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1990

Agronomy and Crop Sciences

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Articles 1 - 30 of 96

Full-Text Articles in Life Sciences

Making Corn Replant Decisions, Garren O. Benson Dec 1990

Making Corn Replant Decisions, Garren O. Benson

Proceedings of the Integrated Crop Management Conference

When the stand of corn from the initial planting is not what a corn producer desired, whether or not to replant becomes an issue. Will the original stand or a replanted stand be the most profitable? The first step in determining the yield potential of the original stand involves taking detailed stand counts. This often is more complicated than simply counting plants, as factors such as plant health and stand uniformity often complicate things. The yield potential of the original stand must then be compared with what one expects from a replant. If a replant will yield more than the ...


Herbicide Presistence In Soil, Mark M. Loux Dec 1990

Herbicide Presistence In Soil, Mark M. Loux

Proceedings of the Integrated Crop Management Conference

Herbicides are applied directly to soils or plant foliage. Interaction of a herbicide with various living and non-living components of the environment ultimately determines how quickly it dissipates or degrades. Dissipation can be defined as the disappearance or loss of herbicide from the target site through a number of processes. Herbicide may move from the target site via processes such as runoff or leaching, or gradually degrade to undetectable or insignificant levels. Degradation, or alteration of the herbicide molecule by primarily chemical and biological processes, is thus one component of dissipation. Alternatively, we can distinguish between the transfer of herbicide ...


Research On Nitrogen Indices In Wisconsin And The Midwest, Larry G. Bundy Dec 1990

Research On Nitrogen Indices In Wisconsin And The Midwest, Larry G. Bundy

Proceedings of the Integrated Crop Management Conference

Development of reliable nitrogen (N) availability indices has long been an important goal of agricultural scientists. However, progress in this area has been slowed by problems with calibrating certain N indices with crop response and by the absence of strong incentives to develop and implement N tests. Nitrogen test development for humid regions of the Midwest and eastern U.S. is more difficult due to climatic conditions in these areas which can cause relatively rapid changes in the amounts of plant-available N in the crop root zone.


Determining Herbicide Carryover Risk- How Close Can We Come?, Mark M. Loux Dec 1990

Determining Herbicide Carryover Risk- How Close Can We Come?, Mark M. Loux

Proceedings of the Integrated Crop Management Conference

Crop injury resulting from herbicide carryover is a function of four variables: 1) the herbicide residue persisting from one year or crop to the next (or the herbicide concentration in soil at the time of planting); 2) the availability of the herbicide for uptake by the germinating seed, emerging seedling, or young plant; 3) the sensitivity of the follow crop to the herbicide; and 4) the environmental conditions in the early part of the growing season. These four factors interact to determine the potential for or the severity of injury due to carryover.


Digitized Soil Maps For Iowa, Gerald A. Miller, Robert C. Mortensen Dec 1990

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

Proceedings of the Integrated Crop Management Conference

The Iowa Cooperative Soil survey 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.


The Potential Role Of Cover Crops In Iowa Cropping Systems, Robert G. Hartzler Dec 1990

The Potential Role Of Cover Crops In Iowa Cropping Systems, Robert G. Hartzler

Proceedings of the Integrated Crop Management Conference

Cover crops play an important role in crop management systems in many parts of the country; however, there has been little use of this practice in Iowa in recent years. Increasing concerns over the impacts of agriculture on the environment has caused a renewed interest in the potential role of cover crops. This paper will discuss potential benefits and risks of cover crops, and also discuss some of the systems currently being investigated.


Results Of Latest Water Quality Surveys, George F. Czapar Dec 1990

Results Of Latest Water Quality Surveys, George F. Czapar

Proceedings of the Integrated Crop Management Conference

Recent state and national surveys have examined both groundwater and surface water quality. These studies have identified the contaminants that are most common, and where they are most likely to occur. This type of background information is critical so that management practices can be modified to protect groundwater and surface water from agricultural chemicals, and to better identify areas that are most vulnerable to contamination.


