Multi-year uniformity trial in Denmark

Usage

data("hansen.multi.uniformity")

Format

A data frame with 662 observations on the following 6 variables.

field: field name
year: year
crop: crop
yield: yield (percent of mean)
row: row
col: column

Details

Uniformity trials were carried out between 1906 and 1911 on two fields at Aarslev, Denmark. The yield values are expressed as percent of mean yield for the year.

The scale on the map in Hansen shows "Alen" as the scale. See https://en.wikipedia.org/wiki/Alen_(unit_of_length) The Danish alen = 62.77 cm.

Field A2:

Based on the map, the field is approximately 60 alen x 70 alen (38 m x 44 m), but the orientation of the field is not clear. Plots are probably circa 7.4 m on a side.

Divided into 30 plots – 6 strips of 5. The crops grown were: 1907 oats, 1908 rye, 1909 barley, 1910 mangolds, 1911 barley.

Sanders said: There appeared to be two printer errors in the paper. In field A2 the yields given for 1908 add up to 3010 instead of 3000: reference to the Fig. 6 given there seemed to indicate that the excess lay in row 3 and eventually it was decided to reduce plots 3c to 96 and 3f to 84.

Field E2:

Field is approximately 120 alen x 200 alen (76m x 125m). Plots are probably circa 8-9m on a side.

Divided into 128 plots: 16 strips of 8. Crops grown: 1906 oats, 1907 barley, 1908 seeds, 1909 rye.

Sanders said, There was a remarkable oscillation in fertility across field E2 in one direction, the 1st, 3rd, ... 15th strips (columns) consistently giving much higher yields than the 2nd, 4th, ... 16th strips (columns). In fact in the four years the odd numbered strips gave a total yield of 27,817, as compared to 23,383 for the even numbered strips. This oscillation apparently arose as a legacy of the old practice of ploughing in high ridges: the tops of the ridges exhibited greater fertility than the borders of the furrows, so that soil was worked from the former to the latter and the field leveled out. This meant that over the site of the old furrows there was a good depth of rich soil, whilst it was very shallow where the ridges had been. The strips were so arranged as to cover the site of the furrow and of the ridge alternately, with the result noted above. Sanders: In order to escape this variation, the table was condensed by taking 2 strips together (so that the new strips each included the whole of one of the old "lands") making it an 8 by 8 square.

Sanders said: In field E2 in 1908, column 10 sums to 791 instead of 786 as shown: reference to Fig. 13 indicated that the yield of plot 10g should probably have been 92 instead of 97.

The version of the data in the package uses the changes suggested by Sanders.

Data were typed by K.Wright.

Source

Hansen, Niels Anton (1914). Prøvedyrkning paa Forsøgsstationen ved Aarslev. Page 557 has field A2. Page 562 has field E2. https://dca.au.dk/publikationer/historiske/planteavl

References

Eden, T. and E. J. Maskell. (1928). The influence of soil heterogeneity on the growth and yield of successive crops. Journal of Agricultural Science, 18, 163-185. https://archive.org/stream/in.ernet.dli.2015.25895/2015.25895.Journal-Of-Agricultural-Science-Vol-xviii-1928#page/n175

Sanders, H. G. 1930. A note on the value of uniformity trials for subsequent experiments. The Journal of Agricultural Science. 20, 63-73. https://dx.doi.org/10.1017/S0021859600088626 https://repository.rothamsted.ac.uk/item/97039/a-note-on-the-value-of-uniformity-trials-for-subsequent-experiments

Examples

if (FALSE) { # \dontrun{

  library(agridat)
  data(hansen.multi.uniformity)
  dat <- hansen.multi.uniformity
  
  # Field A2: Average across years
  libs(dplyr,reshape2)
  #dat 

  # Field E2: Match column totals
  #dat 

  # Heatmaps. Aspect ratio is an educated guess
  libs(dplyr, desplot)
  dat <- dat 
  dat 
  dat 

  # Look at correlation of experimental unit plots across years
  libs(dplyr, reshape2, lattice)
  dat <- mutate(dat, plot=paste(row,col))
  mat1 <- filter(dat, field=="A2") 
  splom(mat1, main="hansen.multi.uniformity field A2")
  mat2 <- filter(dat, field=="E2") 
  splom(mat2, main="hansen.multi.uniformity field A2")

} # }