Agricultural Science Commons^™

Whole-Body And Muscle Protein Metabolism Are Not Affected By Acute Deviations From Habitual Protein Intake In Older Men: The Hormonal Regulators Of Muscle And Metabolism In Aging (Horma) Study, Kevin E. Yarasheski, Carmen Castaneda-Sceppa, Jiaxiu He, Miwa Kawakubo, Shalender Bhasin, Ellen F. Binder, E. Todd Schroeder, Ronenn Roubenoff, Stan P. Azen, Fred R. Sattler

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

Background:

Acute deviations in protein intake before the quantification of protein kinetics in older humans may explain the controversy over the effects of older age on muscle protein synthesis and proteolysis rates.

Objective:

We hypothesized that an acute decrease in protein intake from the habitual intake is associated with lower muscle protein synthesis and higher proteolysis rates, whereas an acute increase in protein intake from the habitual intake is associated with higher muscle protein synthesis and lower proteolysis rates.

Design:

In 112 community-dwelling healthy men aged 65–90 y, we quantified resting whole-body [1,2-¹³C₂]leucine kinetics, muscle mixed …

Relative Contributions Of Animal And Muscle Effects To Variation In Beef Lean Color Stability, D. A. King, S. D. Shackelford, T. L. Wheeler

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

Muscles from beef carcasses (n = 100) were selected from a commercial processor and aged for 14 d. Longissimus lumborum (LL), semimembranosus (SM), biceps femoris (BF), gluteus medius (GM), triceps brachii (TB), rectus femoris, vastus lateralis, adductor, semitendinosus, infraspinatus, teres major, biceps femoris ischiatic head, biceps femoris sirloin cap, and gracillus steaks were placed in display for 9 d. Instrumental color variables [lightness (L*), redness (a*), yellowness (b*), hue angle, chroma, and overall color change from d 0 (ΔE)] were determined on d 0, 1, 3, 6, and 9 of display. Muscle pH and myoglobin content were determined for LL, …

Fluid Fertilizer’S Role In Sustaining Soils Used For Bio-Energy Feedstock Production, John L. Kovar, Douglas L. Karlen

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

The use of corn (Zea mays L.) as a bio-energy feedstock has attracted the attention of many producers. Recently, the focus has shifted from grain-based to cellulose-based ethanol production. In addition to biological conversion of corn stover to ethanol, thermal conversion (pyrolysis) of stover is being explored. Regardless of post-harvest processing, the short- and long-term effects of both increasing grain yields and removing stover on soil nutrient cycling, physical properties, and biological activity must be understood to ensure that soil productivity and ecosystem services are maintained. Our objectives for 2010 were to evaluate: (i) the use of surface or …

2011 Across-Breed Epd Table, Larry Kuehn, Mark Thallman

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

The table of adjustment factors to be used to estimate across-breed expected progeny differences (AB-EPDs) for eighteen breeds was presented at the Beef Improvement Federation Annual Meeting in Bozeman, MT, on June 2 (see Table 1). Across-breed adjustment factors have been calculated for growth traits and maternal milk since 1993. Adjustment factors for carcass traits have been calculated since 2009; to be included, breeds must have carcass data in the U.S. Meat Animal Research Center (USMARC) database and report their carcass EPDs on an actual carcass basis using an age-adjusted endpoint. Bulls of different breeds can be compared on the …

Patterns Of Widespread Decline In North American Bumble Bees, Sidney A. Cameron, Jeffrey D. Lozier, James P. Strange, Jonathan B. Koch, Nils Cordes, Leellen F. Solter, Terry L. Griswold

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

Bumble bees (Bombus) are vitally important pollinators of wild plants and agricultural crops worldwide. Fragmentary observations, however, have suggested population declines in several North American species. Despite rising concern over these observations in the United States, highlighted in a recent National Academy of Sciences report, a national assessment of the geographic scope and possible causal factors of bumble bee decline is lacking. Here, we report results of a 3-y interdisciplinary study of changing distributions, population genetic structure, and levels of pathogen infection in bumble bee populations across the United States. We compare current and historical distributions of eight species, compiling …

