The Role of Bacteria, Fungi, and Enzymes in Today’s Agriculture

Rising Input Costs and a Search for Efficiency

Fertiliser has long been a cornerstone of modern agriculture, but its cost and availability have become increasingly unpredictable. Nitrogen fertilisers are closely tied to natural gas markets, and when gas prices surged in 2021 and 2022, nitrogen costs followed. Phosphorus markets were affected when major exporters such as China and Morocco restricted supply. Potash prices became more volatile after disruptions to exports from Belarus and Russia, which together account for a significant share of global production.

These shifts translated into real cost pressures for farmers across many regions. As a result, attention has increasingly turned toward tools that help crops make better use of nutrients already present in the soil, rather than relying solely on higher external inputs.

What Are Biological Inputs?

Biological inputs are part of this broader category of efficiency-focused tools. They include bacteria, fungi, and enzymes that influence nutrient cycling, root development, water uptake, and the breakdown of crop residues. These are not new concepts. The biological processes involved have always occurred in healthy soils. What has changed is our ability to better understand them and, in some cases, support them through targeted applications.

Rather than replacing natural soil biology, biological inputs are intended to work alongside it, strengthening processes that already exist but may be limited by soil degradation, management history, or environmental stress.

The Role of Bacteria in Soil Function

Bacteria play several important roles in agricultural soils. Some species, such as nitrogen-fixing bacteria, convert atmospheric nitrogen into forms that plants can absorb, contributing to early growth. Others help release phosphorus that is present in the soil but chemically bound and unavailable to roots. Certain bacterial strains produce organic compounds that make this phosphorus accessible to plants.

Bacteria can also influence root architecture. By affecting how roots branch and grow, they help determine how effectively a plant explores the soil for water and nutrients during early development. These effects have been studied for decades and are generally subtle, but they can be meaningful under challenging growing conditions.

How Fungi Support Plant Growth

Fungi contribute through different mechanisms. Mycorrhizal fungi form close associations with plant roots and extend far beyond them through fine networks known as hyphae. These networks increase the effective reach of the root system, improving access to both water and nutrients, particularly phosphorus.

This relationship is especially important in soils where phosphorus availability is low or uneven. In addition to nutrient uptake, some fungi help reduce disease pressure around roots or support stronger root development, contributing to overall plant resilience.

Why Enzymes Matter

Enzymes add another layer to biological inputs. They act as catalysts that speed up natural soil processes. Certain enzymes help release nutrients from organic matter, while others break down cellulose and lignin in crop residues. This accelerates residue decomposition, improves seedbed conditions, and can reduce the need for intensive tillage.

Enzyme-based products are often used when faster nutrient mineralisation or residue breakdown is needed before planting, particularly in systems with short rotations or heavy residue loads.

Linking Biology to Real Field Challenges

The relevance of these biological tools lies in how they address practical challenges farmers face each season. Many soils contain nutrients that are present but not readily accessible to plants. In dry or sandy soils, water availability can fluctuate rapidly. In conservation tillage systems, residue management can affect planting timing and crop establishment.

Biological inputs can help address these constraints by improving nutrient availability, supporting steadier water access, and accelerating residue turnover. During early growth, improvements in root development can lead to more uniform crop establishment and greater resilience to short-term stress.

Learning from Field Applications

A useful example comes from Aotearoa New Zealand, where Māori growers cultivate traditional potato varieties known as taewa. These crops are often grown in low-input systems on light soils with limited phosphorus availability. Researchers working alongside growers introduced selected mycorrhizal fungi and beneficial bacteria to support nutrient uptake.

The results showed increases in root mass, improved phosphorus uptake, and yield gains that varied by site and variety. Importantly, the strongest benefits were observed where traditional low-input practices were already in place. The biological inputs complemented existing methods rather than replacing them.

This illustrates an important point. Biological tools tend to perform best when matched to specific soil conditions and integrated thoughtfully into broader management practices.

Understanding Where and When They Work Best

The effectiveness of biological inputs depends on several environmental factors. Soil pH influences microbial activity, with many organisms performing best in moderately acidic to neutral conditions. Moisture is essential for both microbial movement and enzyme activity, while extreme dryness or temperature limits effectiveness.

Competition with native soil microbes also plays a role. In some soils, introduced organisms establish well and persist. In others, native communities dominate and limit how long added microbes remain active. This variation reflects differences in soil biology rather than product failure.

Storage and handling matter as well. Live microbial products can lose viability if exposed to excessive heat during transport or storage. Enzymes tend to be more stable, but they also have limits. Seasonal differences in results are often linked to these practical factors rather than changes in the underlying biology.

Making Informed Choices

Given the diversity of products on the market, careful evaluation is important. Clear labelling that identifies microbial strains or enzyme activity levels helps farmers understand how a product is intended to work. Independent trials conducted in similar soils and cropping systems provide useful reference points.

Many farmers begin by testing biological inputs on small areas before expanding their use. Setting clear expectations, such as improved early vigour, stronger root systems, faster residue breakdown, or reduced fertiliser requirements, helps assess whether a product is delivering meaningful value.

Conclusions

Biological inputs support processes that already occur within the soil. They are not a complete replacement for fertilisers, but they can improve nutrient efficiency and support more stable crop performance when applied under appropriate conditions. Their effectiveness depends on soil type, climate, crop selection, and management practices.

When these elements align, bacteria, fungi, and enzymes can contribute to healthier soils, improved nutrient uptake, and more efficient use of inputs, all while fitting into existing farming systems.

For those interested in how early-stage biological interventions can support plant establishment and resilience, Phi Earth continues to explore how these principles can be applied within regenerative and conventional systems alike. For more information, contact info@phiearth.com.

Reading time: ~10 minutes
Author: Phi Earth Technologies