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SOIL CONDITION EVALUATION AND MONITORING (SCEAM), TASMANIA KIDD1

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					SOIL CONDITION EVALUATION AND MONITORING (SCEAM), TASMANIA

KIDD1, D., Cotching3, W.E., Dolbey2, B., Gay2, Q., Grose2, C., Hawkins2, H., Hawkins2, K., McDonald1,
D., Moreton1, R., Novakowski2, A., Priestly1, T., Rodgers1, D., Scholz2, G., Tate2, S.

    1. Department of Primary Industries, Parks, Water and Environment, Tasmania
    2. Formerly of the Department of Primary Industries and Water
    3. Tasmanian Institute of Agricultural Research
                       Email: Darren.Kidd@dpipwe.tas.gov.au

Introduction
There is now a well recognised requirement to monitor soil condition across the country to determine the
long-term effects of different land uses and management practices on soil health. Tasmania was one of
the first Australian states to implement a scientifically sound monitoring system, which has established
100 long term reference sites in each NRM Region (300 in total), and a database of Tasmanian state-wide
base-line soil condition data. The Soil Condition Evaluation and Monitoring (SCEAM) Project
commenced in 2004, and was largely based on the “500 Soils” monitoring program in New Zealand
(Sparling et al 2003). It was funded by the Natural Heritage Trust, and is a joint initiative between The
Department of Primary Industries, Parks, Water and Environment, the Tasmanian Institute of Agricultural
Research, and the Cradle Coast, Northern and Southern Natural Resource Management (NRM) Regions.
The intention is to re-visit sites every 5 years to help identify long-term soil health trends for different
land uses, when compared against key soil health target values for different soil types.

Methods
Priority soil/ land use combinations were identified through a work-shop with Tasmanian soils experts
and in conjunction with each NRM Region for targeted reference site establishment. Site locations were
identified using a combination of desktop analysis and field investigations. Selected sites were chosen
depending on where physical investigation had identified required soil orders with appropriate land use,
regionally typical and spatially uniform soil profile characteristics were represented, and theland owner
was cooperative. Samples were collected and bulked from every 2m along a 50m transect for both
surface (0 to 75mm) and sub-surface horizons (75mm cores between 75 and 300mm depth, depending on
horizons depth(s)), and chemically analysed using CSBP Wesfarmers laboratories in Western Australia.
Physical samples for bulk density and aggregate stability were also taken at both depths at 3 points along
the transect, and analysed for bulk density and wet-sieving (Laffan 1996). A soil pit was excavated at
each site to 1.2m (where possible) for full description and classification to Australian standards. Targeted
soil/ land use combinations included agricultural, horticultural, forestry and conservation land uses, such
as Ferrosols-Intensive Cropping, Dermosols-Intensive Cropping, Sodosols-Cropping, Dermosols-
Plantation Forestry, Dermosols-Native Forestry, Chromosols-Grazing (North Facing Slopes), and
Organosols-Conservation. Soil target values were developed (and are subject to review by Tasmania’s
soil expert community) for six key soil health indicators, with range variations dependent on soil order
and land use. The targets consider a balance between environmental health and impacts, while
maximising the intended land use productivity. No targets were deemed suitable for conservation land
uses.
Results
Table 1 shows a state-wide results for each land use category and the proportion of sites not meeting
initially developed soil health targets (variability between soil orders is accounted for within target
ranges).

Table 1. Proportion (%) of Sites Not Meeting Soil Condition Targets in Tasmania (Surface Samples)

                                                Organic
                       % of total               Carbon                     Exchangeable      Bulk         Aggregate
 Land Use Category       sites        pH          %          Olsen P        Sodium %        Density        Stability
 Dryland Cropping         <1           0           0           n/a              0             0               0
 Dryland Grazing/
                          19           19          8            51              12            2              15
 Pasture
 Intensive Cropping       40           4          32            n/a             7             11             28
 Irrigated Pasture         6           6           0            56              6              6             25
 Native Forest            11           0          17            n/a             3              0             10
 Organic Cropping          5           23          8            n/a             8              0             31
 Perennial
                           8           5          23            n/a             0             23             14
 Horticulture
 Plantation Forestry       7           0          26            n/a             16             0              0
 Conservation              3          n/a         n/a           n/a             n/a           n/a            n/a

Results are being developed into a “soil health report card” for each region, with these indicating different
soil health issues relevant in a regional context. State-wide results are generally indicating;
      One third of intensive cropping and one quarter of perennial horticulture sites across the state are
         showing signs of organic carbon decline. (Many native forest sites were sampled immediately
         post-harvest, possibly explaining the 17% of sites low in organic carbon).
      Declining soil pH has generally been addressed across Tasmania for all land uses, with the
         exception of of a few dryland pasture sites. Organic cropping sites are also showing slight acidity
         in about one quarter of sites.
      A significant proportion of grazing sites have below optimum levels of available P with possible
         impacts to production, however, some are displaying a risk of off-site impacts with levels
         exceeding the target range.
Results will be subjected to continued statistical and spatial analysis, with all data, such as the on-going
collection of detailed land use histories, current land management practices, and additional soil chemistry,
to be utilised for further data-mining activities. Cradle Coast NRM sites are currently being sampled for
potential organic and inorganic contaminants, as well as soil biological measures, and additional soil
carbon analyses using Mid-Infra-Red Spectroscopy (MIR Analysis) have also been undertaken.

Acknowledgements
Australian Government – Natural Heritage Trust Funding. NRM North, NRM South, Cradle Coast NRM.
The land holders who allowed sampling of their soils and agreed to be involved in future soil condition
monitoring.

References
Laffan M., Grant J. And Hill R. 1996. A method for assessing the erodobility of Tasmanian forest soils.
Australian Journal of Soil and Water Conservation 9: 4, 16- 23.
Sparling R.B., Frampton C. And Cuff J. 2003. National Soil Quality Review and Programme Design.
Ministry for the Environment, Doc #807593, New Zealand.

				
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