Agriculture Commons^™

Bias In Principal Components Analysis Due To Correlated Observations, Hong Jiang, Kent M. Eskridge

Conference on Applied Statistics in Agriculture

A common practice in many scientific disciplines is to take measurements on several different variables on each unit from a designed experiment. This practice is cost efficient and results in data that may be analyzed using multivariate statistical methods. Usually, principal components analysis (PCA) is conducted by decomposing the covariance matrix of the several dependent variables using eigenanalysis without accounting for possible correlations among the observations. To evaluate how correlated observations bias PCA results, we used algebraic derivation and simulation for several different types of correlation structures. Our results indicated that sampling error generally had a much larger impact on …

Development Of Wild Oat Seed Dispersal Distributions Using An Individual-Plant Growth Simulation Model, William J. Price, Bahman Shafii, Donald C. Thill

Conference on Applied Statistics in Agriculture

An individual-plant growth simulation model for quantifying competition between spring barley and wild oat has been previously described (price, Shafii, and Thill, 1994). Individual plants within a population were modeled independently and competition between plants was determined by resource demand within plant specific areas-of-influence. Calibration of the model to spring barley and wild oat biomass data was performed and shown to have a high degree of accuracy under mono culture conditions. The work presented here applies the specified model to a larger scale simulation for the purpose of demonstrating seed dispersal in wild oat. This is accomplished by breaking the …

Application Of Computer Intensive Methods To Evaluate The Performance Of A Sampling Design For Use In Cotton Insect Pest Management, J. L. Willers, W. L. Ladner, J. M. Mckinion, W. H. Cooke

Conference on Applied Statistics in Agriculture

A scouting protocol for cotton insect pests was developed which combines high resolution, multispectral remotely sensed imagery with a belt transect that crosses rows of cotton. Imagery was used to determine sample site selection while estimating plant bug abundance in a more than 200 ac. cotton field in 1997. Tarnished plant bug (Lygus lineolaris) counts were acquired using a standard drop cloth for each of eight rows along a transect. The sample data indicated that plant bug population densities spatially vary as a function of different spectral (color) classes present on the imagery. We postulate that such classified …

Using Nonlinear Growth Curves To Estimate Heat Stress In Processing Feedlot Cattle, A. M. Parkhurst, T. L. Mader

Conference on Applied Statistics in Agriculture

Summertime heat waves cause excessive discomfort and, in extreme cases, death of feedlot cattle. During such emergencies, extension specialists are called upon for recommendations of management practices to minimize heat stress. Since moving cattle is believed to raise body temperature 1 degree, one recommendation is to move cattle before mid-day or reschedule to another day. More knowledge of body temperature dynamics could lead to more specific recommendations of how far cattle can be moved without stress. Several models are investigated - especially those involving exponential growth(challenge) and decay (recovery) such as the bi-exponential, single compartment and other models in pharmacokinetics. …

Point Estimators Of Heritability Based On Confidence Intervals: A Closed-Form Approximation To The Reml Estimator, Brent D. Burch, Ian R. Harris

Conference on Applied Statistics in Agriculture

Estimating heritability, the proportion of variation in phenotypic values due to (additive) genetic effects, is an important subject matter to plant and animal breeders alike. In most applications there is not an analytic expression for the restricted maximum likelihood (REML) estimator of heritability since it is obtained via an iterative procedure. The focus of this paper is to find a closed-form approximation to the REML estimator of heritability for those scenarios in which mixed linear models having two variance components are appropriate. This procedure is equivalent to constructing approximate pivotal quantities and thus confidence intervals for heritability. See Burch and …

Establishing Population And Individual Bioequivalence Confidence Intervals, Feng Yu, Linda J. Young, Gary R. Stevens

Conference on Applied Statistics in Agriculture

Average bioequivalence is used to assess pharmacokinetic properties of proposed generic drug before they are marketed. The limitations of average bioequivalence have led the U.S. Food and Drug Administration to propose the use of popUlation bioequivalence and individual bioequivalence. In this study, bootstrap confidence intervals were used to evaluate population bioequivalence and individual bioequivalence in the context of a 2 x 4 crossover experimental design. Two bioequivalence criteria were compared: the mean-squared difference criterion and a probability-based criterion. Simulations were conducted to study the properties of the bootstrap confidence intervals under each criterion in establishing population bioequivalence or individual bioequivalence. …

