aqp (version 0.99-8.1)

ca630: Soil Data from the Central Sierra Nevada Region of California

Description

Site and laboratory data from soils sampled in the central Sierra Nevada Region of California.

Usage

data(ca630)

source

http://ssldata.nrcs.usda.gov/

Details

These data were extracted from the NSSL database. `ca630` is a list composed of site and lab data, each stored as dataframes. These data are modeled by a 1:many (site:lab) relation, with the `pedon_id` acting as the primary key in the `site` table and as the foreign key in the `lab` table.

Examples

# 1. check structure
data(ca630)
str(ca630)

# 2. extract site data and convert to SPDF
site <- ca630$site
coordinates(site) <- ~ lon + lat

# 3. aggregate CEC 7 for all profiles into 1 cm slices
# note intermediate steps... will be cleaned-up in AQP 1.0
lab <- ca630$lab
lab$prop <- lab$CEC_7
lab$id <- factor(lab$pedon_id)
s1 <- soil.slot(data=lab)

# 4. plot median & IQR by 1 cm slice
xyplot(top ~ p.q50 + p.q25 + p.q75, 
data=s1, type='S', horizontal=TRUE, col=1, lty=c(1,2,2), 
panel=panel.superpose, ylim=c(150,-5))

# 5. safely compute hz-thickness weighted mean CEC (pH 7)
lab.agg.cec_7 <- ddply(lab, .(pedon_id), 
.fun=summarise, CEC_7=wtd.mean(CEC_7, weights=bottom-top))

# do something with the aggregated data now...