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Genesis And Morphology Of Mima Mounds And Associated Soils At Kalsow Prairie, Iowa, Deann K. Ricks, Lee Burras, M. E. Konen, A. J. Bolender Oct 1997

Genesis And Morphology Of Mima Mounds And Associated Soils At Kalsow Prairie, Iowa, Deann K. Ricks, Lee Burras, M. E. Konen, A. J. Bolender

Agronomy Publications

The objectives of this study were to identify the genesis of Kalsow Prairie Mirna mounds and to compare on-mound and off-mound soil properties. Kalsow Prairie is a 60 ha uncultivated prairie remnant in north-central Iowa. A 4 ha zone near the center of Kalsow Prairie containing 59 mounds was selected for detailed field study. Field methods included mapping the spatial distribution of mounds, measuring mound geometry, and sampling and describing soil profiles associated with both on-mound and off-mound landscape positions. The average height and diameter of the mounds was 0.23 m and 3.7 m, respectively. Twenty-nine of the ...


Potential Theory For Dual-Depth Subsurface Drainage Of Ponded Land, Don Kirkham, R. R. Van Der Ploeg, Robert Horton Jul 1997

Potential Theory For Dual-Depth Subsurface Drainage Of Ponded Land, Don Kirkham, R. R. Van Der Ploeg, Robert Horton

Agronomy Publications

Dual-depth subsurface drainage is considered to be more effective in removing excess water from soil than single-depth drainage, but this problem has not been analyzed in detail. Therefore, assuming that uniform, water-saturated soil covered by ponded water and overlying an impervious barrier is drained by equally spaced, alternating deep circular drain tubes, existing potential flow theory for a single-depth drainage system was extended. Sample calculations with the newly derived equations show that a dual-depth subsurface drainage system can be highly effective to remove excess water from soil. For example, a relative drain discharge of 160% is calculated when new drain ...


Introduction Of A [4fe-4s (S-Cys)4]+1,+2 Iron-Sulfur Center Into A Four-Α Helix Protein Using Design Parameters From The Domain Of The Fx Cluster In The Photosystem I Reaction Center, Marvin Paul Scott, John Biggins Feb 1997

Introduction Of A [4fe-4s (S-Cys)4]+1,+2 Iron-Sulfur Center Into A Four-Α Helix Protein Using Design Parameters From The Domain Of The Fx Cluster In The Photosystem I Reaction Center, Marvin Paul Scott, John Biggins

Agronomy Publications

We describe the insertion of an iron-sulfur center into a designed four α-helix model protein. The model protein was re-engineered by introducing four cysteine ligands required for the coordination of the mulinucleate cluster into positions in the main-chain directly analogous to the domain predicted to ligand the interpeptide [4Fe-4S (S-cys)4] cluster, Fx, from PsaA and PsaB of the Photosystem I reaction center. This was achieved by inserting the sequence, CDGPGRGGTC, which is conserved in PsaA and PsaB, into interhelical loops 1 and 3 of the four α-helix model. The holoprotein was characterized spectroscopically after insertion of the iron-sulfur center ...


Registration Of Eight Selected Bs11 Maize Germplasm Populations, Kendall R. Lamkey, Arnel R. Hallauer Jan 1997

Registration Of Eight Selected Bs11 Maize Germplasm Populations, Kendall R. Lamkey, Arnel R. Hallauer

Agronomy Publications

Eight maize (Zea mays L.) populations were developed cooperatively by the USDA-ARS and the Iowa Agriculture and Home Economics Experiment Station. The populations were developed as part of a larger breeding methods study conducted in the BSll maize population. Hallauer et al. (2) released BSll(FR)C2 after two cycles of full-sib reciprocal recurrent selection using BS10 as the tester population. Population BS1 I, originally designated as Pidneer Two-ear Composite, was developed by W.L. Brown at Pioneer Hi-Bred International by crossing southern prolific germplasm with U.S. Corn Belt lines (2). The main objective of the breeding methods study ...


Immobile Water Content And Mass Exchange Coefficient Of A Field Soil, F.X.M. Casey, Robert Horton Jr., S. D. Logsdon, Dan Jaynes Jan 1997

Immobile Water Content And Mass Exchange Coefficient Of A Field Soil, F.X.M. Casey, Robert Horton Jr., S. D. Logsdon, Dan Jaynes

Agronomy Publications

Determining the preferential flow characteristics of a soil is important because agrichemicals can contaminate groundwater via preferential flow pathways. A model that predicts solute transport due to preferential flow is the mobile-immobile solute transport model, which partitions the total water content (θ, m3 m−3) into a mobile fraction (θm) and an immobile fraction (θim). Recently, an in situ method was proposed for determining the mobile-immobile model parameters of θim and mass exchange coefficient (α) between the fractions by using a tension infiltrometer to apply a series of four fluorobenzoate tracers. The objective of this study ...


Roundup™ Pre-Emergence Treatment To Determine The Presence Of The Roundup Ready™ Gene In Soybean Seed: A Laboratory Test, A. S. Goggi, M. G. Stahr Jan 1997

Roundup™ Pre-Emergence Treatment To Determine The Presence Of The Roundup Ready™ Gene In Soybean Seed: A Laboratory Test, A. S. Goggi, M. G. Stahr

Agronomy Publications

A laboratory test for determining the presence of the Roundup Ready™ gene in soybean seeds was developed by the ISU Seed Testing Laboratory and approved by Monsanto. The procedure recommended to evaluate the percent expression of the Roundup Ready™ gene includes a seed lot of unknown tolerance and two controls, a susceptible soybean seed lot and a known Roundup Ready™ soybean seed lot. All seed lots are imbibed in a 2% solution of the ROUNDUP™ ULTRA formulation (41% active ingredient), for a concentration of 0.82% active ingredient, glyphosate, in the solution. Two replications of 100 seeds of each lot ...


