Physical Sciences and Mathematics Commons^™

Using Interaction In Two-Way Data Tables, Hugh G. Gauch Jr., Richard W. Zobel

Conference on Applied Statistics in Agriculture

Agronomists and breeders frequently collect yield data for a number of genotypes in a number of environments (site-years), resulting in a two-way data table. The Additive Main effects and Multiplicative Interaction (AMMI) model combines regular analysis of variance (ANOVA) for additive main effects with principal components analysis (PCA) for multiplicative structure within the interaction (that is, within the residual from ANOVA). AMMI is effective for (1) understanding genotype-environment interaction, (2) improving the accuracy of yield estimates, (3) increasing the probability of successfully selecting genotypes with the highest yields, (4) imputing missing data, and (5) increasing the flexibility and efficiency of …

The Analysis Of The Additive Mixed Model For Classes Of Non Orthogonal Designs, Christine A. Stidley

Conference on Applied Statistics in Agriculture

Tests for fixed and random effects can be difficult to derive for nonorthogonal designs with mixed models. However, extensions of the intrablock and inter-block analyses of Balanced Incomplete Block Designs can often be obtained. Here we derive the extensions for the broad class of Group Divisible Designs. Decompositions of the design space are used to develop exact tests for fixed and random effects in the additive mixed model with random block effects. Conditions on the design which permit the standard use of the intra-block and inter-block test statistics are given. Important subclasses of Group Divisible Designs include Equireplicate Variance Balanced …

A Combined Analysis Of Experiments When Treatments Differ Among Experiments, Paul N. Hinz, Mario R. Pareja

Conference on Applied Statistics in Agriculture

The advantages of repeating experiments in several locations and years are discussed and standard methods of analysis are reviewed. The methods assume that the same treatments are used in each experiment. This paper discusses a method used for a combined analysis when the treatments represent levels of a quantitative factor but differ among experiments. The method makes use of multiple regression analysis in which a continuous variable represents treatment levels, classification variables represent experiments, and products of the continuous and classification variables represent differences among experiments. The method is illustrated on data from a series of experiments designed to study …

Evaluating The Effect Of Commodity Donation Programs Using The Truncated Normal Distribution, J. William Levedahl

Conference on Applied Statistics in Agriculture

The magnitude of both the displacement of commercial sales and the increase in consumption associated with a commodity distribution program are characterized using the truncated normal distribution. This method is easier to implement and requires less data than previous methods. It is applied to data from the 1986 Survey of TEFAP Recipients and is quite accurate.

Forecasting Corn Ear Weight Using Surface Area And Volume Measurements: A Preliminary Report, Fatu Bigsby

Conference on Applied Statistics in Agriculture

Data from the Corn Ear Weight Study were used to analyze the forecast performance of models estimated using surface area and volune measurements to predict corn ear weight. Two models based on research measurements were compared to models estimated using the operational procedures from the Corn Objective Yield Survey. Research and operational models were estimated both within and across years using data from the 1986 and 1987 Michigan Corn Ear Weight Study. Results show that research models based on surface area and volune measurements have mean square errors that are 32 to 52 percent lower than models estimated using the …

Forecasting Corn Ear Weights From Daily Weather Data, Fred B. Warren

Conference on Applied Statistics in Agriculture

Statistical models were developed to predict the State average grain weight per ear using daily temperature and precipitation data, recorded from May 1 through late July. The required daily weather data was successfully obtained in an operational test of these models for ten major corn producing States in 1988. Relative forecast errors of ear weight averaged almost one-third smaller than those from a regular survey. Additional refinements of the models to make them more responsive to abnormally early adverse weather, as in 1988, are underway.

Kansas Wheat Objective Yield Survey, Eldon J. Thiessen

Conference on Applied Statistics in Agriculture

In response to farmers, millers, and government needs, the USDA began research on objective measurements of wheat yields in 1938. USDA's current objective yield program providing monthly pre-harvest forecasts of wheat production beginning on May 1 now includes 18 states and accounted for 87 percent of the U.S. wheat production in 1988 .

