
Uniformity trial of rice
gomez.rice.uniformity.Rd
Uniformity trial of rice in Philippines in 1968.
Format
A data frame with 648 observations on the following 3 variables.
row
row
col
column
yield
grain yield, grams/m^2
Details
An area 20 meters by 38 meters was planted to rice variety IR8. At harvest, a 1-meter border was removed around the field and discarded. Each square meter (1 meter by 1 meter) was harvested and weighed.
Field width: 18 plots x 1 m = 18 m
Field length: 38 plots x 1 m = 38 m
Gomez and Alicbusan (1969) published 4 heatmaps of uniformity trials. Trial I heatmap matches the 3x3 moving average heatmap example below. The field was planted in 1968.
Used with permission of Kwanchai Gomez.
Source
Gomez, K.A. and Gomez, A.A. (1984). Statistical Procedures for Agricultural Research. Wiley-Interscience. Page 481.
References
Gomez, K.A. and R. C. Alicbusan (1969). Estimation of optimum plot size from rice uniformity data. The Philippine Agriculturist. 52, 586-601
Examples
if (FALSE) { # \dontrun{
library(agridat)
data(gomez.rice.uniformity)
dat <- gomez.rice.uniformity
libs(desplot)
# Raw data plot
desplot(dat, yield ~ col*row,
aspect=38/18, # true aspect
main="gomez.rice.uniformity")
libs(desplot, reshape2)
# 3x3 moving average. Gomez figure 12.1
dmat <- melt(dat, id.var=c('col','row'))
dmat <- acast(dmat, row~col)
m0 <- dmat
cx <- 2:17
rx <- 2:35
dmat3 <- (m0[rx+1,cx+1]+m0[rx+1,cx]+m0[rx+1,cx-1]+
m0[rx,cx+1]+m0[rx,cx]+m0[rx,cx-1]+
m0[rx-1,cx+1]+m0[rx-1,cx]+m0[rx-1,cx-1])/9
dat3 <- melt(dmat3)
desplot(dat3, value~Var2*Var1,
aspect=38/18,
at=c(576,637,695,753,811,870,927),
main="gomez.rice.uniformity smoothed")
libs(agricolae)
# Gomez table 12.4
tab <- index.smith(dmat,
main="gomez.rice.uniformity",
col="red")$uniformity
tab <- data.frame(tab)
## # Gomez figure 12.2
## op <- par(mar=c(5,4,4,4)+.1)
## m1 <- nls(Vx ~ 9041/Size^b, data=tab, start=list(b=1))
## plot(Vx ~ Size, tab, xlab="Plot size, m^2")
## lines(fitted(m1) ~ tab$Size, col='red')
## axis(4, at=tab$Vx, labels=tab$CV)
## mtext("CV", 4, line=2)
## par(op)
} # }