23 research outputs found
Scoping biological indicators of soil quality Phase II. Defra Final Contract Report SP0534
This report presents results from a field assessment of a limited suite of potential biological indicators of soil quality to investigate their suitability for national-scale soil monitoring
Effects of acute gamma irradiation on chemical, physical and biological properties of soils
The use of gamma (-) irradiation as a method for soil sterilisation for laboratory experiments has been recommended over other sterilisation techniques.We reviewed literature dating back over 50 years to investigate the chemical and biological effects on -irradiated soils and to determine its practicality for sterilising soils which will subsequently be used for experimental purposes. Typically, -irradiation at 10 kGy will eliminate actinomycetes, fungi and invertebrates in most soils. The majority of soil bacteria are eliminated by 20 kGy, however, a dose higher than 70 kGy may be required to kill certain radio-resistant bacteria. We recommend prior to experimentation that the radiosensitivity of soils are determined so as to ensure the desired chemical and biological effects are achieved. -Irradiation may not be an appropriate method for all experiments as it can
influence soil chemical properties, in particular soil nitrate and ammonium levels. Where chemical stability is required we recommend sterilising soils air-dry rather than moist
SQID: Prioritising biological indicators of soil quality for deployment in a national-scale soil monitoring scheme. Summary report
This project prioritised thirteen biological indicators of soil quality which showed
high current potential for deployment in a national-scale soil monitoring scheme.
These indicators met a range of scientific and technical criteria that related soil
functions and feasibility within large-scale surveys. The priority indicators with
associated methodologies are:
- Eight soil microbial groups [ammonia oxidisers, denitrifiers, fungi, bacteria,
Archaea, methanogens, methanotrophs and actinomycetes] identified from
TRFLP fingerprinting
- Soil microbial community structure and biomass characterised from PLFA
profiles
- Multiple substrate induced respiration (MSIR) derived by GC or MicrorespTM
- Multi-enzyme profiling via microplate fluorometric assay
- Nematode community structure from Baermann extractions
- Microarthropod community structure from Tullgren dry extractions
The selection process was robust, repeatable and auditable. A structured framework
denoted a 'logical sieve' was developed to support the incorporation and analysis of
a large number of assessments against a wide range of technical and scientific criteria
relevant to national scale soil monitoring. This enabled a consistent synthesis of
available information and the semi-objective assessment of 183 potential biological
indicators identified from the literature. Stakeholder priorities for technical criteria
were identified through consultation, with the UK-SIC and the expert reviewers, and
incorporated into the final prioritisation phase of the logical sieve. The power of this
approach is that it provides a clear audit trail on the decision-making process and
would allow the inclusion of further indicators into the framework.
The process was initially reviewed by experts familiar with biological indicators and
soil monitoring and then assessed at a two-day expert workshop. Comments and
discussions on the relative importance and robustness of potential indicators and
future research priorities proved invaluable to the final selection. As a consequence,
the logical sieve was modified to prioritise biological indicators for all three soil
functions rather than simply biological indicators with the highest universal scores.
The final priority indicators were selected by reviewing the outputs from the logical
sieve. Each priority indicator, with associated method, was assessed for relevance to
ecological services, obvious surrogacy, the range of indicator indices produced and
practicalities of use. Each priority indicator was reviewed and outstanding issues
relating to deployment identified.
Statistical analyses of existing field survey/experimental data for PLFAs, soil
invertebrates and community-level physiological profiling of the soil microbial
community (BIOLOGTM) highlighted generic technical, policy-related and scientific
issues which were considered in the recommendations for a field evaluation of the
priority indicators
The function of soil biodiversity as indicators of soil quality: Insights from the UK Defra SQID project
This presentation outlines the final results from the UK Defra SQID project which identified and piloted a
suite of biological indicators of soil quality for deployment in national-scale soil monitoring programmes to
meet a range of UK policy objectives. The indicators were selected to provide information on the soil
biological processes which underpin soil function and therefore support ecosystem services. A semiquantitative
framework was used to systematically capture the wealth of information in the literature and
from expert knowledge on potential indicators of soil quality with a total of 183 indicators assessed. Six soil
biological methods have now been piloted in the UK using two complementary field approaches. These six
reflect the genotypic, phenotypic and functional characteristics of soil biodiversity. Here we review the
results from the two field approaches, the first to assess the temporal sensitivity of biological indicators to
key environmental pressures across a 12 month window and the second to asses the ability of biological
indicators to discriminate between different habitats. We discuss the relative performance of the indicators
and how these were prioritised for national-scale soil monitoring and finally, how this process has revealed
new insights into the distribution and characteristics of soil biological properties within UK soils and habitats
Natural capital and ecosystem services, developing an appropriate soils framework as a basis for valuation
Natural capital and ecosystem service concepts are embodied in the ecosystems approach to sustainable
development, which is a framework being consistently adopted by decision making bodies ranging from
national governments to the United Nations. In the Millennium Ecosystem Assessment soils are given the
vital role of a supporting service, but many of the other soil goods and services remain obscured. In this
review we address this using and earth-system approach, highlighting the final goods and services soils
produce, in a stock-fund, fund-service model of the pedosphere. We also argue that focusing on final
goods and services will be counterproductive in the long run and emphasize that final goods and services
are derived from an ecosystem supply chain that relies on ecological infrastructure. We propose that an
appropriate ecosystems framework for soils should incorporate soil stocks (natural capital) showing their
contribution to stock-flows and emergent fund-services as part of the supply chain. By so doing, an
operational ecosystems concept for soils can draw on much more supporting data on soil stocks as
demonstrated in a case study with soils data from England andWales showing stocks, gaps in monitoring
and drivers of change. Although the focus of this review is on soils, we believe the earth-system approach
and principles of the ecosystem supply chain are widely applicable to the ecosystems approach and bring
clarity in terms of where goods and services are derived from
Rising atmospheric CO2 reduces sequestration of root-derived soil carbon
Forests have a key role as carbon sinks, which could potentially mitigate the continuing increase in atmospheric carbon dioxide concentration and associated climate change. We show that carbon dioxide enrichment, although causing short-term growth stimulation in a range of European tree species, also leads to an increase in soil microbial respiration and a marked decline in sequestration of root-derived carbon in the soil. These findings indicate that, should similar processes operate in forest ecosystems, the size of the annual terrestrial carbon sink may be substantially reduced, resulting in a positive feedback on the rate of increase in atmospheric carbon dioxide concentration