Comparative Cryopreservation Of Avian Spermatozoa: Benefits Of Non-Permeating Osmoprotectants And Atp On Turkey And Crane Sperm Cryosurvival, Juan M. Blanco, Julie A. Long, George Gee, David E. Wildt, Ann M. Donoghue

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

A comparative approach was used to evaluate the cryosurvival of turkey and crane sperm frozen in a dimethylacetamide (DMA) cryodiluent supplemented with osmoprotectants and ATP. A range (6–26%) of DMA concentrations was used alone or in combination with ATP (30, 60 or 118mM) or one of the following osmoprotectants: (1) sucrose (turkey, 8.0%; crane, 5.0%); (2) 5.0% sucrose and 5.0% trehalose; or (3) betaine hydrochloride (0.1, 0.2 or 0.4 mM). The viability of thawed sperm was assessed using the nigrosin–eosin stain and sperm motility was determined using the hanging-drop technique. For semen frozen only with DMA, post-thaw sperm motility was …

Carbon Exchange By Establishing Biofuel Crops In Central Illinois, Marcelo Zeri, Kristina Anderson-Teixeira, George Hickman, Michael Masters, Evan Delucia, Carl J. Bernacchi

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

Perennial grass bio-fuels may contribute to long-term carbon sequestration in soils, thereby providing a broad range of environmental benefits. To quantify those benefits, the carbon balance was investigated over three perennial grass bio-fuel crops – miscanthus (Miscanthus×giganteus), switch-grass (Panicum virgatum) and a mixture of native prairie plants – and a row crop control (maize–maize–soy) in Central Illinois, USA, during the establishment phase of the perennial grasses (2008–2011). The eddy covariance technique was used to calculate fluxes of carbon dioxide and energy balance components, such as latent and sensible heat fluxes. Whereas maize attained the highest maximal …

Saving The Sagebrush Sea: An Ecosystem Conservation Plan For Big Sagebrush Plant Communities, Kirk W. Davies, Chad S. Boyd, Jeffrey L. Beck, Jon D. Bates, Tony J. Svejcar, Michael A. Gregg

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

Vegetation change and anthropogenic development are altering ecosystems and decreasing biodiversity. Successful management of ecosystems threatened by multiple stressors requires development of ecosystem conservation plans rather than single species plans. We selected the big sagebrush (Artemisia tridentata Nutt.) ecosystem to demonstrate this approach. The area occupied by the sagebrush ecosystem is declining and becoming increasingly fragmented at an alarming rate because of conifer encroachment, exotic annual grass invasion, and anthropogenic development. This is causing rangewide declines and localized extirpations of sagebrush associated fauna and flora. To develop an ecosystem conservation plan, a synthesis of existing knowledge is …

Effects Of Transmission Gear Selection On Tractor Performance And Fuel Costs During Deep Tillage Operations, C.M. Kichler, J.P. Fulton, R.L. Raper, T.P. Mcdonald, W.C. Zech

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

Deep tillage operations required to alleviate soil compaction common in the Southeastern US remain energy intensive and expensive. Equipment performance and in-field efficiency are two variables that can be improved to minimize fuel consumption and ultimately reduce input costs for crop production. The objective of this study was to investigate the effects of transmission gear selection on fuel costs, draft, and other equipment performance variables using two deep tillage implements. Three different transmission gears were selected which represented slow, normal, and fast operating speeds for two typical in-row, integral subsoilers (KMC generation I rip-strip and Bigham Brothers Paratill^TM). …

Differentially Expressed Genes In Populus Simonii×Populus Nigra In Response To Nacl Stress Using Cdna-Aflp, Lei Wang, Boru Zhou, Lili Wu, Baozhu Guo, Tingbo Jiang

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

Salinity is an important environmental factor limiting growth and productivity of plants, and affects almost every aspect of the plant physiology and biochemistry. The objective of this study was to apply cDNA-AFLP and to identify differentially expressed genes in response to NaCl stress vs. no-stress in Populus simonii × Populus nigra in order to develop genetic resources for genetic improvement. Selective amplification with 64 primer combinations allowed the visualization of 4407 transcript-derived fragments (TDFs), and 2027 were differentially expressed. Overall, 107 TDFs were re-sequenced successfully, and 86 unique sequences were identified in 10 functional categories based on their putative functions. …

