The K Extension Project

Determining optimal potassium levels & management options for the West Midlands region.

The K Extension Project, funded by the Grains Research and Development Corporation (GRDC), represents a pivotal initiative aimed at enhancing nutrient management strategies with a focus on Potassium (K) in cropping systems. This three-year project was initiated in response to the 2022 Regional Crop Updates in Moora, where the need for improved K management was identified as a critical issue for grain growers. The West Midlands Group leads this venture, emphasising the importance of K for optimal plant growth and addressing the limited use of K fertilisation in broadacre agriculture.

Commencement: 2023 | Completion: 2025

Funding body(s): Grains Research and Development Corporation (GRDC)
Project Lead Organisation: The West Midlands Group

Background

Growers in the West Midlands region have identified potassium (K) deficiency as an ongoing constraint limiting yield potential in sandy soils. Despite the general agreement that replacement potassium might have been underapplied over the years, there was a consensus that further research was needed, particularly regarding response by soil types, application rates, and the ability of some plants to recycle K from depth.

Growers were particularly interested in understanding when additional K might profitably benefit the crop in terms of timing and method of application. Concerns were raised that diagnostic methods, such as surface-tested Colwell K, were not providing an accurate picture of the level of potassium availability. Fertilizer supplier trials typically indicated low levels of K in many soil profiles (0-30cm), with responses to K application. A key question for growers was the potential yield loss that might not be evident due to a nutrient throttle on production.

Project Objectives

The K Extension Project aimed to investigate the potassium status of 10 paddocks across the West Midlands region to understand the K nutrient budget and determine if current management practices were supplying enough K for crop growth. The objectives were to assess the adequacy of K nutrition budgets for crop growth in the West Midlands region, identify the availability of K in the subsoil and its potential utilisation under favourable growing conditions for high-yielding crop growth. The project also sought to transform complex data into practical, accessible knowledge for growers, with simplified and informative delivery of information on K management.

Latest Updates

• 
  Seeing what NDVI can show: Monitoring potassium responses at Ballidu
  NDVI monitoring at the Ballidu potassium site revealed late-season canopy differences and even highlighted an old N-banking strip that field checks missed. The article shows how NDVI can complement ground assessments and help growers interpret nutrient responses across variable soil types.
• 
  Infographics simplify potassium management for West Midlands growers
  Growers are finding that visual potassium budgets make nutrient data easier to interpret and apply. Through the GRDC-funded K Extension Project, WMG’s infographic tools are helping turn complex soil results into practical insights for managing potassium across different soils and seasons.
• 
  Exploring potassium uptake in Balllidu
  Field testing at Ballidu compared potassium fertiliser rates across two contrasting soils. The emerging trends highlight how rainfall, soil profile and nutrient balance can shape crop uptake and the value of site-specific strategies in variable seasons.
• 
  Potassium in Focus at Ballidu Crop Walk
  The Synergy Consulting spray group visited Corey Mincherton’s farm for WMG’s new potassium trial. Growers discussed soil type differences, K cycling and Corey’s shift toward grid sampling, mapping and variable-rate management to guide decisions.
• 
  Tracking Potassium Behaviour in Two Distinct Soil Types at Ballidu
  Initial soil test results from WMG’s new Ballidu potassium trial highlight how sharply nutrient levels can vary across soil types and depths. This article sets the scene for tracking crop response and fertiliser effectiveness over the 2025 season.
• 
  Optimising Potassium Management in the West Midlands: Results, Analysis and Insights from 2024 Trial Sites
  Explore an in-depth analysis of the 2024 K Extension Project Dandaragan and Badgingarra trial results, offering practical insights for growers looking to optimise nutrient use and improve long-term productivity.
• 
  How does crop species influence subsoil potassium cycling?
  Investigate how different crop species influence subsoil potassium cycling and the impact of deep ripping on potassium uptake and biomass production with results from the K Extension Project Yathroo trial site.
• 
  Fertilising For Profit Crop Walk – Farmer Summary
  Get a look into what attendees at our recent Fertilising for Profit Crop Walk discussed, including K fertiliser strategies, Summit’s range of N inhibitors, and the complexities and economic impacts of fertiliser decisions on farm management practices.
• 
  Rowes Road Crop Nutrition Tour – Farmer Summary
  The WMG & CSBP Rowes Road Crop Nutrition Tour showcased trials across three different sites, exploring legumes, potassium cycling, and nitrogen inhibitors. Read on for a synthesised farmer summary of the key learnings and discussion points of the day.
• 
  Early Post-Emergent Deep Ripping Insights from Bidgerabbie K Extension Trial Site
  Read the latest farmer summary from our first pop-up crop walk at Bidgerabbie. Discover key insights on post-seeding deep ripping, shared experiences from farmers, and strategic practices discussed during the event.
• 
  Early results from the K Extension Project trial site
  Early results from the K Extension Project trial site are showing the impact of early post emergent ripping on different crop varieties, with these initial insights forming part of our ongoing exploration into potassium requirements for the region.
• 
  New Trial Sites for the K Extension Project
  In 2024 the K Extension Project will shift its focus to physical trial sites, with a new site being established in Dandaragan and an historical site being followed, applying the learnings gained across last year.
• 
  Potassium Cycling, Availability and Crop Productivity
  Explore the essential role of potassium in plant health and crop productivity. Understand the K cycle, the impact of deep-rooted plants on nutrient availability, and the need for further research on subsoil potassium uptake, with insights specific to the West Midlands region.
• 
  Talking Crop Nutrition, Stubble Management & Risk
  Discover the insights and key discussions from our recent Crop Nutrition Day, where local farmers and industry experts gathered for a deep dive into nutrient decisions, stubble management and risk in farming.
• 
  Advancing Potassium Management in the West Midlands Region
  Learn about what we’ve found in the K Extension Project in 2023 and how WMG will be exploring effective K cycling in 2024.
• 
  Transforming data into discussions
  WMG and the K Extension Project has produced a practical tool to enhance potassium knowledge for West Midlands growers. Transforming complicated data into a clear, farmer-friendly K nutrient infographic, valuable on-farm discussions are continuing to help set the stage for broader nutrient management conversations in 2024.
• 
  Improving the delivery of information on crop K needs
  The next phase in the K Extension Project is to transform complex data into practical knowledge for host farmers with the introduction of the K Management Triangle, covering soil testing, plant nutrition, and potassium budgeting.

K Nutrient Infographic

One of the K Extension Project key goals is to transform complex data into accessible, practical knowledge for our host farmers.

The final K Nutrient Infographic is a result of several design iterations. The final version (sample displayed below) effectively displays crucial information including management specifics like applied K during the growing season and critical K levels at various crop growth stages for wheat, canola, and barley. It also incorporates detailed graphs on K availability at depths, soil moisture, and soil strength, offering a comprehensive, easy-to-understand nutrient budget (without all the rows of an Excel spreadsheet).

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