Between Carbon Sequestration, Nitrogen Loss, and Yields - Gardening Beyond Basics 60

0:00Welcome to Gardening Beyond Basics. I'm your host Diego, D-I-E-G-O, bringing you podcast since 2013. If you're new here, welcome. Gardening Beyond Basics is a deep dive into the topics that you thought were simple when it comes to gardening. From vegetable varieties to soil to pests to seeds, we'll talk to knowledge experts to go way beyond the basics and dive deep into the nitty-gritty about subjects that you thought were simple, but in reality are much more complex than you can even imagine. In every episode, we'll dive deep into one specific topic to make you a better grower. I hope you enjoy it. It's Gardening Beyond Basics. Let's say we know a lot of cultivated soils are degenerative, and they're low on

1:02that carbon saturation point. Are there specific plants or crops that are net carbon sequesterers, like they are going to end up putting more in than they take out at the end of the day? Okay. That question, like the complexity behind it, depends on if you isolate a plant by itself without management. As you see it with it, it's one story. If you manage, so the example that obviously comes natural would be a corn plant, right? A corn versus a native, a sweet grass or a mix of native vegetation. Corn, if it is managed properly, can reach a significant amount of biomass that is accumulated, and it's still one of the kind of crops. It sequesteres more carbon that are forest at saturation because you will own a saturation

2:09meaning that has already growth. But even nearly when you accumulate the woods, what is the forest brings in terms of sequesting the leaves, then the leaves can't. So that's to put it in numbers. It forest sequests about eight tons, and a corn crop on average will be at least 20 tons. But is it a net? No, because corn uses fertilizer, and that goes down the drain already. The emissions and all the life cycle analysis, and we can go there. The perennials we have, for example, one crop, miscanthus gigantus. I don't know if you've heard, it's one of the bio-new bioenergy cellulosic crop. The yield is 50 tons, okay? Not so big. So no fertilizer. It takes this somehow, it just does anything. So in the amount of roots and rhizobium that accumulates, it's massive. So that will go the problem with miscanthus is that can be an invasive species.

3:11And so DOE, the department of energy that has funded the bioenergy centers across the nations, has almost allocated the University of Illinois looking at miscanthus, missing a state and University of Wisconsin. I'm looking at switchgrass that has much more of a broad range of possibility of growing, but switchgrass on average would accumulate about eight tons of biomass. So those are the natural behavior to answer your question. Yeah, big differences in plant, wheat is by tons, maximum, and half of that could be grains. And so I'm talking about in general average total the primary productivity of their particular crop. But I want to spend a minute on saying that people may not realize that nowadays the level of photosynthesis done through two things, improved genetics and management basically spoon feeding a crop. We have reached

4:11the level of yield of corn of 600 bushels. So the average national is 170 bushels and world record for the last four or five years has been in the range of close to 580, 50, and 600, the last one, actually, which when you convert into total biomass, we're talking about now 50 tons per hectare. But the amount of that's very positive a meter because of the amount of, it doesn't accumulate carbon per state because of the balances through the amount of inputs that they're used as. I initially said they go with agriculture being an anthropogenic component to the climate is through fertilizer addition. We lose 50% of the greenhouse gas emissions coming from agriculture come from main to all emissions. Okay, and so that's another balance because even the potential of

5:15total accumulation of carbon is still requires nitrogen to go with it. There is a CN ratio. So you will always be depleted by nitrogen unless you have fertilizer. So if you want to feel all the soils with 5% in the globe, it will be equivalent to have 75% of the fertilizer production that we currently have in the world, which is really heavy sorts of emissions. Now that doesn't mean that fertilizer has to come from synthetic fertilizer. There are legumes that they can be. So if we want to come back to the species, yes, different species have different capacitors, different photosynthetic capacity and rates of accumulating carbon per unit area. The amount of this carbon remember there is a component above the plant, but there is also roots. So there is this root shoot composition that actually in situation where war is not available, roots become deeper. And so they basically

6:18the plants provide this feedback mechanisms of saying, okay, the root says there is actually a simple way to think and if plants is exposed to a stress and the stress comes from above, what would be a stress coming from above? Reduced light, shading from then all the things and the assimilates will go to the top and the plants will try and go faster, rather than to elevate. If the stress comes from the soil gets the priority, the part of the plants in the soil. So if there is a water stress, plants doesn't grow higher, actually says, okay, no problem, I'm going to invert and shuts down. In some of the assimilates go down to the roots because remember it's not photosynthesizing, but the roots are growing because they are desperately in search of water. And so you get more roots that way. So this mechanism changes by species. But to again, to your question, yes, different species, different capacity. And I mean, separation in the beginning depends