Methodologies For Simulating Impacts Of Climate Change On Crop Production, Jeffrey W. White, Gerrit Hoogenboom, Bruce A. Kimball, Gerard W. Wall

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

Ecophysiological models are widely used to forecast potential impacts of climate change on future agricultural productivity and to examine options for adaptation by local stakeholders and policy makers. However, protocols followed in such assessments vary to such an extent that they constrain cross-study syntheses and increase the potential for bias in projected impacts. We reviewed 221 peer-reviewed papers that used crop simulation models to examine diverse aspects of how climate change might affect agricultural systems. Six subject areas were examined: target crops and regions; the crop model(s) used and their characteristics; sources and application of data on [CO₂] …

Evaluation Of Waxy Grain Sorghum For Ethanol Production, Shuping Yan, Xiaorong Wu, Scott R. Bean, Jeffery F. Pedersen, Tesfaye Tesso, Yuanhong Chen, Donghai Wang

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

The objective of this research was to investigate the fermentation performance of waxy grain sorghum for ethanol production. Twenty-five waxy grain sorghum varieties were evaluated with a laboratory dry-grind procedure. Total starch and amylose contents were measured following colorimetric procedures. Total starch and amylose contents ranged from 65.4 to 76.3% and from 5.5 to 7.3%, respectively. Fermentation efficiencies were in the range of 86.0-92.2%, corresponding to ethanol yields of 2.61-3.03 gallons/bushel. The advantages of using waxy sorghums for ethanol production include easier gelatinization and low viscosity during liquefaction, higher starch and protein digestibility, higher free amino nitrogen (FAN) content, and …

Anointing Chemicals And Hematophagous Arthropods: Responses By Ticks And Mosquitoes To Citrus (Rutaceae) Peel Exudates And Monoterpene Components, Paul J. Weldon, John F. Carroll, Matthew H. Kramer, Robert H. Bedoukian, Russell E. Coleman, Ulrich R. Bernier

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

Some birds and mammals roll on or wipe themselves with the fruits or leaves of Citrus spp. or other Rutaceae. These anointing behaviors, as with anointing in general, are thought to function in the topical acquisition of chemicals that deter consumers, including hematophagous arthropods. We measured avoidance and other responses by nymphal lone star ticks (Amblyomma americanum) and adult female yellow fever mosquitoes (Aedes aegypti) to lemon peel exudate and to 24 volatile monoterpenes (racemates and isomers), including hydrocarbons, alcohols, aldehydes, acetates, ketones, and oxides, present in citrus fruits and leaves in order to examine their …

Reflectance-Based Nitrogen Fertilizer Management For Irrigated Cotton, Kevin F. Bronson

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

Water and nitrogen are the first and second constraints to cotton production in the arid southwestern U.S, respectively (Morrow and Krieg, 1990). Subsurface drip irrigation (SDI) area in cottonland is currently estimated at 300,000 ac, and is growing (Jim Bordovsky, personal communication). Efficiency of water application to cotton in SDI systems is about 90% (Bordovsky and Lyle, 1998). However, N management research for cotton in SDI has not kept up with the water management research. Improving N fertilizer use efficiency would allow lower rates of N fertilizer to be used by producers without hurting lint yields. The reduced costs of …

Nitrous Oxide Emissions From Several Nitrogen Sources Applied To A Strip-Tilled Corn Field, Ardell Halvorson, Stephen J. Del Grosso, Claudia Pozzi Jantalia

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

We evaluated the effects of nitrogen (N) source on nitrous oxide (N₂O) emissions from a clay loam soil that was in strip-tilled (ST), irrigated continuous corn production in 2010 near Fort Collins, CO. Emissions were monitored from six different inorganic N fertilizer sources (urea, ESN¹, SuperU, UAN, UAN+AgrotainPlus, UAN+Nfusion). Each N source was applied at a rate of 202 kg N/ha, surface band applied near the corn row and watered into the soil the day after application including a subsurface band application of ESN (ESNssb). A check treatment (no N applied since 2000) located in separate …

