Abstract

Key Words

Soil data, soil database, soil information, cotton soils, NSW soils.

Introduction

In modern society there has never been more emphasis placed on the accuracy and reliability of spatial information used for management of natural resources. As management decisions regarding environmental and built resources are being more closely scrutinised, so too are data used for decision-making based on alternative land uses. Therefore the collection of accurate natural resource data and their processing into useful information are of utmost importance. In recognition of these requirements, the Australian Cotton Cooperative Research Centre funded (total funding: $3.7 million) a number of research projects since 1994 to make inventories of soil of the cotton-producing regions of Australia. The outcome of this project is a large amount of both quantitative and qualitative soil data covering much of the north-western New South Wales and south-western Queensland.

The soil data covers, among others soil quality indicators, soil salinity, soil physical and chemical properties, and descriptive properties of the soil. There are over 90,000 records covering over 1,500 sites located in the Namoi, Gwydir and Macintyre valleys, and the Bourke and St George Irrigation districts. This is unprecedented in the realm of land resource survey in Australia, as no other industry has such wealth of soil data in a given region. The soil data provide the benchmark of soil quality for future monitoring of the land resources and catchment health. The soil data have also been processed to extract useful information for decisions regarding alternative management practices. Useful products, such as digital soil type and attribute maps, are being used for environmental modelling and regional planning.

To facilitate access to the information and ease of use and manipulation by the end users, the soil data have been put together into a simple-to-use database, which we termed as Australian Cotton CRC Soil Database Assistant (AC-CRC SDBA). The easy-to-use soil database provides a much more dynamic tool which delivers interactive query capabilities such as:

• Searching for site locations of interest
• Displaying and viewing multiple data sets
• Conducting queries for specialised analysis
• Retrieving specialised data services and information

These capabilities of the AC-CRC SDBA are very appropriate for a rural-based group such as cotton-farming community. The AC-CRC SDBA (Odeh et al., 2004) allows for simple query, retrieval and other customised operations specific to the land management requirements under cotton production systems. Potential users of this database include: land managers, agronomists and farm managers, environmental analysts and planners, government employees in EPA, DIPNR (NSW), NSW Agriculture, and Land and Water Researchers.

Background: what was lacking prior to the soil inventory project

There is a growing need for accurate soil information for modelling soil processes, land use planning and environmental protection. Such quality information for environmental modelling are generally lacking for most of the arable land of Australia. This was the case with the cotton-producing regions of Australia until recently. Prior to this project, reliable soil information was lacking or existed in scattered and uncoordinated patterns in the cotton-growing regions. Because of this inadequacy, a project was initiated and funded by the Cooperative Research Centre for Sustainable Cotton Production and later continued and maintained by its successor, the Australian Cotton Cooperative Research Centre. The main aims were to:

• Efficiently sample the soil of the regions and provide soil data that would provide reliable information on soil quality.
• Collate the soil physical, chemical and qualitative data into a queriable database for use by the stakeholders.
• Develop an integrated soil information system for the analysis of, easy assess to and retrieval of the soil physical-chemical data by the stakeholders.
• Publish the database and the soil information system for easy distribution to the stakeholders

Methods

Sampling began in early 1995 in the lower Macintyre Valley, and was later extended to the lower Gwydir (1996), lower Namoi (1997) and upper Namoi (1998). Surveys were carried out in St George Irrigation District (1999), Bourke Irrigation District (2000) and Lachlan Valley (2001), as shown in Figure 1. Soil colour, structure and other morphological properties were observed in the field. Thousands of soil samples were collected and analysed for chemical and physical properties in the laboratory. This resulted in over 9,000 measurements for the combined regions. Details of sampling designs and field sampling are presented elsewhere (Odeh et al, 1998; Odeh and McBratney, 1996).

Figure 1. Map of Southeastern Australia showing the Cotton CRC soil survey sites

Soil properties measured and included in the database

Soil pH: pH is a measure of soil reaction; it affects chemical activities in the soil, hence availability of some plant nutrients.

