BSC Newsletter - August 2006The Benchmarking Soil Chemistry project is funded by the Australian Government through the National Action Plan for Salinity and Water Quality (NAP) in conjunction with the NSW

Government and the Murrumbidgee Catchment Authority.The Project is delivered by the NSW Department of Primary Industries (NSW DPI) and

consists of four workshops and soil testing to enable landholders to benchmark soil chemistry on a paddock basis and to integrate farming practices with better soil management.

Benchmarking Soil Chemistry

The information being compiled is contributing to the overall understanding of soils within the project area. The map shows sampling locations for the project up until April this year.

The Benchmarking Soil Chemistry project has been successfully delivered by NSW DPI to more then 200 landholders across the Upper Murrumbidgee Catchment. Groups have been held at Cooma, Gilmore, Yaven, Brungle, Cootamundra, Sutton, Jugiong, Burra, Kyeamba, Bungendore, Murrumbateman, Harden, Bookham and Smiths Road. The project is currently running workshops for Vineyards around Canberra.In excess of 900 paddocks have been tested altogether.

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The workshops continue to be run across the Project area, with new groups being formed all the time. If you know of anyone who would like to be involved, please encourage them to express their interest by contacting either Susan Tate on 0428 424 566 or 02 6297 1861 or Jennifer Hardwicke on 0428 401 082 or 02 6297 1861.

A common problem across the Upper Murrumbidgee is acidic soils. Soils are acidic in this region for two main reasons: 1. Naturally, from the weathering of some of our common types of bedrock (e.g. Granite) or 2. Agriculturally, from our farming practices.

As soils become more acidic, the Aluminium (Al) which naturally occurs as clay-compounds becomes soluble and available to the plants. The critical limit where this happens exponentially is at a pH (CaCl) of 4.6. Figure 1 shows the pH and Al% across 700 paddocks from a DPI study where this critical limit is evident. We also see this in our BMSC Groups, for example the Bookham Group (Figure 2).

Project Officer Susan Tate leading discussions on soil profiles with the Cootamundra 2 group

The organic matter, bacteria and fungi within the soil aid in binding soil particles into stable aggregates for a well-structured profile.

pH and Aluminium Percentage (ave 700 paddocks)

0%

5%

10%

15%

20%

25%

30%

35%

40%

3.9 4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5 5.1 5.2 5.3+

pH (CaCl)

Alu

min

ium

%

Aluminium % vs pH Calcium Chloride for Bookham 1

0

5

10

15

20

25

30

35

40

45

50

4 4.5 5 5.5 6 6.5 7 7.5 8

pH Calcium Chloride

Alu

min

ium

%

Top

Sub

Expon. (Top)

Expon. (Sub)

Figure 1Figure 2

It becomes evident that managing our soil pH to 5< means that Al is in its insoluble form therefore not harmful to plants.

As discussed in the workshop, there are a few ways of slowing or reversing the acidifying process such as liming, grazing management, managing product removal, or planting Al-tolerant species. However, it is important when considering expensive options such as liming to consider what is the most limiting on your soil test, it may not be pH.

For a refresher on acidifying processes and management, you can look over your Workshop 4 session notes.

Soil profiles can be easily seen along creeks, roadside cuttings, and in excavated pits, and are a useful tool in determining the physical properties of the soil. The profile can be assessed for soil structure, texture, depth of soil, and soil colour, as an indication of fertility and to identify any impediments to root growth such as hard pans.

Within the project area, we have identified a number sodic, saline and compacted soil sites. A healthy profile will consist of a well-structured, friable topsoil with a large percentage of pore spaces, allowing for ease of root development, water entry and air movement.

The topsoil (A1 horizon) is where the majority of nutrient cycling and biological activity occurs. It is therefore important that our soils are protected with sufficient ground cover (70%+) to reduce erosion risk, and ensure that organic matter is cycling back into the soil.

