Get and prepare basic soil hydraulic parameters from SSURGO via SDA
prepare_SSURGO_hydro_data(cokeys, max.depth)a list containing:
SPC: SoilProfileCollection
agg: aggregate representation of hydraulic parameters, by cokey
The following soil hydraulic properties are included:
| variable | description |
| cokey | component key |
| hzname | horizon name |
| hz_top | horizon top depth (cm) |
| hz_bottom | horizon bottom depth (cm) |
| thick | horizon thickness (cm) |
| sat | VWC at saturation (cm/cm) |
| fc | VWC at field capacity defined by 1/3rd bar tension (cm/cm) |
| fc_tenthbar | VWC at field capacity defined by 1/3rd bar tension (cm/cm) |
| pwp | VWC at permanent wilting point or 15 bar tension (cm/cm) |
| awc | total sand content (<2mm fraction, mass %) |
| sand | total silt content (<2mm fraction, mass %) |
| silt | total clay content (<2mm fraction, mass %) |
| clay | total sand content (<2mm fraction, mass %) |
| dbthirdbar | bulk density at 1/3 bar tension (g/cm^3) |
| ksat | Ksat (um/second) |
| soil_fraction | volume fraction of soil (1 - coarse fragment volume fraction) |
vector of component keys (cokey) in current SSURGO snapshot
target depth of aggregation (cm), corrected later by real soil depth as reported by slab()
D.E. Beaudette
Weighted mean soil hydraulic parameters are returned over the interval of 0-max.depth, calculated by aqp::slab().