The Oakdale demonstration site focuses on optimising nitrogen supply for a vegetable brassica crop through strategic use of legume and cereal cover crops. By integrating cover crops into the rotation, the trial aims to reduce input costs, improve soil health, and explore methods for aligning nitrogen release with the brassica crop’s needs.
Legumes, as a natural nitrogen source, are most effective if the timing of nitrogen release is managed to match the crop’s demands, supporting nutrient efficiency and reducing dependency on synthetic fertilisers.
The grower’s goals include lowering costs related to fertiliser, fuel, labour and agricultural chemicals. Initial soil tests showed high nutrient levels, indicating a need to assess and adjust the nutrition program to avoid imbalances. By identifying suitable strategies to enhance nutrient cycling, particularly nitrogen, the trial seeks to offer a more balanced and cost-effective approach to crop nutrition.
The trial will explore key questions to guide cover crop selection and nitrogen release methods, including:
- Cover crop selection: Determining the best legume species or combinations that provide high-quality residues, contribute significant nitrogen, and offer ideal release patterns to match crop demands.
- Nitrogen release manipulation: Investigating methods such as mulching, partial or full incorporation, and spraying to influence how and when nitrogen becomes available to the brassica crop.
- Additional considerations: Evaluating the ease of weed management under different nitrogen management scenarios and addressing practical challenges in integrating reduced tillage with other farm operations, such as applying lime and compost.
The trial management at this site is led by Soil Wealth ICP team members Steph Tabone and Umberto Calvo, with additional support from Dr Kelvin Montagu. Phil Bartolo, the farm manager, serves as the primary contact for the project, with additional guidance from agronomist Anthony Muscat from Ace Ohlsson.