Electrical conductivity (EC): EC is a measure of salt concentration in the soil which, in turn, is determined by intensity of salinisation processes; the amount of salts in the soil has some physiological effects on certain crops to a varying degree.

Bicarbonate extracted phosphorus (P): Soluble P is a measure of available P, and hence P fertility. Soluble P is also a measure of P-sorptivity of the soil.

Exchangeable basic cations: The amount of basic cations is a measure of their availability to plants;

Effective Cation Exchange Capacity (CEC): CEC influences physicochemical processes in the soil and, in conjunction with exchangeable sodium, can be used to quantify sodicity which affects structural and physical processes in the soil.

Organic carbon (OC): The amount of OC is important as a structural constituent in addition to its usefulness as a nutrient source for plants and soil microflora and fauna important for overall soil health. Also carbon sequestration through soil management is important for limiting greenhouse effect.

Total organic nitrogen: Like OC, it is a measure of soil fertility and the ratio of it to OC reflects biological activities in the soil.

Particle-size fractions (clay and silt and sand): The particle-size distribution of a soil affects the physical and chemical processes of the soil and hence the latter’s overall fertility and degradability. The consequence of flux of contaminant into the water system is also important.

Additionally, field soil descriptions, in accordance with McDonald et al. (1984), important for soil classification are included.

Results

A major outcome of the large amount of both quantitative and qualitative soil data incorporated in a Soil Database covering much of the cotton-producing regions of New South Wales and south-western Queensland.

Figure 2. The Australian Cotton CRC Soil Database and Soil Information System (CDROM)

The database initially incorporates soil data from the cotton-producing areas in the three NSW northern and boarder river valleys: the Macintyre, Gwydir and the Lower Namoi (Figure 1), in addition to the Lachlan valley. The database will be updated with data from other regions.

The data have been incorporated into a Microsoft® Access database form. This form includes a ‘Database Assistant’ to make it easy to retrieve appropriate soil data for a specific region/area and purpose. The Database Assistant, which is written into CD-ROMs (Figure 2) for easy distribution to the end-users, also facilitates the updating and maintenance of the database itself. The Soil Database comprises four main tables of data: Regions, Sites, Samples and Farms (Figure 3). There is a clear hierarchy in the database. At the top level are Regions, which are large geographical areas. Each Region contains numerous Sites, which are point locations where soil samples were taken. And each Site contains numerous Samples, which are soil samples taken from different depths at a Site. Farm information is separate from this hierarchy. Sites may sometimes be located on farms or other properties, and where this information was recorded it is linked to the relevant Site. Private details of farms, such as owner names and phone numbers, are not available.

Figure 3. Soil Database Schematic

The Soil Database Assistant

To access and run the Soil Database Assistant you require a Microsoft Windows computer with Microsoft Access 2000 or newer) installed. To run the Soil Database Assistant, simply double-click on the file or icon on your computer. You will see the introductory screen – click OK to continue.

You will next see the Soil Database Assistant screen, as illustrated in Figure 4.

Figure 4. Soil Database Assistant Screen

You can access all the functions of the Soil Database Assistant from this main screen. You can also click Close to hide this main screen, and still access all functions from the toolbar at the top of the window. Many of these functions are administrative and require a password to access them. The only exception is Query the Database, which can be used by anyone and is covered in the next section. To exit the Soil Database, click the Exit button.

Querying the Database

To retrieve the particular data you require from the Soil Database, click Query the Database on the Soil Database Assistant screen or the toolbar (Figure 5). You will see the Query the Database screen as shown in Figure ??:

Figure 5. Query the Database Screen

Select Query section: Use this section to select previous queries or rename the current query.

Display Fields section: Use this section of the screen to select which fields you want displayed when the query is run.

Criteria section: Use this section of the form to filter the database so that only data from particular regions or sites are returned. You can also apply detailed filters eg. return site data where the soil calcium below 0.5 metres is greater than 20 mmol/kg.

Click Run Query to display the query results.

