Soil Wise trials
The Soil Wise project is designed to give farmers greater confidence in addressing constraints that limit pasture production. Through evidence-based nutrient decisions, farmers can manage their macro-nutrients (like nitrogen, phosphorus, potassium and sulfur) and trace-elements to optimise plant growth and profitability.
At least eight fertiliser trials will be conducted across south-west WA from 2023 to 2024. These trials build on the work of the uPtake program, examining phosphorus as well as other nutrients of interest.
What we know so far
- Using evidence-based fertiliser management can increase production and reduce fertiliser costs.
- Fertiliser can influence pasture species composition.
- Timing of fertiliser application is important, especially in sandy soils with a very low Phosphorus Buffering Index (PBI).
Objectives
- Test the relevance of the national critical soil test values for potassium (K) and sulfur (S) to south-west WA soils.
- Promote best practice in sustainable agriculture and increase farmer and industry confidence in evidence-based fertiliser recommendations.
- Demonstrate the efficient use of fertiliser products to ensure their on-farm agronomic potential is maximised and losses to waterways are minimised.
- Continue to develop a successful collaboration between farmers, industry, State Government agencies and catchment groups to support productivity and profits in grazing and reduce nutrient runoff off into waterways.
Trial design
The design and methodology of the fertiliser trials have been developed through a collaborative Technical Reference Group with representatives from the fertiliser industry, the dairy and beef industries and State Government agencies, along with farmers, independent agronomists and scientists.
Treatments
The Soil Wise trials established in 2023 include the eight treatments listed below. Each treatment is replicated three times at each trial site.
Phosphorus (P), potassium (K), sulfur (S), nitrogen (N), trace element and lime rates are included below.
- Nil
- P, K, S and trace elements
- K, S and trace elements
- P, S and trace elements
- P, K and trace elements
- P, K, S only
- P, K, S, trace elements, and N
- P, K, S and lime
Trial and plot dimensions
- Eight treatments with three replications of each treatment for a total of 24 plots.
- Plots are at least 1.2 m wide and at least 10 m long with an effective buffer of at least 0.30 m between plots.
Rates and timing of fertiliser application
|
Nutrient |
Rate of nutrient (kg/ha) |
Timing of application |
|
Phosphorus (P) |
20 |
Autumn and spring |
|
Potassium (K) |
100 |
Autumn and spring |
|
Sulfur (S) |
40 |
Autumn and Spring |
|
Nitrogen (N) |
25 |
Six weeks after the break |
|
Nitrogen (N) |
50 |
Mid to late August |
|
Trace elements |
||
|
Magnesium (Mg) |
6 |
Autumn |
|
Maganese (Mn) |
6 |
Autumn |
|
Copper (Cu) |
2 |
Autumn |
|
Zinc (Zn) |
2 |
Autumn |
|
Boron (B) |
1.5 |
Autumn |
|
Molybdenum (Mo) |
0.12 |
Autumn |
|
Iron (Fe) |
2.8 |
Autumn |
|
Lime |
|
Establishment |