Fungi: Delicious or Deadly?
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When most people think of fungi the either think of a delicious meal or their toenails. And this is important to keep in mind as fungi can be beneficial (or delicious) or they can be detrimental (at least very least to toenails). But when it comes to soil, plants and overall health of the ecosystem, fungi are very important and managing them is one key to successful farming.
A gram of living soil can contain around one million fungi, such as yeasts and moulds and many species which all do different jobs. Two of the most important jobs they do are with nutrient holding capacity of the soil and disease suppression in soils and plants. So, when we spray fungicides, herbicides or over fertilize, we kill the fungi that are trying to put things back in balance and solve the problem. I talk to many famers that have been spraying for pests for years not realizing they are actually killing the (fun) guys that will help them.
Soil fungi make up to 30 percent of the soil rhizosphere. There are fewer individual fungi than bacteria, but fungi have more total biomass due to their larger size. Fungi biomass in the soil is equal to as many as six cows in a healthy soil or 500 to 5000 Kilos of biomass per hectare. Bacteria are single-celled microbes that need a film of water to survive, while fungi are multi-celled organisms that grow rapidly and in great lengths in the soil . This allows fungi to bridge gaps in the soil and transport nutrients quite long distances back to the plants. In terms of soil and humus creation, the most important fungi tend to be saprotrophic they live on dead or decaying organic matter. They break down the organic matter and converting it to forms that are available to the higher plants.
Fungi is key to nutrient holding capacity. Elaine Ingham did trials that demonstrated when fungal dominated compost was added to soils they retained 100% of applied calcium. The control without the added fungi leached most of the calcium. Beneficial fungi, including mycorrhizal fungi, are seriously lacking in most soils.
Creating a Fungal Loving Soil
Many plants have a preferred fungi to bacteria ratio (F:B ratio).
Most vegetable crops prefer more bacteria with an F:B ratio of 0.3:0.8
Tomatoes, corn and wheat like an F:B ratio of 0.8-1:1.
Lawns do well with an F:B ratio of 0.5-1:1
Forested soils, like an F:B ratio of 10:1 where the soil is more acidic.
Cultivation in agricultural soils reduce fungal numbers which results in a F:B ratio of 0.1:0.3. These soils that are often high in nitrogen, low carbon, neutral pH, and with disturbed soil conditions promotes weed production.
Annual crops prefer lower F:B ratios and perennials prefer a higher F:B ratio. Many plants cultivate certain species of both bacteria and fungus to increase nutrient extraction from the soil.
Interestingly fungi tend to like more acidic conditions. Many growers are obsessed with balancing pH, is it possible that this practice is not the most conducive to good fungal populations?
Follow these simple practices to encourage beneficial fungi in your soils
Reduce cultivation when possible.
Avoid all fungicides and Herbicides
Reduce chemical fertilizers
Add compost or liquid compost extracts. Compost can very greatly so be sure the compost you are using has high numbers of beneficial fungi. Compost also has humic and fulvic acids and a variety of enzymes and organic compounds that feed fungi.
Humates, fish hydrolysates, seaweed and many plant extracts are also great fungal foods.
Check out our website for more great information on managing soils and Creating on Farm Fertility. www.chaossprings.co.nz
