mcleod.barley {agridat} | R Documentation

## Multi-environment trial of barley in South Canterbury with yield and yield components

### Description

Yield and yield components for barley with different seeding rates.

### Format

A data frame with 40 observations on the following 10 variables.

`year`

  year, numeric

`site`

  site factor

`rate`

  rate, numeric

`plants`

  plants per sq meter

`tillers`

  tillers per plant

`heads`

  heads per plant

`surviving`

  percent surviving tillers

`grains`

  grains per head

`weight`

  weight of 1000 grains

`yield`

  yield tons/hectare

### Details

Trials were conducted at 5 sites, 3 years in South Canterbury. (not all sites in every year). Values are the average of 6 blocks. In 1974 there was a severe drought. The other years had favorable growing conditions.

### Source

C. C. McLeod (1982). Effects of rates of seeding on barley sown for grain. New Zealand Journal of Experimental Agriculture, 10, 133-136. http://doi.org/10.1080/03015521.1982.10427857.

### References

Maindonald (1992).

### Examples

    data(mcleod.barley)
    dat <- mcleod.barley

    # Table 3 of McLeod.  Across-environment means by planting rate
    d1 <- aggregate(cbind(plants, tillers, heads, surviving, grains,
                          weight, yield) ~ rate, dat, FUN=mean)
    # Calculate income based on seed cost of $280/ton, grain $140/ton.
    d1 <- transform(d1, income=140*yield-280*rate/1000)
    signif(d1,3)
    ##  rate plants tillers heads surviving grains weight yield
    ##    50 112.12    5.22  4.36     83.95  21.25  46.11  3.97
    ##    75 162.75    4.04  3.26     80.89  19.95  45.10  4.26
    ##   100 202.62    3.69  2.73     74.29  19.16  44.66  4.38
    ##   125 239.00    3.28  2.33     71.86  18.45  43.45  4.41
    ##   150 293.62    2.90  2.00     69.54  17.94  42.77  4.47

    # Even though tillers/plant, heads/plant, surviving tillers,
    # grains/head, weight/1000 grains are all decreasing as planting
    # rate increases, the total yield is still increasing.
    # But, income peaks around seed rate of 100.

    require(lattice)
    xyplot(yield +income +surviving +grains +weight +plants +tillers +heads ~ rate,
           data=d1, outer=TRUE, type=c('p','l'),
           scales=list(y=list(relation="free")),
           xlab="Nitrogen rate", ylab="Trait value",
           main="mcleod.barley - nitrogen response curves"  )

[Package agridat version 1.16 Index]