Soil for Drought Resilience

Building Drought Resilience with Precision Phosphorus Management

Enhancing drought resilience by improving phosphorus fertiliser efficiency and soil health through precision agriculture practices.

  • Optimising Phosphorus (P) Fertiliser Use for Maximum Impact

    Phosphorus fertiliser is a significant cost for farmers. This project showed that targeting P fertiliser to areas of greatest need improves return on investment, optimises yield, and enhances resilience against future droughts.

  • Farmer Participation and Real-World Impact

    Farmers actively participated in trials, including a standout case on calcareous soils, where even with prior high P inputs, a yield response to additional P was observed, reinforcing the value of precision P application.

  • Precision Agriculture Adoption

    The project focused on farmers already equipped with Variable Rate Technology (VRT), demonstrating how precision agriculture optimises fertiliser use, improves efficiency, and encourages adoption among others as benefits become evident.

Project Overview

Maximising ROI and Resilience Through Targeted Phosphorus Application

P fertiliser input is an important variable cost for all farms in the region. Targeting P fertiliser where it is most needed will improve the return on investment (ROI) from this input by reducing excessive input where it is not required. Furthermore, increasing P inputs where they are required to optimise yield potential and grower returns offers a significant opportunity. Greater ROI from this important input will improve the resilience of the farming system and justify the investment in P fertiliser despite future droughts.

Justification for the project

Investment in P fertiliser is one of the highest variable costs on-farm today, and record-high prices in recent seasons have only exacerbated this. Soil P supply and crop P status can be highly variable. A better understanding of this variability in P can help target P fertiliser inputs more precisely for better return on investment, improving farm resilience in future droughts.

Discoveries

Key outcomes

  • 1
    Step

    Adding Value Through Expertise and Information

    Expertise and information provided by team members added value and aided adoption and uptake by farmers.
  • 2
    Step

    Farmer Collaboration and Case Study Participation

    Farmers were willing to participate in case studies, donating time and inputs.
  • 3
    Step

    Impact of Seasonal Conditions on Fieldwork

    Seasonal conditions restricted fieldwork activities. Greater field activity would have helped to increase farmer participation
  • 4
    Step

    P Fertiliser Trial Success on Calcareous Soils

    A trial hosted by farmer James Venning on a calcareous soil type demonstrated that despite high annual P inputs over four seasons previously (33kg P/ha/year), the soil was still responsive to P inputs in a 2024 rate response trial, with the maximum yield occurring at 30kg P/ha.
  • 5
    Step

    Encouraging VRT Adoption Through Targeted Engagement

    The project focused on targeting those farmers who are currently using VRT and who have the equipment and technology available and accessible. As more farmers interact, adoption rates are expected to increase.

Optimising Fertiliser Use for Sustainable and Resilient Farming

This project highlighted the importance of precision agriculture in optimising fertiliser use and improving drought resilience. By demonstrating targeted P application and ROI through real-world trials, NSS aimed to increase the adoption of these practices among farmers, enhancing sustainability and profitability.

  • Barriers to adoption - Land knowledge

    Understanding the variability in soils and P status across paddocks and farms: Readily available data layers will be used to demonstrate a method for delineating zones of predicted higher and lower P response.

  • Barriers to adoption - Fertiliser knowledge

    Knowing what fertiliser rates to apply to a given zone depending on its P status: Demonstration paddocks and large-scale strip trials will be used to showcase results from two previous SAGIT projects that link P rate to predicted P response to optimise ROI.

  • Barriers to adoption - Technology know-how

    Although the input data layers are readily available and many modern seeding setups can apply inputs at variable rates, many growers are unaware of how to manage the data or use their equipment’s functionality to its full potential. The demonstration trials will explain and showcase this process, and relevant experts will address specific technology issues.

Overcoming adoption constraints

  • Demonstrate methods for delineating high- and low-P response zones using map data.
  • Showcase P rate trials and ROI through field demonstrations.
  • Provide expert guidance on using precision technology.

Contact Persons: Sam Trengove and Jordan Bruce from Trengove Consulting

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