CO2 growth modifier — fCO2_growth

Function describing the effects of elevated CO2 on growth.

Usage

fCO2_growth_mod(c_CO2, b = 0.5, c_ref = 360)

c_CO2: numeric Atmospheric CO2 concentration in ppm
b: numeric Strength of CO2 effect on growth. Kellner et al. report values bewtween 0 and 2 with the interval of highest likelihood (0.1, 0.3). However, Soltani and Sinclair discuss that b = 0.4 in C4 plants and b = 0.8 in C3 plants. The difference on the output of this function of choosing a small (0.1) and large (0.8) value for b has an effect on the result for an atmospheric concentration of 700 ppm of roughly 40 percent!.
c_ref: numeric Reference CO2 concentration in ppm.

The function for the effects on growth is as proposed by Soltani et al (2012) and later adapted by equation (5) in Kellner et al. (2017)

Soltani A, Sinclair TR (2012). Modeling Physiology of Crop Development, Growth and Yield. CABI. ISBN 978-1-84593-971-7, xnHT6YOlk00C.

Kellner J, Multsch S, Houska T, Kraft P, Müller C, Breuer L (2017). “A Coupled Hydrological-Plant Growth Model for Simulating the Effect of Elevated CO2 on a Temperate Grassland.” Agricultural and Forest Meteorology, 246, 42–50. ISSN 0168-1923, doi:10.1016/j.agrformet.2017.05.017 , https://www.sciencedirect.com/science/article/pii/S0168192317301831.

fCO2_growth_mod(420)
#> [1] 1.077075
# The modifier is always relative to *c_ref*. This returns 1.
fCO2_growth_mod(420, c_ref = 420)
#> [1] 1