Acidic soils and Aluminium trends extending across the Project Area

Soil Profiles

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For information on Pastures you can try these links:• http://www.agric.nsw.gov.au/reader/past-establishment/p226.htm• http://www.agric.nsw.gov.au/reader/bmp-temp-pastures

Soil Acidity:• http://www.agric.nsw.gov.au/reader/soil-acid/2991-soil-acidity-and-liming-.pdf?MIvalObj=25847&doctype=document&MItypeObj=application/pdf&name=/2991-soil-acidity-and-liming-.pdf• http://www.agric.nsw.gov.au/reader/soil-acid/acidsoil-4-2.pdf?MIvalObj=3679&doctype=document&MItypeObj=application/pdf&name=/acidsoil-4-2.pdf• http://www.agric.nsw.gov.au/reader/soil-acid/ss592-liming-material.htm• http://www.agric.nsw.gov.au/reader/soil-acid/acidsoil-6.pdf?MIvalObj=3681&doctype=document&MItypeObj=application/pdf&name=/acidsoil-6.pdf

Salinity:• http://www.agric.nsw.gov.au/reader/salinity/salinitynote8.pdf?MIvalObj=7698&doctype=document&MItypeObj=application/pdf&name=/salinitynote8.pdf

Soil Pack:• http://www.agric.nsw.gov.au/reader/soilpak-si

Fertilisers:• http://www.agric.nsw.gov.au/reader/fertilisers-for-pastures• http://www.agric.nsw.gov.au/reader/soil-fertilisers• http://www.agric.nsw.gov.au/reader/soil-fertilisers/fert-calcs-dpi496.pdf?MIvalObj=25157&doctype=document&MItypeObj=application/pdf&name=/fert-calcs-dpi496.pdf

Ground Cover:• http://www.agric.nsw.gov.au/reader/past-management/groundcover-for-pastures.pdf?MIvalObj=25403&doctype=document&MItypeObj=application/pdf&name=/groundcover-for-pastures.pdf

Sodicity:• http://www.dpi.nsw.gov.au/aboutus/resources/majorpubs/guides/managing-heavy-clay-soils-bland

Soil Biology:• http://www.dpi.nsw.gov.au/aboutus/resources/factsheets/soil-biology-basics

Information that is available on the Internet

The web can be an excellent source of information to assist landholders in making decisions to maintain or improve their land. There are a wide variety of resources available to you, including some of the publications that you received by participating in the Benchmarking Soil Chemistry workshops.

By opening Internet Explorer and typing “http://www.agric.nsw.gov.au/reader/bmp-temp-pastures” into the address and then hitting the enter key, you will be taken to a page on the internet with the Best Management Practices for Temperate Perennial Pastures in New South Wales.

↑ Type the website address here

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Compiled and written by Susan Tate, Project Officer, Jennfer Hardwicke, Project Officerand David Daley, Clerical Officer - Benchmarking and Understanding Soil Chemistry

NSW Department of Primary Industries, 1/28 Morisset Street, QueanbeyanPO Box 408, Queanbeyan NSW 2620

Phone: (02) 6297 1861 Fax: (02) 6299 4215Email: david.daley@dpi.nsw.gov.au

Rainfall Cooma1

Cootamundra2

Gundagai3

Wagga Wagga4

Yass5

Rainfall Over the Past Six Months

Feb-06 10.1 mm 3.6 mm 0 mm 1.8 mm 9 mmMar-06 14.6 mm 11.6 mm 25.6 mm 10.6 mm 30.6 mmApr-06 19.1 mm 15.6 mm 21 mm 17.4 mm 12 mmMay-06 14 mm 4.2 mm 13.6 mm 4.4 mm 7.1 mmJun-06 34.6 mm 42.8 mm 37.4 mm 39.4 mm 55 mmJul-06 26.7 mm 44.6 mm 64 mm 45.4 mm 66.6 mm

LongTerm

Averages

Feb 53.5 mm 39 mm 41.1 mm 39.4 mm 44.4 mmMar 50.2 mm 47.1 mm 43.6 mm 42.3 mm 47.5 mmApr 35.4 mm 49.9 mm 54.9 mm 42.5 mm 49.6 mmMay 34 mm 52.5 mm 67 mm 53.6 mm 51.3 mmJun 34.9 mm 59 mm 60 mm 50.2 mm 57.3 mmJul 26.3 mm 58.7 mm 78.6 mm 55.7 mm 58.8 mm

(All figures from the Bureau of Meteorlology) 1. Cooma Visitors Centre 2. Cootamundra Airport3. Gundagai (William Street) 4. Wagga Wagga AMO 5. Yass (Linton Hostel)

The Regions Rainfall

Fiona Leech, Yass District Agronomist, with Project Officers Jen Hardwicke and Susan Tate

Benchmarking Soil Chemistry is managed by Brett Upjohn who is the Project Leader and the District Agronomist at Tumut.

Susan Tate and Jennifer Hardwicke are Project Officers who run workshops from Queanbeyan.

David Daley is a Clerical Officer with the project and runs the soil database from Queanbeyan.

BSC is also run with the assistance of District Agronomists in the Murrumbidgee area like Fiona Leech at Yass.