Demonstration Of A Weed Management Expert System For Crop Production, Edward E. Schweizer Dec 1990

Demonstration Of A Weed Management Expert System For Crop Production, Edward E. Schweizer

Proceedings of the Integrated Crop Management Conference

Abstract. The employment of a computer model to facilitate weed management decisions has the potential to reduce herbicide use when weed densities are below an economical threshold as opposed to applying prophylactic herbicide treatments in anticipation of weed problems. The computer model was constructed by linking two submodels representing soil-applied and postemergence weed management decisions. The models are farm specific, user friendly, and consider most herbicide options and herbicide efficacy by weed species. The submodels were developed in LOTUS.


Weed Aggressivity In Agronomic Crops, Edward E. Schweizer Dec 1990

Weed Aggressivity In Agronomic Crops, Edward E. Schweizer

Proceedings of the Integrated Crop Management Conference

The quantity of herbicides applied in crops has disturbed environmentalists for many years and several environmental groups have voiced distress about the impact of herbicides on water quality, the food supply, and human health. These concerns are causing administrators, scientists, and farmers to search for farming practices and research programs that can effectively balance agri chemical usage with the protection of national resources, food supplies, and human health (Anonymous, 1989a; Anonymous, 1989b). "Society will become more environmentally sensitive, and agricultural practices will become more environmentally friendly. Pesticides that cause unacceptable environmental damage or threaten health will be withdrawn. During the ...


Water And Risk Assessment, Vernon N. Houk Dec 1990

Water And Risk Assessment, Vernon N. Houk

Proceedings of the Integrated Crop Management Conference

Thank you for giving me the opportunity to speak to you today about carcinogens in drinking water and water quality standards. In this emotion-filled, media-hyped, chemo-phobic society in which we live, the more we spend to comply with regulations that supposedly reduce the risk of cancer, the less safe the American public seems to feel.


Managing Alfalfa, Stephen K. Barnhart Dec 1990

Managing Alfalfa, Stephen K. Barnhart

Proceedings of the Integrated Crop Management Conference

Alfalfa is the most important forage crop grown in Iowa. It is an economical source of home grown protein, energy, minerals, and vitamins for livestock. High quality alfalfa allows producers to reduce dependency on protein supplements and feed grains, which translates into greater efficiency and profitability for the producer and better nutrition for the animal.


Herbicide Resistance In Crops And Weeds, Michael D. K. Owen Dec 1990

Herbicide Resistance In Crops And Weeds, Michael D. K. Owen

Proceedings of the Integrated Crop Management Conference

Herbicide resistance, whether as a potential problem in weeds, or as a potentially important agronomic tool, has become an extremely volatile issue in agriculture. Documents such as Biotechnology's Bitter Harvest suggest that herbicide resistance in crops will be a major environmental and economic disaster. Industry representatives suggest that herbicide resistant crops will be excellent tools for growers and actually improve the environmental safety of herbicide use. Agronomists voice concerns about the appearance of weed biotypes that demonstrate herbicide resistance. This paper will provide an objective review of herbicide resistance in crops and weeds and suggest possible results of herbicide ...


Effects Of Previous Hybrid On Corn Yields The Following Year, I. C. Anderson, D. N. Sundberg Dec 1990

Effects Of Previous Hybrid On Corn Yields The Following Year, I. C. Anderson, D. N. Sundberg

Proceedings of the Integrated Crop Management Conference

Approximately 25% of Iowa's annual 12.5 million acres of corn is grown where corn was grown the previous year. With adequate N fertilizer, corn following corn usually yields less than corn following soybeans or some other crop. The magnitude of this yield reduction usually is about 10%, but it varies between fields, locations and years. During 1988 in southeastern Iowa, farmers and researchers reported yield differences as great as 100 bufacre between the yield of corn after soybeans and corn after corn. There are many possible explanations for the rotation effect such as differences in residual soil moisture ...


