Vegetative and Reproductive Nutrients with John Kempf

Hi friends, I am John Kempf, hosting this podcast. I am passionate about developing regenerative agriculture systems that improve soil health, produce crops that are completely resistant to diseases and insects, and produce fruit of such an exceptional quality that we can have a legitimate conversation about growing food as medicine. I've discovered that there are many people with incredible knowledge and information about soil and plant systems and how to develop regenerative agriculture systems. However, much of this knowledge and this information is scattered. It's found all over the place, some of it has been published in peer reviewed publications, but there are many incredible stories and a lot of knowledge that has not been published and that hasn't been shared with many people. I started advancing EcoAgriculture in 2006 to bring this knowledge together in a more coherent fashion and incorporate it into products and growing systems that growers can easily put into practice. It's my personal mission to have these regenerative agricultural systems become adopted globally and become the mainstream, the status quo against which all other growing systems are compared. To help achieve this goal, I want to share the knowledge that we have learned in the last decade and make it available to everyone while we have developed products at AEA that embody the principles of regenerative agriculture systems and make them easier for growers to apply this knowledge and these principles can be applied anywhere and when they are applied properly, they will always increase farm profitability and resilience to climate stress. If you have any questions, suggestions, comments or ideas, topics that you would like for me to discuss, Please connect on LinkedIn or on Twitter where my username is visionbuilder7 or you can also email me at john kempf.com I would very much like to hear from you and to hear your feedback. Be sure to subscribe to this podcast and thank you very much for listening. Enjoy the show.

Hi friends, welcome to the Regenerative Agriculture Podcast. I've been asked a lot recently about how to use nutrients to manage vegetative growth versus reproductive growth and how we can produce high quality fruit wood on trees while still getting strong vegetative growth at the same time. This is a very important topic. I've been asked a lot about it recently and so I wanted to share some thoughts with you about some of the things that we've observed and that we have learned over the years. There are some nutrients which drive strong vegetative growth and there are some nutrients which drive strong reproductive growth and reproductive development. And then for some of these nutrients in both categories, they interact with and synergize with different groups of plant hormones. So you can have this synergistic effect where you have certain nutrients synergizing with certain hormones and then others antagonizing other hormones. You have this kind of two tier effect where you can really shape how plants trigger reproductive buds, reproductive bud development and fruit wood development. So I wanted to talk about some of those pieces. So perhaps to begin from a nutrient management perspective, there are four nutrients which drive strong vegetative growth, or a different terminology, different way of thinking about it might be to say that they have a strong male energy and male energy development. So that is strong vegetative growth. So those four nutrients which drive vegetative growth are nitrate, nitrogen, specifically nitrate, not ammonium or urea or other forms, and potassium and chloride and calcium. So those four, nitrate, potassium, chloride, calcium, will drive very strong vegetative growth. And we can see this being expressed in how we manage agronomy and plant nutrition on a number of different crops. For many grassy plants, such as corn and sorghum, etc. We use nitrate to get our strong vegetative growth to shot with very strong nitrogen applications. And this is true of many tree fruit production as well almonds, etc. And then there are other crops where we use potassium to get a very strong vegetative growth response, such as alfalfa. Chloride also contributes a very strong growth response because of the energy similarities that it carries to potassium and some of the ways that it functions in cells and in cell membranes. So you have these four nutrients giving us strong vegetative growth on the reproductive side. Essentially everything else, all the other nutrients, excluding these four, will trigger a slight reproductive response in plants. But there are three in particular which are the heavyweights of the reproductive category. The three nutrients which drive strong reproductive development or bud initiation would be manganese, phosphorus and ammonium. In that sequence, in that order of priority, manganese tends to have a very strong reproductive crop response, followed by phosphorus, and then lastly followed by ammonium, which is then followed by the long