich and poor, environmental degradation, and a re-evaluation of energy use and alternatives will shape life in the 21st century. We will be challenged to increase food supplies for a global population one-and-a-half to two times its current size. But as agricultural systems grow to meet the demands of more people, increased pressure will be placed on our natural resources: competition for land, water and energy resources from both urban and industrial sectors becomes more acute and the available land base remains static or shrinks. Under current practices increased food production will greatly …

Impact Of Egg Storage On Embryo Development, M. R. Bakst, V. Akuffo

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

1. New information is introduced and other information reviewed regarding the impact of egg storage on the integrity of the avian embryo.

2. Morphologically, the blastoderm from an egg which has been stored more than 10 days is often asymmetrical and may have an attenuated appearance.

3. Fresh egg breakouts coupled with the perivitelline layer sperm-hole determination procedure provide detailed information on the male's contribution to overall fertility.

4. The biological basis for embryonic mortality in eggs stored for longer than 10 days remains the subject of speculation.

Recycled Paper Products As Substitutes For Gelling Agent In Screwworm (Diptera: Calliphoridae) Larval Diet, M. F. Chaudhury, L. Alfredo Alvarez, L. Lopez Velazquez

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Absorbent recycled paper products were tested and compared with a sodium polyacrylate gelling agent, Aquatain, for solidifying larval diets of the screwworm, Cochliomyia hominivorax (Coquerel). A recycled newsprint product, Terra-Mulch, when mixed with water and dietary ingredients produced a diet medium of homogeneous texture that supported larval growth and development comparable to the standard diet prepared with the gelling agent. Biological yields as calculated from number of pupae per tray from both the diets were similar. Three other types of recycled paper products were tested. Although less homogeneous in texture, these diets were as good as the diet with Terra-Mulch. …

Biomass And Nitrogen Traits Of Summer Pigeon Peas And Winter Wheat Grown For Three Rotations In Containers, Srinivas C. Rao, Charles T. Mackown, James E. Bidlack

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Pigeon pea [Cajanus cajan (L.) Millsp.] cultivars, ‘Georgia-1’ and ‘ICPL-87’, were grown without inoculation and with Bradyrhizobium inoculation (multistrain, TAL 1127, or TAL 1132) to evaluate legume dry weight (DW) and nitrogen (N) content, soil mineral N, and subsequent wheat (Triticum aestivum L.) productivity. Pigeon peas were grown during summer and ‘TAM 101’ wheat was grown during winter, along with summer fallow controls fertilized with 0, 45, and 90 kg N ha^-1, in 36-cm diam. 20-L pots from 1992 to 1995. Representative pigeon peas were harvested in the fall and remaining plants were incorporated into the …

Growing Rice Grain With Controlled Cadmium Concentrations, Urszula Kukier, Rufus L. Chaney

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Two solution studies were conducted a) to investigate the uptake of zinc (Zn) and cadmium (Cd) by rice plants (Oryza sativa L.) and interaction between these elements, and b) to determine experimental conditions for growing rice grain with desired Cd concentration for an animal feeding study. In both studies, free metal activities of cadmium and cationic microelements were buffered by an excess of chelating agents. The first study was a factorial design with two Zn levels (1.0 and 3.89 μM) and four Cd levels (0.81, 1.44, 2.56 and 4.55 μM) in the solution. In the second study, rice was …

Kura Clover And Birdsfoot Trefoil Response To Soil Ph, L. R. Dehaan, M. P. Russelle, C. C. Sheaffer, N. J. Ehlke

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Use of the rhizomatous perennial forage legume kura clover (Trifolium ambiguum M. Bieb.) has been limited by slow establishment. Mature kura clover responds to liming on some acid soils, but the soil pH required for vigorous growth of young plants is unknown. A factorial greenhouse experiment was conducted with two kura clover cultivars (Rhizo and Endura) and one cultivar of birdsfoot trefoil (Lotus corniculatus L., Norcen) planted in three soil types (Sartell loamy fine sand, Hubbard loamy sand, and Sanborg clay loam) amended with Ca(OH)₂ to obtain six soil pH levels. The experiment was performed twice, once …

Quantifying Laboratory And Field Variability To Assess Potential For Carbon Sequestration, R. A. Bowman, J. D. Reeder, B. J. Wienhold

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Accurate measurements of soil organic carbon (SOC) levels are essential to assess changes in C sequestration rates. To this end we conducted studies to evaluate laboratory variability in SOC concentration measured at USDA-ARS laboratories in Akron, CO, Cheyenne,WY, and Lincoln, NE. At the Akron laboratory we also evaluated field spatial variability within common cropping treatments in order to assess the potential to quantify significant changes in SOC content associated with rotations of varying cropping intensities. Our data showed very low coefficients of variation for SOC values from each of the three laboratories, and the same average SOC values for soils …

