larsen.timothy.uniformity: Uniformity trial of timothy grass in Norway

In kwstat/agridat: Agricultural Datasets

Uniformity trial of timothy grass in Norway

Description

Uniformity trial of timothy grass in Norway

Usage

data("larsen.timothy.uniformity")

Format

A data frame with 960 observations on the following 3 variables.

yield

plot yield, kg

row

row ordinate

col

column ordinate

Details

The experiment was probably conducted shortly before 1898. Ehrenberg says the data come from Norway.

The test plot was a 3-year old Timothy grass meadow, uniform to the eye. The individual plots were square 1/16 are in size. An are is 10m x 10m, so 1/16 are is 2.5m x 2.5m

Bastien Larsen sent the data to Ehrenberg, who published the plot yields. Although Ehrenberg does not give the dimensions of the entire field, we can figure that out using 3 facts. Fact 1: The other uniformity trials in Ehrenberg's paper are given column-wise. This was determined by comparing those datasets with other published papers. Fact 2: When all the yield values in Ehrenberg are plotted in time-series format, it is easy to seek peaks in the values that are 80 plots apart. Only a heatmap of 12 plots by 80 plots has a reasonable amount of "patchiness". All other heatmaps of different dimensions (e.g. 16x60, 20x40, 24x40, 30x32, 32x30, etc show streaks). Fact 3: The holtsmark.timothy.uniformity data shows the same spatial pattern, but at lower resolution.

Field width: 12 plots * 2.5 m = 30 m

Field length: 80 plots * 2.5 m = 200 m

Note: The two datasets in agridat, holtsmark.timothy.uniformity and larsen.timothy.uniformity refer to the same trial. Heatmaps show the same trends for the two datasets. The 'larsen' data has been aggregated 2x2 to create the 'holtsmark' data. Both versions appear in published papers and are included here.

Source

Ehrenberg, P. (1920). Versuch eines Beweises für die Anwendbarkeit der Wahrscheinlichkeitsrechnung bei Feldversuchen. Die Landwirtschaflichen versuchs-stationen, 95, 157-294. Table Ih. Page 254-276. https://archive.org/details/dielandwirtschaf9519reun/page/156/ https://www.google.com/books/edition/Die_Landwirtschaftlichen_Versuchs_Statio/h9FGAAAAYAAJ

References

Holtsmark, G and Larsen, B R (1905). Om Muligheder for at indskraenke de Fejl, som ved Markforsog betinges af Jordens Uensartethed. Tidsskrift for Landbrugets Planteavl. 12, 330-351. (In Danish) https://books.google.com/books?id=MdM0AQAAMAAJ&pg=PA330 https://dca.au.dk/publikationer/historiske/planteavl/

Holtsmark, G. and Bastian R. Larsen (1907). Uber die Fehler, welche bei Feldversuchen, durch die Ungleichartigkeit des Bodens bedingt werden. Die Landwirtschaftlichen Versuchs-Stationen, 65, 1–22. (In German) https://books.google.com/books?id=eXA2AQAAMAAJ&pg=PA1

Larsen, B. R. (1898). Om metoder för fältförsök. Ber. Andra nordiska Landsbrukskongressen in Stockholm 1897. P. 72-84. Discussion 85-94. (document not found)

Examples

## Not run: 
data(larsen.timothy.uniformity)
dat <- larsen.timothy.uniformity

library(desplot)
desplot(dat, yield~col*row,
        tick=TRUE, flip=TRUE, aspect=80/12,
        main="larsen.timothy.uniformity")

## End(Not run)

kwstat/agridat documentation built on Dec. 17, 2024, 3:56 p.m.