Select Query

Use the Select Query section of the Query the Database screen to create new queries and to run or delete previous queries:

Figure 6. The Select Query section of the Query the Database screen

Select Query: Type in this box to rename the current query, or drop down the list to select one of the previous queries (Figure 6).

New: Click to create a new Query. You will see the New Query screen. Type a name and description, then click OK.

Delete: Click the delete the query currently shown in the Select Query box.

Display Fields

Use the Display Fields section of the Query the Database screen to select what information you want displayed when the query is run. The information in the database is divided into ‘Fields’, all of which are visible, shown here in Figure 7. You can also change the order that the fields will be displayed, from left-to-right.

Figure 7. The Select Fields section of the Query the Database screen

Criteria

Use the Criteria section to filter the results of your query so that only data matching the criteria you specify appears in the query when you run it. The grid displays all criteria for the currently selected query. In the example above, only data belonging to the Region “GYD” (Gwydir River Valley) will be displayed when the query is run (Figure 8).

Figure 8. The Criteria section of the Query the Database

Alternatively you can click the New button to add a new criterion to the query using the Edit Criterion screen To Edit, click the Edit button to edit the criterion currently selected in the grid. The Edit Criterion screen will be displayed. You can delete, add or optimise the selection criteria.

The database set operators

And/Or Operators: Select the prefix for the criteria, which can be “And”, “Or”, “And (“ or “Or (”. This is important when you have multiple criteria.

• Two criteria with an “And” between them mean an intersection, so that only data matching both criteria will be displayed in the query results.
• Two criteria with an “Or” between them mean a union, so that data matching either or both criteria will be displayed in the query results.
• Use the “And (” or “Or (” to commence a parenthesised group of criteria. A group of criteria inside parentheses are evaluated before other criteria. You can add the right parenthesis “)” in the Criteria section of the Query the Database screen.

Run Query

When you have selected the query, fields, and criteria that you want, click the Run Query button to display the query results as illustrated in Figure 9.

Figure 9. The Query result screen from the Soil Database Assistant.

The query results are displayed on a screen as shown in Figure 9. You can also Click on Export Query button on the toolbar, as shown at the top of Figure 9, to export the query results into various different file formats.

Conclusion

The AC-CRC-SDB allows for simple query, retrieval and other customised operations on the soil database specific to the land management requirements under cotton production systems. The resulting easy-to-use data format would allow researchers, farmers, and other stakeholders have access to the soil databases, through the widely available Microsoft^® Access software (developed by Microsoft Corporation). The Soil Database Assistant has been published along with the easy-to-use Australian Cotton Soil Information Systemsreadable and displayable with ESRI^® ArcReader on CD-ROMs for distribution to the users, and thus provides added flexibility to technological diffusion of our research results (Odeh et al., 2004).

Acknowledgements

Data were obtained by various groups with the assistance of ex-students of the Faculty of Agriculture, The University of Sydney: Macintyre Valley Peter Johnson and Alison Todd; Gwydir Valley Data Hagen Ganahl, and Mohammad Faruque Ahmed; Lower Namoi Valley Data Eugenia Figueroa and Andrew Huckle; Lachlan Valley Data: Alex Onus

References

McGarry, D., Ward, W.T., McBratney, A.B., 1989. Soil Studies in the lower Namoi: Methods and Data. 1. The Edgeroi Data Set. CSIRO, Australia.

Odeh, I.O.A., Cattle, S, Triantafilis, J. and McBratney, A.B. 2004. The Australian Cotton Soil Database and Geographic Information System. Proceedings of the 12^th Australian Cotton Conference, August 10-12, 2004, Gold Coast Convention and Trade Centre, Broadbeach, QLD. Interactive CDROM Conference Proceedings ACGRA, Orange NSW.

McDonald, R.C., Isbell, R.F., Speight, J.G., Walker, J. and Hopkins, M.S. 1984. Australian Soil and Land Survey Field Handbook. Inkata Press, Melbourne, 160 pp.