KSSL

KSSL

The USDA-NRCS NCSS Kellogg Soil Survey Laboratory (KSSL) soil libraries from the United States and other territories

VNIRNIRMIR
National
60,000+ samples Snapshot Jul 2025 Other (Custom)

Database access

Data originally provided by:

Available files

Type Filename Link
MIR spectra — CSV (gzip) ossl_mir_v1.3.csv.gz Download
MIR spectra — Parquet ossl_mir_v1.3.parquet Download
Soil lab measurements — CSV (gzip) ossl_soillab_v1.3.csv.gz Download
Soil lab measurements — Parquet ossl_soillab_v1.3.parquet Download
Soil site metadata — CSV (gzip) ossl_soilsite_v1.3.csv.gz Download
Soil site metadata — Parquet ossl_soilsite_v1.3.parquet Download
VisNIR spectra — CSV (gzip) ossl_visnir_v1.3.csv.gz Download
VisNIR spectra — Parquet ossl_visnir_v1.3.parquet Download

Map

Soil site information

  • Coordinates precision: precise, county, country
  • Sampling depth: various
  • Geography: soil taxonomy, soil horizon
  • Variables available (OSSL): 14 out of 14 — see Database description for full schema
  • Populated columns: id.layer_local_c, id.layer_uuid_txt, id.dataset.site_ascii_txt, layer.upper.depth_usda_cm, layer.lower.depth_usda_cm, layer.texture_usda_txt, pedon.taxa_usda_txt, horizon.designation_usda_txt, observation.date.begin_iso.8601_yyyy.mm.dd, observation.date.end_iso.8601_yyyy.mm.dd, longitude.point_wgs84_dd, latitude.point_wgs84_dd, longitude.county_wgs84_dd, latitude.county_wgs84_dd

Soil laboratory information

  • Total samples: 64,667
  • Properties available (original): 1000+
  • Properties standardized (OSSL): 51 — summarized in Table 1 below
  • Categories: physical, chemical, biological, hydrological, carbon & nutrients, metal elements
  • Original source: see Database access

Hover over any OSSL code in the table below to see its full description.