Weed Seed Bank Emergence Across The Corn Belt, Frank Forcella, Robert G. Wilson, Robert J. Kremer, John Cardina, Randy L. Anderson, David Alm, Karen A. Renner, Robert G. Harvey, Sharon Clay, Douglas D. Buhler Jan 1997

Weed Seed Bank Emergence Across The Corn Belt, Frank Forcella, Robert G. Wilson, Robert J. Kremer, John Cardina, Randy L. Anderson, David Alm, Karen A. Renner, Robert G. Harvey, Sharon Clay, Douglas D. Buhler

Agronomy Publications

Field experiments, conducted from 1991 to 1994, generated information on weed seedbank emergence for 22 site-years from Ohio to Colorado and Minnesota to Missouri. Early spring seedbank densities were estimated through direct extraction of viable seeds from soil cores. Emerged seedlings were recorded periodically, as were daily values for air and soil temperature, and precipitation. Percentages of weed seedbanks that emerged as seedlings were calculated from seedbank and seedling data for each species, and relationships between seedbank emergence and microclimatic variables were sought. Fifteen species were found in 3 or more site-years. Average emergence percentages (and coefficients of variation) of ...


Registration Of Five Inbred Lines Of Maize: B102, B103, B104, B105, And B106, Arnel R. Hallauer, Kendall R. Lamkey, Paul R. White Jan 1997

Registration Of Five Inbred Lines Of Maize: B102, B103, B104, B105, And B106, Arnel R. Hallauer, Kendall R. Lamkey, Paul R. White

Agronomy Publications

Inbreds B102 (Reg. no. PL-281, PI 594045), B103 (Reg. no. PL- 282, PI 594046), B104 (Reg. no. PL-283, PI 594047), BIOS (Reg. no. PL-284, PI 594048), and B106 (Reg. no. PL-285, PI 594049) are yellow dent maize (Zea mays L.) lines developed cooperatively by the Iowa Agriculture and Home Economics Experiment Station and USDA-ARS. The lines were released on 8 Apr. 1996 because of their potential value as sources of germplasm in pedigreeselection breeding programs.


Dedication: Arnel R. Hallauer, Scientist, Maize Breeder, Quantitative Geneticist, Kendall R. Lamkey Jan 1997

Dedication: Arnel R. Hallauer, Scientist, Maize Breeder, Quantitative Geneticist, Kendall R. Lamkey

Agronomy Publications

Arnel R. Hallauer has dedicated his life to breeding; therefore, it is appropriate that this issue of Plant Breeding Reviews be dedicated to him. Dr. Hallauer's primary contributions have been in understanding quantitative inheritance in maize, developing breeding methodology, evaluating and utilizing recurrent selection for population improvement, and developing inbred lines for use in maize hybrids. Dr. Hallauer has also been very involved in graduate student education. The success of is students in academia and industry is a measure of his ability as a graduate educator and represents one of his greatest contributions to plant breeding. He has also ...


Testing A Nitrogen Fertilizer Applicator Designed To Reduce Leaching Losses, D. E. Ressler, R. Horton, J. L. Baker, T. C. Kaspar Jan 1997

Testing A Nitrogen Fertilizer Applicator Designed To Reduce Leaching Losses, D. E. Ressler, R. Horton, J. L. Baker, T. C. Kaspar

Agronomy Publications

Conventional practices for nitrogen fertilization of corn produce soil conditions that are conducive to preferential water flow and nitrate leaching. A new fertilizer applicator is proposed that will more effectively protect the fertilizer from infiltrating water and thus reduce the potential for leaching. The device forms a small compacted layer of soil above the subsurface fertilizer band and then mounds soil into a surface dome directly above the fertilizer band. This new localized compaction and doming (LCD) method is evaluated by measuring soil physical properties around the fertilizer band and comparing them with measurements made within the conventional knifing system ...


Molecular Genetic Diversity After Reciprocal Recurrent Selection In Bsss And Bscb1 Maize Populations, Joanne A. Labate, Kendall R. Lamkey, Michael Lee, Wendy L. Woodman Jan 1997

Molecular Genetic Diversity After Reciprocal Recurrent Selection In Bsss And Bscb1 Maize Populations, Joanne A. Labate, Kendall R. Lamkey, Michael Lee, Wendy L. Woodman

Agronomy Publications

Iowa Stiff Stalk Synthetic (BSSS) and Iowa Corn Borer Synthetic #1 (BSCB1) are undergoing reciprocal recurrent selection as part of Iowa's Federal-State maize (Zea mays L.) breeding program. This study focused on molecular genetic variation in BSSS(R) and BSCBI(R) cycle 0 (CO) and cycle 12 (C12) populations, as well as the inbred progenitor lines (P) used to synthesize BSSS and BSCB1. The objectives were to quantify amounts of genetic variation within populations, to estimate what proportion remained after selection, and to compare genetic diversities between BSSS and BSCB1 populations. Genotypic data for 82 restriction fragment length polymorphism ...