The Acute Toxicity Of The Death Camas (Zigadenus Species) Alkaloid Zygacine In Mice, Including The Effect Of The Methyllycaconitine Coadministration On Zygacine Toxicity, K. D. Welch, K. E. Panter, D. R. Gardner, B. L. Stegelmeier, B. T. Green, J. A. Pfister, D. Cook

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

Death camas (Zigadenus spp.) is a common poisonous plant on foothill rangelands in western North America. The steroidal alkaloid zygacine is believed to be the primary toxic component in death camas. Poisonings on rangelands generally occur in the spring when death camas is abundant, whereas other more desirable forage species are limited in availability. In most cases where livestock are poisoned by plants in a range setting, there is more than one potential poisonous plant in that area. One common poisonous plant that is often found growing simultaneously in the same area as death camas is low larkspur ( …

Arkansas Cotton Variety Test 2010, Fred M. Bourland, A. B. Beach, D. P. Roberts Jr.

Arkansas Agricultural Experiment Station Research Series

The primary goal of the Arkansas Cotton Variety Test is to provide unbiased data regarding the agronomic performance of cotton varieties and advanced breeding lines in the major cotton-growing areas of Arkansas. This information helps seed companies establish marketing strategies and assists producers in choosing varieties to plant.

Stacking Resistance Alleles From Wild And Domestic Soybean Sources Improves Soybean Cyst Nematode Resistance, Myungsik Kim, D. L. Hyten, Terry L. Niblack, Brian W. Diers

Department of Agronomy and Horticulture: Faculty Publications

The soybean cyst nematode (SCN; Heterodera glycines Ichinohe) is the most economically important soybean [Glycine max (L.) Merr.] pathogen in the United States. Field SCN populations are adapting to the narrowly based SCN resistance currently deployed in soybean cultivars. The objective of our research was to measure the effects of combinations of SCN resistance genes or quantitative trait loci (QTL) from the wild soybean (Glycine soja Siebold & Zucc.) PI 468916 and the domesticated soybean accessions PI 88788 and PI 437654. Two populations were developed to test the combinations of QTL and genes. Both populations segregated for the …

Mutational Analysis Of The Major Soybean Uref Paralogue Involved In Urease Activation, Joe C. Polacco, D. L. Hyten, Mônica Medeiros-Silva, David A. Sleper, Kristin D. Bilyeu

Department of Agronomy and Horticulture: Faculty Publications

The soybean genome duplicated ~14 and 45 million years ago and has many paralogous genes, including those in urease activation (emplacement of Ni and CO₂ in the active site). Activation requires the UreD and UreF proteins, each encoded by two paralogues. UreG, a third essential activation protein, is encoded by the single-copy Eu3, and eu3 mutants lack activity of both urease isozymes. eu2 has the same urease-negative phenotype, consistent with Eu2 being a single-copy gene, possibly encoding a Ni carrier. Unexpectedly, two eu2 alleles co-segregated with missense mutations in the chromosome 2 UreF paralogue (Ch02UreF), suggesting …

The Composition And Origins Of Genomic Variation Among Individuals Of The Soybean Reference Cultivar Williams 82, William J. Haun, D. L. Hyten, Wayne W. Xu, Daniel J. Gerhardt, Thomas J. Albert, Todd Richmond, Jeffrey A. Jeddeloh, Gaofeng Jia, Nathan M. Springer, Carroll P. Vance, Robert M. Stupar

Department of Agronomy and Horticulture: Faculty Publications

Soybean (Glycine max) is a self-pollinating species that has relatively low nucleotide polymorphism rates compared with other crop species. Despite the low rate of nucleotide polymorphisms, a wide range of heritable phenotypic variation exists. There is even evidence for heritable phenotypic variation among individuals within some cultivars. Williams 82, the soybean cultivar used to produce the reference genome sequence, was derived from backcrossing a Phytophthora root rot resistance locus from the donor parent Kingwa into the recurrent parent Williams. To explore the genetic basis of intracultivar variation, we investigated the nucleotide, structural, and gene content variation of different …

