Michelle Comins : Following my trip to Ambootia in 2018 I always loved receiving my copy of Krishnendu Chatterjee [KCs] ‘Maverick’ in my inbox every week - every issue packed full of thoughts on many aspects of agriculture & soil and always ending with ‘golden words of wisdom'. Having had the good fortune to travel all over the tea world I’ve noticed myself growing more and more fascinated in organic & biodynamic agriculture. So, during lockdown, I finally plucked up the courage to ask if KC would offer to share some of his wisdom with me every week. He kindly accepted - so for the last month or so we have come together one early morning a week & let the conversation flow - guided by our interests & the topics that emerge - it was been wonderful, eye-opening & another example of the generosity that exists in #tea
In our very first meeting KC shared how his love of agriculture started at a very young age but it was not until he joined Ambootia that he knew what true agriculture was - here biodynamics are at the centre - an approach that talks about the intervention of all the elements and teaches respect for the microbes/creatures of this world
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In these 'Wednesday Wisdom : for tea lovers who like to dig a little deeper' blogs I [Michelle] will share my discussions with KC - much of which is based around organic and biodynamic tea but also around the Assam & Darjeeling region - with an aim to offering us all some inspiration about soil, organic & biodynamic. I finish by saying that in the tea world and indeed the wider world we are all students. My aim in sharing these interests is not to be 'right' indeed in many cases I expect to return to these topics and add more details - it is merely to ignite thought, conversation and interest in these fascinating topics that sit behind the cup of tea we all enjoy. Feel feel free to add, comment and get involved! I hope you enjoy the journey!
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Chemical communication in and among plants is very interesting [especially when communicated so passionately by KC]. In a long-ago part of my life my degree was actually Biochemistry so this part of our conversation really triggered my interest. So, early skiffing this year has resulted in a ‘stressed’ tea plant whose first thought is ‘defence’ and whose action is to produce defensive compounds for a variety of roles : not only defence but also repair and signalling. The chemical signal in question here is the phytohormone Salicylic acid - an important plant hormone that primarily functions in the immune response; in plants it is converted either to Methyl salicylate or Methyl jasmonate. KC adds 'The signal is amplified with the absorption of sodium and potassium by the plant - the rapid exchange of ions ( Na+ / K+) creates static electricity that amplifies signalling processes' In a plant body there is already a lot of Sodium and Potassium they use this to supplement their food and also for body building
>> Potassium is associated with the movement of water, nutrients and
carbohydrates in plants. It's involved with enzyme activation within the plant
>> Sodium is used in small quantities, similar to micronutrients, to aid in
metabolism and synthesis of chlorophyll
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When a plant is bitten or attacked the plant must guard the cell so that the wound does not spread. We all know that when we have a wound it eventually hardens -KC explains 'this is 'silicon' or salicylic acid - which is why salicylic acid is used for wounds'. When the plant is attacked by an insect it signals methyl jasmonate and methyl salicylate - meaning that salycylic acid rushes to the site of the attack and the plant converts the salycylic acid to methyl jasmonate and methyl salicylate.
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Methyl Jasmonate & methyl salicylate are both what are known as volatile organic compounds and are known to have significant effects on plants. By volatile we mean that they are capable of travelling outside the plant. Methyl Jasmonate was one of the first compounds implicated in plant-to-plant communication as cited in this 1990 paper This means that any neighbouring plant senses it and absorbs it. These compounds are not only produced in response to a human attack such as 'skiffing' but also in response to weather attacks [such as extreme heat or drought] or to attacks from insects. In the case of any such attack a plant produces these volatile wound signals and 'signal' to another plant or another part of itself [airborne signalling is much faster than internal chemical signalling]
Volatile signals enter through pores in the leaves and enable the plant to work to stop the wound through defensive actions. A plant attacked in the full flow of its growth will stop using its energy for growth and now start using energy to protect itself, to survive. There is so much more that you can read about this - such as how this 'signalling' helps improve disease resistance and whether plants selectively communicate with others [i.e. those considered 'friends'] - Ill leave you with a story from KC 'On the subject of plant communication there was a study conducted in the Masai with Giraffe. These creatures love to eat and munch from higher plants - if they eat only high plants then these plants will die - research shows that when giraffes start eating a plant other plants react to become alkali - the giraffe, not liking the taste, moves along to another area so that the plants are not depleted. Plants are wise & on the topic of chemical signalling there is a touch of god inside it' What can most definitely be said is that plants are so much wiser and resilient and their systems so much more advanced than we give them credit for.