Use Of Nonsettable Eggs To Evaluate Turkey Hen Fertility, M. R. Bakst, S. Mcgary, I. Estevez, T. Knapp

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The use of nonsettable eggs (checked, cracked) to perform fresh egg breakouts to estimate true fertility and to assess the rate of sperm penetration of the perivitelline layer overlying the germinal disc was evaluated. Germinal discs and the perivitelline layer overlying the germinal disc were accessible for assessments. The stage of blastodermal development positively correlated (r = 0.65, P < 0.0001) with eggshell thickness. It was also determined that the perivitelline layer of nonsettable eggs could be isolated and stained to determine the presence or absence of sperm holes. True fertility of nonsettable eggs (checked and cracked only) and settable eggs was 90 and 95%, respectively. It was concluded that checked and cracked eggs could be used to estimate the true fertility of a flock.

Phenotypic Traits As Reliable Indicators Of Fertility In Male Broiler Breeders, S. Mcgary, I. Estevez, M. R. Bakst, D. L. Pollock

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Genetic selection procedures applied to improve broiler performance may negatively impact the subsequent reproductive efficiency of breeders, particularly in males. Identification of traits that reliably indicate individual male fertility would facilitate selection for reproduction. We hypothesized that physical traits, such as comb area, relative testicular weight, and testicular weight asymmetry, may correlate with fertility in two male-selected primary broiler breeder strains (A and B). Thirty males per strain, individually housed with an average of 10 females, were evaluated at five age periods within the 30-to-50-wk breeding cycle. Flock fertility by candling eggs at Day 19 of incubation and sample fertility …

Mutual Interference Of Pheromone Traps Within Trap Lines On Captures Of Boll Weevils (Coleoptera: Curculionidae), Thomas W. Sappington

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Traps baited with the synthetic aggregation pheromone of the boll weevil (Anthonomus grandis Boheman) are often used to monitor population fluctuations, distribution, and behavior. However, many factors generate variability in daily captures, making interpretation of trapping data difficult. Previous studies have shown that wind speed in the microenvironment around a trap can greatly affect numbers captured on a given day. It is possible that variation in air movement may also generate variation in trap captures through its effects on the pheromone plume. The current study was conducted to determine whether five traps placed in a line at two commonly …

Nitrogen Fertilization Of Irrigated Corn In A High Residual Soil N Environment In The Arkansas River V Alley, Ardell D. Halvorson, Frank Schweissing, Curtis Reule

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

High levels of residual soil NO₃-N are present in the soils in the Arkansas River Valley where melons and other vegetable crops are produced. The amount of N fertilizer required to optimize the yield potential of crops, such as corn, following vegetables needs to evaluated to reduce NO₃-N leaching potential in the Valley where high NO₃-N levels have been reported in the ground water. This study evaluated the effects of N fertilizer rate (0, 50, 100, 150, 200, and 250 lb N/a) and N source (urea and Polyon®³) on corn yields following …

One Plus One Equals Three: The Synergistic Effects Of Crop Rotation On Soil Fertility And Plant Nutrition, Walter E. Riedell, Joseph L. Pikul Jr., Lynne Carpenter-Boggs

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Corn grown under annual corn-soybean crop rotation has greater accumulation of certain mineral nutrients and higher yields than corn grown in monoculture. This study was conducted to determine if complex crop rotations (with legumes in the rotation as alfalfa hay as well as soybean row crops) and different levels of agriculture chemical input affect soil fertility and corn mineral nutrient composition. The effects of crop rotation [monoculture corn, corn-soybean 2-yr rotation, corn-soybean- wheat underseeded with alfalfa-alfalfa 4-yr rotation] and input level [high input (fertilizer application for 8.15 Mg ha^-1 yield goal, prophylactic herbicide and insecticide application, fall moldboard plow/spring …

Mineralization Of N In Swine Manure Amended Soils As A Function Of Soil Temperature, Moisture, And Texture, Brian J. Wienhold, Bahman Eghball

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Manure can serve as an effective fertilizer source if used properly or can lead to environmental contamination if used improperly. Proper use of manure requires some know ledge of the availability of nutrients contained in the manure. To better understand how soil and environmental variables effect N mineralization in manure amended soils a laboratory study was conducted to measure N-mineralization rates as a function of soil texture, water regime, and temperature. This study is part of a national effort to develop a model to predict nutrient availability from various manure sources across a range of soil and environmental conditions. There …

A Personal Account Of Creating The Sterile Insect Technique To Eradicate The Screwworm From Curacao, Florida And The Southeastern United States, Alfred H. Baumhover

