hessling.argentina {agridat} | R Documentation

## Relation between wheat yield and weather in Argentina

### Description

Relation between wheat yield and weather in Argentina

### Format

A data frame with 30 observations on the following 15 variables.

`yield`

  average yield, kg/ha

`year`

  year

`p05`

  precipitation (mm) in May

`p06`

  precip in June

`p07`

  precip in July

`p08`

  precip in August

`p09`

  precip in Septempber

`p10`

  precip in October

`p11`

  precip in November

`p12`

  precip in December

`t06`

  june temperature deviation from normal, deg Celsius

`t07`

  july temp deviation

`t08`

  august temp deviation

`t09`

  september temp deviation

`t10`

  october temp deviation

`t11`

  november temp deviation

### Details

In Argentina wheat is typically sown May to August. Harvest begins in November or December.

### Source

N. A. Hessling, 1922. Relations between the weather and the yield of wheat in the Argentine republic, Monthly Weather Review, 50, 302-308. http://doi.org/10.1175/1520-0493(1922)50<302:RBTWAT>2.0.CO;2

### Examples

    data(hessling.argentina)
    dat <- hessling.argentina

    # Fig 1 of Hessling.  Use avg Aug-Nov temp to predict yield
    dat <- transform(dat, avetmp=(t08+t09+t10+t11)/4) # Avg temp
    m0 <- lm(yield ~ avetmp, dat)
    plot(yield~year, dat, ylim=c(100,1500), type='l',
    main="hessling.argentina: observed (black) and predicted yield (blue)")
    lines(fitted(m0)~year, dat, col="blue")

    # A modern, PLS approach
    if(require(pls)){
      yld <- dat[,"yield",drop=FALSE]
      yld <- as.matrix(sweep(yld, 2, colMeans(yld)))
      cov <- dat[,c("p06","p07","p08","p09","p10","p11", "t08","t09","t10","t11")]
      cov <- as.matrix(scale(cov))
      m2 <- plsr(yld~cov)

      # biplot(m2, which="x", var.axes=TRUE, main="hessling.argentina")
    }

    if(require(corrgram)){
      corrgram(dat, main="hessling.argentina - correlations of yield and covariates")
    }

[Package agridat version 1.16 Index]