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1992

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Articles 1 - 30 of 1688

Full-Text Articles in Life Sciences

Denitrification And Oxygen Consumption In Sediments Of Two South Texas Estuaries, Won Bae Yoon, Ronald Benner Dec 1992

Denitrification And Oxygen Consumption In Sediments Of Two South Texas Estuaries, Won Bae Yoon, Ronald Benner

Faculty Publications

Spatial and temporal variations in rates of denitrification and oxygen consumption were measured in sediments of the Nueces and Guadalupe Estuaries in southern Texas, USA. Denitrification rates varied from 4.0 to 71.1 µmol N2 m-2 h-1 in the Nueces Estuary and from 4.6 to 34.7 µmol N2 m-2 h-1 in the Guadalupe Estuary. Denitrification accounted for 29 to 80% of total benthic N flux in the study areas. Oxygen consumption rates ranged from 176 to 818 µmol O2 m-2 h-1 in Nueces Estuary and from 208 to ...


South Dakota Beef Cow-Calf Producer Management Practices, Donald Taylor, Dillon M. Feuz Dec 1992

South Dakota Beef Cow-Calf Producer Management Practices, Donald Taylor, Dillon M. Feuz

Economics Research Reports

This research report is based on the results of a mail survey of randomly selected South Dakota beef cow-calf operators undertaken during late 1991. The purpose of the survey was to determine the nature of management practices followed by the state's cow-calf producers and whether those practices differ by size and/or location of herd. Attention was given to producers' overall cowcalf, breeding, feeding, and health management practices.


Northeast Research Station Watertown, South Dakota Annual Progress Report, 1992, Agricultural Experiment Station, Plant Science Department Dec 1992

Northeast Research Station Watertown, South Dakota Annual Progress Report, 1992, Agricultural Experiment Station, Plant Science Department

Agricultural Experiment Station and Research Farm Annual Reports

This is the 1992 annual progress report for the Northeast Research Station in Watertown, South Dakota. This report is issued by the South Dakota Agricultural Experiment Station and the South Dakota State University Plant Science Department. This report includes information on the 1992 crop season, including growing season precipitation data from 1956-1992, crop performance trials, oat and rye research, spring wheat breeding, soybean studies, weed control effects on crops, W.E.E.D. project demonstration, soybean breeding, yield testing, farming system studies, 1992 yields, soil moisture, soil tests results.


Cases, Regulations And Statutes, Robert P. Achenbach Jr. Dec 1992

Cases, Regulations And Statutes, Robert P. Achenbach Jr.

Agricultural Law Digest

No abstract provided.


When Discharge Of Indebtedness Occurs If The Debtor Is Not In Bankruptcy, Neil Harl Dec 1992

When Discharge Of Indebtedness Occurs If The Debtor Is Not In Bankruptcy, Neil Harl

Agricultural Law Digest

As was noted in the March 30, 1990 issue of Agricultural Law Digest, whether discharge of indebtedness occurs for debtors in bankruptcy depends upon the chapter of the Bankruptcy Code. For Chapter 12 debtors, discharge of indebtedness takes place upon completion of payments under the plan.

For debtors not in bankruptcy, the rules for when discharge of indebtedness take place are different and the consequences are also quite different.


Cumulative Index, Volume 3 Nos. 13–24, Agricultural Law Digest Dec 1992

Cumulative Index, Volume 3 Nos. 13–24, Agricultural Law Digest

Agricultural Law Digest

No abstract provided.


Bacterial Numbers And Activity, Microalgal Biomass And Productivity, And Meiofaunal Distribution In Sediments Naturally Contaminated With Biogenic Bromophenols, Charles C. Steward, James L. Pinckney, Yvette Piceno, Charles R. Lovell Dec 1992

Bacterial Numbers And Activity, Microalgal Biomass And Productivity, And Meiofaunal Distribution In Sediments Naturally Contaminated With Biogenic Bromophenols, Charles C. Steward, James L. Pinckney, Yvette Piceno, Charles R. Lovell

Faculty Publications

Sediment cores were collected inside and outside of a bed of a bromophenol-producing marine polychaete, Notomastus lobatus, and examined for impact of the bromophenols on sediment microflora and meiofauna around N. lobatus burrows. No significant differences were found between microbial parameters measured inside and outside of the N. lobatus bed. Integrated 6 cm cores taken adjacent to N. lobatus burrows contained 1.2 x 109 bacteria ml-1. Cell numbers were similar at control sites within the bed, but away from burrows, and not significantly different from cell numbers (1.0 X 109 cells ml-1) at a ...


