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United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
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Full-Text Articles in Life Sciences
Maize Hybrid Response To Tillage Under Irrigated And Dryland Conditions, Wallace Wilhelm, Mark Reed Hinze, C. O. Gardner
Maize Hybrid Response To Tillage Under Irrigated And Dryland Conditions, Wallace Wilhelm, Mark Reed Hinze, C. O. Gardner
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
The popularity of reduced-tillage cropping systems has emphasized the need to determine if maize (Zea mays L.) developed under conventional tillage systems (moldboard plow, disk, and harrow) is readily adaptable to conservation production systems (greater than 30% residue cover after planting). Past research has indicated that crops grown under conservation production systems are subjected to cooler and wetter soil conditions than crops grown with conventional tillage practices. Information is needed to determine if a significant interaction exists between tillage and hybrid in maize. Field experiments were conducted in 1982 and 1983 near Lincoln, Nebraska, U.S.A., on an Abruptic Argiaquoll and …
A Three-Dimensional Field Study Of Solute Transport Through Unsaturated, Layered, Porous Media 1. Methodology, Mass Recovery, And Mean Transport, T. R. Ellsworth, W. A. Jury, F. F. Ernst, P. J. Shouse
A Three-Dimensional Field Study Of Solute Transport Through Unsaturated, Layered, Porous Media 1. Methodology, Mass Recovery, And Mean Transport, T. R. Ellsworth, W. A. Jury, F. F. Ernst, P. J. Shouse
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
A field experiment is reported which monitored the three-dimensional movement of cubic solute plumes through an unsaturated, loamy sand soil. The plumes were created with one of two methods, a two-dimensional flux application and an initial resident distribution. Soil coring was used to sample resident concentrations for the three solutes studied. The data were analyzed using the method of moments. In addition to the solute transport experiments, a detailed set of physical properties of the field was obtained by excavating three pits to a depth of 5.0m and also by taking soil cores throughout the study area. This paper explains …
Simulation Of Shoot Vegetative Development And Growth Of Unstressed Winter Wheat, Gregory S. Mcmaster, Betty Klepper, R. B. Rickman, Wallace Wilhelm, W. O. Willis
Simulation Of Shoot Vegetative Development And Growth Of Unstressed Winter Wheat, Gregory S. Mcmaster, Betty Klepper, R. B. Rickman, Wallace Wilhelm, W. O. Willis
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
Mechanistic crop simulation models can aid in directing research and improving farm management. Recent research on winter wheat (Triticum aestivum L.) canopy development was consolidated into a model of aboveground vegetative development and growth called SHOOTGRO 1.0. The model assumes that water, nutrients, and light do not limit development and growth. Initial conditions of cultivar type (dwarf, semidwarf, mid-tall, and tall), seeding rate, planting depth and date, and latitude are inputs. Daily temperature, expressed as growing degree-days, drives SHOOTGRO 1.0. Processes are simulated with a daily time step. Computer code is standard Fortran 77. The morphological nomenclature used allows …
Effects Of Breed Group By Location Interaction On Crossbred Cattle In Nebraska And Florida, T. A. Olson, K. Euclides Filho, L. V. Cundiff, M. Koger, W. T. Butts Jr., K. E. Gregory
Effects Of Breed Group By Location Interaction On Crossbred Cattle In Nebraska And Florida, T. A. Olson, K. Euclides Filho, L. V. Cundiff, M. Koger, W. T. Butts Jr., K. E. Gregory
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
Data on 2,744 calves produced in Clay Center, Nebraska, and Brooksville, Florida, were used to evaluate the importance of genotype × location interactions on the reproductive and maternal performance of eight breed groups of F1 crossbred cows. A total of 648 F1 crossbred cows included Bos taurus × Bos taurus (Bt × Bt) crosses: Hereford × Angus reciprocal crossbreds (HA and AH), Pinzgauer × Angus (PA), Pinzgauer × Hereford (PH); and Bos indicus× Bos taurus (Bi × Bt) crosses: Brahman × Angus (BA), Brahman × Hereford (BH), Sahiwal × Angus (SA) and Sahiwal × Hereford (SH). The first calf …
Economic Effects Of Horn Fly (Diptera: Muscidae) Populations On Beef Cattle Exposed To Three Pesticide Treatment Regimes, Jerome Hogsette, David Prichard, Joseph Ruff
Economic Effects Of Horn Fly (Diptera: Muscidae) Populations On Beef Cattle Exposed To Three Pesticide Treatment Regimes, Jerome Hogsette, David Prichard, Joseph Ruff
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
Horn flies could not be maintained below 50 per animal with sprays or dusts during a 21-wk study. However, weights of cows and calves and condition scores of cows were not influenced by suppression of Haematobia irritans (L.) populations. Results show that cattle in northwest Florida can tolerate average populations of >200 flies for 70 d with no adverse economic effects. Spray treatments providing the best fly control were Lintox-D and Ra-Vap. The most economical products for use were Del-Tox, Lintox-D, and Ra-Vap.
