llwrPTF | R Documentation |
It calculates Least Limiting Water Range (LLWR) using pedo-transfer functions in according to Silva \& Kay (1997) and Silva et al. (2008), for Canadian and Brazilian soils, respectively.
llwrPTF(air, critical.PR, h.FC, h.WP, p.density, Bd, clay.content, org.carbon = NULL)
air |
the value of the limiting volumetric air content, m^3 m^{-3} |
critical.PR |
the value of the critical soil penetration resistance, MPa |
h.FC |
the value of matric suction at the field capacity, hPa |
h.WP |
the value of matric suction at the wilting point, hPa |
p.density |
the value of the soil particle density, Mg m^{-3} |
Bd |
a numeric vector containing values of dry bulk density, Mg m^{-3}. Note that Bd can also be a vector of length 1. |
clay.content |
a numeric vector containing values of clay content to each bulk density, \% |
org.carbon |
a numeric vector containing values of organic carbon to each bulk density, \%, for Canadian soils. Default is 2\%. See details. |
Note that org.carbon is only required for Canadian soil. If it is not passed, LLWR for Canadian soil is calculated with 2\% of organic carbon.
A list of
LLWR.B |
LLWR for Brazilian soils |
LLWR.C |
LLWR for Canadian soils |
Renato Paiva de Lima <renato_agro_@hotmail.com>
Anderson Rodrigo da Silva <anderson.agro@hotmail.com>
Alvaro Pires da Silva <apisilva@usp.br>
Keller, T; Silva, A.P.; Tormena, C.A.; Giarola, N.B.F., Cavalieri, K.M.V., Stettler, M.; Arvidsson, J. 2015. SoilFlex-LLWR: linking a soil compaction model with the least limiting water range concept. Soil Use and Management, 31:321-329.
Silva, A.P.; Kay, B.D. 1997. Estimating the least limiting water range of soil from properties and management. Soil Science Society of America Journal, 61:877-883.
Silva, A.P., Kay, B.D.; Perfect, E. 1994. Characterization of the least limiting water range. Soil Science Society of America Journal, 61:877-883.
Silva, A.P., Tormena, C.A., Jonez, F.; Imhoff, S. 2008. Pedotransfer functions for the soil water retention and soil resistance to penetration curves. Revista Brasileira de Ciencia do Solo, 32:1-10.
# EXEMPLE 1 (for Brazilian Soils) llwrPTF(air=0.1,critical.PR=2, h.FC=100, h.WP=15000,p.density=2.65, Bd=c(1.2,1.3,1.4,1.5,1.35),clay.content=c(30,30,35,38,40)) # EXEMPLE 2 (for Canadian Soils) llwrPTF(air=0.1,critical.PR=2, h.FC=100, h.WP=15000,p.density=2.65, Bd=c(1.2,1.3,1.4),clay.content=c(30,30,30), org.carbon=c(1.3,1.5,2)) # EXEMPLE 3 (combining it with soil stress) stress <- stressTraffic(inflation.pressure=200, recommended.pressure=200, tyre.diameter=1.8, tyre.width=0.4, wheel.load=4000, conc.factor=c(4,5,5,5,5,5), layers=c(0.05,0.1,0.3,0.5,0.7,1), plot.contact.area = FALSE) stress.p <- stress$Stress$sigma_mean layers <- stress$Stress$Layers n <- length(layers) def <- soilDeformation(stress = stress.p, p.density = rep(2.67,n), iBD = rep(1.55,n), N = rep(1.9392,n), CI = rep(0.06037,n), k = rep(0.00608,n), k2 = rep(0.01916,n), m = rep(1.3,n),graph=TRUE,ylim=c(1.4,1.8)) # Grapth LLWR, considering Brazilian soils plot(x = 1, y = 1, xlim=c(0,0.2),ylim=c(1,0),xaxt = "n", ylab = "Soil Depth",xlab ="", type="l", main="") axis(3) mtext("LLWR",side=3,line=2.5) i.LLWR <- llwrPTF(air=0.1,critical.PR=2, h.FC=100, h.WP=15000,p.density=2.65, Bd=def$iBD,clay.content=rep(20,n)) f.LLWR <- llwrPTF(air=0.1,critical.PR=2, h.FC=100, h.WP=15000,p.density=2.65, Bd=def$fBD,clay.content=rep(20,n)) points(x=i.LLWR$LLWR.B, y=layers, type="l"); points(x=i.LLWR$LLWR.B, y=layers,pch=15) points(x=f.LLWR$LLWR.B, y=layers, type="l", col=2); points(x=f.LLWR$LLWR.B, y=layers,pch=15, col=2) # End (not run)
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