This branch of the project sets out to model, research and develop an adaptation of an approach to horticulture that prioritises the proliferation of Arbuscular Mychorhizal Fungi (AMF), a type of soil fungi that form mutualistic symbiosis with up to 95% of plants.
Species of Arbuscular Mycorrhizal Fungi (AMF) belong to the phylum Glomeromycota, to date 230 species have been identified. Also known as Endomycorrhizae, these types of soil fungi penetrate the root cells of partner plants and exchange nutrients for carbohydrates. Plants allocate as much as 30% of carbon to the fungi. A plant that has formed a symbiosis with AMF has access to a far larger surface area within the soil through the mycelial network compared to relatively cumbersome root hairs of the plant. The fungal partner is much more chemically adept in accessing nutrients looked up in the soil. AMF can provide their plant partners with up to 80% nitrogen and 100% phosphorus as well as other important nutrients such as zinc and copper. This increased surface area also means better access to water conferring much greater drought tolerance for the plant partner.
Thus the plant’s fungal partner can make a significant difference on its growth and development. It also appears that different species of AMF can affect the behaviour of the plant in different ways. Once study showed that the different species of AMF affected the flavour in strawberries, other aspects were affected such as attraction to pollinators, yield, and appearance. Studies carried out on other crops have shown similar changes in growth, development and behaviour in plants depending on the species of AMF. *
In developing a horticultural practice that seeks to enhance these plant and fungal interactions we have taken a keen interest in innovative and alternate methods of horticulture within what can be broadly described as the organic movement. From traditional organic practices in soil health to an understanding of the practices within other methods that fall under descriptions such as biodynamics, no-dig/till farming, and regenerative/natural agriculture.
One particular horticultural practice that has gained notoriety in recent years is that of Shumei Natural Agriculture. This approach assumes that excessive tillage, crop rotation and the addition of animal manures is detrimental to the long term health of the soil and metabolic potential of the plants. Instead, the Shumei Method looks to create permanent succession schemes using polycultures of complimentary plants, minimal disturbance to the soil, the absence of manure fertilization, and the conscientious saving of seed.
The “no-dig” or “no-till” approach to horticulture is now more widely appreciated promoting a more holistic understanding of soil health as an expression of the totality of the interrelated organisms in that particular ecosystem. From this perspective soil can be viewed as a living organism in itself or a complex digestive system in a similar way that the health of our own metabolic processes are dependent on a microbiome consisting of a diversity of microorganisms. The no-dig approach involves little or no disturbance of the soil horizons, the use of mulching and biofertilisers such as liquid or folio feeds and complimentary cropping plans to preserve and enhance the soil food web. Interestingly, practitioners that apply this approach to horticulture report that they find crop rotation of less importance.4
In light of the recent research into the significance of AMF we theorise that the Shumei approach as well as “no-dig/till” methods, coincidentally maximise the conditions for the co-adaptation of AMF with particular plant families. With a minimal disturbance of soil and permanent succession schemes, particular species of AMF gradually adapt and predominate to create beneficial conditions in the soil microbiome most suitable for the anticipated plant species.
Our approach can be summarised as a process of “provisioning the hyphosphere”, by focusing our attention on the extra-radical zone in the soil where hyphal exudates recruit other microorganisms depending on the nutrient demands of the plant species present.
We intend to this region, the hyphosphere, with minimal disturbance techniques, the use of succession specific AMF inoculum (following the Roledale Institute technique), extensive seed saving, cover crops, perennial green manures (including “living paths”) and the application bio-fertilisers. In doing so we hope to demonstrate economic benefit in the reduction off site inputs, increased carbon sequestration, enhanced nutrient density, and improved resilience of plants in the face of changes in climatic conditions.
To prove that this approach can be effective and scalable we are creating a market garden on a 2 acre site at the National Botanic Gardens of Wales. The market garden will test the method with a control area on 1/5 of the growing site where a crop rotation plan will be applied over 5/6 years. Another 1/5 of the garden will applying a similar cropping plan but will strictly apply the Shumei methods used at the UK centre in Yatesbury. We will carry out annual tests for levels of soil carbon, diversity of microbial activity, the quantity of glomalin and levels of water retention.
The Market Garden site will also serve as a demonstration of various mushroom cropping schemes that compliment and can easily be adapted to horticultural enterprise. The grow rooms will be used to exemplify methods of intensive “indoor” cropping cycles that can avoid the use of single use plastic. We will be using reusable cropping containers to grow Oyster (Pleurotus ostreatus) and Golden Reishi (Ganoderma curtsii). We will cultivate Wood Blewitts (Clitocybe nuda) in the marginal areas used for biomass crops such as willow and sida hermaphrodite. Wine Cap (Stropharia rugussoanulata) mushroom beds will serve as a mulch under sweetcorn, strawberries and garlic and other soft fruit. We will also test two other mushroom mulches, the Elm Oyster (Hypsizygus Ulmarius) as a companion mushroom for brassicas and the Almond Portabello (Agaricus subfrunescens) with tomatoes and cucumbers in polytunnels.
Two small mushroom grow rooms built through converting used refrigerated truck boxes are sited adjacent to one of our two 14ft x 42ft polytunnels. The exhaust fans of these mushroom grow rooms is directed into the polytunnel creating elevated levels of CO2. We will be comparing the growth rates and yield of the tomatoes and cucumber grown in these tunnels to test whether the rise in CO2 increases levels of photosynthesis.
We are working towards ensuring that the project can sustain itself through revenue from crop sales. We will be selling directly to the Botanic Gardens Café, and may look towards developing a small CSA share scheme, explore the possibility of supporting a local “REKO” style direct sales market and participate the in current procurement schemes supported by Welsh Government.
The horticultural activities at Coed Talylan will work in symbiosis with the project adopting the same practices in the cropping schemes to increase the capacity for seed saving. There are three separated growing areas situated within the 70 acre woodland at Coed Talylan. This provides good conditions for seed saving with increased possibilities of isolation.
We will also be making and using “Biochar” as a substitute for vermiculite in the soil mix used for culturing AMF inoculum with a ratio of 4:1 biochar to compost. Using a starter soil of indigenous AMF taken from associated plants, rye and sorghum grass will be grown in 25l plant pots over a year. This inoculum is then used in seed and potting mixtures. We will be mostly using cell trays for propagation but for some crops such as squash, cucumbers and tomatoes we will be experimenting with soil blocking.
Other elements in the design of the market include the restoration of small forest garden area, cultivation of herbs and soft fruit; perennial green manure breaks between growing areas; a small area for testing biofertilisers with wheat cultivation; the use of 2 caterpillar tunnels for leaf salad and other covered crops; automated drip irrigation; and the use of rainwater collection pump to a main storage tank using a small solar PV setup.
We will be regularly sharing updates with our progress at the garden and elaborating on elements of the garden as they are implemented so if you would like to follow us you can find the Farming with Fungi project on social media:
*For AMF and crop interatcions see: Orell (2019) strawberries; plant pollinator interactions Davis et al (2019); basil Copetta et al(2006); Tomoates Copetta et al (2011), Rouphael et al (2015); mint Gupta et al (2002); lettuce Baslam et al (2011) Artichokes Ceccarelli et al (2010); St John’s wort and echinacea Rouphael et al (2015); bread Torri et al (2013)