The document discusses parna deposits in the Yass Valley of New South Wales. Key points: - Parna deposits in the area have properties comparable to deposits further west and impart favorable properties for agriculture, particularly wine grape production. - Seven study sites were analyzed to characterize the morphology, distribution, and properties of the parna soils. Analytical tests showed the parna has stronger structure and fewer dispersive particles than underlying clay layers. - The parna soils satisfy criteria for classification as high quality agricultural land due to their structural stability, available water capacity, and suitability for crops and pastures. However, current land mapping may underestimate the agricultural value of areas with parna soils.

1. Properties and significance
of parna deposits in the Yass
Valley, NSW
Richard Greene, ANU
Peter Fogarty, CPSS, Soil and Land Conservation Consulting Pty Ltd

2. Introduction to Parna in the Yass Valley
 Most easterly of significant deposits
 Properties comparable to parna deposits to west
 Occurs as discrete layer and also incorporated into
upper part of soil profile
 We have expanded detailed set of sites in the area from
three (Scott et al. 1998) to seven
 Imparts favourable properties for agriculture, of
particular value for wine grape production

3. Structure of talk
 A. PF to talk on morphology and distribution
 B. RG to talk on more detailed analytical properties
 C. PF to link to land use and potential capability

4. Study sites

5. Study sites: Clonakilla winery (1)
0-22cm: A horizon, unbleached loam, weak
sabl structure;
22-46: B2 horizon; dark red medium clay; fine
polyhedral structure; SP II*
46-90+: B3 horizon; red brown heavy clay;
weakly structured; grades to sap rock
* Sub plasticity class from McIntyre (1976) classes 0-III

6. Study sites: MacIntosh Cct (2)
0-20cm: A horizon, unbleached
heavy loam, moderate structure
20-70: B2 horizon; dark red
medium clay; strong fine
polyhedral structure; SP II
70+: C horizon; yellow brown
crumbly sap rock with clay
parna rich layer
saprolite

7. Study sites: Dog Trap Rd (3)
0-35cm: A horizon, unbleached silty
loam, massive structure
35-75: B2 horizon; brownish red light
clay; moderate sabl structure; SP1
75-90cm: stone line; angular pieces
of dacite and quartz, weakly
weathered
90-150cm: variable, saprolite and
clay due to in situ weathering

8. Study sites: Yass railway cutting (4)
0-10cm: A horizon, unbleached clay
loam, moderate structure
10-50: B2 horizon; reddish brown medium
clay; strong fine polyhedral structure; SPII
50-110cm: brown heavy clay; moderate
coarse blocky structure
110cm+: saprolite with discontinuous
silica pan

9. Previous study sites in Yass Valley
Gundaroo
(Chen, 1998)
Yass River
Crossing
(Gatehouse,1998)
Sutton (Walker and Chartres, 1988;
Cattle and Greene, 2009

10. Parna characteristics: general morphology
➢Strong red to red brown colours
➢Strong structure with coarse peds
breaking into strong fine aggregates
➢Medium to heavy clay
➢Clear horizon boundaries
➢Stone layer indicating deposition onto
former surface
➢Good correspondence with previous
studies

11. Parna distribution in Yass Valley
Distribution based on
extrapolation from:
➢ Existing sites
➢ Road cuttings
➢ Other soil profiles

12. Parna distribution: in relation to regional terrain
Terrain key control on distribution
mountains to west create barrier
occurs on gently undulating
terrain, upper and midslopes
(as per Summerell et al, 2000 in
Young area)
slope grades around 5%, all <10%,
due to local hillslope redistribution

13. Parna distribution: in relation to geology
Discrete parna layer across
➢ Silurian acid volcanics,
➢ Ordovician metasediments
Incorporated parna
➢ Sutton granite
From: NSW Seamless Geology

14. Richard
 1. ASWAT data for 4 profiles; as a method of differentiating
parna and relating to land capability. Field et al. (1997)
developed a system to measure dispersion in water; score
0-16. Used air dry and remoulded.
 2. Mastersizer data for 2 profiles (Yass Rail Cut, MacIntosh
Crt.); measure of parna strength.
 3. Stability diagram of Rengasamy et al. (1984) with data
from 4 profiles where CEC/EC properties are used to relate
to structural stability and land use.

15. Yass Rail Cut samples (remoulded) at 10 mins
(30-40 cm) parna layer (70-80 cm) dispersive clay layer

16. Yass Rail samples (remoulded) at 2 hrs.
(30-40 cm) parna layer (70-80 cm) dispersive clay layer

17. Yass Rail Cut layers
Suspended samples:Parna has larger aggregates and less dispersive material
than clay layer
Ultrasonified: parna has distinctive 30 µm material
Parna Dispersive clay layer
layer Particle Size Distribution
0.01 0.1 1 10 100 1000 3000
Particle Size (µm)
0
1
2
3
4
5
6
7
Volume
(%)
Yass Rail Profile 30-40 cm - Average, Monday, 16 March 2020 1:43:04 PM
Yass Rail Profile 30-40 cm plus 30 secs US - Average, Monday, 16 March 2020 1:47:51 PM
ParticleSizeDistribution
0.01 0.1 1 10 100 1000 3000
Particle Size (µm)
0
1
2
3
4
5
6
Volume
(%)
RepeatYass Rail Profile 70-80cm - Average, Monday, 16March20202:38:33PM
RepeatYass Rail Profile 70-80cm plus 30secs US - Average, Monday, 16March20202:44:00PM

