Soil Quality Index

Estimating the Soil Quality Index (SQI).

BACKGROUND

This tool will allow you to input soil physical, chemical and biological parameters to estimate a Soil Quality Index (SQI).

A full description of the tool can be found in https://excaliburh2020.eu/en/work-packages/.

In brief, this index is calculated using an algorithm (SIMCA) that classifies the sample relative to a large set of samples in current databases, positioning the sample based on the provided input values relative to existing samples within the same soil texture class.

Outlier values are seen as indication of poor quality. The soil chemical parameters were chosen based on their relevance for agricultural crop performance, including organic matter content, concentrations of macro- and micronutrients, pH, and cation exchange capacity, an important determinant of the biological availability of soil nutrients.

Soil biological parameters are based on the soil nematode community, a sensitive indicator of the quality of the soil environment.

INPUT

1. Soil location:

• Year: Refers to the year when the sample was taken
• Sample Name
• GPS Lat:GPS latitude positioning of the sample in Decimal Degrees (D.D°) coordinates
• GPS Lon:GPS longitude positioning of the sample in Decimal Degrees (D.D°) coordinates

2. Soil texture:

• Clay: Percentage of clay (mandatory field).
• Sand: Percentage of sand (mandatory field).
• Silt: Percentage of silt (automatically calculated as 100 minus the sum of clay and sand percentage).

The button “Get texture” calculates texture as Category, Class, and USDA class.

3. Soil chemical parameters:

• OM (%): Organic matter content (mandatory field).
• pH (mandatory field).
• P available (ppm): Available phosphorus.
• K exchangeable (ppm): Exchangeable potassium.
• Ca exchangeable (ppm): Exchangeable calcium.
• Mg exchangeable (ppm): Exchangeable magnesium.
• CEC (meq/100 g): Cation exchange capacity.

The interface calculates the model “Soil Chemical Physical Quality”.

4. Biological parameters:

• Herbivorous/Tot Nematodes (%): Ratio between herbivorous (i.e. plant parasitic) and total number of nematodes.
• Total number of nematodes.

The interface calculates the models “General Soil Fertility” and “Qualified Soil Fertility” indices.

OUTPUT

1. Summary of the input data.
2. Metric bar of the soil quality index, divided into five categories defining the soil quality associated with a colour code: Excellent (within model) (Green), Good (within model), Discrete (Outlier), Sufficient (Outlier), Bad (Outlier) (Red).
3. QR code with the same colour as the quality metric bar corresponding to the soil quality index category of the sample
4. Positioning of the sample into a geographic map if the GPS data were provided in the initial user interface. The QR code can be saved and printed.