The Wheat Objective Yield Survey is a systematic subsample of the March Agricultural Survey conducted by Kansas Agricultural Statistics as part of the Quarterly Agricultural Survey program of the National Agricultural Statistics Service (NASS). The fields and sample plots within the fields are selected following very carefully …

Model Building To Measure Impact Of Weather On Crop Yields, Arlin M. Feyerherm, Gary M. Paulsen

Conference on Applied Statistics in Agriculture

The object of this research was to identify and evaluate alternatives when building mathematical models to measure the impact of weather on crop yields. Alternatives exist relative to selection of: (1) observational units with attention to size and coverage (areal and temporal), (2) observational periods for defining weather variables, and (3) mathematical forms and types of weather variables to measure impacts of moisture and temperature. The study involved an analysis of four weather-yield functions for winter wheat. The functions represented combinations of levels of two factors: (1) size and coverage of the observational units (plot yields from a multi-state area …

Teaching Statistical Methods To Graduate Students In Colleges Of Agriculture, D. F. Cox

Conference on Applied Statistics in Agriculture

One method of judging the effectiveness of the teaching of statistical methods is to rate the quality of their use in the research journals of the agricultural sciences. A conclusion that improvement is possible is easily supported by such a review. Basic concepts such as the meaning of replication, the definition of an experimental unit and the nature of experimental error are misunderstood, and this leads to faulty analyses and incorrect conclusions. Changes in teaching that would improve the product are not specified easily because research on the topic is difficult. Perhaps more emphasis on the basic concepts of experimental …

Evaluation Of Presentation Graphics For The Agricultural Sciences, Kathy Shelley

Conference on Applied Statistics in Agriculture

Professional-looking text and graphic slides enable an audience to comprehend the main ideas of a presentation more quickly. With the advent of easy-to-use graphic software packages and the affordability of personal computer hardware to run this software, researchers may now prepare their own slides or transparencies. This paper describes basic graphic software design and offers criteria for selection of an appropriate software package for scientific research presentations. Comparisons between two prototype graphics packages, Harvard Graphics and SAS/Graph, are made on the basis of the following selection criteria: (1) basic software design, (2) available hardware, (3) output device drivers, (4) available …

The 2-Sprt As An Alternative To Wald's Sprt When Testing Hypotheses Concerning Insect Populations, Linda J. Young, Jerry H. Young

Conference on Applied Statistics in Agriculture

Exact and Wald's approximations for the operating characteristic and average sample number functions are compared for a sequential probability ratio (SPRT) test commonly used in cotton integrated pest management (IPM) programs in southwestern Oklahoma. The 95th percentile of the sample size is also given. For the same set of hypotheses and stated error probabilities, the exact operating characteristic and average sample number functions and the 95th percentile of sample size are compared for the SPRT and 2-SPRT.

Multiple Regression Analysis Of Soil Properties On Eroded And Native Deep Loess Missouri Soils, S. J. Indorante, J. M. Maatta, R. D. Hammer, J. R. Brown

Conference on Applied Statistics in Agriculture

Researchers have described the difficulty of studying the effects of cultivation on soil properties unless native (uncultivated) areas can be used as a baseline for comparison. Even when suitable areas are located the problems of quantifying and comparing the horizontal and vertical distributions of soil properties remain. Areal distributions of soil surface, subsurface, and upper subsoil properties were compared in cultivated and forested deep loess soils on similar geomorphic surfaces and hillslope positions in two counties adjacent to the Missouri River. A 3-dimensional grid was used to sample selected soils from the summit to the lower backs lope on 3 …

Evaluation Of The Three Plantain (Musa Aab) Cultivars For Agronomic Characteristics, Ahmad R. Rafie, Carlos Medina

Conference on Applied Statistics in Agriculture

Plantains (Musa AAB) are widely used as a source of carbohydrate in Latin America and Africa. The most commonly grown plantain cultivar, "Horn plantain" is tall which makes it susceptible to losses by wind. Recently, two dwarf mutants of "Horn plantain" were selected. A randomized complete block design experiment with four replications was conducted to compare the agronomic characteristics of the dwarf mutants with those of the traditional cultivar. The data was analyzed as if the experiment was strip-plot design with cultivar as the horizontal factor and harvest as the vertical factor. "Analysis of variance" and "Least significant difference" test …