tail of everything else. The way to think about this as this relates to plant management and crop management, is that there is both vegetative growth and reproductive growth happening all the time in every single organelle and every cell within the plant. There is never a complete dominan where you have 100, 0 or even 9010 ratio between these two. Instead, this is a relatively sensitive fulcrum balance beam where the ratio might be 55, 45, where you have 55% vegetative energy, 45% reproductive energy, or vice versa. So what this means, because there is both vegetative and reproductive growth happening all the time, it means that very small amount of nutrient applications can actually trigger and switch from one side to the other. And for example, one of the common challenges that we see sometimes with tomato production, some varieties of tomatoes under some management systems, when we have an over application of nitrogen, which converts in the soil to the nitrate form, we end up with a tomato plant that is lush and green, has a lot of vegetative energy, but has no fruit. You have this beautiful green plant, but it doesn't have a single blossom on it doesn't have a single bud. That's a plant that is completely vegetatively dominant. You can switch a plant like that from being vegetative dominant to reproductive dominant with a single foliar application of manganese and phosphorus, for example, the nutrients, which have a very strong reproductive trigger. You can literally paint a tomato field from green to yellow in a matter of about seven to 10 days with the right foliar application. So it's possible by managing nutrients, to produce a very rapid switch from vegetative growth to reproductive growth, or vice versa. But there's another layer here which is where it starts getting to be really fascinating. And when we understand how these two layers interact, we can begin producing very reproductive dominant plants that also have very strong vegetative growth. But it's very high quality vegetative growth. And I want to describe this because it's very important. So the second layer is understanding how plant hormones interact with these base nutrients. So there are five major groups of plant hormones. You have auxins, your cytokinins, your gibberellins, ethylene, cystic acid, et cetera, acetic acid. But the two that I want to focus on are kind of the two foundational groups for plant development, which would be auxins and cytokinins. So auxins are. For those of you not familiar with this terminology, auxins is spelled A U X I N S. And you can do more research looking at some of these various plant hormones. But the very simplistic explanation is that auxins are produced in two parts or two locations inside a plant. One is they're produced in growing shoot tips. So the shoot tip at the top of the plant, the apical meristem, has to be growing every day, every 24 hours. And as that growing shoot tip is growing, it is producing auxin. The second place that auxin is being produced is in the developing seed. So once you have blossoming and pollination and the seed begins forming, the Seed begins developing. Now you have auxin production in the seed. Now, the interesting part about auxin is that you can think of auxin to some degree as being the sugar magnet. Wherever auxin is in the highest concentrations, that is where the sugar goes from the photosynthesis factory called the leaves. So every 24 hour photoperiod, as we have photosynthesis and sugar production in the leaves, that sugar moves out of the leaves in the afternoon and evening, moving to the sugar sinks. And those sugar sinks are determined by the auxin concentrations. So when we have high auxin concentrations in developing seed or in the new shoots, that's where most of the sugar is going to go. Now, the interesting part is that auxin, when it's produced in the shoots or in the seeds, but particularly in the shoots, it will move out of the shoot, move down through the plant, out through the root system to the growing root tips. And when it gets to the growing root tips, it shuts down cytokinin production. So let's switch gears from auxin to cytokinin for just a moment. Cytokinins, unlike auxins, auxins are produced in growing shoot tips and seeds. Cytokinins are produced in growing root tips. So again, this means that we need to have the root tips growing every single day for new cytokinin production if we want to maintain a balance between cytokinins and auxins. So cytokinins, when cytokinins are produced in growing root tips, they now move up to the upper part of the plant and they slow down shoot growth, they slow down vegetative shoot growth, and they trigger reproduction. So, so you can think of these two hormones, cytokinins and auxins, to some degree as having an antagonistic relationship. They're constantly competing with each other. Each is trying to be dominant inside the plant structure. Auxins are trying to be dominant and suppress cytokinin formation. Cytokinins are trying to be dominant and slow down shoot growth and auxin formation. So these two