Adding Crop Consulting Services To Your Business, Dean Grundman Dec 1990

Adding Crop Consulting Services To Your Business, Dean Grundman

Proceedings of the Integrated Crop Management Conference

The increasing emphasis on production efficiency and environmental concerns has many farm suppliers considering offering crop management services to expand their businesses. While most agricultural suppliers have provided some agronomic services to customers, these services were often limited to soil fertility recommendations and investigating product performance or crop damage complaints. Adding a consulting service for hire is a major change of direction for many businesses and the transition can be difficult.


Immunoassays For Pesticide Detection, Robert G. Hartzler Dec 1990

Immunoassays For Pesticide Detection, Robert G. Hartzler

Proceedings of the Integrated Crop Management Conference

The occurrence of herbicides and other agricultural chemicals in groundwater continues to be a major concern in Iowa and across the country. Analytical capabilities have improved dramatically in the past twenty years, resulting in the ability to detect ever smaller quantities of chemicals (the vanishing zero). Detection of pesticides has been based primarily on conventional technology, such as gas or high-performance-liquid chromatographic methods. Although these methods are highly sensitive, they are also very expensive and time consuming. Immunoassay tests are alternative analytical methods that are also highly sensitive, but can be used by persons with little or no scientific background ...


Agriculture: Environmental Problems And Directions, Ubbo Agena, Bill Bryant, Tom Oswald Dec 1990

Agriculture: Environmental Problems And Directions, Ubbo Agena, Bill Bryant, Tom Oswald

Proceedings of the Integrated Crop Management Conference

Review of Iowa's water quality situation has both "good news" and "bad news" components. The "good news" is that since passage of the 1972 federal Clean Water Act, commendable progress has been made in reducing the discharge of municipal and industrial waste pollutants into Iowa's waters. The progress made in reducing pollution from these point sources is attributable to a number of factors, including the enactment of effective laws and regulations, development and implementation of improved waste management practices, and voluntary and enforced compliance.


Long-Term Trends For Selected Iowa Weather Variables, Richard E. Carlson Dec 1990

Long-Term Trends For Selected Iowa Weather Variables, Richard E. Carlson

Proceedings of the Integrated Crop Management Conference

In recent times, the state of climate earth is of concern to many people. Accounts of global warming, ozone holes, floods, droughts, and year-to-year variability of the weather in the decade of the SO's appear in popular media. Much attention has been focused on the possibility of growing crops in a changing environment (Rosenberg, 1981). Actual measurements of changing concentrations of trace gases in the atmosphere give credence to some of these fears (Schneider, 1990). Their actual impact on our weather is, however, controversial (Schneider, 1990). Computer models describing the atmosphere responding to these changes in gaseous composition predict ...


Woolly Cupgrass Biology And Management, Michael D. K. Owen Dec 1990

Woolly Cupgrass Biology And Management, Michael D. K. Owen

Proceedings of the Integrated Crop Management Conference

Woolly cupgrass (Eriochloa villosa [Thumb.] Kunth.) is a relatively new weed in Iowa. Woolly cupgrass is native to East Asia, specifically China and Korea, and was first reported in the United States during the 1940's. The first identified infestation in Iowa was located in Ringgold County and reported in 1957. Since then, economically important infestations have been discovered throughout Iowa, Illinois, Minnesota, and Wisconsin. Recent estimates suggest that woolly cupgrass infests approximately 7 to 10% of the row crop acres in Iowa. While this weed can be found in most areas of Iowa, localized and severe infestations occur in ...


Fertilizer Placement Consideration For Conservation Tillage, R. M. Cruse Dec 1990

Fertilizer Placement Consideration For Conservation Tillage, R. M. Cruse

Proceedings of the Integrated Crop Management Conference

The environment surrounding plant roots is extremely complex and variable. For example, it is not uncommon for the surface one to two inches of soil to be very dry while very wet conditions exist at deeper areas within the root zone. Surface soil temperatures may differ by 20 °F or more from that observed at deeper layers within the rooting zone. A zone of compactions causes by wheel traffic may create very different conditions on one side of a crop row compared to the other side where no traffic occurs. The environmental variations occurring in the root zone tend to ...


