Africa Soil Profiles Database

Description

A merge of the Africa Soil Profiles Database (AFSP) with 17,000+ geo-referenced legacy soil profile records, and AfSIS Sentinel Site database with 9000+ sampling locations.

Usage

data(afsp)

Format

The afsp data set contains two data frames — sites and horizons. Sites table contains the following columns:

SOURCEID

factor; unique label to help a user identify a particular site (ProfileID in the AFSP)

SOURCEDB

factor; source data base

LONWGS84

numeric; longitude in decimal degrees on the WGS84 datum (X_LonDD in the AFSP)

LATWGS84

numeric; latitude in decimal degrees on the WGS84 datum (Y_LatDD in the AFSP)

TIMESTRR

character; the date on which this particular soil was described or sampled (T_Year in the AFSP)

TAXGWRB

factor; abbreviated soil group based on the WRB classification system (WRB06rg in the AFSP)

TAXNUSDA

factor; Keys to Soil Taxonomy taxon name e.g. "Plinthic Udoxic Dystropept" (USDA in the AFSP)

BDRICM

numeric; depth to bedrock in cm

DRAINFAO

factor; drainage class based on the FAO guidelines for soil description: E (excessively drained), S (somewhat excessively drained), W (well drained), M (moderately well drained), I (somewhat poorly drained) and V (very poorly drained)

Horizons table contains the following columns:

SOURCEID

factor; a short label to help a user identify a particular site

UHDICM

numeric; upper horizon depth from the surface in cm

LHDICM

numeric; lower horizon depth from the surface in cm

MCOMNS

factor; Munsell color moist

ORCDRC

numeric; soil organic carbon content in permilles

PHIHOX

numeric; pH index measured in water solution

SNDPPT

numeric; weight percentage of the sand particles (0.05–2 mm)

SLTPPT

numeric; weight percentage of the silt particles (0.0002–0.05 mm)

CLYPPT

numeric; weight percentage of the clay particles (<0.0002 mm)

CRFVOL

numeric; volume percentage of coarse fragments (> 2 mm)

BLD

numeric;bulk density in tonnes per cubic-meter

CEC

numeric; Cation exchange capacity (fine earth fraction) in cmolc/kg

NTO

numeric; total N content in permille or g/kg

EMGX

numeric; exchangable Mg in cmolc/kg

Author(s)

The Africa Soil Profiles Database have been prepared by Johan Leenaars <johan.leenaars@wur.nl>. This is a subset of the original database that can be downloaded via http://africasoils.net. The AfSIS Sentinel Site database is one of the main deliverables of the Africa Soil Information Service project.

References

• Hengl, T., Heuvelink, G.B., Kempen, B., Leenaars, J.G., Walsh, M.G., Shepherd, K.D., Sila, A., MacMillan, R.A., de Jesus, J.M., Tamene, L. and Tondoh, J.E., (2015) Mapping soil properties of Africa at 250 m resolution: Random forests significantly improve current predictions. PloS one, 10(6), p.e0125814.

• Leenaars, J.G.B. (2014) Africa Soil Profiles Database, Version 1.2. A compilation of geo-referenced and standardized legacy soil profile data for Sub Saharan Africa (with dataset). ISRIC report 2012/03. Africa Soil Information Service (AfSIS) project and ISRIC — World Soil Information, Wageningen, the Netherlands.

• Africa Soil Information Service (http://africasoils.net)

Examples

## Not run: 
library(rgdal)
library(aqp)
library(sp)

data(afsp)
sites <- afsp$sites
coordinates(sites) <- ~ LONWGS84 + LATWGS84
proj4string(sites) <- "+proj=longlat +datum=WGS84"
## obtain country borders:
library(maps)
country.m = map('world', plot=FALSE, fill=TRUE)
IDs <- sapply(strsplit(country.m$names, ":"), function(x) x[1])
require(maptools)
country <- as(map2SpatialPolygons(country.m, IDs=IDs), "SpatialLines")
proj4string(country) = "+proj=longlat +datum=WGS84" 
## overlay and plot points and maps:
plot(country, col="darkgrey", xlim=c(-25.3,57.8), ylim=c(-34.8, 37.4))
points(sites, pch=21, bg="white", cex=.6, col="black")

## End(Not run)