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Lets turn our attention to our relationship with plants : in these times of crisis human action can help the plant to use energy in the right way - one simple way is to remove flowers as when a plant flowers and fruits all of its energy goes into these. The recovery of a plant will depend on the plant itself : as KC says 'a robust man will recover - as will a robust plant' In 2016 : Indias worst year : organic gardens did much better than other gardens. One of the reasons for this may be in the resilience of the tea plants. When you have more resilient plants they recover more quickly. Conversations with KC led to how to build this resilence in tea plants - lets explore this topic in more detail for the remainder of this Wednesday Wisdom blog
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Exploring factors which may HELP A TEA PLANT TO DEVELOP RESILIENCE
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1. RESILIENCE IN SOILS : Healthy soil is the basis of healthy life. KC shared 'We may ask, why are Organic plants are more sensitive / smart/ adaptive and resilient? Well one component is that in organic farming you find much more humus in soil & more humus means more CEC'
What is CEC? : Ill try and be brief here and give you links to a couple of articles to read more for yourself. The below is a summary from this article
>> Cation exchange capacity (CEC) is a useful indicator of soil fertility because
it shows the soil's ability to supply three important plant nutrients: calcium,
magnesium and potassium
>> These three elements are positively charged - also known as Cations
Calcium (Ca++ ), Magnesium (Mg++), Potassium (K+)
>> What CEC actually measures is the soil's ability to hold these cations by
electrical attraction : they are held by negatively charged particles of clay and
humus called colloids. Clay = an inorganic colloid / humus = organic colloid.
This article gives a very straightforward description of colloids summarised below
>> Soil colloids are the most active portion of the soil and determine the physical
& chemical properties of a soil. They are -vely charged and as this article says
'they act as a storehouse of nutrients for plant roots'
>> Inorganic colloids usually make up the bulk of soil colloids, but the humus
particles/ organic colloids are the most reactive chemically and generally
have a greater influence on soil properties than the clay particles
>> The -ve charge of the colloid attracts cations & holds them on the surface
>> The colloid then becomes a site of continuous exchange : cations attached to
the colloids are released into the soil solution where plant roots take them up.
Other cations in the soil water then replace them on the colloid.
>> Through this role leaching from the soil is avoided and plant roots have access
to the cations they need
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SO lets link this back to ORGANIC soils and humus content. As KC stated at the beginning of this section 'In organic farming you find much more humus' How this impacts CEC is described well in this article 'CEC varies according to the type of soil. Humus, the end product of decomposed organic matter, has the highest CEC value because organic matter colloids have large quantities of negative charges. Humus has a CEC two to five times greater than montmorillonite clay and up to 30 times greater than kaolinite clay, so is very important in improving soil fertility'. So more humus = higher CEC = greater soil fertility as the soil has a greater ability to supply three important plant nutrients to the tea plants!
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Tea ROOT STRUCTURE : Tea plants develop extensive root systems close to the surface, and are also noted to send roots deep into the soil if possible. Before we delve into this lets return to the importance of the soil [which links us back to organic cultivation] : studies have shown that the roots form, shape and structure and depth is often affected by plant hormones, physical and chemical properties of the soil [soil pH, and soil microbes], rainfall and its distribution, depth of permanent water table ands on....
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Having worked in organic and biodynamic tea cultivation for many years KS offers his perspective on roots in a conventional farm vs an organic farm :
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Why are organic roots deep? - 'If we analyse ourselves we get the answer - if we are part of a rich family - we get everything with no toil - with conventional farms the plants get everything. In terms of nourishment - give kids fast foods this is also not good - in both these cases we do not have to seek to understand ourselves neither do we understand what we need. With plants we so often only give food to plants as per our knowledge and our knowledge is not good. There are 96 elements required for a plant we cannot give all of these. When we try, with this limited knowledge, to guide plants we often make them sick and our food does not taste good. Let us contrast this with a natural farm where a plant expresses itself as it is - in organic agriculture we treat plants in a way that allows them to express themselves meaning that it will go down to search for foods - thus longer roots'
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Tea : A Mycorrhizal plant...One of the really interesting parts of my discussion with KC around tea rooting systems was the discussions around the fact that tea bushes are mycorrhizal plants. As concisely described by the RHS on their website 'Mycorrhizas are fungal associations between plant roots and beneficial fungi. Mycorrhizas are beneficial fungi growing in association with plant roots, and exist by taking sugars from plants ‘in exchange’ for moisture and nutrients gathered from the soil by the fungal strands. The mycorrhizas greatly increase the absorptive area of a plant, acting as extensions to the root system. Phosphorus is often in very short supply in natural soils. When phosphorus is present in insoluble forms it would require a vast root system for a plant to meet its phosphorus requirements unaided. It is therefore thought that mycorrhizas are crucial in gathering this element in uncultivated soils. Phosphorus-rich fertilisers are widely used in cultivated ground and not only reduce the need for this activity but are thought to actually suppress the mycorrhizas. For this reason it is best not to use phosphorous rich fertilisers in conjunction with mycorrhizal fungi. Neither fungi nor plants could survive in many uncultivated situations without this mutually beneficial arrangement. Mycorrhizas also seem to confer protection against root diseases'
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So : concluded KC : 'Plants obtain phosphate and other minerals through the fungus, while the fungus obtains sugars from the plant root - roots touch each other allowing sharing between roots. Fungi is therefore a friend - there are millions of fungi they allow touching of roots together - this is how plants harness food' AMAZING!