Application And Comparison Of Three Spatial Statistical Methods For Mapping And Analyzing Soil Erodibility, George Gertner, Guangxing Wang, Pablo Parysow, Alan Anderson

Conference on Applied Statistics in Agriculture

The Revised Universal Soil Loss Equation (RUSLE) is a model to predict longtime average annual soil loss, related to rainfall-runoff, soil erodibility, slope length and steepness, cover management, and support practice. The soil erodibility factor K accounts for the influence of soil properties on soil loss during storm events in upland areas.

In this paper, ordinary kriging, sequential Gaussian and indicator simulation methods were used and compared for spatial prediction and uncertainty analysis of soil erodibility based on a data set from a very intensive soil survey (524 observations, 10 m by 10 m grid). Half the data was used …

Yield Prediction In 60ft2 Grids, S. Aref, D. G. Bullock

Conference on Applied Statistics in Agriculture

Large detailed yield databases incorporating GPS makes it possible to predict yield on a small scale. The objective of this study was to determine how closely yield could be predicted in grids of 60-ft² units. Com and soybean yields were averaged to the 60-ft² grid. The yields were modeled on previous yields, soil fertility, soil type, and terrain variables. Soil fertility variables were kriged from a I-acre grid to the 60-ft² grid. Terrain data and soil type data were available at the same scale. Multiple regression models and models with spatial correlation determined from yield semivariograms differed …

Exploring Factors Affecting Atrazine Concentration In The Big Blue River Basin, Steven R. Kirby, Linda J. Young

Conference on Applied Statistics in Agriculture

Atrazine is a herbicide commonly used on corn and sorghum. Consumption of atrazine adversely affects humans. Environmental factors are related to atrazine concentration in the surface waters of the Big Blue River Basin using regression techniques. The usefulness of environmental factors as predictors of surface water atrazine contamination appears to depend on the time period.

Analysis Of The Allelopathic Potential Of Rice Using K-Means Clustering Of Hplc Chromatograms, Edward E. Gbur, John D. Mattice, Robert H. Dilday

Conference on Applied Statistics in Agriculture

Allelopathy is the ability of an organism to affect the growth of another organism through the introduction of chemical compounds into the environment. Several researchers have reported rice inhibition of the growth of weed species such as barnyard grass and ducksalad. The objective of this study was to relate patterns found in HPLC chromatograms for leaf extracts of different rice accessions to their weed control activity. K-means cluster analysis was performed on 20 peak heights from chromatograms from 40 rice accessions. The resulting clusters corresponded to observed behavior of the accessions reported in other sources. Stepwise discriminant analysis was used …

An Introduction To Model Selection For Quantitative Trait Locus Analysis In Polyploids, R. W. Doerge, Bruce A. Craig

Conference on Applied Statistics in Agriculture

Substantial gains have been made in locating regions of agricultural genomes associated with characteristics, diseases, and agroeconomic traits. These gains have relied heavily on the ability to estimate the association between DNA markers and regions of a genome (quantitative trait loci or QTL) related to a particular trait. The majority of these advances have focused on diploid species (two homologous chromosomes per set), even though many important agricultural crops are, in fact, polyploid (more than two homologous chromosomes per set). The purpose of our work is to initiate an algorithmic approach for model selection and QTL detection in polyploid species. …

A Fertilizer-Rate Experiment Involving Young Citrus Trees: Does More Fertilizer Mean Higher Producing Trees?, John A. Cornell

Conference on Applied Statistics in Agriculture

Citrus growers are interested in making money. So, the most common practice among growers is to push young trees into early production by the application of high amounts (rates) of fertilizer. This practice can lead to disaster in terms of tree formation (canopy shape) and production stress. In contrast, when the applied fertilizer approaches both the optimum rate and the optimum N -P -K -Ca ratio for citrus, then the trees are more uniform in size and with compact canopies and the incidence of decline is less. Cordieropolis station in Sao Paula, Brazil, is the site of a large 3-component …

Editor's Preface, Table Of Contents, And List Of Attendees, George A. Milliken

Conference on Applied Statistics in Agriculture

These proceedings contain papers presented in the twelfth annual Kansas State University Conference on Applied Statistics in Agriculture, held in Manhattan, Kansas, April 30-May 2, 2000..