Purification And Ligand Binding Of A Soluble Class I Mhc Molecule Consisting Of The First Three Domains Of H-2kd Fused To B2-Microglobulin Expressed In The Baculovirus/Insect Cell System, Francois Godeau, Immanuel F. Luescher, David M. Ojcius, Cecile Saucier, Estelle Mottez, Lucien Cabanie, Philippe Kourilsky Dec 1992

Purification And Ligand Binding Of A Soluble Class I Mhc Molecule Consisting Of The First Three Domains Of H-2kd Fused To B2-Microglobulin Expressed In The Baculovirus/Insect Cell System, Francois Godeau, Immanuel F. Luescher, David M. Ojcius, Cecile Saucier, Estelle Mottez, Lucien Cabanie, Philippe Kourilsky

Dugoni School of Dentistry Faculty Articles

A recombinant baculovirus encoding a single-chain murine major histocompatibility complex class I molecule in which the first three domains of H-2Kd are fused to beta 2-microglobulin (beta 2-m) via a 15-amino acid linker has been isolated and used to infect lepidopteran cells. A soluble, 391-amino acid single-chain H-2Kd (SC-Kd) molecule of 48 kDa was synthesized and glycosylated in insect cells and could be purified in the absence of detergents by affinity chromatography using the anti-H-2Kd monoclonal antibody SF1.1.1.1. We tested the ability of SC-Kd to bind antigenic peptides using a direct binding assay based on photoaffinity labeling ...


Effect Of N Rate And Time Of Application On Corn Grain Yield And N Recovery, Randy Killom, Regis Voss, Joyce Hornstein Dec 1992

Effect Of N Rate And Time Of Application On Corn Grain Yield And N Recovery, Randy Killom, Regis Voss, Joyce Hornstein

Proceedings of the Integrated Crop Management Conference

Iowa crop producers purchase and apply 7.6% of all the nitrogen (N) fertilizer used in the United States to support production of com, small grains, and pasture on nearly twenty million acres annually (Hargett and Berry, 1990). The annual cost of the nitrogen fertilizer (1.5 million tons in 1990) exceeds $300 million.


Application Of Chromosome Maps To Soybean Improvements, Lisa Lorenzen, Randy Shoemaker, Sam Boutin, Nevin Young Dec 1992

Application Of Chromosome Maps To Soybean Improvements, Lisa Lorenzen, Randy Shoemaker, Sam Boutin, Nevin Young

Proceedings of the Integrated Crop Management Conference

The mention of a trademark or proprietary product does not constitute a guarantee or warranty of the product by the United Sates Department of Agriculture or Iowa State University and does not imply its approval to the exclusion of other products that may be suitable.


The Role And Responsibility Of The Agricultural Professional In Promoting Farmers' Safety And Health, C. J. Lehtola Dec 1992

The Role And Responsibility Of The Agricultural Professional In Promoting Farmers' Safety And Health, C. J. Lehtola

Proceedings of the Integrated Crop Management Conference

Farmers indicate they expect and request farm safety services and information from the local farm chemical dealers. This workshop identifies agricultural hazards associated with crop production; e.g., tractors, machinery, and chemicals. Emphasis is placed on discussing the roles and responsibilities of the agricultural professional towards enhancing and promoting farmers' safety and health by means of various intervention strategies. Workshop participants will participate in group discussions in order to identify and recommend additional ways in which they can better serve their clientele in this crucial area.


Digital Soil Maps For Iowa, Gerald A. Miller, Robert C. Mortensen Dec 1992

Digital Soil Maps For Iowa, Gerald A. Miller, Robert C. Mortensen

Proceedings of the Integrated Crop Management Conference

The Iowa Cooperative Soil Survey (ICSS) initiated a program in 1987 to transfer printed soil maps in each county soil survey report to an electronic database. The purpose of this cooperative project is to provide a computerized database of the county soil maps to support federal, state, local and private sector decision-making concerning use and management of Iowa's soil resources.