Vegetation And Soil Zonation Associated With Juniperus Pinchotii Sudw. Trees, Guy R. Mcpherson, G. Allen Rasmussen, David B. Wester, Robert A. Masters
Vegetation And Soil Zonation Associated With Juniperus Pinchotii Sudw. Trees, Guy R. Mcpherson, G. Allen Rasmussen, David B. Wester, Robert A. Masters
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
Herbaceolis vegetation pattern and soil properties around individual Juniperus pinchotii Sudw. trees were studied on a grazed and a relict grassland in western Texas. Herb standing crop and soil samples were obtained under the canopy, at canopy edge, and beyond the canopy edge of three to five trees on each of four dates. Standing crop was lowest midway between the bole and canopy edge. Soil organic matter was highest under juniper canopies on both sites. Soil pH and P were not related to distance from tree bole on either site. Herbaceous pattern from under the canopy to canopy edge apparently …
Pituitary And Testicular Responses Of Beef Bulls To Active Immunization Against Inhibin Alpha, B. D. Schanbacher
Pituitary And Testicular Responses Of Beef Bulls To Active Immunization Against Inhibin Alpha, B. D. Schanbacher
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
Prepubertal crossbred beef bulls served as controls or were actively immunized against the N-terminal, 30-amino acid synthetic fragment of porcine inhibin alpha, pIα,(1-30). Antibody titers were detected in sera (>40% B/Bo in sera diluted 1,000-fold) but not in rete testis fluid of 390-d-old bulls. Serum FSH and inhibin remained static during a 5-h intensive bleed; inhibin was not acutely affected by a 15-fold LH rise and a threefold FSH rise induced by exogenous GnRH. Serum FSH, but not LH or testosterone, was consistently elevated (P < .05) in immunized bulls compared with control bulls. Neither pituitary weight, pituitary gonadotropin content nor pituitary FSH/LH ratios were affected (P > .10) by pIα,(1-30) active immunization. Testicular sperm density was greater (60 x 10 …
Prepubertal Changes In Plasma Fsh And Inhibin In Holstein Bull Calves: Responses To Castration And(Or) Estradiol, R. D. Macdonald, D. R. Deaver, B. D. Schanbacher
Prepubertal Changes In Plasma Fsh And Inhibin In Holstein Bull Calves: Responses To Castration And(Or) Estradiol, R. D. Macdonald, D. R. Deaver, B. D. Schanbacher
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
The objectives of two studies were to detennine 1) whether plasma concentrations of inhibin (INH) changed with age in prepubertal bulls and whether these changes were related to changes in FSH, testosterone or testis length; and 2) whether castration and(or) estradiol implants affected plasma concentrations of INH and FSH. In Exp. 1, plasma INH remained constant from 4 until 8 wk of age then increased from 120 pM to 202 pM between 8 and 12 wk. Thereafter, INH decreased to 90 pM by 36 wk. Between 4 and 10 wk, plasma FSH increased from .32 to .43 …
A Three-Dimensional Field Study Of Solute Transport Through Unsaturated, Layered, Porous Media 2. Characterization Of Vertical Dispersion, T. R. Ellsworth, W. A. Jury
A Three-Dimensional Field Study Of Solute Transport Through Unsaturated, Layered, Porous Media 2. Characterization Of Vertical Dispersion, T. R. Ellsworth, W. A. Jury
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
Solute plumes were created in an unsaturated field soil with either flux application or by leaching an initial resident distribution (see Ellsworth et al., this issue). The spatial variance of the plumes initially increased with time between the soil surface and a depth of 2.5m, within which the soil was a nearly structureless loamy sand. Below this depth, the plumes were observed to compress in the vertical direction as they moved into, and through, a region of subangular blocky structure and loam texture (between 2.5 and 4.0m depth). As the solute moved below the layer of fine texture, the plume …