Pedological inputs to the CLUES model included
• an assessment for each soil of its potential to leach nitrate
and contribute contaminants to ground or surface water
bodies; and
• assessment of the potential for nitrate removal from soil
water by passage through poorly oxygenated (reduced)
soils, particularly Gley Soils, either Perch-gley or
groundwater gleys, before the water reaches a groundwater or a river or lake.
The two inputs were combined to produce a generalised
national map of the potential for nitrate to reach freshwater
bodies.
The nitrate soil vulnerability concept was developed
further by extending it to include mapping of other potential
contaminants or degradation processes and by expressing the
concept in terms of risk analysis. Risk was assessed by
identifying a possible hazard, its likelihood of occurrence,
and its possible consequence. Likelihood depended on the
pressure of a particular management practice, and the vulnerability of the landscape to that pressure. The consequence
of the hazard depended on the environmental sensitivity of
the response to the hazard, and the effect of the risk on the
values of environmental services. The vulnerability classes
were based only on soil or land factors. Trevor Webb and
others provided an example of mapping of soil vulnerability
of nitrate and phosphorus leaching, microbial bypass flow,
and soil runoff potential, for two areas of Canterbury in a
book published by Canterbury Regional Council. Similar
maps are now available through S-map that use a range of
‘pedotransfer’ (soil modelling) functions to generate
derivative maps of vulnerability and other properties.
18.4.8 Soil Quality
Over the last century, agriculture has changed many of our
soils that were originally ill-suited for farming. Acidity has
been corrected by liming, low fertility by fertilisers, drought
by irrigation, wetness by drainage, and subsoil pans by deep
ripping. These and other interventions have contributed
greatly to national prosperity and to increasing intensity of
land use. However, more intensive production, whether by
horticulture, cropping, or intensive pastoralism, raises the
issue of sustainability. Can the soil functions we rely on to
be sustained without loss of soil quality or adverse effects on
the wider environment? It is essential that soil quality is
monitored so that loss of quality can be identified and
managed or mitigated.
Soil quality was defined broadly by Else Bünemann and
others in 2018, as ‘the capacity of a soil to function within
ecosystem and land-use boundaries to sustain biological
productivity, maintain environmental quality, and promote
plant and animal health’. Thus, soil quality more specifically
is about the status of important soil properties that change
with the effects of land management (called ‘dynamic soil
properties’ or ‘management dependant properties’ or simply
‘soil quality indicators’). Soil quality indicators may change
in response to land management over short periods of time
(days, weeks, or years). Soil quality is assessed using soil
quality indicators that show levels of soil properties that
imply the status of important soil health processes. Indicators
are used to identify any factor that may be amiss and
requires further attention. If the indicator points to a possible
issue then further investigation, using a wider range of soil
properties, including more detailed and expensive measurements, may be required. The scientific literature mostly uses
the term ‘soil quality’ rather than ‘soil health’ because
‘health’ is encumbered by many shades of meaning. However, general literature on the state of the environment often
uses the terms interchangeably.
Systematic soil quality monitoring in New Zealand was
initiated at a regional scale by Manaaki Whenua Landcare –
Research with support from regional councils. Following the
investigation of a wide range of potential indicators, they
selected seven soil quality indicators: total carbon, total nitrogen, pH, Olsen phosphorus, mineralisable nitrogen, soil
dry bulk density, and macroporosity (Table 18.5). The
selected indicators were based on dynamic soil properties
that indicated soil biological reserves, fertility reserves,
chemical reserves, and physical reserves. Research continues
into soil quality indictors and monitoring and there is scope
for the development of new and powerful indicators
employing new technology.
The SINDI (soil indicators) website [http://sindi.
landcareresearch.co.nz/] provides a means for interpreting
the indicator values derived from the soil sampling and
analysis to aid in developing appropriate management
response. The focus for indicator research has been on soil
condition and does not include soil erosion or soil contamination. Although the SINDI was designed for regional-scale
monitoring it can be applied at any scale given an appropriate sampling strategy.
Soil quality indicators are being incorporated into the
national state of the environment monitoring programmes
with rapid changes occurring over recent years. The latest
information is on the Ministry for the Environment website
[https://www.mfe.govt.nz/land/state-of-our-land].