1999 Oregon Winery Report, Oregon Agricultural Statistics Service, Homer K. Rowley, Bruce Eklund, Douglas C. Marousek, Ronald F. Kriesel

Oregon Wine Board Documents

This statewide survey report on Oregon wineries covers crush, equivalent wine production, inventory and equivalent inventory, and sales. The report also contains some comparisons of data for 1998 and 1999. According to this report, Oregon saw the second-largest harvest in terms of tonnage of crushed grapes; additionally, cooperage capacity continued to grow.

New Generation Cooperatives, Jeffrey S. Royer

Cornhusker Economics

New Generation Cooperatives (NGCs) are farmerowned cooperative organizations generally characterized by an involvement in value-added processing activities and a linkage of producer capital contributions to product delivery rights. Although the earliest NGCs were established in the North Central United States, particularly in North Dakota and Minnesota, interest in this organizational form has spread to other regions of the country because of the perceived success of many of these cooperatives. Recently, NGCs have been involved in traditional value-added activities such as corn sweetener production, sugar beet processing, pasta production and hog operations, as well as activities related to emerging niche markets …

Producer Ownership In The Marketing Chain, Allen Prosch

Cornhusker Economics

Pork producers continue to seek avenues to retain ownership of their product as it moves along the “Pork Supply Chain.” The activities being considered have the potential to improve the return that producers receive for their products. Many of the activities have broader implications to all production agriculture.

Divide And Conquer Marketing, Deb Rood

Cornhusker Economics

Why is commodity marketing so hard to learn? Whenever you start you become overwhelmed with information. You hear from one advisory telling you to sell puts, another is telling you to buy calls. You are told to cover your costs of production. They want you to watch the charts for a head and shoulders, which you thought was in the shampoo isle at the grocery store. Learning marketing can be confusing and daunting, causing many producers to just give up. But the hard fact is, that if you are selling grain or livestock some basic knowledge in marketing is a …

Fuel Prices And Farm Costs, Larry L. Bitney, Wade Nutzman

Cornhusker Economics

We have received questions lately on the impact of increased fuel prices on Nebraska's agricultural producers. While the direction is certain, the magnitude of the effect is a difficult question to answer. Strategies employed by individual producers that we have visited with range from a few who locked in diesel fuel prices at lower levels, to those who were waiting as long as possible to buy their fuel for spring work.

Seed Fairs In Seed Security Programmes, Sarah Kimakwa

Faculty Publications

No abstract provided.

Seven Hills Winery Spring 2000 Newsletter, Casey Mcclellan

Seven Hills Winery Documents

This file copy of a newsletter (Letter No. 2) from Seven Hills Winery announces the grand opening of the winery and tasting room in May 2000. The winery and tasting room is in the Whitehouse-Crawford Building, a converted mill building located in downtown Walla Walla, Washington. This newsletter also announces the release of wines from 1997-1999 at their Spring Tasting Weekends events and includes an order form.

Louisiana Agriculture Spring, 2000, Lsu Agcenter

Louisiana Agriculture

No abstract provided.

Seed Fairs In Seed Security Programmes, Sarah Kimakwa

Sarah Kimakwa

No abstract provided.

The Nebline, April 2000

NEBLINE Newsletter Archive from Nebraska Extension in Lancaster County

Contents:
Earth Wellness Festival – A Splashing Success!
Rhubarb in the Garden
Thank You Master Gardeners!
Plant a Tree
Great Plants: 2000 Plants of the Year
Prevent Termites With Landscaping, Home Maintenance
Let’s Make a Difference – Earth Day 2000
A Plague of Rabbits
What’s Buggin’ You?
Effect of Soaring Fuel Prices on Cost of Field Operations
Managing Fertilizer Use in Dry Soils
SNAP Producer Alliance Takes Next Steps
The Management Team
Road Maintenance
Rodent Proofing Your Home
Knowledge of Animal Laws Important-State Leash Law
Good Nutrition, Better Health
You Can’t Serve From an Empty Plate. So, F-E-A-S-T Frequently
Focus …