7:23how they manage. So if corn is managed, we know fertilizer and it lets grow for so many years, it would be far from where it is, you barely get 100, 100 bushels at the end because you run out of corn is a very highly consumptive crop because of the sizes and it doesn't fix nitrogen on its own like scams. So I actually switch glass glass pretty well without fertilizer. So there is that mechanism that complicates even things. On fertilizer emissions, being a big source of greenhouse gases are all fertilizers critical. So if we had chemical fertilizers and organic fertilizers, manuars or, you know, byproducts from the animal processing industry, do those contribute to greenhouse gases equally? No, they don't. So synthetic fertilizer are immediate emission. You put them and you have these big flushes of, again, the color biological station, we have a series of long-term data, the long-term ecological research site led by

8:26Phil Robertson for so many years now, Nikadad. They've been measuring end to just basically continuously, right, on automatic chambers. And so it's very de-eurnal depends on the amount of water that after the rain there is. So synthetic fertilizer immediately and you may be aware of this is basically about roughly 1% of the fertilizer there is added. This is a very simple concept. It's called the mission factor that the intergovernmental panel on climate change has done a very comprehensive review of looking at fertilizer rates comparison and emission. And so there was a consistent number. You put 100 times, you lose one pound. And the problem is that one kilogram of N2L is 300 kilograms of CO2. It's 300 times more powerful in the global warming potential, like much rougher in the atmosphere. It traps a lot more 300 times more powerful.

9:32And so manure, it's an organic form, okay, does not have plans to do not use nitrogen in the organic form. And you have to be mineralized. So mineralized first in form of N2L from N2 to N03. And then it can be used or nitrification to NH4 ammonia. So this takes time. So the release is the decomposition it takes time. It doesn't immediately make nitrogen available from an organic compound available to the plains. So there is not an immediate loss. And that percentage is lower because it builds carbony, retains carbony, nitrogen is trapped more. The problem with the amendments of organic amendments is you also may have CH4, methane and emission associated to that application, which is about 25 times more powerful than CO2. But overall, no, synthetic fertilizer

10:34are the ones that they used the most, obviously, and they are the greatest. But there is a new approach to slow release fertilizer. So basically, they have shown to, they're still synthetic, the cost is still very high, but it does reduce N2O emissions because it slowly releases the amount of mineral nitrogen that could be volatilized. And the other aspect of N2O emissions and fertilizer is that has to be in a conditions that creates D-nitrification. So back to N2 in the form. And that occurs when there is a flooding conditions, right? When there is lack of oxygen. And normally, when you add organic compounds, that doesn't happen. You are back on the healthy side of having greater porosity, better conditions in general. So synthetic fertilizer are certainly the ones

11:35that you think the most. But it's not even a natural, a cover crop will have emissions, not SI, obviously, as a fertilizer, but it's a natural process. Where would a crop be in terms of net nitrogen loss? If I planted corn year after year in the same place, and I wasn't doing tillage, and let's say I had really good soils, would I, would I need to add nitrogen? Or could I get that system to function without nitrogen addition? If I left all that biomass. Very good question. It goes back on the temporal time. It's on the first year. So I, you may have seen in some of my research by scaling and understanding this spatial variation, as I identify that each field as like a farmer will know, but don't all the farmers know that, and then come and scale that there are parts of the field that they're much better because they have deeper soil, like deeper volume. And so those, they, it becomes back to the

12:43virtuous cycle where you have greater biomass, greater roots, greater decompositions, and you do accumulate that. The mineralization, so an organic, fully, let's say, in this way, would be an organic source of management. If it's managed correctly, it could compensate, but you may not have the same level of yields. The yield could have a penalty in the beginning. In the first years, it may not be sufficiently to compensate what you were used to. So we also seen at this long-term study that organic systems, and in our case, it was only cover crop and no tillage. It could come close to the yields of the mineralization just because it isn't just about all nitrogen. They have more water. And the conventional tillage ran out of water much quicker.

13:45So it's really a system. So to answer your question, immediately, no, long-term certainly can. But the yields are not obviously the 600 bushels, but they can easily get to the level of average yields, which will bring the benefits of trade-off analysis of the cost of doing things. Farmers need to understand that, and they do process it for sure, and not necessarily all of them, but profit is also obtained by spending less. Investing. So it's now, unfortunately, nitrogen is a cheap and economic source of insurance as a thing. It costs the significantly lower to put an extra pound compared to its basically 50 cents versus $4 a bushels that you could get from the addition. And that's again, back onto the trade-offs. Are we serious about accumulating carbon and using it carbon to store and offset emissions and so on versus the profit? I'm always of the idea that

14:51we need to be able to reward farmers for what they do in long-term sustainability, basically and keep carbon there and using more sustainable management, which is to reduce among the fertilizer. To reduce the amount of fertilizer, it's very interesting back to the space of variation. There are parts of the fields shouldn't even be cultivated with the same crop, but they are even cultivated with the same management. So a corn crop that yields 100 bushels on either on the edge of the field, on some poor conditions, that receives 200 pounds per acre of on average, on depending on, let's say, typical. And that's unacceptable because you're really omitting much more. So converting those areas into more perennial in legumes, then you will build the soil and the system to be able to mineralize that. Given some of the work you do with SIBO and just some of the academic work you've done, it seems like a lot of the focus is on carbon emissions, but if you have nitrous oxide,