Farmstead Well Assessment, Richard O. Pope Dec 1990

Farmstead Well Assessment, Richard O. Pope

Proceedings of the Integrated Crop Management Conference

Agricultural management practices have increasingly come under general scrutiny as potential sources of water supply contamination. The 1987 Iowa Groundwater Protection Act set a goal of determining these potential contamination sources and to eliminate contamination and restore water quality to the greatest extent practical. One clearly documented path of Iowa groundwater contamination is through farmstead wells. Farmstead well assessment is an organized means to look at farm activities that involve either handling or generation of contaminants near the well head.


Lupin Logic Number 6, Peter Nelson Dec 1990

Lupin Logic Number 6, Peter Nelson

Lupin Logic

Contents

The lupin breeders of Western Australia

Lupin varieties for 1991 by John Gladstones

Prospects for the next few years

Cucumber Mosaic Virus (CMV) testing

Prospects brighten for Koreanmarket by Rory Coffey, Grain Pool of W.A.

1989/90 Pool payments


Analysis And Formulation Of Food Crop Policy For Indonesia, Stanley R. Johnson, William H. Meyers, Helen H. Jensen, Paul M. Heytens, Basile P. Goungetas, Thulasiram Kesavan, Gary L. Stampley, Patrick C. Westhoff, Jori Elisiana, Justo Manrique Dec 1990

Analysis And Formulation Of Food Crop Policy For Indonesia, Stanley R. Johnson, William H. Meyers, Helen H. Jensen, Paul M. Heytens, Basile P. Goungetas, Thulasiram Kesavan, Gary L. Stampley, Patrick C. Westhoff, Jori Elisiana, Justo Manrique

CARD Staff Reports

This study of Indonesia's food policy formulation was initiated in February 1989. The study, conducted in collaboration with the Ministry of Agriculture, was funded by the U.S. Agency for International Development. Junior Minister Sjarifuddin Baharsjah of the Ministry of Agriculture, and Faisal Kasryno, director of the Bureau of Planning, were on the study's steering committee and helped to plan, organize, and implement the study and associated workshops. Their support of efforts to enhance the Ministry's capabilities for policy analysis greatly benefited the course of study activities.


Elliptical Combing Motion For Harvesting Bell Peppers, J. H. Wilhoit, George A. Duncan, Larry G. Wells Nov 1990

Elliptical Combing Motion For Harvesting Bell Peppers, J. H. Wilhoit, George A. Duncan, Larry G. Wells

Biosystems and Agricultural Engineering Faculty Publications

A new concept for mechanically harvesting bell peppers, intended specifically for multiple-pass harvesting, utilized spaced horizontal fingers combing vertically upward through plant foliage in an elliptical path alternating from both sides of the row. An apparatus based on this concept was designed and built, and harvest tests were conducted to determine the effect of two main machine operating parameters, vertical picking speed and disk angle. Harvesting performance was evaluated in terms of harvest efficiency, fruit damage, and plant damage as it related to multiple-pass harvesting. Fruit removal, both harvestable size and immature, increased significantly as vertical picking speed increased. Branch ...


Lupin Logic Number 5, Peter Nelson Nov 1990

Lupin Logic Number 5, Peter Nelson

Lupin Logic

Contents

The 1991 lupincrop starts now with high quality seed

- Why test the seed

- Are farmers using the tests?