Table 1: Summary statistics (mean, SD, percentiles) for OSSL-standardized soil properties.
skim_variable n_missing mean sd p0 p25 p50 p75 p100
acidity_usda.a795_cmolc.kgAcidity, BaCl2-TEA Extractable, pH 8.2Method: usda.a795Unit: cmolc.kg 29776 14.47 24.31 0.00 3.70 7.14 13.48 291.92
aggstb_usda.a1_w.pctAggregate StabilityMethod: usda.a1Unit: w.pct 60668 39.45 30.11 0.00 12.00 33.00 65.00 123.00
al.dith_usda.a65_w.pctAluminum, Crystalline, Total Pedogenic IronMethod: usda.a65Unit: w.pct 26780 0.20 0.35 0.00 0.05 0.11 0.21 7.70
al.ext_usda.a1056_mg.kgAluminum, Extractable, Mehlich3Method: usda.a1056Unit: mg.kg 63153 878.63 774.47 0.07 318.70 751.04 1158.34 6748.01
al.ext_usda.a69_cmolc.kgAluminum, Extractable, KClMethod: usda.a69Unit: cmolc.kg 47387 2.27 3.39 0.00 0.31 1.03 2.88 63.01
al.ox_usda.a59_w.pctAluminum, Amorphous, Total Non-Crystalline IronMethod: usda.a59Unit: w.pct 32485 0.27 0.56 0.00 0.06 0.12 0.23 12.63
awc.33.1500kPa_usda.c80_w.fracAvailable Water Content, Difference 33-1500 kPaMethod: usda.c80Unit: w.frac 43223 0.15 0.07 0.00 0.11 0.14 0.19 0.81
bd_usda.a21_g.cm3Bulk Density, <2 mm fraction, CoreMethod: usda.a21Unit: g.cm3 57051 0.94 0.50 0.01 0.53 1.04 1.32 8.10
bd_usda.a4_g.cm3Bulk Density, <2mm fraction, ClodMethod: usda.a4Unit: g.cm3 42189 1.38 0.26 0.02 1.26 1.40 1.54 2.53
c.tot_usda.a622_w.pctCarbon, Total NCSMethod: usda.a622Unit: w.pct 223 4.33 9.51 0.00 0.41 1.27 3.13 63.45
ca.ext_usda.a1059_mg.kgCalcium, Extractable, Mehlich3Method: usda.a1059Unit: mg.kg 63153 5634.75 9321.06 3.09 656.32 2258.41 4789.45 44723.96
ca.ext_usda.a722_cmolc.kgCalcium, Extractable, NH4OAcMethod: usda.a722Unit: cmolc.kg 4650 22.04 32.60 0.00 2.94 11.46 29.25 388.18
caco3_usda.a54_w.pctCarbonate, <2mm FractionMethod: usda.a54Unit: w.pct 41377 9.42 14.87 0.00 0.26 2.56 13.24 105.77
cec_usda.a723_cmolc.kgCEC, pH 7.0, NH4OAc, 2M KCl displacementMethod: usda.a723Unit: cmolc.kg 4656 20.63 22.91 0.00 7.49 14.97 24.63 584.59
cf_usda.c236_w.pctCoarse Fragments, Greater 2mmMethod: usda.c236Unit: w.pct 1655 8.79 17.05 0.00 0.00 0.41 8.00 100.00
clay.tot_usda.a334_w.pctClayMethod: usda.a334Unit: w.pct 8058 22.87 16.30 0.00 9.61 20.84 32.50 96.14
cu.ext_usda.a1063_mg.kgCopper, Extractable, Mehlich3Method: usda.a1063Unit: mg.kg 63153 2.59 4.25 0.00 0.44 1.66 3.06 77.82
ec_usda.a364_ds.mElectrical Conductivity, (w/w)Method: usda.a364Unit: ds.m 28827 2.85 12.00 0.00 0.11 0.26 0.87 313.13
fe.dith_usda.a66_w.pctIron, Crystalline, Total Pedogenic IronMethod: usda.a66Unit: w.pct 26778 1.24 1.64 0.00 0.32 0.80 1.55 28.44
fe.ext_usda.a1064_mg.kgIron, Extractable, Mehlich3Method: usda.a1064Unit: mg.kg 63153 113.04 124.91 0.00 51.58 89.31 140.02 2708.08
fe.ox_usda.a60_w.pctIron, Amorphous, Total Non-Crystalline IronMethod: usda.a60Unit: w.pct 32486 0.43 0.71 0.00 0.09 0.23 0.53 22.27
k.ext_usda.a1065_mg.kgPotassium, Extractable, Mehlich3Method: usda.a1065Unit: mg.kg 63153 177.58 170.73 0.00 77.71 139.78 234.39 1699.61
k.ext_usda.a725_cmolc.kgPotassium, Extractable, NH4OAc, 2M KCl displacementMethod: usda.a725Unit: cmolc.kg 4652 0.64 1.04 0.00 0.14 0.34 0.72 32.33
mg.ext_usda.a1066_mg.kgMagnesium, Extractable, Mehlich3Method: usda.a1066Unit: mg.kg 63153 510.49 528.72 0.00 91.39 369.35 788.47 5608.60
mg.ext_usda.a724_cmolc.kgMagnesium, Extractable, NH4OAc, 2M KCl displacementMethod: usda.a724Unit: cmolc.kg 4650 5.36 8.26 0.00 0.87 2.82 6.55 172.64
mn.ext_usda.a1067_mg.kgManganese, Extractable, Mehlich3Method: usda.a1067Unit: mg.kg 63153 73.41 81.38 0.00 16.19 45.74 102.72 544.19
mn.ext_usda.a70_mg.kgManganese, Extractable, KClMethod: usda.a70Unit: mg.kg 47390 13.25 103.15 0.00 0.12 0.80 4.10 9787.33
n.tot_usda.a623_w.pctNitrogen, Total NCS, usda.a623Method: usda.a623Unit: w.pct 223 0.24 0.55 0.00 0.04 0.09 0.20 41.90