Genome-Wide Association Analysis Identifies Candidate Genes Associated With Iron Deficiency Chlorosis In Soybean, Sujan Mamidi, Shireen Chikara, R. Jay Goos, D. L. Hyten, Deepti Annam, Samira Mafi Moghaddam, Rian K. Lee, P. B. Cregan, Phillip E. Mcclean

Department of Agronomy and Horticulture: Faculty Publications

Iron deficiency chlorosis (IDC) is a significant yield-limiting problem in several major soybean [Glycine max (L.) Merr.] production regions in the United States. Soybean plants display a variety of symptoms that range from a slight yellowing of the leaf to interveinal chlorosis, to stunted growth that reduces yield. The objective of this analysis was to employ single nucleotide polymorphism (SNP)-based genome-wide association mapping to uncover genomic regions associated with IDC tolerance. Two populations [2005 (n = 143) and 2006 (n = 141)] were evaluated in replicated, multilocation IDC trials. After controlling for population structure and individual relatedness, and selecting …

Construction Of A Ssr-Based Genetic Map And Identification Of Qtl For Domestication Traits Using Recombinant Inbred Lines From A Cross Between Wild And Cultivated Cowpea (V. Unguiculata (L.) Walp.), Mebeaselassie Andargie, Remy S. Pasquet, Bhavani S. Gowda, Geoffrey M. Muluvi, Michael P. Timko

All Peer-Reviewed Publications

Cowpea (Vigna unguiculata (L.) Walp.) is a grain legume commonly grown and consumed in many parts of the tropics and subtropics. A genetic linkage map was constructed using simple sequence repeat (SSR) markers and a recombinant inbred (RI) population of159 individuals derived from a cross between the breeding line 524B, a California Blackeye, and 219-01, a perennial wild cowpea from Kenya. Out of 912 primer combinations predicted to amplify SSRs in cowpea, 639 reliably produced amplification products in PCR assays and 202 (31.6%) were polymorphic between the two parents. These polymorphic SSRs were used to construct a genetic map consisting …

Antibody Recognition Of Porcine Circovirus Type 2 Capsid Protein Epitopes After Vaccination, Infection, And Disease, Benjamin R. Trible, Maureen Kerrigan, Nicholas Crossland, Megan Potter, Kay Faaberg, Richard Hesse, Raymond R. R. Rowland

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

Open reading frame 2 (ORF2) of porcine circovirus type 2 (PCV2) codes for the 233-amino-acid capsid protein (CP). Baculovirus-based vaccines that express only ORF2 are protective against clinical disease following experimental challenge or natural infection. The goal of this study was to identify regions in CP preferentially recognized by sera from experimentally infected and vaccinated pigs and to compare these responses to those of pigs diagnosed with porcine circovirus-associated disease (PCVAD), including porcine multisystemic wasting syndrome (PMWS) and porcine dermatitis and nephropathy syndrome (PDNS). The approach was to react porcine sera with CP polypeptide fragments followed by finer mapping studies …

Conventional And Glyphosate-Resistant Maize Yields Across Plant Densities In Single- And Twin-Row Configurations, Kipling S. Balkcom, Jason L. Satterwhite, Francisco J. Arriaga, Andrew J. Price, Edzard Van Santen

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

Maize (Zea mays L.) produced in narrow rows can increase yields and accelerate canopy closure. Costly equipment modifications make narrow rows impractical, but a twin-row configuration may boost production with fewer equipment modifications. Four field experiments were conducted to measure weed biomass, leaf area index (LAI), and yield for a conventional (CN) and a glyphosate-resistant (GR) hybrid across three plant densities (low 4.0–4.4 plants m⁻²; medium 5.9–6.4 plants m⁻²; and high 7.9–8.4 plants m⁻²) and two row configurations (single vs. twin) in a conservation tillage system during the 2005 growing season. The experimental design …

Moving Micronutrients From The Soil To The Seeds: Genes And Physiological Processes From A Biofortification Perspective, Brian M. Waters, Renuka P. Sankaran

Department of Agronomy and Horticulture: Faculty Publications

The micronutrients iron (Fe), zinc (Zn), and copper (Cu) are essential for plants and the humans and animals that consume plants. Increasing the micronutrient density of staple crops, or biofortification, will greatly improve human nutrition on a global scale. This review discusses the processes and genes needed to translocate micronutrients through the plant to the developing seeds, and potential strategies for developing biofortified crops.