Comparison Of Hop Downy Mildew Epidemics Using Spatial Analysis, J. Richard Alldredge, Dennis A. Johnson, Rochelle Allwine

Conference on Applied Statistics in Agriculture

Methods of spatial analysis including distribution fitting, variance-to-mean ratios, Morisita's index, doublet and runs analyses, Greig-Smith analysis and variography were used to investigate the spatial pattern of hop downy mildew. Use of these methods allowed examination of the spatial structure of hop downy mildew at three spatial scales: within hop hills, between nearby hop hills, and for hop hills more separated in space. The results obtained were in general agreement for methods of analysis which assessed spatial structure at the same spatial scale with the exception of Morisita's index of clumping which did not identify clumps of diseased hills of …

The Use Of Near Infrared Reflectance For Evaluating Cotton Fineness And Maturity, Vicki A. Lancaster, Steven M. Buco, Joseph G. Montalvo Jr.

Conference on Applied Statistics in Agriculture

The U.S. Department of Agriculture has proposed to develop Ii new high speed, high volume technique to assess cotton quality. This goal has led us to investigate the feasibility of near infrared reflectance spectroscopy as a technique for evaluating cotton fiber perimeter size and wall thickness, two of the physical characteristics used in the evaluation of cotton fineness and maturity.

In order to isolate the effects of perimeter size and wall thickness, nineteen cotton samples were selected on the basis of their having a nonsignificant correlation between these 2 measurements. The reflectance spectra from 1100 to 2500 nanometers was recorded …

Statistical Design And Analysis Of Dairy Nutrition Experiments To Improve Detection Of Milk Response Differences, Stephen R. Lowry

Conference on Applied Statistics in Agriculture

The objective of many dairy nutrition experiments is to determine the effect of certain dietary treatments on milk production and quality responses. However, milk responses are quite variable and cows (experimental units) are expensive and have substantial maintenance costs. This manuscript reviews principles for planning to obtain good data relevant to the hypothesis, experimental design to control inherent variation, and interpreted analyses to facilitate understanding of dairy relationships. Emphasis is placed on assurance that milk response differences due to dietary treatments will have a high probability of being detected as significant. Guidelines addressing these principles along with suggested computer programs …

Statistical Models For Analysis Of Dose-Response Data, Karan P. Singh

Conference on Applied Statistics in Agriculture

In this paper we propose three families of functional models for analysis of dose-response data. The first family is for modeling data which have a steep sloping line for an ascending portion of the response curve and a plateau representing maximum response or a sloping line representing little response at higher application levels. The second family is for modeling data which represent a steep sloping line on the ascending portion of the response curve and a declining curvature for declining response at higher application levels. The third family is for fitting data which show an initial plateau followed by increased …

Analysis Of A Two Lactation Target Animal Safety Study Of Somidobove Sustained Release Injection In Multiparous Dairy Cows, L. V. Tonkinson, R. P. Basson, R. K. Mcguffey, A. Deldar, L. Fisher

Conference on Applied Statistics in Agriculture

An overview is given of the primary basis for the scientific inference that somidobove sustained release injection is safe for multiparous dairy cows. The process of analysis and interpretation of the voluminous data collected from a target animal safety study which started with 28 cows and lasted two lactations is described. This was a repeated measures study with most of 60 variables being measured or summarized every 28 days resulting in approximately 1500 measurements per cow. The statistical analysis was designed to screen the variables for biological change caused by treatment and consisted of a univariate analysis of variance for …

Statistical Issues In Studies Of Thermoregulation In Farm Animals, A. M. Parkhurst, G. L. Hahn

Conference on Applied Statistics in Agriculture

Patterns of tympanic temperature response were identified in ad-lib-fed cattle exposed to constant or cyclic (±7 C) conditions at two levels of air temperature: 10 C and 28 C. Use of time series analysis following the DDS approach of Pandit and Wu indicate the thermoregulatory control dynamics for steers at 28±7 C were markedly different from those at the other conditions. Preliminary evaluations using the ideas of chaos and non-linear dynamics show promise of further characterization of stress responses in farm animals.