15:55which is worse at the end of the day, shouldn't there also be some concern about containing nitrogen within the system? And is nitrogen the same as carbon? If you reach that carbon saturation point in the soil, where it's at equilibrium, could nitrogen be the same in a cis-natural system where everything that's being used is being stored in the soil, either in the biomass or in the living microbial biomass in the soil? Yes, very good. The first question, Diego, that's not necessarily, when we say carbon emissions, everything is converted into SIBO to equilibrium. So everybody knows that the greatest emissions come from into all. And we reduce angle, we aim to use angle emissions, but there are address lots of SIBO to equilibrium. So I am working on a way to basically create carbon credits

16:56by reducing, but better managed in fertilizer, it comes as a benefit to the atmosphere because you reduce the SIBO to equivalent from nitrogen. Nitrogen is critical also because people have talked enough, but it's lost now in terms of benefit from water quality as a critical aspect of nitrogen, where the system by definition is a liquid system. So nitrates, because of them, the way the molecule has these negative charts, they are basically very mobile. So the point of saturation is really hard to get, because you get a flush and it very goes down to the next layer and so on. So the nitrogen in general, it's never on a fully positive accumulation, because it's used by the wind, is the de-volatized. The most of it is basically lost as nitrate leaching.

17:57And in addition, some will be surface runoff, so that soil is taken with that. But a third or more, so back to the spatial variation, in the areas of low nitrogen use efficiency, these areas will take only 40 to 50% at the most of what it was applied. So I bring this example often when I talk to growers, it's imagine you buy this pound, a hundred pound bag, and you've done the first 15, the parking lot, and then you go back to your field and you apply. Why did you apply for so much more on these areas? It's just an example. They don't necessarily know. But now technology with eventually, possibly in the end of the talk, we could go on the future of how data and digital technologies could help. But we have a very good knowledge of where these low areas in a field are, and so you could now have 100% efficiency by putting 50% of the amount, because the yield is basically

19:01that plain small and only requires half for what it was humanity initially. So again, the point is saturation. It's impossible because of an open container. It doesn't have a bucket at the end. Carbon doesn't move as tight, and it reaches, if you can only put so much around it, then we nitrates because of the nature in the leaky system. They're lost as nitrate leaching. And so that's very difficult to manage just because of that. You know, this time you may notice that there's still a tendency for various reasons. I'm not here to judge, but the majority of the application of fertilizer, it's done at the end of the season, without even knowing what you're going to basically get in the year. And so obviously for reason of logistics, reason of possible lower prices, and in the middle of the summer, you may very

20:03well be sure, but they don't necessarily go back. And so what did they do? They compensate with a larger amount in the beginning. That's changing, and they're doing all the way to now variable rates of application where one area gets one amount and another gets a different amount. So there's quite a bit of improvements, both in science of understanding the dynamics, detecting this deficiency, but there's a combination of a culture of managing maybe more traditionally, but that's very split. There are lots of progressive farmers. And so as a suggestion in general, imagine not going to be like your food. You don't just stand up and cook and use your mouth. You will be eating it through time. You won't be eating it all at once. So what's the point of cooking 10 states when you can only eat one, then the rest is thrown away, because it will be spoiled. That's equivalent of the leech. And so if you apply the nitrogen,

21:08when it's needed, which is difficult because synchronizing supply and demand is as a conflict, sometimes you cannot go back in the field, but there are times when you can, and there is a limit when you can. There are alternatives with high boys and I'm more describing, obviously, a mid-west phase. In vegetables, it's very important to feed with more of the spoon type of the fruits and having all the ones because a fraction of that will be lost through water. Yeah. So even in the healthiest or best managed system, you're going to be needing to add some, because it just is leaky. There are pores. There are micro pores and water comes down. It takes you don't lose it just to give you an idea is how long will it take for me to lose what I put in. It's usually nitrates are never lost in the season. They're always lost when the plants are not there to be taken up. So what's good about, you know, growing vegetables, you do have nitrogen that, if you have another crop coming in, very sleptovers that can be used.

22:12The difficult thing is remember because of the nature of leaching, some of these nitrates are not in the surface. They're now a little bit deeper, quite a bit deeper, and now they are on the second foot of sorts. So you could prevent some of it when you know deeper roots back. So again, the leaching could be up to 50%, but you know, you'll be dropped to be as low as between. If you enjoy farm podcasts, then tune in to Kerrick Cash Flow for all things farm business. Join us as we explore the latest trends, tips, and stories from market farmers running businesses just like yours. Whether you're a seasoned farmer or just starting out, our podcast has something for everyone. Listen in and grow with us. Available on all major podcast platforms. Don't miss out. Subscribe to Kerrick Cash Flow today.