What's With The Weather?, S. Elwynn Taylor Dec 1992

What's With The Weather?, S. Elwynn Taylor

Proceedings of the Integrated Crop Management Conference

Most crops are well adapted to the prevailing climate. Nevertheless, weather remains the most significant factor in successful crop production. Weather-wise management of production and marketing can greatly reduce the risk of crop loss and of fmancial failure in crop production. The cyclic nature of midwest weather, the relationship of potential yield to soil moisture, and the effects of temperature on the development of crops and crop pests should be understood by the farmer and by the farm service representative. Com yield in Iowa and Illinois improved slowly during the first half of the 20th century. There was considerable yield ...


Understanding And Reducing Pesticide Losses, James Baker, Ed Adcock, Gerald Miller Dec 1992

Understanding And Reducing Pesticide Losses, James Baker, Ed Adcock, Gerald Miller

Proceedings of the Integrated Crop Management Conference

A small portion of pesticides applied on farms inadvertently reaches surface and groundwater. The amount varies from nearly zero to sometimes more than 5 percent of the amount applied, depending on several factors discussed below. That may not seem like much, but a 1 percent loss of a 1-pound-per-acre pesticide application can contaminate all of the drainage from a field in a normal year at 5 parts per billion (ppb). This level can be of concern if the drainage water enters drinking water supplies. The U.S. Environmental Protection Agency has established Health Advisory Levels for most pesticides in drinking ...


Evaluating Weed Management Programs For The Development Of Herbicide Resistance, Bob Hartzler Dec 1992

Evaluating Weed Management Programs For The Development Of Herbicide Resistance, Bob Hartzler

Proceedings of the Integrated Crop Management Conference

The phenomena of herbicide resistance is not a new concern; triazine resistant weeds were first reported in the late 1960's. Since then, resistance has developed to many other important classes of herbicides. Although there are isolated infestations of triazine resistant weeds across Iowa, these weeds are not considered a major problem in the state. Recent shifts in herbicide use patterns has increased the potential for the development of resistant biotypes. This paper will describe factors which influence the development of resistance and how weed management programs can be manipulated to minimize the potential for resistance.


The Insects Of 1992: A Review Of Problems And Management Strategies, Marlin E. Rice Dec 1992

The Insects Of 1992: A Review Of Problems And Management Strategies, Marlin E. Rice

Proceedings of the Integrated Crop Management Conference

Each growing season seems to be unique when we reflect back on the insects that captured our attention. This year, com rootworms grabbed the limelight as probably the most economically destructive insect of the year. Com flea beetles were early season problems in the southeastern region of the state, while thistle caterpillars fascinated us with their destructive potential on small soybeans.


Waste Corn As A Source Of Inoculum Of Aspergillus Flavus, The Cause Of Aflatoxin, D. C. Mcgee, O. M. Olanya, L. H. Tiffany Dec 1992

Waste Corn As A Source Of Inoculum Of Aspergillus Flavus, The Cause Of Aflatoxin, D. C. Mcgee, O. M. Olanya, L. H. Tiffany

Proceedings of the Integrated Crop Management Conference

Aspergillus Flavus occurs worldwide in diverse habitats on a variety of plant and animal substrates. In the United States, contamination of susceptible crops particularly maize, peanuts, cottonseed, and tree nuts has become a major health concern because of the development of the carcinogen, aflatoxin. Extensive research into all aspects of the biology of A. flavus over the past twenty years still has left many unanswered but very basic questions about the ecology of this important organism.


Soybean Cyst Nematode- Identification And Extraction Techniques, Gregory L. Tylka Dec 1992

Soybean Cyst Nematode- Identification And Extraction Techniques, Gregory L. Tylka

Proceedings of the Integrated Crop Management Conference

A major factor limiting soybean production in Iowa is parasitism by the soybean cyst nematode, Heterodera glycines. Soybean cyst nematode is now known to be present in 54 counties within Iowa. It is very likely that the nematode is present in many other counties as well, but the nonspecific nature of the above-ground symptoms of soybean cyst nematode damage makes early identification or diagnosis of infestations difficult.


