LRI: Limiting Rootability

In GSIF: Global Soil Information Facilities

Description

Derive Limiting Rootability using observed soil properties at at least three depths.

Usage

LRI(UHDICM, LHDICM, SNDPPT, SLTPPT, CLYPPT, CRFVOL, BLD,
   ORCDRC, ECN, CEC, ENA, EACKCL, EXB, PHIHOX, CRB, GYP, tetaS, 
   fix.values=TRUE, thresholds, print.thresholds=FALSE)

Arguments

UHDICM	numeric; upper horizon depth in cm
LHDICM	numeric; lower horizon depth in cm
SNDPPT	numeric; sand content in percent
SLTPPT	numeric; silt content in percent
CLYPPT	numeric; clay content in percent
CRFVOL	numeric; volume percentage of coarse fragments (> 2 mm)
BLD	numeric; bulk density in kg per cubic-meter for the horizon/solum
ORCDRC	numeric; soil organic carbon concentration in permille or g per kg
ECN	numeric; electrical conductivity in dS per m
CEC	numeric; Cation Exchange Capacity in cmol per kilogram
ENA	numeric; exchangable Na in cmol per kilogram
EACKCL	numeric; exchangable acidity in cmol per kilogram
EXB	numeric; exchangable bases in cmol per kilogram
PHIHOX	numeric; soil pH in water suspension
CRB	numeric; CaCO3 (carbonates) in g per kg
GYP	numeric; CaSO4 (gypsum) in g per kg
tetaS	numeric; volumetric percentage (optional; if not provided it will be derived using the AWCPTF Pedo-Transfer Function)
fix.values	logical; specifies whether to correct values of textures and bulk density to avoid creating nonsensical values
thresholds	data.frame; optional table containing threshold values for "CRFVOL", "tetaS" (volumetric percentage), "BLD.f" (clay-adjusted BLD), "SNDPPT", "CLY.d" (difference in clay between horizons), "SND.d" (difference in sand between horizons), "PHIHOX.L" (lower limits for pH), "PHIHOX.H" (upper limits for pH), "ECN", "ENA.f" (exchangable saturated Na), "ENA", "EACKCL.f" (exchangable saturated acidity), "CRB" (carbonates), and "GYP" (gypsum)
print.thresholds	logical; specifies whether to attach the threshold values to the output object

Value

Returns a vector with TRUE / FALSE values where FALSE indicates rooting not possible. Threshold values used to derive Limiting Rootability scores are set based on common soil agricultural productivity tresholds (e.g. in this case for maize), and can be adjusted via the thresholds argument. This functions also accounts for textural changes (sudden changes in sand and clay content) and saturated water content.

Note

Horizons need to be sorted by depth e.g. 0-5, 5-15, 15-30... For each soil property at least three depths are needed otherwise the function reports an error. Missing values are automatically replaced using smoothing splines.

Author(s)

Johan Leenaars and Maria Ruiperez Gonzalez

References

• Driessen, P. M., & Konijn, N. T. (1992) Land-use systems analysis. Wageningen Agricultural University.

• Rijsberman, F. R., & Wolman, M. G. (1985) Effect of erosion on soil productivity: an international comparison. Journal of soil and water conservation, 40(4), 349-354.

See Also

AWCPTF, ERDICM

Examples

## sample profile from Nigeria (ISRIC:NG0017):
UHDICM = c(0, 18, 36, 65, 87, 127)
LHDICM = c(18, 36, 65, 87, 127, 181)
SNDPPT = c(66, 70, 54, 43, 35, 47)
SLTPPT = c(13, 11, 14, 14, 18, 23)
CLYPPT = c(21, 19, 32, 43, 47, 30)
CRFVOL = c(17, 72, 73, 54, 19, 17)
BLD = c(1.57, 1.60, 1.52, 1.50, 1.40, 1.42)*1000
PHIHOX = c(6.5, 6.9, 6.5, 6.2, 6.2, 6.0)
CEC = c(9.3, 4.5, 6.0, 8.0, 9.4, 10.9)
ENA = c(0.1, 0.1, 0.1, 0.1, 0.1, 0.2)
EACKCL = c(0.1, 0.1, 0.1, NA, NA, 0.5)
EXB = c(8.9, 4.0, 5.7, 7.4, 8.9, 10.4)
ORCDRC = c(18.4, 4.4, 3.6, 3.6, 3.2, 1.2)
x <- LRI(UHDICM=UHDICM, LHDICM=LHDICM, SNDPPT=SNDPPT, 
   SLTPPT=SLTPPT, CLYPPT=CLYPPT, CRFVOL=CRFVOL, 
   BLD=BLD, ORCDRC=ORCDRC, CEC=CEC, ENA=ENA, EACKCL=EACKCL, 
   EXB=EXB, PHIHOX=PHIHOX, print.thresholds=TRUE)
x
## Most limiting: BLD.f and CRFVOL, but nothing < 20

## Effective Rootable Depth:
sel <- x==FALSE
if(!all(sel==FALSE)){ 
  UHDICM[which(sel==TRUE)[1]] 
} else {
  max(LHDICM)
}

xI <- attr(x, "minimum.LRI")
## derive Effective rooting depth:
ERDICM(UHDICM=UHDICM, LHDICM=LHDICM, minimum.LRI=xI, DRAINFAO="M")

GSIF documentation built on May 2, 2019, 5:44 p.m.