SINDI development

Soil quality is a term that describes the relative condition of soil under a particular land use.

To understand a soils condition, a number of key indicators are measured to identify current condition and trend of chemical, physical and biological attributes of a soil as it is utilized under a particular land use. Different land uses impart different pressures on soil quality, and different soils react in different ways to those land use pressures.

Online tool

SINDI is a web-based tool designed to help land managers interpret the quality or health of a soil under a particular land use relative to:

  1. an expert interpretation,
  2. sites that have been analysed within a monitoring program, and
  3. sites from the National Soils Database.

The indicators selected to assess soil quality in SINDI reflect the idea that soil quality is not a single concept but encompasses aspects of the soil physical structure, chemical fertility, nutrient storage, organic matter resources, and the biological life in the soil. 

SINDI flask thumb

Statistical techniques

Statistical techniques were used to determine a key set of seven indicators that together describe soil quality.

The indicators themselves do not measure soil quality. Soil quality is a value judgement about how suitable a soil is for a particular use. The indicators measure attributes of a soil (e.g. pH, bulk density). Consequently different target values for indicators are needed for different land uses. For example, soils with pH <5 may be of suitable quality to grow radiata pine, but not for a good crop of white clover. Soils that are stony and excessively free-draining may be of poor quality for pasture production, but of excellent quality for vineyards.

Note that other indicators excluded from SINDI still have value for specific questions. Additionally, these indicators were selected specifically for New Zealand soils and a different set of indicators may be more appropriate for soils from different areas.

Within the SINDI programme the quality criteria alter depending on the land use selected. We have not attempted to cover all possible land uses within the current SINDI package. The indicators are not intended as a basis for fertiliser requirements.

Target ranges have been defined by a small group of experts for each of the indicators on a variety of soil types and land uses. These target ranges form the basis of the graphical interpretation used in SINDI. As a user of SINDI you can enter in values for the seven indicators, the soil type and land use, and each value is then graphically compared with the appropriate target range.

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Soil quality