Uniformity trial of sorghum at Ames, Iowa, 1959.
A data frame with 2640 observations on the following 3 variables.
The uniformity trial was conducted at the Agronomy Farm at Ames, Iowa, in 1959. The field was planted to grain sorghum in rows spaces 40 inches apart, thinned to a stand of three inches between plants. The entire field was 48 rows (40 inches apart), each 300 feet long and harvested in 5-foot lengths. Threshed grain was dried to 8-10 percent moisture before weighing. Weights are ounces. Average yield for the field was 95.3 bu/ac.
Field width: 48 rows * 40 inches / 12in/ft = 160 feet
Field length: 60 plots * 5 feet = 300 feet
Plot yields from the two outer rows on each side of the field were omitted from the analysis.
CV values from this data do not quite match Lessman's value. The first page of Table 17 was manually checked for correctness and there were no problems with the optical character recognition (other than obvious errors like 0/o).
Lessman, Koert James (1962). Comparisons of methods for testing grain yield of sorghum. Iowa State University. Retrospective Theses and Dissertations. Paper 2063. Appendix Table 17. https://lib.dr.iastate.edu/rtd/2063
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## Not run: library(agridat) data(lessman.sorghum.uniformity) dat <- lessman.sorghum.uniformity libs(desplot) desplot(dat, yield ~ col*row, aspect=300/160, tick=TRUE, flip=TRUE, # true aspect main="lessman.sorghum.uniformity") # Omit outer two columns (called 'rows' by Lessman) dat <- subset(dat, col > 2 & col < 47) nrow(dat) var(dat$yield) # 9.09 sd(dat$yield)/mean(dat$yield) # CV 9.2 libs(reshape2) libs(agricolae) dmat <- acast(dat, row~col, value.var='yield') index.smith(dmat, main="lessman.sorghum.uniformity", col="red") # Similar to Lessman Table 1 # Lessman said that varying the width of plots did not have an appreciable # effect on CV, and optimal row length was 3.2 basic plots, about 15-20 ## End(Not run)
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