- Sample size and cost

Currency fluctuations - efffect on equity by Trevor Lovelle, Grain Pool of WA


Lupin Logic Number 4, Peter Nelson Oct 1990

Lupin Logic Number 4, Peter Nelson

Lupin Logic

Contents

Lupin harvesting

- Seed for 1991

- Green radish

- Calculating harvest losses

Deacreasing lupin harvesting losses by Edward Blanchard

- Cutterbar modifications

- Improving crop flow

Stubble survey by Wes Horwood

Seminar

Production and price outlook -1990

Food for thought


Genetic Diversity For Restriction Fragment Length Polymorphisms And Heterosis For Two Diallel Sets Of Maize Inbreds, A. E. Melchinger, M. Lee, K. R. Lamkey, A. R. Hallauer, W. L. Woodman Oct 1990

Genetic Diversity For Restriction Fragment Length Polymorphisms And Heterosis For Two Diallel Sets Of Maize Inbreds, A. E. Melchinger, M. Lee, K. R. Lamkey, A. R. Hallauer, W. L. Woodman

Agronomy Publications

Changes that may have occurred over the past 50 years of hybrid breeding in maize (Zea maize L.) with respect to heterosis for yield and heterozygosity at the molecular level are of interest to both maize breeders and quantitative geneticists. The objectives of this study were twofold: The first, to compare two diallels produced from six older maize inbreds released in the 1950's and earlier and six newer inbreds released during the 1970's with respect to (a) genetic variation for restriction fragment length polymorphisms (RFLPs) and (b) the size of heterosis and epistatic effects, and the second, to ...


Lupin Logic Number 3, Peter Nelson Sep 1990

Lupin Logic Number 3, Peter Nelson

Lupin Logic

Contents

Heliothis by Kevin Walden

- Life cycle

- Research

- Walden's prediction for 1990

- Monitoring

- When to spray

- Heliothis - what to spray with

Superphosphate - Not just how much, but how much? where? and with what by Ron Jarvis

- Machinery modification

1989/90 Pool payments


Soybean Chlorosis Studies On High Ph Bottomland Soils, E. J. Penas, R. A. Wiese, R. W. Elmore, G. W. Hergert, R. S. Moomaw Sep 1990

Soybean Chlorosis Studies On High Ph Bottomland Soils, E. J. Penas, R. A. Wiese, R. W. Elmore, G. W. Hergert, R. S. Moomaw

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

Soybean varieties are different in tolerance to lime-induced chlorosis. Field trials were conducted to evaluate variety performance on soils where chlorosis in soybeans was a known problem. Thirty-six varieties out of 177 were identified as tolerant to soil conditions that cause chlorosis. Eleven varieties of these 36 were found to have the most consistent yield performance on high pH soils. Tolerant varieties must be planted at adequate densities for best performance. A seeding rate of 13.5 seeds per foot of row, the highest seeding rate employed, did not appear to maximize yield on soils where chlorosis was severe. On ...


Farm-Level Evaluation Of Planting Flexibility Proposals For The 1990 Farm Bill, Effects On Use Of Corn Rootworm Insecticides And Nitrogen, Derald J. Holtkamp Sep 1990

Farm-Level Evaluation Of Planting Flexibility Proposals For The 1990 Farm Bill, Effects On Use Of Corn Rootworm Insecticides And Nitrogen, Derald J. Holtkamp

CARD Staff Reports

Since the 1985 Food Security Act (1985 FSA), increased concern for environmental and health risks associated with the use of chemicals in U.S. agriculture has changed the focus of legislative debate. One of the major responses to these concerns has been discussion of ways to give farmers greater flexibility in planting. Those proposing more flexibility promote it as a means of encouraging crop rotations and other alternatives to intensive chemical use. This study investigates the effectiveness of such provisions for (1) shifting rotations and (2) reducing applications of corn rootworm insecticide and nitrogen on a case-study Iowa farm. A ...


Lupin Logic Number 2, Peter Nelson Aug 1990

Lupin Logic Number 2, Peter Nelson

Lupin Logic

Contents

Aphids

- Population increase

- Population decrease

- Aphid species

- Time of attack

- Damage to crop

Stubble handling seeders by Glen Riethmuller

Lupin Marketing by Rory Coffey

- Saudi Arabia

- Japan

- Lupin vs protien by-products

1989/90 Lupin Pool payments