are constantly butting heads. This becomes very important because when we think about vegetative growth, vegetative growth is not all equal. We that we can have vegetative new shoot growth on, let's say a cherry or an apple tree or a peach or any tree fruit or berry plant or any annual vegetable crop, we can have poor quality shoot growth and high quality shoot growth. And the way that that's commonly defined and looked at is on annual crops and also to some degree, on perennial crops, we look at internode Spacing, we want to have internodes spaced as tightly together as possible. So if we have internodes that are 2 inches apart, instead of being 6 inches apart, we know that we have that much more opportunity for reproductive buds in the future, and that is much higher quality fruit wood. At the same time, wood that has more closely spaced internodes also is going to have a higher carbon content and higher carbohydrate concentrations. So again, you have the potential to have much more reproductive fruit wood. So when we look at quality of shoot growth, we're looking at internode spacing for all crops. And on tree fruit, we're also looking at carbon content. And what really defines high quality shoot growth. The interesting part is that you can have equally rapid growth. You can have a shoot that extends 18 inches in three weeks. I'm just making up a hypothetical example. A shoot that extends 18 inches in three weeks with internodes that are spaced at 2 inches or internodes that are spaced at 6 inches. The same amount of lateral growth can happen in the same amount of time. But the number of internodes that are spaced along that shoot are determined by the nutrient ratios and by the hormone ratios that are present inside the plant. So this brings us back to our discussion of these four nutrients which drive vegetative growth and how they combine with these two hormones. Actually, before I go there, let's back up on just one piece. I mentioned that auxins are produced in two locations. One is in the shoots and the second is in the seed as the seed is developing. What often happens for many crops is as the seed begins developing, as the fruit begins developing, it becomes the dominant auxin source, and it becomes the dominant sugar sink. So most of the sugars that are being produced are moving into the fruit, which is appropriate as long as not so many sugars are moving into the fruit that they are sabotaging root growth and sabotaging shoot growth. So the root growth and the shoot growth will be the first to get less sugar. The sugar is always going to move into the fruit because the plant has a desire to reproduce. We can monitor sugar production, photosynthesis, and the overall energy of a plant or a tree by monitoring the shoot growth while we have fruit on the plant or on the tree. So we do. If we're growing blueberries or cherries or stone fruit or apples, it doesn't really matter. The same principle holds true. We want to have the new shoot tips constantly growing. As long as there is fruit on the tree, it doesn't need to be growing rapidly. But we never Wanted to set the terminal bud the moment the growing shoots set their terminal bud. We know that has happened because the plant did not have enough energy to both fill the fruit and maintain shoot growth. So we can actually look at shoot growth and shoot extension as an indicator for whether a plant had enough energy. But there's another aspect to this as well, which is the shoot growth is actually not the first to drop off and to decline. It's actually the root growth which is the first to be sacrificed. So because shoots are producing auxins, seeds are producing auxins, but the roots are not producing auxins. So the auxin concentration in the root system is the first to decline, which means that it is the sugar sink which will get the least amount of sugar and will no longer be supplied sugar first when the plant cannot produce enough to fully fill the fruit load that it has on the tree. What this means for annual plants in particular, and to some degree, perennials as well, is when the root system no longer gets enough Sugars in every 24 hour photoperiod, it no longer has the energy to keep growing. So root growth declines, or in many cases, stops entirely. Now, when the root growth stops, remember, you need cytokinin production in growing root tips. So when the growing root tips stop, you no longer have any new root tip extension. That means you also halt the production of cytokinins. Now, there is no cytokinins. There are no cytokinins moving up to the upper parts of the plant to trigger the initiation of reproductive buds. So on some crops, take tomatoes, for example, it's very common to see indeterminate tomato varieties that are staked and tied. Fresh market tomatoes. The field looks like an absolute picture. Every row looks like a hedge. They're 40 to 42 inches tall. The crop that the top is very dense and it looks like a clipped hedge. You have very tight internode spacing 3 to 4 inches apart. And as the fruit begins sizing and the seed begins