eden.potato {agridat} | R Documentation

## Potato yields in response to potash and nitrogen fertilizer

### Description

Potato yields in response to potash and nitrogen fertilizer. Data from Fisher's 1929 paper Studies in Crop Variation 6. A different design was used each year.

### Format

A data frame with 225 observations on the following 9 variables.

`year`

  year/type factor

`yield`

  yield, pounds per plot

`block`

  block

`row`

  row

`col`

  column

`trt`

  treatment factor

`nitro`

  nitrogen fertilizer, cwt/acre

`potash`

  potash fertilizer, cwt/acre

`ptype`

  potash type

### Details

The data is of interest to show the gradual development of experimental designs in agriculture.

In 1925/1926 the potato variety was Kerr's Pink. In 1927 Arran Comrade.

In the 1925a/1926a qualitative experiments, the treatments are O=None, S=Sulfate, M=Muriate, P=Potash manure salts. The design was a Latin Square.

The 1925/1926b/1927 experiments were RCB designs with treatment codes defining the amount and type of fertilizer used. Note: the 't' treatment was not defined in the original paper.

### Source

T Eden and R A Fisher, 1929. Studies in Crop Variation. VI. Experiments on the response of the potato to potash and nitrogen. Journal of Agricultural Science, 19: 201-213.

### References

McCullagh, P. and Clifford, D., (2006). Evidence for conformal invariance of crop yields, Proceedings of the Royal Society A: Mathematical, Physical and Engineering Science, 462, 2119–2143.

### Examples

    data(eden.potato)
    dat <- eden.potato

    # 1925 qualitative
    d5a <- subset(dat, year=='1925a')
    if(require(desplot)){
      desplot(trt~col*row, d5a,
              text=yield, cex=1, shorten='no', # aspect unknown
              main="eden.potato: 1925 qualitative")
    }
    anova(m5a <- aov(yield~trt+factor(row)+factor(col), d5a)) # table 2

    # 1926 qualitative
    d6a <- subset(dat, year=='1926a')
    if(require(desplot)){
      desplot(trt~col*row, d6a,
              text=yield, cex=1, shorten='no', # aspect unknown
              main="eden.potato: 1926 qualitative")
    }
    anova(m6a <- aov(yield~trt+factor(row)+factor(col), d6a)) # table 4

    # 1925 quantitative
    d5 <- subset(dat, year=='1925b')
    if(require(desplot)){
      desplot(yield ~ col*row, d5,
              out1=block, text=trt, cex=1, # aspect unknown
              main="eden.potato: 1925 quantitative")
    }
    # Trt 't' not defined, seems to be the same as 'a'
    require(lattice)
    dotplot(trt~yield|block, d5,
            # aspect unknown
            main="eden.potato: 1925 quantitative")
    anova(m5 <- aov(yield~trt+block, d5)) # table 6

    # 1926 quantitative
    d6 <- subset(dat, year=='1926b')
    if(require(desplot)){
      desplot(yield ~ col*row, d6,
              out1=block, text=trt, cex=1, # aspect unknown
              main="eden.potato: 1926 quantitative")
    }
    anova(m6 <- aov(yield~trt+block, d6)) # table 7

    # 1927 qualitative + quantitative
    d7 <- droplevels(subset(dat, year==1927))
    if(require(desplot)){
      desplot(yield ~ col*row, d7,
              out1=block, text=trt, cex=1, col=ptype, # aspect unknown
            main="eden.potato: 1927 qualitative + quantitative")
    }

    # Table 8.  Anova, mean yield tons / acre
    anova(m7 <- aov(yield~trt+block+ptype + ptype:potash, d7))
    if(require(reshape2)){
    me7 <- melt(d7, measure.vars='yield')
    acast(me7, potash~nitro, fun=mean) * 40/2240 # English ton = 2240 lbs
    acast(me7, potash~ptype, fun=mean) * 40/2240
    }

[Package agridat version 1.16 Index]