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The history is recounted of developing the sterile insect technique to eradicate the screwworm, Cochliomyia hominivorax (Coquerel), from the Caribbean island of Curacao, Florida and the southeastern U.S. Observations of screwworm biology and challenges faced in conducting these eradication projects are described by the author who worked on all aspects of the research and field operations. Eradication was first demonstrated on Curacao, essentially a 170 mi² outdoor laboratory. The population dynamics of the wild screwworm was determined and overflooding ratios and dispersal patterns essential for population suppression were defined. Eradication was achieved with minimal resources by attacking the pest …

Threat Of Foreign Arthropod-Borne Pathogens To Livestock In The United States, Ralph A. Bram, John E. George, Robert E. Reichard, Walter J. Tabachnick

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

There are many exotic animal pathogens throughout the world that, if introduced into the United States, could have a significant detrimental impact on the health of livestock, agricultural economy, the environment, and public health. Many of these pathogens are arthropod-borne and potential vectors are readily available in the United States. A number of these arthropod-borne pathogens are discussed here as examples that illustrate the potential risk and the consequences of inadvertent introductions. Several International agencies have a role in global surveillance and in controlling animal diseases should they begin to expand their range. The risk to the United States is …

Soil- And Plant-Water Dynamics In A C3/C4 Grassland Exposed To A Subambient To Superambient Co2 Gradient, H. Wayne Polley, Hyrum B. Johnson, Justin D. Derner

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Plants may be more sensitive to carbon dioxide (CO₂) enrichment at subambient concentrations than at superambient concentrations, but field tests are lacking. We measured soil-water content and determined xylem pressure potentials and δ¹³C values of leaves of abundant species in a C3/C4 grassland exposed during 1997-1999 to a continuous gradient in atmospheric CO₂ spanning superambient concentrations (200-560 µmol mol^-1).

Arsenic(Iii) Oxidation And Arsenic(V) Adsorption Reactions On Synthetic Birnessite, Bruce A. Manning, Scott E. Fendorf, Benjamin Bostick, Donald L. Suarez

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The oxidation of arsenite (As(III)) by manganese oxide is an important reaction in both the natural cycling of As and the development of remediation technology for lowering the concentration of dissolved As(III) in drinking water. This study used both a conventional stirred reaction apparatus and extended X-ray absorption fine structure (EXAFS) spectroscopy to investigate the reactions of As(III) and As(V) with synthetic birnessite (MnO₂). Stirred reactor experiments indicate that As(III) is oxidized by MnO₂ followed by the adsorption of the As(V) reaction product on the MnO₂ solid phase. The As(V)-Mn interatomic distance determined by EXAFS analysis …

Differences Among Mycorrhizal Fungi For Mineral Uptake Per Root Length Of Switchgrass Grown In Acidic Soil, R. B. Clark

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Plants commonly encounter deficient and=or toxic levels of mineral elements when grown in acidic soil, and arbuscular mycorrhizal fungi (AMF) have potential to overcome many of these effects. Switchgrass (Panicum virgatum L.) was grown in acidic Lily soil (Typic Hapludult) at pH_Ca 4 and 5 (soil : 10mM CaCl₂, 1 : 1) and inoculated with Glomus (G.) clarum, G. diaphanum, G. etunicatum, G. intraradices, Gigaspora (Gi.) albida, Gi. margarita, Gi. rosea, and Acaulospora (A.) morrowiae to determine differences among mycorrhizal (AM) plants for mineral uptake per root length (RL). Shoots of AM plants grown …

Density Effects Of The Banana Weevil, Cosmopolites Sordidus (Germar), On Its Oviposition Performance And Egg And Larval Survivorship, Clifford S. Gold, Godfrey H. Kagezi, Pontiano Nemeye, Philip E. Ragama

All Peer-Reviewed Publications

The influence of banana weevil, Cosmopolites sordidus (Germar)(Coleoptera: Curculionidae), population density on oviposition rates and larval survivorship was studied in the laboratory at the Kawanda Agricultural Research Institute in Uganda. This study was undertaken to elucidate the relationship between density-dependent factors and rates of banana weevil increase in the field. Oviposition substrates (corm pieces) were offered to a range of densities of weevils maintained in buckets. Mean oviposition rates per female at densities of 10, 20 and 40 females per bucket were 29, 37 and 53%, respectively, lower than that at a density of 5 females. Nevertheless, total oviposition for …

Electrical Conductivity Monitoring Of Soil Condition And Available N With Animal Manure And A Cover Crop, R. A. Eigenberg, John W. Doran, John A. Nienaber, Richard B. Ferguson, B. L. Woodbury

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Development of sustainable agricultural management systems will depend, in part, on the ability to better use renewable resources, such as animal manure, and to synchronize the levels of soil available N with crop plant needs during the growing season. This study was conducted at the US Meat Animal Research Center in the central USA to determine whether differences in electromagnetic (EM) soil conductivity and available N levels over a growing season can be linked to feedlot manure/compost application and use of a green winter cover crop. A series of soil conductivity maps of a research cornfield were generated using global …