Low Chill

Quantifies the chill accumulation by means of converting temperatures to chill-units.

lowchill_model(x, total = TRUE)

Arguments

x

Vector containing temperature values (Celsius-degree).
total

TRUE Shows the total value of accumulation, FALSE shows the value of chill-unit for each temperature (TRUE is default).

Value

The function returns values the chill-units for each temperature of vector (Total = FALSE), or returns the chill-units accumulation (Total = TRUE).

Details

The model is based on chill-units, where 1 chill-unit is when the tree is exposure between 1.8°C and 8°C. When the temperature is above 19.5°C, the chill-unit is -1. The chill-units accumulation is 0 when occurs temperature below -1°C and between 14°C and 17°C.

References

GILREATH, Phyllis R. & BUCHANAN, D. W. (1981). Rest Prediction Model for Low-chilling 'Sungold' Nectarine. J. Amer. Soc. Hort. Sci.

Examples


x <- rnorm(500, 12, 5)
lowchill_model(x)
#> [1] 133.5
lowchill_model(x, FALSE)
#>   [1]  0.5  0.5  1.0  0.5  1.0 -0.5  1.0  1.0  1.0  0.5  1.0  0.5  0.5  0.0  0.5
#>  [16]  0.5 -0.5 -1.0  1.0  0.5  0.5  0.5  0.0 -1.0  1.0 -1.0  0.5  1.0  0.0  0.5
#>  [31] -0.5 -0.5  1.0 -1.0 -1.0  0.5  0.5  1.0  0.5  1.0  1.0  0.5  1.0  1.0  0.5
#>  [46]  0.5  0.5  0.5  0.5  0.0  0.5  0.0 -0.5  0.5  0.0  0.5  0.0 -0.5  0.5  0.5
#>  [61]  1.0  0.5  1.0  0.5  1.0  1.0  0.5  1.0  0.5 -0.5  0.5  0.5 -1.0  0.0 -1.0
#>  [76] -1.0  0.0  1.0  0.0 -0.5  0.5 -0.5 -1.0  1.0  0.5  0.0 -1.0  0.5  1.0  0.0
#>  [91]  0.5  0.0  1.0  0.5  0.0  0.5 -0.5  0.5  1.0 -0.5  0.0  0.5 -0.5 -1.0  0.0
#> [106]  0.0 -0.5  1.0 -1.0  0.5  0.5  0.5 -0.5  0.5  0.5  0.0 -1.0  1.0 -0.5  1.0
#> [121]  0.5  0.5  1.0  0.5  0.5  0.5  0.5  0.5  1.0  0.5  0.0  0.0 -0.5 -0.5  1.0
#> [136]  0.5  0.5  0.5 -1.0  1.0  0.0  1.0  0.5  0.5  0.0  0.5  1.0  0.5 -0.5  0.5
#> [151]  0.5  0.5  0.5  0.5  0.5  0.0  0.0  1.0 -0.5  0.0 -1.0  0.5  0.5  0.5  0.0
#> [166]  0.5  0.0  0.5  0.5  0.5  0.0 -0.5  0.5 -1.0  0.5  0.0  0.5  0.0  1.0  0.0
#> [181]  0.5  0.5  0.5  0.0  1.0  0.5 -1.0  0.0  0.0  1.0  0.5  0.5  0.5  0.5 -1.0
#> [196]  0.5  0.5  0.5  1.0  0.5  0.0 -0.5  0.5  0.5  1.0  0.5  0.0  1.0  0.0 -0.5
#> [211]  0.5 -0.5  0.5  0.5  0.5  0.5  1.0  0.0 -0.5  0.5  0.0 -0.5  1.0 -1.0 -1.0
#> [226]  0.0  0.5 -0.5 -1.0  0.5  0.5  0.5  0.5  0.0  0.5  0.5 -0.5  0.5  1.0  0.0
#> [241]  0.0 -1.0  0.5  1.0  1.0  0.5  0.0  0.5  1.0  0.5 -1.0 -1.0  0.0 -0.5  0.0
#> [256]  0.5  0.5  0.5  0.5  0.0  1.0  1.0  0.5  0.5  0.5 -0.5 -0.5 -0.5  1.0  0.5
#> [271] -1.0 -1.0  0.0  0.5  1.0  0.0 -1.0  0.5  1.0  0.5 -0.5  0.0  0.0  0.5  0.5
#> [286]  1.0  0.5 -1.0  0.5  1.0 -0.5  0.5  0.5 -0.5  1.0  1.0  0.5  1.0 -0.5 -1.0
#> [301]  0.5  0.5  0.5  0.5 -1.0  0.0 -1.0  0.5  0.5  0.5  0.0  1.0  0.5  0.5 -0.5
#> [316]  0.0  1.0  0.5  1.0  0.5 -1.0 -0.5  0.5  0.5  1.0 -0.5  1.0  1.0  0.5 -1.0
#> [331] -0.5  0.5  0.0 -0.5  0.5 -1.0  0.5  0.0  0.5  0.5  1.0  0.5  1.0  0.5  0.0
#> [346]  0.5  1.0  0.5  0.5  1.0 -1.0  0.5  1.0  0.5  0.5  0.5  0.0  0.0  0.5  0.5
#> [361]  0.5  0.0  0.5  1.0  0.5  0.5  1.0 -1.0 -0.5 -1.0  0.0  0.5 -0.5  0.5  1.0
#> [376]  0.5  0.0  1.0 -1.0  0.5 -1.0  0.5  0.5  0.5  0.0  0.5  0.5 -0.5  0.5  0.5
#> [391]  0.5 -0.5  0.0  0.5  0.5  0.0  1.0  0.5 -0.5  0.5  0.5  1.0  0.0  1.0  0.0
#> [406]  0.5  0.0  0.5  1.0  0.5  0.0  0.0  0.5  1.0  0.5  0.0  1.0  0.5  0.0  0.5
#> [421]  0.5 -1.0  0.5  0.5  0.5  0.5 -1.0  0.5  0.5  1.0  0.5  0.5  0.5  0.5  0.5
#> [436]  0.0 -1.0  1.0  0.5  0.5  1.0  0.0  0.0  0.0  0.5  0.5  0.5  0.5  0.5  0.5
#> [451]  0.5  0.0  0.0  0.5  0.5  0.5  0.5 -1.0  0.5  0.5  1.0  0.5  0.5  0.5  0.5
#> [466]  0.5  0.0  0.5  0.5  0.5  1.0  0.5 -1.0  1.0  0.5 -1.0  0.0  1.0  0.5  1.0
#> [481]  0.0  0.5  1.0  1.0  0.5  0.5 -0.5  0.0  0.5  0.0 -0.5 -1.0  0.5  0.5  0.5
#> [496] -1.0 -0.5  0.5  0.5  0.0