Feeding the Fungi: What’s Happening Beneath Your Pasture?

A closer look beneath the pasture. 

You know which paddocks recover well after grazing and which ones keep falling behind. You can check the fertiliser history, dig a hole and look at the roots. But what about the living community around those roots?

Fungi are part of that community. Understanding their role gives you another way to think about pasture management, alongside soil fertility, drainage and grazing decisions.

At Bio Charge, we want that conversation to lead to something practical: establish what is there, decide what needs attention, and check the response. Our mates at Soil Foodweb New Zealand can help with the measurement, through their soil microbial assessment service.

Here is how fungi fit into the picture, what feeding soil biology really means, and how to build a programme you can assess on your own farm.

Many fungi grow as fine threads called hyphae. Different groups do different jobs, so it helps to distinguish decomposers from fungi that form partnerships with living roots.

Decomposer fungi break down organic material, including tougher plant residues. Their work is part of the process that moves nutrients through the soil food web. Fungal threads can also help hold soil particles together in aggregates. These small clusters contribute to soil structure and the spaces through which air and water move. USDA NRCS: Fungi

Mycorrhizal fungi associate with plant roots. The plant supplies carbon compounds made through photosynthesis; the fungus explores soil beyond the root surface and can help the plant acquire nutrients, particularly relatively immobile phosphorus. Arbuscular mycorrhizal fungi are an important group in agriculture. The relationship depends on a suitable plant host; brassicas are a familiar exception. USDA NRCS: Mycorrhiza

This distinction matters when you read a test report. A measurement of fungi in a soil sample and a measurement of mycorrhizal colonisation inside roots answer different questions. Be clear about which one you want to investigate before choosing an assessment.

Pasture roots and soil structure, Microscopic fungi cannot be identified from this image.

Living roots release carbon compounds into the surrounding soil. This active area, called the rhizosphere, supports organisms that use those compounds. Different plants release different mixtures, helping shape the community around them. Organic matter also provides food and habitat for soil organisms. University of Minnesota Extension: Soil biology

That makes pasture recovery part of the discussion. Plants need an opportunity to restore their energy reserves after grazing. DairyNZ’s perennial ryegrass guide explains how leaf stage reflects recovery and why grazing too early can limit subsequent regrowth. Use the grazing guidance appropriate to your pasture and season. DairyNZ: Perennial ryegrass grazing guide

Our practical takeaway is to consider the plant and the soil programme together. When you review an application plan, also ask how the pasture is recovering and whether the grazing interval suits current growth.

The word “carbon” covers very different materials. Easily used compounds and tougher plant residues do not behave alike in soil. Bacteria often use readily decomposed compounds, while fungi are important in breaking down more complex material. These roles overlap within a wider community of organisms. USDA NRCS: Biological Underground Community

This is why we would not judge a biological input simply by whether it contains sugar. Soil Foodweb New Zealand lists molasses among foods for bacteria, and whole fish products among foods used to support fungi. Those categories are useful context when discussing a formulation; they are not a prediction of the response in every paddock. Soil Foodweb NZ: Microbial assessments

A sensible question is: what are we trying to support, and how will we check whether the programme is helping?

Food is only part of the picture. Soil organisms also respond to moisture, temperature, oxygen and soil chemistry. A dry spell or poorly aerated soil can affect activity, even when organic material is present. USDA NRCS: Biological Underground Community

Before settling on an input, look at the paddock. Are roots exploring the soil, or following cracks around a dense layer? Does water linger in particular areas? Is the pasture recovering evenly? Record these observations so your adviser has more than a product history to work with.

For planning purposes, we suggest putting any obvious physical constraint, your nutrient information and the biological assessment on the same page. That gives you a clearer basis for deciding which change to make first.

Soil Foodweb New Zealand is an independent soil biology business based in Hanmer Springs, North Canterbury. We feature them among Our Mates because we value their practical focus on understanding life in the soil.

Their services cover biological assessments of soil, compost and liquid materials. They provide written interpretations and include a telephone or Zoom consultation to help customers understand their results. Contact them directly to discuss your farm and select a suitable service. Soil Foodweb New Zealand

Their listed soil assessment options include:

Packages contain different combinations of assessments. Confirm what is included and whether roots need to be collected for the question you want answered. View assessment options

Contact Phil and Viv Gray at 021 0821 4323 or info@soilfoodweb.co.nz.

Active biomass and total biomass are different measurements. Soil Foodweb explains that activity reflects organisms metabolising under the conditions assessed, while total biomass gives a broader measure. Food availability, moisture and temperature help explain why activity can change. Soil Foodweb NZ: Reference guide

Ask the laboratory to interpret the result for your pasture, season and sampling conditions. Soil Foodweb itself notes that appropriate fungal and bacterial ranges vary with crop, climate and season. A fungal-to-bacterial ratio needs that context; it should not become an isolated target for every farm. About microbial assessments

Keep the original reports, sample details and field notes together. If you change laboratories or methods, ask whether the results can be compared directly before treating a difference as a trend.

Follow the laboratory’s current sampling instructions.

Contact the laboratory before collecting your samples. Decide which areas should be assessed separately and what information to record.

Soil Foodweb’s instructions call for representative sampling across a chosen area, recognising that different soils or landforms may need separate samples. They also advise avoiding cow pats and provide submission forms and guidance for collecting roots. Follow their current directions for depth, quantity, packaging and delivery. Sampling instructions and forms

For your own records, note the sample location, date, recent grazing, rainfall and applications. Agree on a repeat sampling approach with the lab so the next result has a useful comparison. A simple paddock map and consistent sample names will help you keep those records connected.

If you want to assess a new product or management change, plan the comparison before starting. A before-and-after result can show change, but it cannot by itself separate treatment effects from weather, season or other management.

Where practical, retain comparable areas under your existing programme alongside areas receiving the change. Replicated, randomised comparisons are more informative than one treated paddock beside one untreated paddock because paddocks and soil vary. An adviser can help design something workable with your equipment. University of Minnesota Extension: On-farm research

We suggest agreeing on three things at the outset:

• The question: for example, whether a particular programme changes the measured biological indicators under your farm conditions.
• The records: laboratory results, application details, grazing dates, pasture measurements and relevant observations.
• The review: when you will compare results, who will interpret them, and what evidence would justify continuing or changing the programme.

For example, if you change both grazing management and an input at once, record both. You may learn something useful about the combined programme, but you will not have isolated the contribution of the product. Decide which question matters before spending money on the comparison.

Bio Charge Fungal Feeder combines fish hydrolysate, molasses and charged biochar. We position it as a soil biology input, intended to support the living environment around roots within a wider farm programme. Its ingredients describe the formulation; they do not establish a measured increase in mycorrhizal colonisation on your farm.

The current product programme is:

Rates are litres of Fungal Feeder product, before added water. Follow the current label and confirm compatibility with equipment and other inputs. Bio Charge Fungal Feeder and application guidance

Video credit: AHDB Cereals & Oilseeds, Agronomists’ Conference 2020. Duration: 10:10.

The later project summary reports mixed outcomes, including trials where more fungi did not correspond with higher crop growth or yield. That is a useful reason to measure pasture performance alongside biology. These trials concern UK cropping systems and do not establish results for Fungal Feeder or New Zealand pasture. AHDB: Research findings

Choose one question about your pasture, speak with Soil Foodweb New Zealand about an appropriate assessment, and use that baseline to help plan your next step.

Bring the laboratory interpretation into the conversation with your farm adviser and Bio Charge. Together with good records, it gives you a practical way to review what you are doing and why.