Table 3: Transport, sorption, and root parameters used in the NST 3.0 model to describe P uptake by smooth brome for the 0–120, 0–30, 30–60, and 60–120 cm soil depths.
ParameterUnits0–120 cm0–30 cm30–60 cm60–120 cm
𝐷 𝑒 Diffusion coefficient in water†cm2 s−1 8 . 9 𝐸 − 6 8 . 9 𝐸 − 6 8 . 9 𝐸 − 6 8 . 9 𝐸 − 6
ΘVolumetric soil water contentcm3 H2O/cm3 soil 0.256 0.25 0.26 0.26
𝑓 Impedance factorUnitless 0.243 0.23 0.25 0.25
𝑉 𝑜 Water uptake at rootcm s−1 8 . 1 6 𝐸 − 7 8 . 1 6 𝐸 − 7 8 . 1 6 𝐸 − 7 8 . 1 6 𝐸 − 7
𝐶 l i Initial solution concentration 𝜇 mol cm−3 1 . 1 4 1 𝐸 − 2 3 . 7 4 𝐸 − 2 2 . 5 8 𝐸 − 3 2 . 5 8 𝐸 − 3
𝑏 Buffer powerUnitless 73 28 98 92
𝐼 m a x Maximum influx at high concentration 𝜇 mol cm−2 s−1 3 . 2 7 𝐸 − 8 3 . 2 7 𝐸 − 8 3 . 2 7 𝐸 − 8 3 . 2 7 𝐸 − 8
𝐾 𝑚 Solution concentration when influx is 0.5  𝐼 m a x 𝜇 mol cm−3 2 . 7 1 𝐸 − 5 2 . 7 1 𝐸 − 5 2 . 7 1 𝐸 − 5 2 . 7 1 𝐸 − 5
𝐶 m i n Solution concentration when influx is zero 𝜇 mol cm−3 1 . 2 2 𝐸 − 6 1 . 2 2 𝐸 − 6 1 . 2 2 𝐸 − 6 1 . 2 2 𝐸 − 6
𝑟 𝑜 Root radiuscm0.01140.01350.0090.0117
𝑟 1 Half distancecm0.5050.2550.3470.914
𝐿 𝑜 Initial root lengthcm m−32,486,3791,464,477793,155228,747
𝑘 Root growth ratecm d−13,5728,6311,622464
†From Edwards and Huffman [18].