Ard News April 2000

Agricultural Research Division: News and Annual Reports

CONTENTS:

Comments from the Dean
Procedures for Processing Grant Proposals
Criteria for Authorship of Scientific Papers
Change in the Indirect Cast Rate for Grants
Proposals Submitted for Federal Grants
Grants and Contracts Received February and March 2000
Change in the Indirect Cast Rate for Grants
Proposals Submitted for Federal Grants
Grants and Contracts Received February and March 2000

Urbanization Of Rural Landscapes Ii: Second Syllabus And Teaching Materials From A University Course, Spring 2000, Charles A. Francis, David Mortensen

CARI Extension and Education Materials for Sustainable Agriculture

Editors' Introduction and Executive Summary 2

Table of Contents 3

Other Volumes in Series and Ordering Information 4

Syllabus, Spring 2000 5

Principles of Planning for Lincoln and Lancaster County, Student Reports, 2000 9

Recommended Amendments to the 1994 Comprehensive Plan, Student Report, 1999 35

Course Evaluations, Spring 2000, by students and faculty evaluators 45

Resource Materials, some with Student Summaries (with permission of the publishers) 50

Stevens Creek study heralds new era for city, Lincoln Journal-Star 50

Developer, city closer on north Lincoln project, Lincoln Journal-Star 51

Study outlines new vision for Lincoln-Omaha corridor, Lincoln Journal-Star 53

Smart growth …

Leafhoppers In The Home Garden, Jay B. Karren

All Current Publications

Leafhoppers are common problems in home gardens and orchards throughout the state of Utah. There are many species of leafhoppers, several of which attack apples, roses, grapes, and potatoes. Most species overwinter in the egg stage in the bark of the host plant or among the fallen host plant leaves.

Millipedes, Jay B. Karren, Alan H. Roe

All Current Publications

Millipedes are related to trilobites, spiders and ticks, sowbugs, and crayfish, centipedes, and insects. Each group represents a different class of arthropods. Millipedes or "thousandlegged worms" include over 800 species of the class Diplopoda in North America.

Feedgrain Prices, Hog Production And Fixity, Glenn A. Helmers

Cornhusker Economics

One of the characteristics of the feedgrain sector in recent years has been its large year to year price fluctuations. There are two possible causes for these fluctuations in prices: 1) short-run (one year or less) changes in domestic and export demands, and (2) weather-related shifts in the supply of feedgrains in the face of a feedgrain demand, which exhibits little price responsiveness in the short-run. While both aspects may be involved, here we will examine only the second issue of why fluctuations in domestic feedgrain supply result in such wide fluctuations in prices, due to feedgrain demand being so …

The Risks And Benefits Of Genetically Modified Crops: A Multidisciplinary Perspective, Garry D. Peterson, Saul Cunningham, Lisa Deutsch, Jon Erickson, Allyson Quinlan, Ernesto Ráez-Luna, Robert Tinch, Max Troell, Peter Woodbury, Scot Zens

Dartmouth Scholarship

Worldwide, the area planted in genetically modified (GM) crops has increased dramatically in recent years. Between 1996 and 1999, it rose from 1.6 X 10⁶ ha to more than 35 X 10⁶ ha (James 1998, May 1999). This rapid increase has provoked an explosion of concern, particularly in Europe, over the health and environmental impacts of these crops. Despite claims of safety and warnings against popular panic, public concern over GM crops has resulted in changes in their marketing, labeling, planting, and trade. These changes have fueled an increasingly heated debate among environmental advocates, critics of industrial agriculture, …

Transgenic Sugarbeets: Potential For Increased Farm Income, Dillon Feuz

Cornhusker Economics

Sugarbeets are grown on nearly 1.5 million acres in the United States, with a production value in excess of $1.1 billion for the 1997 crop year. In Nebraska, sugarbeets are grown on over 65,000 acres in a dozen western counties generating over $36 million dollars in farm revenue. There are two active sugar refineries in the area that contribute to the local economy in terms of value added activity.