18. MacIntosh Crt samples (showed similar
properties to Yass Rail Cut)
Parna (20-50 cm) Saprolite (70-90 cm)
ParticleSizeDistribution
0.01 0.1 1 10 100 1000 3000
Particle Size (µm)
0
1
2
3
4
5
6
7
Volume
(%)
Murrumbateman 20-50 - Average, Thursday, 7 April 2016 2:27:19 PM
Murrumbateman 20-50+30US - Average, Thursday, 7 April 2016 2:32:56 PM
ParticleSizeDistribution
0.01 0.1 1 10 100 1000 3000
Particle Size (µm)
0
1
2
3
4
5
6
Volume
(%)
MurrumbatemanSub-layer - Average,Thursday,7April20162:43:40PM
MurrumbatemanSub-layer+30US - Average,Thursday,7April20162:47:03PM

19. ASWAT test results for 4 new sites

20. Rengasamy et al. 1984 stability diagram for parna soils
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2
ESP (%)
EC (1:5) dS/m
Parna samples plotted as EC and ESP
Boundary Class 1
and 2B
Boundary Class
2A and 2B
Boundary Class 2
and Class 3
Class
2a
Class
2b
Class
3c
Class
1
Class
3a
P
P = Parna
P
P
P

21. Agricultural qualities of parna soils
Generally mildly acid pH trend
➢pH(w) 0-10 5.0 - 6.0
➢pH (w) 40-60 5.5 - 6.5
Low salt, non sodic
➢EC1:5 in upper 60cm < 0.2dS/m
➢ESP in upper 60cm <5%;
➢Exch calcium ~40%
Well drained
➢Lack A2 development, no perched watertable

22. Agricultural qualities of parna soils
Structural stability high
➢ ASWAT Topsoil 2
Parna layer 0 (1 site = 4)
60-90cm variable, 2-8
Available water moderately high*
➢ 0-60 100-120mm
Terrain favourable
➢ Slope grades typically 5%, up to 10%
* Estimated using tables 2.5, 2.6, Hazelton and Murphy, 2007

23. Parna and land capability
➢ Soil qualities reflected in land
capability
➢ NSW 8 class system
➢ Land with parna cover mapped
as class 4
▪ range of limitations including poor
structure, salinity and acidification
risk, slope grades 10-20%
▪ suited to perennial pastures with
occasional cultivation
➢ Should be mapped as class 3
Base map from NSW Government eSpade 2.1

24. Biophysical strategic agricultural land
➢ Identifies high value agricultural land associated with
coal and petroleum leases
➢ BSAL (NSW Govt 2013) comprises “……the best quality
landforms, soil and water resources which are naturally capable of
sustaining high levels of productivity and require minimal
management practices to maintain this high quality.”
➢ Essential criteria reliable water supply, capability classes
I-III, inherent fertility high to moderate
➢ Parna soils in Yass-Murrumbateman area satisfy Bsal
criteria

25. Parna and viticulture
➢ Canberra region has a well established small wine industry
with 40 wineries
➢ Much of wine grape acreage on gently undulating land
with parna soils
➢ One example, Clonakilla winery on south east side of
Murrumbateman
➢ Parna soils form discrete layer in “Tims Block”, 1.7ha which
produces varieties of Shiraz and Viognier which are
blended
➢ Retail value of wine approximately $1.8m annually

26. Planning controls
 Rapidly developing into peri
urban “acreage” style
developments
 Corresponds closely to parna
soils, high proportion of class III
land
 Recent changes to LEP 2013
increased zoning for rural-
residential developments
 Image shows latest zonings in
relation to wineries near
Murrumbateman
From: Yass Valley Council LEP 2013

27. Conclusions
 Parna more widely distributed in upper catchment than
generally appreciated
 Morphology and detailed lab properties reinforce
presence of parna.
 Mapping and local government zoning fail to represent
true value of parna soil for agriculture.

28. References
S Cattle, R Greene & A McPherson, 2009, 'The role of climate and local regolith-landscape processes in
determining the pedological characteristics of Aeolian dust deposits across south-eastern Australia', Quaternary
International, vol. 209, no. 1-2, pp. 95-106.
XY Chen, KM Scott & R Gatehouse (1998) South Gundaroo Site in Aeolian Dust: Implications for Australian Mineral
Exploration and Environmental Management. Field Guide, CRC LEME Report 101
R Gatehouse (1998) Yass River Site in Aeolian Dust: Implications for Australian Mineral Exploration and
Environmental Management. Field Guide, CRC LEME Report 101
NSW Government (2013) Interim protocol for site verification and mapping of biophysical strategic agricultural
land
PH Walker, CJ Chartres and J Hutka (1988) The effect of Aeolian accessions on soil development on granitic-rocks
in south eastern Australia. I. Soil morphology and particle-size distributions. Australian Journal of Soil Research 26(1)
1 – 16
DJ Field, DC McKenzie and AJ Koppi (1997) Development of an improved Vertisol stability test for SOILpak.
Australian Journal of Soil Research, 35, 846-852.
P Rengasamy, RSB Greene, GW Ford and AH Mehanni (1984) Identification of dispersive behaviour and the
management of red-brown earths. Australian Journal of Soil Research, 22, 413-431.