Seed Quality Evaluation Methods, Tim J. Gutormson Dec 1992

Seed Quality Evaluation Methods, Tim J. Gutormson

Proceedings of the Integrated Crop Management Conference

Seed quality evaluation methods will be discussed during a tour of the I.S.U. Seed Testing Laboratory. The following discussion of seed quality is provided as background or reference information. The importance of quality seed stocks is often taken for granted in U.S. agriculture. High quality seed supplies of the major crops have evolved through the competitive nature of the U.S. seed industry. However, occasionally an emergence, contamination, or seed quality question arises. To help answer these seed quality questions it is useful to understand seed evaluation methods and labeling requirements.


Theory And Practice: Weed Management In No Tillage Soybeans, Micheal D. K. Owen Dec 1992

Theory And Practice: Weed Management In No Tillage Soybeans, Micheal D. K. Owen

Proceedings of the Integrated Crop Management Conference

Recent changes in government policy and concerns for soil conservation have resulted in considerable interest in no tillage soybean production. Further, there has been a coincidental shift in narrow row production. These efforts represent an interest to increase the amount of plant residue left intact on the soil surface after planting thus reducing soil erosion and an attempt to manipulate row spacing to improve soybean yield potential. However, growers intuitively recognize that weed management becomes increasingly challenging as the amount of soil disturbance is decreased. The difficulty in weed management when seed bed preparation tillage is eliminated is the result ...


Refinement Of Rootworm Thresholds For New, Commercially-Available Sticky Traps, Jon J. Tollefson Dec 1992

Refinement Of Rootworm Thresholds For New, Commercially-Available Sticky Traps, Jon J. Tollefson

Proceedings of the Integrated Crop Management Conference

Sampling adult com rootworms is a proven method of gathering information about the insect population to assist com growers in managing this pest. Specifically, if the adult population reaches a prescribed density, a com grower should consider rotating to a crop other than com or apply a rootworm insecticide if planting com the following spring. Conversely, if the adult population fails to reach this density, a com grower can forego a control option without expecting to suffer economic yield losses.


Spray-Wind-Inversion, S. Elwynn Taylor Dec 1992

Spray-Wind-Inversion, S. Elwynn Taylor

Proceedings of the Integrated Crop Management Conference

Wind, clouds, humidity, stability--there are numerous properties of the atmosphere that influence effective application of agricultural chemicals. Whenever a material is dispersed in the atmosphere, some of it will, inevitably not reach the intended target. The responsibility of the applicator is to minimize drift that is to apply at a time and in a manner that will not result in the movement of significant concentrations of material away from the target zone: Drift can result from wind carry, from high concentrations of fine mist suspended in the air, and from vapor drift. Drift may be hazardous to nontarget crops, to ...


Residue Management With Chisel-Type Implements, Richard Johnson Dec 1992

Residue Management With Chisel-Type Implements, Richard Johnson

Proceedings of the Integrated Crop Management Conference

Where chisels are improperly used, it may be difficult to end up with 30% surface cover. But by considering one or more of the following, 30 to 50% surface cover after planting should be possible:


Tillage Equipment Adjustment For Surface Residue, Mark Hanna Dec 1992

Tillage Equipment Adjustment For Surface Residue, Mark Hanna

Proceedings of the Integrated Crop Management Conference

Crop producers are increasingly interested in methods to manage higher levels of surface residue. Both economics and soil conservation are responsible for this attention. Six million additional Iowa acres will be shifted to a conservation tillage system during 1992-94 to comply with soil loss goals of the Food Security Act according to plans filed with the Soil Conservation Service. From a production cost viewpoint, fewer machine operations on the land lower input costs and increase net profit if output can be maintained.


Subsurface Flow Barriers To Reduce Nitrate Leaching, R. Horton, T. C. Kaspar, J. L. Baker, M. Kiuchi Dec 1992

Subsurface Flow Barriers To Reduce Nitrate Leaching, R. Horton, T. C. Kaspar, J. L. Baker, M. Kiuchi

Proceedings of the Integrated Crop Management Conference

Groundwater is a very important natural resource which directly affects many human lives. In the United States, groundwater is the source of about 22 percent of the freshwater used. About 53 percent of the total population and 97 percent of the rural population use groundwater supplies for their drinking water (Moody, 1990). Although contamination of groundwater can occur naturally, agriculture is considered to be one of the most widespread nonprofit sources of groundwater contamination. Among agricultural chemicals, nitrogen-fertilizer has been used most extensively, especially by com producers. About one million tons of nitrogen-fertilizer are used annually in Iowa. In some ...


