Improving Nitrogen Efficiency with Humic and Fulvic Acids

Improving Nitrogen Efficiency with Humic and Fulvic Acids for Australian Farmers

Nitrogen is a critical input for large-scale farming, driving crop growth and yields. However, losses from leaching, volatilisation, and soil fixation can reduce its effectiveness, impacting profitability and the environment. Products (like Worm Brew) containing humic and fulvic acids can buffer nitrogen applications, improving retention and uptake. Biological liquids derived from worm castings, rich in these compounds, offer a practical way to enhance soil biology and nutrient use. Here’s how it works and why it matters for Aussie farmers.

The Problem with Nitrogen Losses

In Australia’s diverse soils, nitrogen efficiency varies. Sandy soils, common in Western Australia and parts of Queensland, are prone to leaching, with up to 30-50% of applied nitrogen lost in high-rainfall areas (DAFF, 2022, Nitrogen Losses in Australian Agricultural Systems). In alkaline soils, like those in the Murray-Darling Basin, volatilisation can claim 10-20% as ammonia gas. These losses mean nutrients aren’t fully utilised, requiring higher fertiliser rates to compensate. Buffering nitrogen with humic and fulvic acids can help to address these inefficiencies.

How Humic and Fulvic Acids Work

Humic and fulvic acids are organic compounds from decomposed plant matter. They enhance nitrogen performance in measurable ways:

1. Nutrient Retention
   Humic acids bind nitrogen ions, reducing leaching. Research found humic-treated soils retained 15-25% more nitrogen after irrigation compared to untreated controls (University of Adelaide, 2021, Effects of Humic Substances on Soil Nutrient Retention). Fulvic acids improve nitrogen transport to roots, increasing uptake efficiency.
2. Soil Structure Benefits
   Humic acids increase soil aggregation and water retention. Trials in Victoria showed a 10% improvement in water-holding capacity after humic application (Agriculture Victoria, 2020, Soil Structure Improvements with Organic Amendments), keeping nitrogen accessible in the root zone.
3. Microbial Support
   These acids stimulate soil microbes that convert nitrogen into plant-available forms. A Queensland study noted a 20% rise in microbial activity with fulvic acid use (Queensland Department of Agriculture and Fisheries, 2019, Microbial Activity and Fulvic Acid Applications), speeding up nutrient cycling.
4. Environmental Gains
   Reduced leaching cuts nitrogen runoff, a priority in Great Barrier Reef catchments. Less volatilisation also lowers greenhouse gas emissions.
5. Plant Resilience
   Data shows humic and fulvic acids improve crop tolerance to drought and salinity—key concerns in Australia’s dryland farming regions. Wheat trials in South Australia reported a 5-10% yield increase under water stress (CSIRO, 2023, Wheat Yield Responses to Humic Acids Under Drought Stress).

Biological Liquids as a Microbial Input

Worm Brew, derived from worm castings, is high in humic and fulvic acids and boosts soil biology to unlock nutrients already present. By enhancing microbial activity, these liquids ensure more applied nitrogen—and other nutrients like phosphorus and potassium—is used efficiently rather than locked up in unavailable forms. Studies on worm-derived products show they can improve nutrient availability and reduce dependency on synthetic fertilisers (van Groenigen et al., 2014, Earthworm Activity Increases Crop Yield in a Meta-Analysis, Scientific Reports). For farmers, this means lower fertiliser requirements and reduced bills, as crops access a greater share of nutrients without increasing inputs.

Application Guidelines

• Rate: Start with 10-15 L/ha of Worm Brew alongside your nitrogen fertiliser, adjusting based on soil type and crop needs. 
• Timing: Apply during or soon after nitrogen fertilisation for maximum retention.
• Compatibility: Test mixes with your fertiliser to ensure no clogging in spray equipment.

Why It Matters for Farmers

For farmers, improving nutrient efficiency directly impacts the bottom line. Biological liquids derived from worm casting and/or direct applications of humic and fulvic acids don’t just buffer nutrients —they reduce reliance on synthetic fertilisers by enhancing soil biology. More efficient nutrient use means lower application rates over time, easing budget pressures. In Australia, where soil variability and climate challenges are constant, this approach maximises what’s already in the ground.

Next Steps

Buffering nitrogen with humic and fulvic acids, paired with the microbial benefits of biological liquids from worm castings, is an excellent strategy for Australian conditions. If you'd like to chat further about how Worm Brew can be incorporated into your soil programs, book a call here or call us on 07 3195 6969.

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Footnotes:

1. DAFF (2022). Nitrogen Losses in Australian Agricultural Systems.
2. University of Adelaide (2021). Effects of Humic Substances on Soil Nutrient Retention.
3. Agriculture Victoria (2020). Soil Structure Improvements with Organic Amendments.
4. Queensland Department of Agriculture and Fisheries (QDAF) (2019). Microbial Activity and Fulvic Acid Applications.
5. CSIRO (2023). Wheat Yield Responses to Humic Acids Under Drought Stress.
6. van Groenigen et al. (2014). Earthworm Activity Increases Crop Yield in a Meta-Analysis. Scientific Reports.