The National Soil Inventory (NSI) topsoil data is a spatial, point dataset
with 6,127 points, located in a 5km grid across England and Wales.
NSI topsoil contains a comprehensive record of many of the important elemental
abundances in the soils of the UK. See below for a complete list.
This dataset can be used to highlight areas of element abundance, and
the links between these and some soil properties. It also provides a pH
reading of the soil at that point, which can be used to plot the areas
more suitable for the growth of acidic soil loving plants.
Amongst other projects, NSI topsoil data has been used as the basis of
soil quality indicators employed by DETR/EPSIM, the Environment Agency,
the Countryside Agency and certain local authorities.
The table below describes the various properties within this data product.
Each point contains the information outlined below.
| Property |
Example from data |
Description |
| EAST_NSI |
466000 |
National Grid reference easting at 5km resolution with 1km offset
from true grid |
| NORTH_NSI |
316000 |
National Grid reference northing at 5km resolution with 1km offset
from true grid |
| PH |
6.4 |
pH of soil measure after shaking 10ml of soil for 15 minutes with
25ml of water |
| CARBON |
1.6 |
Organic Carbon (% by wt) measured either by loss-on-ignition for
soils estimated to contain more than about 20% organic carbon or by
dichromate digestion. |
| AL_ACID |
16836 |
Total Aluminium concentration (mg/kg) determined by Inductively Coupled
Plasma Emission Spectrometry (ICP) in an aqua regia digest |
| AS_ACID |
4 |
Total Arsenic concentration (mg/kg) determined by Hydride Atomic
Absorption Spectrometry (AAS), extracted into hydrochloric acid after
digestion with nitric acid and ashing with magnesium nitrate |
| BA_ACID |
89 |
Total Barium concentration (mg/kg) determined by Inductively Coupled
Plasma Emission Spectrometry (ICP) in an aqua regia digest |
| CA_ACID |
2541 |
Total Calcium concentration (mg/kg) determined by Inductively Coupled
Plasma Emission Spectrometry (ICP) in an aqua regia digest |
| CD_ACID |
0.6 |
Total Cadmium concentration (mg/kg) determined by Inductively Coupled
Plasma Emission Spectrometry (ICP) in an aqua regia digest |
| CD_EDTA |
0.2 |
Extractable Cadmium concentration (mg/l) determined by Inductively
Coupled Plasma Emission Spectrometry (ICP) after shaking 10ml of soil
with 50ml of 0.05M EDTA at pH 7.0 for 1h at 20 deg. C and then filtering |
| CO_ACID |
6.2 |
Total Cobalt concentration (mg/kg) determined by Inductively Coupled
Plasma Emission Spectrometry (ICP) in an aqua regia digest |
| CO_EDTA |
0.3 |
Extractable Cobalt concentration (mg/l) determined by Inductively
Coupled Plasma Emission Spectrometry (ICP) after shaking 10ml of soil
with 50ml of 0.05M EDTA at pH 7.0 for 1h at 20 deg. C and then filtering |
| CR_ACID |
27.3 |
Total Chromium concentration (mg/kg) determined by Inductively Coupled
Plasma Emission Spectrometry (ICP) in an aqua regia digest |
| CU_ACID |
20.3 |
Total Copper concentration (mg/kg) determined by Inductively Coupled
Plasma Emission Spectrometry (ICP) in an aqua regia digest |
| CU_EDTA |
8.3 |
Extractable Copper concentration (mg/l) determined by Inductively
Coupled Plasma Emission Spectrometry (ICP) after shaking 10ml of soil
with 50ml of 0.05M EDTA at pH 7.0 for 1h at 20 deg. C and then filtering |
| F_ACID |
44.46 |
Flouride extracted with 1mol / l sulphuric acid and determined by
Ion Selective Electrode (ISE) |
| FE_ACID |
31096 |
Total Iron concentration (mg/kg) determined by Inductively Coupled
Plasma Emission Spectrometry (ICP) in an aqua regia digest |
| HG_ACID |
|
Total Mercury concentration (mg/kg) determined by Hydride Atomic
Absorption Spectrometry (AAS), digested in a nitric/sulphuric acid
mixture |
| K_ACID |
2210 |
Total Potassium concentration (mg/kg) determined by Inductively Coupled
Plasma Emission Spectrometry (ICP) in an aqua regia digest |
| K_NITRATE |
101 |
Extractable Potassium concentration (mg/l) determined by shaking