Moving Magnesium In Plant Cells, Brian M. Waters

Department of Agronomy and Horticulture: Faculty Publications

Magnesium (Mg) is among the most abundant mineral elements in plants, yet the knowledge of which genes control its accumulation in specific tissues and organelles lags behind that of many other mineral elements. Only in recent years has identification of important molecular players begun to take shape. In this issue of New Phytologist, Conn et al. (pp. 583–594) shed additional light on two Mg transporters that play important roles in accumulation of Mg in leaf cell vacuoles. Using subcellular-level ion measurements on leaves, gene expression measurements after single-cell sampling, a genetic approach, and clever use of calcium (Ca) and …

The Role Of Transition Metal Homeostasis In Plant Seed Development, Elsbeth L. Walker, Brian M. Waters

Department of Agronomy and Horticulture: Faculty Publications

Copyright © 2011 Elsevier Ltd. Used by permission.

Estimation Of Surface Soil Organic Matter Using A Ground-Based Active Sensor And Aerial Imagery, D. F. Roberts, V. I. Adamchuk, J. F. Shanahan, R. B. Ferguson, J. S. Schepers

Department of Agronomy and Horticulture: Faculty Publications

Active canopy sensors are currently being studied as a tool to assess crop N status and direct in-season N applications. The objective of this study was to use a variety of strategies to evaluate the capability of an active sensor and a wide-band aerial image to estimate surface soil organic matter (OM). Grid soil samples, active sensor reflectance and bare soil aerial images were obtained from six fields in central Nebraska before the 2007 and 2008 growing seasons. Six different strategies to predict OM were developed and tested by dividing samples randomly into calibration and validation datasets. Strategies included uniform, …

Switchgrass Contains Two Cinnamyl Alcohol Dehydrogenases Involved In Lignin Formation, Aaron J. Saathoff, Christian M. Tobias, Scott E. Sattler, Eric J. Haas, Paul Twigg, Gautam Sarath

Department of Agronomy and Horticulture: Faculty Publications

Lignin content of switchgrass (Panicum virgatum L.), a bioenergy species, is a critical determinant of biomass quality since it can negatively impact conversion of biomass into liquid fuels via biochemical platforms. Cinnamyl alcohol dehydrogenase (CAD) is a key enzyme in lignin biosynthesis. Here, we have shown that cv. Kanlow switchgrass contains at least two closely related CAD genes (PviCAD1 and PviCAD2) that code for proteins containing highly conserved domains and residues that identify them as bona fide CADs. Both recombinant proteins displayed substrate kinetics consistent with their presumed role in cell wall lignification. Proteomic and immunoblotting detected …

Soil Fertility And Crop Yields In Long-Term Organic And Conventional Cropping Systems In Eastern Nebraska, Samuel E. Wortman, Tomie D. Galusha, Stephen C. Mason, Charles A. Francis

Department of Agronomy and Horticulture: Faculty Publications

Organic agriculture aims to build soil quality and provide long-term benefits to people and the environment; however, organic practices may reduce crop yields. This long-term study near Mead, NE was conducted to determine differences in soil fertility and crop yields among conventional and organic cropping systems between 1996 and 2007. The conventional system (CR) consisted of corn (Zea mays L.) or sorghum (Sorghum bicolor (L.) Moench)–soybean (Glycine max (L.) Merr.)–sorghum or corn–soybean, whereas the diversified conventional system (DIR) consisted of corn or sorghum– sorghum or corn–soybean–winter wheat (wheat, Triticum aestivum L.). The animal manure-based organic system (OAM) …