fnc_PTF: PTF application and humus layer creation

In rhabel/modLWFB90: R-package for applying LWF-Brook90 directly from FVA-BW servers

PTF application and humus layer creation

Description

This function takes the data frame of soil physics data and creates the hydraulic parameters. It further creates humus-layers using the MvG-parameters from Hammel&Kennel (2001)

Usage

fnc_PTF(df, PTF_used, limit_humus)

Arguments

df	data frame containing information on soil physics in the following columns: sand, silt, clay - soil texture in mass % bd - bulk density in g cm-1 oc.pct - organic carbon in mass % humus - thickness of the humus-layer (repeated nrow - times. a bit clumsy, but building on existing code it was the most convenient way) LWFB90 has problems if the first row is too thin and creates surface flow if it becomes saturated, which can happen if the humus layer is too thin. So, if humus is <= 2cm, it will be removed, 3 cm will be turned into 4 cm. Anything above is fine.
PTF_used	PTF-options from the LWFBrook90R - package. Choices are "HYPRES", "PTFPUH2", or "WESSOLEK".
limit_humus	if ilayer = 0 and infexp = 0, which is the default setting in set_paramLWFB90, water can only infiltrate in the first layer. If thin humus layers (e.g. 2 cm) are put on top of the first mineral soil layer, there's a risk of creating unrealisic amounts of surface runoff, when the water storage capacity of the thin humus layer can't take the incoming amount of daily rain. Hence, this parameter deletes humus lazers smaller or equal 2 cm, and increases humus layers of 3 cm to 4 cm. Default is T. If ilayer and infexp are greater than 0, this issue shouldn't occur and this parameter should be set to F

Value

Returns a longer data.table that already includes an earlier version of ls.soils. Further processed in fnc_get_soil.

References

Hammel, K., & Kennel, M. (2001). Charakterisierung und Analyse der Wasserverfügbarkeit und des Wasserhaushalts von Waldstandorten in Bayern mit dem Simulationsmodell BROOK90. Frank.

rhabel/modLWFB90 documentation built on Nov. 21, 2024, 3:28 a.m.