18.4.9 Visual Soil Assessment
Visual soil assessment (VSA) is a relatively simple, quick,
method of assessing the state of the soil, in the field, to help
inform land management decisions and, if repeated
302
18 Conclusion: Global Context, Formation Pathways …
• an assessment for each soil of its potential to leach nitrate
and contribute contaminants to ground or surface water
bodies; and
• assessment of the potential for nitrate removal from soil
water by passage through poorly oxygenated (reduced)
soils, particularly Gley Soils, either Perch-gley or
groundwater gleys, before the water reaches a groundwater or a river or lake.
The two inputs were combined to produce a generalised
national map of the potential for nitrate to reach freshwater
bodies.
The nitrate soil vulnerability concept was developed
further by extending it to include mapping of other potential
contaminants or degradation processes and by expressing the
concept in terms of risk analysis. Risk was assessed by
identifying a possible hazard, its likelihood of occurrence,
and its possible consequence. Likelihood depended on the
pressure of a particular management practice, and the vulnerability of the landscape to that pressure. The consequence
of the hazard depended on the environmental sensitivity of
the response to the hazard, and the effect of the risk on the
values of environmental services. The vulnerability classes
were based only on soil or land factors. Trevor Webb and
others provided an example of mapping of soil vulnerability
of nitrate and phosphorus leaching, microbial bypass flow,
and soil runoff potential, for two areas of Canterbury in a
book published by Canterbury Regional Council. Similar
maps are now available through S-map that use a range of
‘pedotransfer’ (soil modelling) functions to generate
derivative maps of vulnerability and other properties.
18.4.8 Soil Quality
Over the last century, agriculture has changed many of our
soils that were originally ill-suited for farming. Acidity has
been corrected by liming, low fertility by fertilisers, drought
by irrigation, wetness by drainage, and subsoil pans by deep
ripping. These and other interventions have contributed
greatly to national prosperity and to increasing intensity of
land use. However, more intensive production, whether by
horticulture, cropping, or intensive pastoralism, raises the
issue of sustainability. Can the soil functions we rely on to
be sustained without loss of soil quality or adverse effects on
the wider environment? It is essential that soil quality is
monitored so that loss of quality can be identified and
managed or mitigated.
Soil quality was defined broadly by Else Bünemann and
others in 2018, as ‘the capacity of a soil to function within
ecosystem and land-use boundaries to sustain biological
productivity, maintain environmental quality, and promote
plant and animal health’. Thus, soil quality more specifically
is about the status of important soil properties that change
with the effects of land management (called ‘dynamic soil
properties’ or ‘management dependant properties’ or simply
‘soil quality indicators’). Soil quality indicators may change
in response to land management over short periods of time
(days, weeks, or years). Soil quality is assessed using soil
quality indicators that show levels of soil properties that
imply the status of important soil health processes. Indicators
are used to identify any factor that may be amiss and
requires further attention. If the indicator points to a possible
issue then further investigation, using a wider range of soil
properties, including more detailed and expensive measurements, may be required. The scientific literature mostly uses
the term ‘soil quality’ rather than ‘soil health’ because
‘health’ is encumbered by many shades of meaning. However, general literature on the state of the environment often
uses the terms interchangeably.
Systematic soil quality monitoring in New Zealand was
initiated at a regional scale by Manaaki Whenua Landcare –
Research with support from regional councils. Following the
investigation of a wide range of potential indicators, they
selected seven soil quality indicators: total carbon, total nitrogen, pH, Olsen phosphorus, mineralisable nitrogen, soil
dry bulk density, and macroporosity (Table 18.5). The
selected indicators were based on dynamic soil properties
that indicated soil biological reserves, fertility reserves,
chemical reserves, and physical reserves. Research continues
into soil quality indictors and monitoring and there is scope
for the development of new and powerful indicators
employing new technology.
The SINDI (soil indicators) website [http://sindi.
landcareresearch.co.nz/] provides a means for interpreting
the indicator values derived from the soil sampling and
analysis to aid in developing appropriate management
response. The focus for indicator research has been on soil
condition and does not include soil erosion or soil contamination. Although the SINDI was designed for regional-scale
monitoring it can be applied at any scale given an appropriate sampling strategy.
Soil quality indicators are being incorporated into the
national state of the environment monitoring programmes
with rapid changes occurring over recent years. The latest
information is on the Ministry for the Environment website
[https://www.mfe.govt.nz/land/state-of-our-land].
18.4.9 Visual Soil Assessment
Visual soil assessment (VSA) is a relatively simple, quick,
method of assessing the state of the soil, in the field, to help
inform land management decisions and, if repeated
302
18 Conclusion: Global Context, Formation Pathways …