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Thoughts on Rice
This podcast is for growers, PCAs, consultants, and other industry professionals in the California rice industry. We'll primarily be focusing on the Sacramento Valley and Delta Region of California. The UCCE Rice Farm Advisors aim to deliver extension information relating to the California rice industry.
Find out more about UCCE and California rice here!
Thoughts on Rice
Effects of crop rotations on soil microbes with Sara Rosenberg
On this episode, Sarah Marsh Janish welcomes back colleague Dr. Sara Rosenberg, a UCANR Farm Advisor for Mariposa, Merced and Stanislaus counties, to discuss a recent paper she has published. Dr. Rosenberg recently published a paper about part of her dissertation work, the first study to assess soil health and agronomic outcomes in diversified and continuous rice systems in California. This journal article is called "Benefits and tradeoffs of diversifying rice-based cropping systems: Impacts on soil health, productivity, and agroecosystem multifunctionality" and was published in volume 391 of Agriculture, Ecosystems, and Environment. The conversation focused in on one aspect of this fascinating work: how crop rotation in rice systems affects soil microbial communities.
Links
Addressing economic barriers to crop diversification in rice-based cropping systems
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January 21, 2026: Richvale 8 am /Willows 1 pm
January 22, 2026: Colusa 8 am/ Yuba City 1 pm
January 23, 2026: Woodland 8 am
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March 18-19, 2026
8:30 am - 3:00 pm
Lundberg Family Farms, 5311 Midway, Richvale, CA
Other Resources
Rice in the Delta
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The views, thoughts, and opinions expressed are the speaker's own and do not represent the views, thoughts, and opinions of the University of California. The material and information presented here is for general purposes only. The "University of California" name and all forms and abbreviations are the property of its owner and its use does not imply endorsement of or opposition to any specific organization, product, or service.
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Hello and welcome to Thoughts on Rights, a podcast hosted by the University of California Cooperative Extension Rights of My South. I'm one of your hosts Sarah Mark County, and I'm a rights from advisor for Calistoniola County.
SPEAKER_00:I'm a cooperative extension rights of counties. My point is farming advisor for yoga and county.
SPEAKER_03:I won't like other miles, farm buttons for all sorts of four.
SPEAKER_02:On this episode, we welcome back our colleague, Dr. Sarah Rosenberg, a UC AR farm advisor for Mariposa Merced in Stanislaus Counties. If you've been listening to the podcast for a while, you may remember Sarah from last year, when we had her on to talk about her research into cover crops and rice systems. Now, Sarah has recently published a paper as part of her dissertation work, the first study to assess soil health and agronomic outcomes in diversified and continuous rice production systems in California. This journal article, if you're interested in reading it for yourself, is called Benefits and Trade-offs of Diversifying Rice-Based Cropping Systems, Impact on Soil Health, Productivity, and Agroecosystem Multifunctionality. It was published in volume 391 of Agriculture, Ecosystems and Environment. Although there is a lot to work with with this paper, in this episode, we're going to focus on one aspect of this fascinating work: how crop rotation and rice systems affects soil microbial communities. With that, I'd just like to officially welcome back Sarah. So nice to see you. How are you? Hi, Sarah.
SPEAKER_04:Yeah, thanks so much for having me back on this podcast. I'm doing well, thanks.
SPEAKER_02:Great. Sarah's a reunited. I love it. Now, I just want to check in with you. When we last talked, you had just begun in your position as a UCNR advisor in the counties of Mariposa, Merced, and Stanislaus. Can you give us an update on what you're working on or any exciting things that have happened over the last year? Certainly, yeah.
SPEAKER_04:Well, I'd say that moving into year 1.5 of this new and very broad position, it's been quite a roller coaster. Up in the foothills, we've had a lot of really interesting kind of events and opportunities in terms of working with locals and local farms and local communities to like lift up local agriculture through this really big annual event called the Agri Nature Tour. So we did that just last month, and it was a big event where Mariposans and people that are coming into the area, mostly tourists into the Yosemite area, are touring local farms and learning about the local ag in the community and what's going on. Outside of that, we've been working with local vineyards and small farms to adopt cover crops and kind of look at different cover crop species implementation, and everyone's been really interested in those things thus far. And yeah, I guess down in the valley, I don't know, things are a little slow moving, but more gearing up towards implementing some regenerative research in tree crops. So looking at integrative livestock management and pistachios and almonds. We've got a partnership going on at UC Mercedes Smart Farm with the Almond Board and Cooperative Extension to implement a regenerative almond orchard demonstration. So kind of pushing the program towards the, I guess, cropping system design of regenerative orchards in the San Joaquin Valley. So those are those are a few highlights, I would say.