Phosphorus And Potassium Fertilization Of Corn And Soybean, Antonio P. Mallarino Dec 1992

Phosphorus And Potassium Fertilization Of Corn And Soybean, Antonio P. Mallarino

Proceedings of the Integrated Crop Management Conference

Fertilization practices for phosphorus (P) and potassium (K) during the last three decades have increased soil-test P (STP) values and soil-test K (STK) values of most agricultural soils in Iowa. This tendency for soil-test values to increase with time generally has been considered a desirable consequence of fertilization. This was especially true about 30 or 40 years ago when many Iowa soils tested very low or low in STP and STK. Recent soil-test summaries (Killom, Voss, and Eik, 1990) and surveys (Blackmer and Mallarino, unpublished), however, indicate that more than 70% of Iowa soils test high or very high in ...


Soybean Cyst Nematode- Biology And Management, Gregory L. Tylka Dec 1992

Soybean Cyst Nematode- Biology And Management, Gregory L. Tylka

Proceedings of the Integrated Crop Management Conference

The soybean cyst nematode, Heterodera glycines, is a small, unsegmented plant-parasitic roundworm that attacks the roots of soybeans. While many plant-parasitic nematodes are believed to be endemic or native to the United States, the soybean cyst nematode was apparently introduced from Japan. Soybean cyst nematode was first discovered in the United States in 1954 in North Carolina (Winstead et al., 1955). It has since spread to 28 additional states in the Southeast and Midwest (Noel, 1992). It was first discovered in Iowa in Winnebago County in 1978. The presence of soybean cyst nematode has been confirmed in 54 counties within ...


Beneficial Microorganisms In Low-Input Agriculture, Thomas E. Loynachan Dec 1992

Beneficial Microorganisms In Low-Input Agriculture, Thomas E. Loynachan

Proceedings of the Integrated Crop Management Conference

The overall involvement of microorganisms in crop production still remains much of a mystery. Because of their distribution and size, most studies have been done in the laboratory and the implications of these studies referred back to the field. With this approach, unfortunately, much remains unknown, not only about the growth of individual organisms, but certainly the interactions of organisms in nature. Several "nontraditional" soil amendments have been marketed over the years that capitalize on our lack of understanding of soil microbial processes. Terms such as soil activators, soil enhancers, and enzyme stimulators have been used, claiming to improve soil ...


Reducing Pesticide Movement To Surface Water, Margaret A. Smith Dec 1992

Reducing Pesticide Movement To Surface Water, Margaret A. Smith

Proceedings of the Integrated Crop Management Conference

Pesticides (largely herbicides) can be detected in Iowa surface waters---but when found, are usually at very low concentrations (ppb). Concentrations and total herbicide losses to surface waters are often highest in the spring after chemical applications and heavy rains. Many management practices can be used to help minimize pesticides in Iowa waters. Farmers, dealers, and pesticide applicators may address the issue by focusing only on herbicide management. Other crop management tools are as important and should be considered before changing pest control strategies. The following checklist may be helpful for farm advisors reviewing options for reducing pesticides in surface waters.


Economic Comparison Of Biological Control And Insecticidal Control Of The European Corn Borer, David B. Orr, Leslie C. Lewis, John J. Obrycki, Marlin E. Rice Dec 1992

Economic Comparison Of Biological Control And Insecticidal Control Of The European Corn Borer, David B. Orr, Leslie C. Lewis, John J. Obrycki, Marlin E. Rice

Proceedings of the Integrated Crop Management Conference

The European com borer has been considered a damaging pest of com in Iowa since its arrival in 1942 (Harris & Brindley 1942). Estimates of annual losses to this pest in Iowa alone range from 100 to 500 million dollars (Bergman et al. 1985). Damage by this insect can be either direct or indirect. Direct damage to grain yield results when com borer feeding occurs on the grain itself, or when feeding in the stalk or shank causes breakage below the ear resulting in loss of the entire ear. Indirect losses are usually more important, and result from leaf and stalk feeding which reduces the amount of nutrients directed to the ear; this has also been referred to as "physiological loss" (Showers et al. 1989).