Free Nitrogen & Biological Nitrogen Fixation Case Study

Summary.

DCT products support biological nitrogen fixation by improving soil structure, root-zone conditions, and microbial activity. This enables clover-associated bacteria to fix nitrogen from the air and convert it into forms plants can use, reducing reliance on applied nitrogen fertiliser.

The Problem.

Many pasture systems rely heavily on applied nitrogen fertiliser, but soil biology and structure often limit the ability of clover to fix nitrogen naturally. Poor soil structure restricts oxygen, root growth, and microbial activity — limiting nitrogen fixation and nutrient cycling.

What Was Done.

DCT products were applied to improve soil structure and support soil biology, creating the conditions required for effective biological nitrogen fixation.

The Result.

The pasture system becomes capable of fixing nitrogen through biological processes, which is then converted into plant-available forms. This reduces reliance on external nitrogen applications and supports healthier pasture growth.

How DCT Products Support Biological Nitrogen Fixation.

When DCT products are applied to pasture, they support a sequence of soil processes that enable effective biological nitrogen fixation:

✔ Soil aggregation improves
DCT products help bind soil particles into stable aggregates, creating pore spaces that allow oxygen and moisture to move through the soil.

✔ Root-zone conditions improve
Better aeration and moisture balance support healthier clover roots and nodulation, where nitrogen-fixing bacteria live.

✔ Microbial activity increases
Improved habitat and carbon availability support soil organisms that drive nutrient cycling.

✔ Nitrogen is fixed and processed
Nitrogen fixed by clover-associated bacteria is released through normal plant and microbial processes and converted into plant-available forms.

✔ Nitrogen becomes available to the pasture system
Grasses and clover utilise this nitrogen, reducing reliance on applied fertiliser inputs.

Why This Matters.

By supporting each step in this biological process, DCT products help soils function as a working nitrogen system — rather than relying solely on external nitrogen applications. This improves pasture performance and long-term soil health.