producing a lot of auxin, the root system is no longer getting enough sugar, because now the sugar is moving into the fruit. And all of a sudden you see this rapid shoot extension happening out of the top of the plant, where you get now get internodes, where for the first 10 weeks of this plant's life, 10, 12 weeks of this plant's life, you have all these tight internodes that are 3 to 4 inches long. And now you get this rapid shoot extension where the shoots are 6 to 8 inches long or 10 to 12 inches long. And all of a sudden this Tight clipped hedge appearance becomes very ragged. You have all this shoot extension happening out of the top of the plant. That is your first indication, your first signal that the root system has gone into decline. There is no longer any active root growth because sugars are all moving into the fruit and no longer moving down to the root system. When that happens, you see that is the trigger that triggers a lot of root disease susceptibility. So when you first begin seeing challenges with Phytophthora or Rhizoctonia or Anthracnose or any number of these various soil borne diseases, it often becomes exacerbated and begins developing quickly when you reach this stage of fruit development, because the plant is not producing enough sugars to sustain both the fruit and the root system. And I should just clarify that plants, this doesn't need to be the case. This is what is common, this is what is normal, but it's not what needs to be the case. It is possible plants have the genetic capacity to photosynthesize to much higher levels and be able to fill a fruit load and be able to sustain constant root growth and root development throughout the entire fruit fill period. So circling all the way back to understanding the synergies between nutrients and hormones, there are. Of the four vegetative nutrients, three of them have a synergistic relationship with auxin. They drive rapid vegetative development and they drive auxin formation. Those three nutrients are nitrate, potassium and chloride. So when a plant has a generous supply of nitrate, potassium and or chloride, either of those three can trigger this response. This is when you get very rapid growth, but you have auxin dominance. And because you have auxin dominance, you have very wide internode spacing where you'll have internodes that are 6 to 8 inches apart or longer, depending on what plant and crop we're talking about. But the fourth of these vegetative nutrient drivers, calcium, does not have a synergistic relationship with auxin. Instead, it has a synergistic relationship with cytokinin. So this is kind of the secret. You can achieve the same amount of shoot extension when you use calcium to drive your vegetative growth as you can when you use nitrate or potassium or chloride. But instead of having internodes that are spaced, that are widely spaced, you now have internodes that are very tightly spaced because you have cytokine and DOM dominance instead of auxin dominance. And this is also how you produce high carbon wood on perennial tree crops and berries, etc. So the key kind of the bottom line, if I were to summarize it all and wrap it all up very neatly. If you want to produce plants that tree structure and plant structure that can support and sustain a heavy fruit load and be extremely reproductive and extremely healthy while also getting strong vegetative growth, high quality vegetative growth, at the same time, you want to balance plant nutrition in such a fashion so that you have cytokine and dominance and calcium dominance at the same time. In other words, you want to get your vegetative growth energy from calcium instead of from nitrate and potassium and chloride. You still need those nutrients, nitrate and potassium in particular, on some crops. So I'm not suggesting you discontinue the use of those. But instead of using those nutrients to get your vegetative growth response, when you use calcium to get your vegetative growth response, you can achieve the same quantity of growth, but a much higher quality growth. And that is the bottom line for producing exceptional yields and quality at the same time. Thanks for listening. I appreciate all the work that you guys do in the field and please give me any feedback and let me know if there's any questions that you have on this topic and I will follow up. Thanks guys.

This podcast was brought to you by a great company that I work for, AEA Advancing Eco Agriculture, the leader in regenerative agriculture since 2006. At AEA, we believe in challenging the status quo to find more profitable and regenerative ways to grow crops. We also believe that healthy plants are resistant to pests and disease and that to grow healthy plants, we must first think differently about agriculture, about empowering life instead of suppressing life, about regeneration instead of degeneration. To achieve this, we formulate and sell products that help growers produce higher quality yield with less risk of crop failure. In short, we help growers make more money with less risk. Thank you for listening.