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This insight led me to read a number of really interesting studies including this one looking at the role of Mycorrhizal inoculation in increasing, amount other factors, root length and depth - Ill leave you to explore if interested!
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3. RESILIENCE THROUGH AN understanding of MAINTAINANCE FOLIAGE :
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When you cut a tea bush you leave some foliage and this is called maintainence foilage. The maintainance foliage is the mature leaves left on the tea bush below the tipping and plucking surface. This foliage is incredibly important in determining the growth of new shoots which are harvested from a tea bush. Why? A tea leaf does not develop the capacity to manufacture food material (carbohydrate) fully until it has grown to about half of its full size (about 5 weeks from unfolding of a leaf). The young, shoots on a bush, therefore must develop by gaining photosynthates from the more mature maintenance leaves During plucking young shoots are removed fast and on a regular basis - a process that stimulates production of new shoots at a rapid rate. This production relies on the maintenance leaves for 'food' : the maintainence foilage is therefore essential for sustained productivity and survival of a plucked tea bush. The maintainance foliage will retain its photosynthetic efficiency for about 6 months. After this it gradually declines and the leaves ultimately drop off after about 18 months. This process is incredibly important for the those managing the tea garden to understand : they must ensure that light pruning or skiffed bushes are cut to different heights so that a new layer of maintenance leaves are provided to the bush for efficient photosynthesis.
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4. RESILIENCE THROUGH BIODIVERSITY vs MONOCULTURE : Natural balance is created through complex ecosystems. KC and I started our conversation by talking about conventional vs biodynamic farming, Many of us have seen the vast mono-cultures of teas growing picturesquely on hillsides. In the natural world we would rarely see vast swathes of land covered by one single crop : we know that monocultures are more prone to disease [leading to the use of pesticides etc] vs utilising the land in a way that promotes the natural balance of nature. KC explains ’ You should not have a monoculture of plants - the main plant needs a diverse range of foods. In conventional farming anything other than the main crop is seen as an enemy. In organic and biodynamic farming this is not the case. Microbes are very plant specific for example if you took a ginger plant or a rose you would find very different microbes on the plant - picture soil as the biggest fast food chain you can imagine - in the soil there are million and billions of microbes eating together. The microbes are mobilising the food of the plants turning it into something that the plant will be able to take up. When these diverse microbes die the minerals in their bodies are available to plants’ Indeed there is much to explore in this topic beyond the scope of this blog but there are many studies which show strong relationships between plant diversity and soil microorganisms suggesting the importance of plant diversity in maintaining soil quality. KC suggests we even need to change our views on ‘pests’ -‘Weeds need to be seen as co-plants - not pests’ he shared ‘However - not all plants make good companions - there are plants that don't get on : Allelopathy is a biological phenomenon where one plant inhibits the growth of another. How? Through the release of allelochemicals, certain plants can greatly affect the growth of other plants either in a good or bad way by leaching, decomposition, etc. Wherever two plants grow together you can be assured that there is synergy’
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5. RESILIENCE BY ALLOWING FREE 'EXPRESSION' in TEA PLANTS Over to KC 'In organic farming tea plants are allowed more 'expression' - if they are allowed more freedom in the way they grow they develop special qualities. If you observe highly cultivated and manicured tea gardens you have very many plants and you simply cannot allow them to grow freely. Don't misunderstand me : plants love socialising and growing together - a single tea plant cannot exist alone - it is a friend loving plant - plant tea trees together or not at all. However when you tame a plant you make a servant of it. A plant 'servant' in conventional tea monoculture is enslaved - in organic farming we prefer to think of our tea plants as 'hired help' - the plants are allowed to express themselves and they then taste reward us with the profile in the cup!'
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6. RESILIENCE THROUGH NATURAL GROWTH vs APPLICATION OF FERTILISERS You want to get the right balance of amino acids and sugars in the cup - why?. In commercial farming you essentially 'design' the food for the plant. When you put Nitogen and phosphorous in the soil the plant might not be at a point in its growth where it needs it - however it takes it in never-the-less and builds up amino acids. If the plant is not at a point where it needs to do this it brings imbalance in the plant - an imbalance of sugars and amino acids. This is often why, when you compare a conventional and organic Assam they may look the same but taste completely different. KC shares how conventional teas can often be described as 'lopsided' in tasting.
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The final words from this session shine a spotlight on the relationship between humans and plants 'Life started from a single cell and most plants and humans share many genes although we use them in different ways. We must love and respect plants' One area of interest at Ambootia and a particular area of interest for KC is plant psychology. Many of us experience 'plant blindness' or the inability to see or notice the plants in one's own environment' This not surprisingly, results in an under-appreciation of plants – and in a limited interest in plant conservation. This area is not much talked about but is something that KC believes we should acknowledge and take action on.
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UNTIL NEXT TIME WE HOPE THIS HAS PROVIDED SOME food for thought
