Felix Egerer: Sap Testing, Plants as Indicators & Fostering Abundance

Felix Egerer: Sap Testing, Plants as Indicators & Fostering Abundance 800 800 Sectormentor

Regenerative Viticulture Series #9: Felix Ereger in conversation with Abby Rose

In our 9th episode of the Regenerative Viticulture Series, Abby Rose is joined by Felix Ereger, a hugely knowledgeable and progressive viticulturist. Felix’s perspectives on sap testing, soil chemistry, plant indicators, and fostering abundance make for an incredibly engaging session.

Felix began his viticulture journey by completing the Viticulture & Enology programs at UC Davis (2015) and Geisenheim University (2014) in Germany. Felix’s extensive education transported him to positions in the USA, Australia, France, and Germany. Felix then began to manage a vineyard in the summer of 2019 in British Columbia, Canada. In 2022, Felix moved to Vancouver Island, where he now manages Unsworth vineyard, where they practise no herbicides, no high energy input fertilisers, and treat the farm as one living, breathing, holistic entity. When Felix began discovering more about regenerative viticulture, he described his experience as ‘falling into the rabbit hole and never returning’. Felix then joined Nicole Masters’ CREATE program at Integrity Soils, where he met Abby Rose and came to learn about Sectormentor. He later became a coach for the program. 

Key Takeaways:

Sap testing

Unsworth vineyard uses sap testing as a way to understand their vines and ensure all their vines’ needs are met. Sap testing tests the nutrients and sugars that are present in your intercellular sap. Through this method, you can decipher the current state of a plant’s health and how nutrient levels are affecting the plant’s photosynthetic activity; Felix describes it as the testing of a plant’s ‘blood’. The results of this test can give an indicator as to what the plant’s nutrient needs or deficiencies are, and how they are impacting the plant’s health or growth. The results can also forecast certain obstacles to plant health and growth before they have occurred. Present nutrient deficiencies in the vines can then be treated by applying mineral foliar sprays. 

Felix and Abby also discuss the importance of certain cofactor nutrients to catalyse key processes in the plant and how sap testing can help understand when these micronutrients are required. For example, in terms of plant growth, the plant being able to efficiently metabolise nitrogen is vital, but certain micronutrients are key to unlocking the metabolization potential of the plant. Felix specifically mentions the importance of the micronutrients Molybdenum and Manganese. Molybdenum is responsible for increasing nitrate intake and metabolising it into amino acids in the plant; at Unsworth, getting levels of Molybdenum right for their vines has increased the vines’ efficiency of converting nitrates to amino acids to 100% this year, as indicated by the most recent sap test results. Manganese governs the splitting of water in the plant cells, without which photosynthesis cannot take place. In his experience, Felix says that he has found the application of Manganese to have huge benefits for photosynthetic efficiency, with a little going a long way. 

Plants as indicators

Observations are a key part of managing Unsworth vineyard. Felix shared about how he uses ‘weeds’ to diagnose what is happening in certain parts of the vineyard. Felix has noticed that there is an abundance of plants that are known to bring Calcium to the surface of the soil, such as buttercups, indicating that their soils are low in calcium. Felix has also noted a high number of docks, which often spring up where the soil is compacted and phosphorus is not bioavailable. There is also horsetail in waterlogged parts of the fields, a plant which loves ‘wet feet’ (having roots submerged in water, with no oxygen available). These nutrients can become inaccessible to plants when they are trapped in the soil through very condensed layers of negatively charged clay. Felix describes this like a ‘layer cake’. Calcium, Magnesium and Potassium are held in between these cake ‘layers’ because they are positively charged and therefore attracted to the negative charge of the clay layers. After many years of intensive ploughing and agrochemical use (notably Potassium application), these layers become very tightly compacted and ‘collapsed’. So when the inter-row management changes and deeper rooting plants begin to establish, the soil chemistry starts to shift and show different indicator species. This is because the plant roots push the layers apart and form aggregates, breaking the charged bonds between the clay/nutrient layers and releasing the nutrients. Felix explained how, at a previous vineyard, they saw a huge Potassium release once they’d introduced deep-rooting plants, illustrated through an influx of Potassium indicator plants, such as thistles. Felix elaborates that these indicator plants (commonly known as ‘weeds’) play a role in natural systems; they turn locked up inorganic nutrients into organic matter, making them bioavailable. 

Fostering abundance

Felix likes to say that ‘fostering abundance is his job, he just happens to grow grapes’. Fostering abundance, to Felix, looks like: more species, shifting away from singular grass species, diversity, insects sounds, bird numbers, birds of prey and native plants finding their way into your system. When your system is thriving, you can tell because there is an ‘explosion of life’. The key management decisions which resulted in fostering abundance at Unsworth vineyard were: moving away from the use of agrochemicals, removing recreational mowing, changing the timing and height of mowing, letting the cover crops grow wild until bud break, crimping if possible, and introducing new species which will increase underground biodiversity too. Felix also speaks about the importance of fostering abundance with the workers on the vineyard; employees on their vineyard are considered farmers with a valuable skill set. They are paid well and looked after, because developing a relationship with your farming team will result in more abundance on the vineyard.