Year of study:
1997-8
Lead Organisation & collaborators:
Department of Natural Resources and Environment
Contact:
Anne Crawford
DNRE
Project details
Objectives:
A suite of indicators were assessed for use in monitoring short and long term changes in soil quality under grazed pastures.
Hypotheses:
Key soil chemistry, physical and biological properties contribute to soil fertility and would provide a sound basis to assess the health of pastoral soils.
Basis of trial:
Use of soil property indicators to monitor short and long term changes.
Best available science assessment:
Overall score: 28
Overall rating: High
|
Objectives |
Conceptual model |
Study design |
Soil analysis |
Production & financial |
Method reporting |
Data analysis |
Results reporting |
Publication |
|
4 |
3 |
4 |
3 |
1 |
4 |
3 |
3 |
3 |
Trial site details:
July 1997
Dry conditions
| Site | Rainfall | Soil type | ||
| Ellinbank | Warragul (BoM) 1026.8mm/a | Krasnozem | ||
| Ellinbank | Warragul (BoM) 1026.8mm/a | Krasnozem | ||
| Ellinbank | Warragul (BoM) 1026.8mm/a | Krasnozem | ||
| Ellinbank | Warragul (BoM) 1026.8mm/a | Krasnozem | ||
| Strzelecki | Korumburra (BoM) 1207.7mm/a | Sedimentary | ||
| Loch | Nyora (BoM) 1008.5mm/a | Sedimentary | ||
| Nyora | Nyora (BoM) 1008.5mm/a | Sandy Loam | ||
| Mardan | Mirboo North (BoM) 1020.3mm/a | Sedimentary | ||
| Koonwarra | Koonwarra (BoM) 951.8mm/a | Sandy Loam | ||
| Tarwin Lower | Tarwin Lower (BoM) 940.0mm/a | Sandy Loam | ||
Pre-trial management:
| Site | Type | Management inputs |
| Ellinbank | Dairy | Medium |
| Ellinbank | Dairy | Low |
| Ellinbank | Dairy | High |
| Ellinbank | Beef | Low/medium |
| Strzelecki | Dairy | Medium/high |
| Loch | Beef | Low |
| Nyora | Dairy | High |
| Mardan | Beef/sheep | Low/medium |
| Koonwarra | Beef/sheep | Low |
| Tarwin Lower | Beef | Medium/high |
Summary of key findings of trial:
These transects provided a snapshot of soil quality beneath grazed pastures. Soils were generally of good to high fertility, moderately acidic and reasonable CEC and organic carbon content.
Soil pH and carbon generally decreased with soil depth across this assessment.
Trend indicators, such as pH were appropriate for measuring short term change in soil fertility, as a result of farm management practices such as the application of lime.
Soil Sampling Method:
Initial sample July 1997. (Single bulked samples)
Transect lengths between 50-250m were taken at the sites. Soils were sampled at 0-2.5, 2.5-5 and 5-10cm at 30 points along the transect.
Duplicate 0-10 and 10-20cm samples were taken from 30 points each.
Sampled over two years 4-6 weeks after the autumn break (July 1997 and May 1998), and mid spring (November 1997 and 1998).
15 cores, 50mm diameter were taken at 0.6m depth on the transect. The cores were sub-sampled for chemical analyses at 02.-0.3, 0.3-0.4 and 0.4-0.6.
Stored at 2-4 degrees for no more than 4 weeks. Slaking and dispersion tests- 8 to 10 aggregates were selected and dried at 40 degrees.
The 0-10cm and 10-20cm samples were dried at 40 degrees and passed through a 2mm sieve.
Tested for:
- pH (water and calcium chloride)
- Electrical conductivity
- Olsen and Colwell P
- Colwell K
- Available sulphur
- Exchangeable Al
- Oxidisable organic carbon
- Total carbon
- Total Nitrogen
- Exchangeable cations
Ellinbank, Rutherglen and State Chemistry Laboratory
Reportage:
How results have been reported:
Technical report, Anne Crawford DNRE
How a copy of any relevant reports can be obtained:
Maintaining soil quality of grazed pastures: final report, Crawford, Anne. DPI library.
Level of review of results:
Internal peer review
Results:
Variation in soil C with time and management influence:
There was a general decrease of oxidisable organic carbon levels with depth in the soils measured. Pasture soils had a higher organic carbon level than cropping soils.
| Site | Trend over time (from July 97-Nov 98) | ||||
| 0-2.5cm | 2.5-5cm | 5-10cm | 10-20cm | ||
| Ellinbank | – | + | – | None | |
| Ellinbank | + | None | – | – | |
| Ellinbank | None | + | + | None | |
| Ellinbank | – | – | – | – | |
| Strzelecki | – | None | None | None | |
| Loch | None | + | None | None | |
| Nyora | – | + | None | None | |
| Mardan | – | – | – | – | |
| Koonwarra | None | – | + | – | |
| Tarwin Lower | – | – | + | + | |
Further detail provided in the report
Variation in soil pH with time and management influence:
In general, the soil pH decreased with depth. Soil pH responds to farm management and should be monitored on a regular basis to understand the influence of management practice.
Sampling detected a marked decline in pH with depth in ferrosols, whereas pH was more uniform in dermosols.
| Site | Trend over time (from July 97-Nov 98) | |||||
| 0-2.5cm | 2.5-5cm | 5-10cm | 10-20cm | |||
| Ellinbank | – | + | + | None | ||
| Ellinbank | – | + | + | + | ||
| Ellinbank | None | + | + | + | ||
| Ellinbank | – | – | – | + | ||
| Strzelecki | + | – | + | + | ||
| Loch | + | None | None | None | ||
| Nyora | None | + | – | – | ||
| Mardan | – | – | + | – | ||
| Koonwarra | + | + | + | – | ||
| Tarwin Lower | + | + | + | + | ||
Further detail provided in the report
Next steps
Soil indicators are a useful tool for land managers to monitor soil fertility over time. It is important that the indicators chosen are “fit for use” to be able to interpret according to the land use of the property.