Grid soil mapping to define the variability in multiple soil properties.

Kirsten Barlow1, Sebastian Ie2, Ben Fleay2

1 Precision Agriculture, 113 Main Street, Rutherglen, Vic, 3685,,  

2 Precision Agriculture, PO Box 691, Ballarat, Vic 3353,,


Soil constraints such as acidity, sodicity and nutrient availability can cause significant losses in production, limit crop choice, and further reduce the health of our soil resources if untreated. Grid soil sampling is a proven strategy to identify and enable targeted amelioration of soil constraints across a paddock. This paper presents the results of grid soil mapping on 289 commercial paddocks, investigating the relationships between soil pH, CEC, ESP and soil test P observed in the grid mapped surface soil data. The results highlight the variability within individual paddocks for these soil characteristics. Whilst some soil characteristics (e.g., pH and CEC) were well correlated in some paddocks, for most other characteristics up to 75% of paddocks had no consistent trends between the soil test data with correlation coefficients of between -0.5 to 0.5. Grid soil sampling allows the different patterns of spatial variation to be determined for individual soil properties, and enables separate variable rate strategies to be developed.

Variable rate lime for cropping systems in the HRZ: an economic analysis

Kirsten Barlow1, Kerry Stott2, Sebastian Ie1

1 Precision Agriculture, 113 Main Street, Rutherglen, Vic, 3685,,  

2 Agriculture Victoria Research, AgriBio, 5 Ring Road, La Trobe University, Bundoora Vic, 3083


Soil acidity affects 50% of Australia’s agricultural land and significantly affects crop production. Results from grid soil sampling (0-10 cm) for pHCa across hundreds of cropping paddocks in the high rainfall zone (HRZ) in Victoria highlight the variability in soil pH across a paddock, where the coefficient of variation averaged 4.7% and ranged from 0.7 up to 16%. The range in soil pH and the coefficient of variation from the field data were used to develop eight hypothetical paddocks. A discounted cash flow model was used investigate the economics of grid soil mapping and variable rate lime application to ameliorate surface soil acidity. Both variable rate and fixed rate lime addition had a positive net present value (NPV) across the hypothetical scenarios, with the inclusion of a pH-sensitive pulse crop increasing the NPV. With a pulse crop in the rotation, variable rate lime had a greater NPV in six of the eight hypothetical paddocks, while in the remaining two paddocks variable rate and fixed rate applications produced similar NPV results.

Mind the Gap: targeting profile amelioration in Southern region sandy soils.

Lynne M Macdonald1, Therese McBeath1, Melisa Fraser2, Nigel Wilhelm3, David Davenport3, Sam Trengove4, Michael Moodie5, Rachael Whitworth6, Barry Haskins6, Jack Desbiolles7, Chris Saunders7, Mustafa Ucgul7, Rick Llewellyn1.

1 CSIRO Agriculture & Food, PMB2, Glen Osmond, SA 5064,

2 Primary Industries and Regions South Australia (PIRSA), 74 Struan House Rd, Naracoorte, SA, 5271,  

3 Primary Industries and Regions South Australia (PIRSA), Adelaide, South Australia, 5000

4 Trengove Consulting, Bute, South Australia

5 Frontier Farming Systems, Mildura, Victoria, 3500

6 AgGrow Agronomy and Research, Yoogali NSW 2680

7 University of South Australia, Mawson Lakes, SA, 5095,


Soil profile amelioration practices are gaining momentum to improve productivity on sandy soils in the Southern region. Diagnosing the underlying soil constraints and understanding the yield gap are important factors in supporting cost-effective management decisions. Drawing on findings from nine multi-year trials, we present the impact of different deep tillage practice (ripping, topsoil slotting, spading) with/without amendments on crop production in a range of sandy soils with different soil constraints. In sands with physical and nutritional constraints, yield responses to ripping alone ranged from nil responses in very dry seasons (decile 1) to 1.1 t/ha (average ~0.5 t/ha). Further yield gains, of 0.5 t/ha or more over-and-above the ripped treatment were commonly achieved through the addition of chicken manure, and sometimes with fertilisers. In water repellent sands, spading led to annual gains of between nil and 1.4 t/ha. However nil responses are also observed on acidic sands and/or under dry seasonal conditions. In water repellent sands, additional gains achieved from incorporation of N-rich hays lead to further gains, largely in the first 2-3 years, with 5-year cumulative gains of around 2.3 t/ha. Further trials will be undertaken to optimise the timing of nutrient release through managing the form of nutrition and the depth of placement, and to improve the understanding of the timing of nutrient availability, mineralisation/immobilisation dynamics and the contribution of micronutrients.



International student education in Australia – is agriculture gaining its fair share?

Jim Pratley1, 2

1School of Agriculture and Wine Science, Charles Sturt University, Wagga Wagga NSW 2678

2Australian Council of Deans of Agriculture


International student education arising from international students studying in Australia contributed $30 billion to Australia’s economy, ranking as the third largest export (Department of Education and Training 2018). Big winners are courses in Business Studies and Information Technology. Since Australian agriculture is considered amongst world’s best practice, it might be expected that international students interested in agriculture might seek education in Australia. So, what are the opportunities for regional universities under this scenario and what is the current situation that might provide an indication of realising that opportunity? International students favour prestigious universities and the five Group of 8 (Go8) universities captured 83% of the international student market in agriculture over the 2001-2016 period. There is a considerable discrepancy in total income between the Go8 and regional universities from international fee-paying students, both overall and in agriculture. While there is little evidence for major differences in quality of course offerings between universities, it is clear that the capability to invest in research and other areas from international student income will be compromised for regional universities. The rhetoric offered by governments to international students to promote study in regional areas is likely to fail as the ‘client’ seeks to gain qualifications from higher-ranked metropolitan universities.

Indigenous students do not choose agriculture at University

Jim Pratley1, 2

 1School of Agriculture and Wine Science, Charles Sturt University, Wagga Wagga NSW 2678

 2Australian Council of Deans of Agriculture      


The Indigenous peoples of Australia pride themselves on their ‘connection with country’ as it comprises animals, plants and soils. Yet enrolments in agriculture courses at universities nationally show very few are from Indigenous students. This raises the question as to whether university agricultural education is appropriate for this cohort of students or whether there are other issues that are creating barriers to Indigenous entry into academia. This paper looks at the data to understand the status quo and whether there might be steps that can be taken to encourage better representation from Indigenous students.


The Australian Society of Agronomy is the professional body for agronomists in Australia. It has approximately 500 active members drawn from government, universities, research organisations and the private sector.

Photo Credits

David Marland Photography Graham Centre for Agricultural Innovation, Charles Sturt University

Conference Managers

Please contact the team at Conference Design with any questions regarding the conference.

© 2015 - 2019 Conference Design Pty Ltd