10ml of air dry soil with 50ml of 1.0M ammonium nitrate for 30mins,
filtering and then measuring the concentration by flame photometry |
| MG_ACID |
1703 |
Total Magnesium concentration (mg/kg) determined by Inductively Coupled
Plasma Emission Spectrometry (ICP) in an aqua regia digest |
| MG_NITRATE |
55 |
Extractable Magnesium concentration (mg/l) determined by shaking
10ml of air dry soil with 50ml of 1.0M ammonium nitrate for 30mins,
filtering and then measuring the concentration by flame photometry |
| MN_ACID |
297 |
Total Manganese concentration (mg/kg) determined by Inductively Coupled
Plasma Emission Spectrometry (ICP) in an aqua regia digest |
| MN_EDTA |
27 |
Extractable Manganese concentration (mg/l) determined by Inductively
Coupled Plasma Emission Spectrometry (ICP) after shaking 10ml of soil
with 50ml of 0.05M EDTA at pH 7.0 for 1h at 20 deg. C and then filtering |
| MO_ACID |
0.67 |
Total Molybdenum concentration (mg/kg) determined by Atomic Adsorption
Spectrometyr (AAS) in an aqua regia digest |
| NA_ACID |
147 |
Total Sodium concentration (mg/kg) determined by Inductively Coupled
Plasma Emission Spectrometry (ICP) in an aqua regia digest |
| NI_ACID |
18.9 |
Total Nickel concentration (mg/kg) determined by Inductively Coupled
Plasma Emission Spectrometry (ICP) in an aqua regia digest |
| NI_EDTA |
1 |
Extractable Nickel concentration (mg/l) determined by Inductively
Coupled Plasma Emission Spectrometry (ICP) after shaking 10ml of soil
with 50ml of 0.05M EDTA at pH 7.0 for 1h at 20 deg. C and then filtering |
| P_ACID |
885 |
Total Phosphorus concentration (mg/kg) determined by Inductively
Coupled Plasma Emission Spectrometry (ICP) in an aqua regia digest |
| P_OLSON |
15 |
Extractable Phosphorus concentration (mg/l) determined by shaking
5ml of air dry soil with 100ml of 0.5M sodium bicarbonate for 30mins
at 20 deg.C, filtering and then measuring the absorbance at 880 nm
colorimetrically with acid ammonium molybdate solution |
| PB_ACID |
36 |
Total Lead concentration (mg/kg) determined by Inductively Coupled
Plasma Emission Spectrometry (ICP) in an aqua regia digest |
| PB_EDTA |
13.8 |
Extractable Lead concentration (mg/l) determined by Inductively Coupled
Plasma Emission Spectrometry (ICP) after shaking 10ml of soil with
50ml of 0.05M EDTA at pH 7.0 for 1h at 20 deg. C and then filtering |
| SE_ACID |
0.24 |
Total Selenium concentration (mg/kg) determined by Hydride Atomic
Absorption Spectrometry (AAS), extracted into hydrochloric acid after
digestion with nitric acid and ashing with magnesium nitrate |
| SR_ACID |
25 |
Total Strontium concentration (mg/kg) determined by Inductively Coupled
Plasma Emission Spectrometry (ICP) in an aqua regia digest |
| V_ACID |
38.34 |
Total Vanadium concentration (mg/kg) determined by Atomic Adsorption
Spectrometyr (AAS) in an aqua regia digest |
| ZN_ACID |
72 |
Total Zinc concentration (mg/kg) determined by Inductively Coupled
Plasma Emission Spectrometry (ICP) in an aqua regia digest |
| ZN_EDTA |
3.1 |
Extractable Zinc concentration (mg/l) determined by Inductively Coupled
Plasma Emission Spectrometry (ICP) after shaking 10ml of soil with
50ml of 0.05M EDTA at pH 7.0 for 1h at 20 deg. C and then filtering |
The National Soil Inventory (NSI) topsoil data was partially (about a third of the points) resampled in the mid 1990s. These points match with the original survey, and are located on the same 5km grid across England and Wales.
NSI topsoil contains a comprehensive record of many of the important
elemental abundances in the soils of the UK. See below for a complete
list.
This dataset can be used to highlight areas of element abundance, and
the links between these and some soil properties. It also provides a
pH reading of the soil at that point, which can be used to plot the areas
more suitable for the growth of acidic soil loving plants.
Amongst other projects, NSI topsoil data has been used to set the standards
outlined in the DEFRA Sludge to Land report.