na.ext_usda.a1068_mg.kgSodium, Extractable, Mehlich3Method: usda.a1068Unit: mg.kg 63153 183.75 701.06 0.00 12.05 30.59 104.68 15207.10
na.ext_usda.a726_cmolc.kgSodium, Extractable, NH4OAc, 2M KCl displacementMethod: usda.a726Unit: cmolc.kg 4652 3.95 23.24 0.00 0.00 0.02 0.24 868.36
oc_usda.c1059_w.pctOrganic Carbon, Total C without CaCO3, N prepMethod: usda.c1059Unit: w.pct 63499 4.46 9.77 0.01 0.50 1.28 2.81 56.40
oc_usda.c729_w.pctOrganic Carbon, Total C without CaCO3, S prepMethod: usda.c729Unit: w.pct 2231 3.95 9.59 0.00 0.28 0.82 2.36 63.45
p.ext_usda.a1070_mg.kgPhosphorus, Extractable, Mehlich3Method: usda.a1070Unit: mg.kg 63153 22.20 36.86 0.00 3.47 10.64 24.97 506.24
p.ext_usda.a270_mg.kgPhosphorus, Extractable, Bray1Method: usda.a270Unit: mg.kg 56546 18.52 48.21 0.00 1.00 4.49 16.07 1436.68
p.ext_usda.a274_mg.kgPhosphorus, Extractable, OlsenMethod: usda.a274Unit: mg.kg 49180 12.43 20.91 0.00 1.74 5.15 14.59 623.13
p.ext_usda.a652_mg.kgPhosphorus, Extractable, Mehlich3Method: usda.a652Unit: mg.kg 39184 26.05 159.17 0.00 2.45 9.18 29.22 24425.23
ph.cacl2_usda.a477_indexpH, 1:2 Soil-CaCl2 Suspension, 0.01 M CaCl2Method: usda.a477Unit: index 62992 4.73 1.25 1.74 3.74 4.61 5.60 8.27
ph.cacl2_usda.a481_indexpH, 1:2 Soil-CaCl2 SuspensionMethod: usda.a481Unit: index 5087 5.93 1.41 2.14 4.74 5.76 7.33 10.68
ph.h2o_usda.a268_indexpH, 1:1 Soil-Water SuspensionMethod: usda.a268Unit: index 5086 6.44 1.35 1.97 5.35 6.32 7.70 10.70
s.tot_usda.a624_w.pctSulfur, Total NCSMethod: usda.a624Unit: w.pct 224 0.16 0.90 0.00 0.00 0.01 0.04 25.24
sand.tot_usda.c405_w.pctSand, Total, N prepMethod: usda.c405Unit: w.pct 63774 33.76 27.17 0.30 8.90 24.70 59.70 98.40
sand.tot_usda.c60_w.pctSand, Total, S prepMethod: usda.c60Unit: w.pct 8988 39.33 28.88 0.10 13.30 34.70 61.70 100.00
silt.tot_usda.c407_w.pctSilt, Total, N prepMethod: usda.c407Unit: w.pct 63774 35.09 15.41 0.90 24.40 31.30 46.20 78.10
silt.tot_usda.c62_w.pctSilt, Total, S prepMethod: usda.c62Unit: w.pct 8988 37.93 20.20 0.00 22.70 38.00 53.00 94.50
wr.10kPa_usda.a414_w.pctWater Retention, 1/10 Bar (10 kPa)Method: usda.a414Unit: w.pct 61617 30.38 20.43 0.68 17.75 30.53 38.83 355.29
wr.10kPa_usda.a8_w.pctWater Retention, 1/10 Bar (10 kPa), ClodMethod: usda.a8Unit: w.pct 62384 30.93 33.40 2.65 19.60 25.58 31.90 553.17
wr.1500kPa_usda.a417_w.pctWater Retention, 15 Bar (1500 kPa)Method: usda.a417Unit: w.pct 15316 14.27 16.29 0.02 6.54 11.11 16.37 303.03
wr.33kPa_usda.a415_w.pctWater Retention, 1/3 Bar (33 kPa)Method: usda.a415Unit: w.pct 61046 26.09 23.85 0.26 13.04 23.13 31.96 221.34
wr.33kPa_usda.a9_w.pctWater Retention, 1/3 Bar (33 kPa), ClodMethod: usda.a9Unit: w.pct 42185 26.20 27.11 1.34 17.67 23.20 28.90 2124.87
zn.ext_usda.a1073_mg.kgZinc, Extractable, Mehlich3Method: usda.a1073Unit: mg.kg 63153 2.48 12.06 0.00 0.36 0.99 2.02 314.72

MIR

  • Acquisition mode: DRIFT
  • Intensity: absorbance
  • Original range: 400-4000
  • Standardized range: 600-4000
  • Instrument: Vertex 70 FT-IR
  • Manufacturer: Bruker Optics
  • Scan accessory: HTS-XT
  • Sample preparation: Air-dried, finely ground < 80mesh
  • Additional info: Liquid N2–cooled MCT (mercury cadmium telluride) detector

MIR plot

VNIR

  • Acquisition mode: Diffuse Reflectance
  • Intensity: reflectance
  • Original range: 350-2500
  • Instrument: ASD FieldSpec FR
  • Manufacturer: Malvern Panalytical
  • Instrument co-scans: 100
  • Scan repeats: 1
  • Scan accessory: MugLite (most samples) and Contact Probe accessories
  • Original resolution: 1
  • Sample preparation: Air-dried, Sieved < 2 mm
  • Additional info: The library contains measurements taken both with Muglight (~21k) and Contact Probe (~5k). About 5k samples were measured by both accesories

VNIR plot

References

  1. Publication 1
  2. Publication 2
  3. Publication 3