Nonlinear Modeling Of Ph Decline In Beef Carcasses, James R. Schwenke, Curtis L. Kastner

Conference on Applied Statistics in Agriculture

Electrical stimulation speeds the rate of pH decline in beef muscle. A study was conducted to evaluate an electrical stimulation (ES) method for beef sides and its effect on pH decline compared to non-stimulated control counterparts using nonlinear modeling. The pH of each carcass in the study was measured at selected times over a 24-hour time period postmortem. A statistical methodology is described for comparing two treatments based on the mean pH decline over time. The repeated measures structure of the data is incorporated into the statistical procedure. A nonlinear exponential decay model is used to characterize the mean pH …

Recent Developments In Variance Component Estimation, R. R. Hocking

Conference on Applied Statistics in Agriculture

The purpose of this paper is to introduce some recent developments in variance component estimation with emphasis on techniques which provide diagnostic information on the data and the model assumptions. This paper concentrates on the balanced data situation, but suggests a natural extension to the case of unbalanced data. The basic ideas are illustrated by several numerical examples.

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

Conference on Applied Statistics in Agriculture

These proceedings contain papers presented at the first annual Kansas State University Conference on Applied Statistics in Agriculture, held in Manhattan, Kansas, April 30 through May 2, 1989.

Small Farmland Experimental Catchments In Western Australia, K J. Bligh

Resource management technical reports

No abstract provided.

Finishing Kimberley Cattle In The South-West, Brian L. Mcintyre, Bill Ryan, Neville Macintyre

Journal of the Department of Agriculture, Western Australia, Series 4

The idea of integrating the Kimberley cattle industry with that in the south-west of Western Australia is no new, but until recently it had not been critically evaluated.

Over the past eight years the Department of Agriculture's Beef Cattle Branch has been assessing the performance of Kimberley cattle transported south for finishing in the agricultural areas.

This research has show that Kimberley weaners can be finished in the south, and that under the present (December 1988) economic conditions it is more profitable than running breeding cattle in the south-west and comparable with fattening store steers.

Farming Systems Research/Extension And The Concepts Of Sustainability, Charles A. Francis, Peter E. Hildebrand

Department of Agronomy and Horticulture: Faculty Publications

Farming Systems Research and Extension (FSR/E) has strongly influenced the direction of agricultural development over the past two decades. Involving farmers, change agents and researchers, this participatory approach to technological improvement has evolved as an efficient means to develop individual components and more integrated systems that are uniquely suited to specific biophysical and socioeconomic conditions. Farmers with similar conditions and for whom specific recommendations are appropriate are grouped, in FSR/E, into identifiable Recommendation Domains. The technologies recommended conform with the biophysical and socioeconomic constraints that create environments within the domains, based on the philosophy that new technologies must conform with …

Land Capability Assessment Methodology For Rural-Residential Development And Associated Agricultural Land Uses, M R. Wells, Peter Donald King

Land resources series

No abstract provided.

Land Capability Study Of The Shires Of Mandurah And Murray, M R. Wells

Land resources series

No abstract provided.

The Effect On Farm Profit Of Conserving Stubble To Prevent Wind Erosion, A D. Bathgate

Journal of the Department of Agriculture, Western Australia, Series 4

Over-grazing of stubbles is a major cause of winf erosion on WesternAustralian farms. Stubble contributes to the 'roughness' of the paddock; as the roughness is reduced, the risk of winf erosion is increased.

The risk of lupinosis in sheep has previously reduced the likelihood of lupin stubble being over grazed, but the development of Gungurru, a phomopsis-resistent variety of lupin, has increased the potential for over-grazing and hence the probability of wind erosion.

This article describes the economic benefit (or cost) of conserving stubble at the conservation standards.