SPEAKER_02:That's quite a bit. And I we were talking about this a little bit earlier, but there's so much diversity and variability in the work that you do, but not only the work, but also the stakeholders as well. Would you say that it's an exciting challenge to try and bridge that gap between, like you said, the tourists who might be in the area for Yosemite versus the people who are landowners and managers?
SPEAKER_04:Yeah, I mean, this this position and like all farm advisor positions, I feel like we just wear so many hats and work with so many people, like trying to narrow down the clientele is is really just like a it's it's based on your scope of work, but it's also a personal choice of like who you want to work with. And I think as the agriculture landscape and challenges change, so do our clientele. So for myself, really trying to lift up agritourism in the regions of the foothills is going to mean working outside of the community clientele of farmers, but also in the Sierra Foothills, landowners, people who are not quite defining themselves as for profit farmers, but are really just trying to live off the land in the sustainable means, those are part of my clientele too. And so kind of redefining the definition of a farmer up here versus what a medium-scale commodity crop farmer looks like in the San Joaquin Valley.
SPEAKER_02:That is really exciting. And I'm sorry to kind of stay on this, but this is so interesting because I feel like that might be a gap that we as an organization have kind of overlooked, that intermediary between production farmers and then those people who, as you said, are living off the land.
SPEAKER_04:Oh, well, certainly. I mean, absolutely. I mean, in in general, I think that parity-wise, right, we just don't have the same population demand in the foothills as we do in the valley, as as far as like sizable operations are concerned, but I do see a shift, especially a lot of beginning farmers trying to, like, you know, post-COVID moving into more of these rural forested parts of California, and a lot of them don't know what to do, where to start. They have this kind of idea where they want to, you know, lower their footprint. They're also moving into these regions that are really, really high risk for things like wildfire. Right. And so there's a nexus of as I've been up here and learning about these things of how do I maximize sustainability, biodiversity, habitat, you know, conservation, but also fire mitigation. And where does that come into play? So a lot of really interesting collaborations with different folks up here. The fire advisor for one, the Master Gardeners program, you know, people like that.
SPEAKER_02:We do a love of collaboration. And it sounds like you've really hit the ground running and started some very interesting work. Uh, later on in this conversation, I'll actually ask you to share some links and information so that we can direct people in the area who might be interested. With that, although it's a bit of a shift from your usual day to day, I do want to kind of talk about something you used to spend quite a bit of time on when you were up here up in the north with us. And that's kind of about this project that you worked on a few years ago as part of your dissertation. First off, congratulations on getting this journal article published Benefits and Trade-offs of Diversifying Rice-based cropping systems, impacts on soil health, productivity, and agroecosystem multifunctionality.
SPEAKER_04:It's quite a mouthful, I know.
SPEAKER_02:Well, it is, but you've got so much to cover in this article. And I'm just gonna caveat this. I've read the article a few times, definitely not an expert, but it's really interesting how much you all manage to combine and analyze. Can you just, I guess, briefly for everybody, kind of give us an explanation of the rationale behind this study?
SPEAKER_04:Sure. Well, I've always been interested in multifunctionality of a concept in agriculture, which is really about like laying out the implications of an agriculture system across many dimensions. I think it's pretty traditional that we have the lens of success of agriculture coming from one or two different indicators, right? Whether that be yield, whether that be economics, profit, some type of productivity indicator, right? But multifunctionality is the concept that says agriculture landscapes landscapes can provide multiple services beyond producing food and fiber. This looks at biodiversity conservation, the contributions to water conservation and water cycling events, the contributions to different socioeconomic viability outcomes and even perhaps cultural outcomes. There's many different multifunctionality frameworks that one can use, but I really wanted to take that framework and say, how do rice systems that are under this, you know, diversification practice of crop rotation and then continuous rice systems differ across all of these different dimensions. So that's why it's kind of like, you know, analyzing so many different aspects rather than just one or two things.
SPEAKER_02:Absolutely. And I think part of the reason you all looked at this is because of the way that multifunctionality can affect resilience. Is that right? Can you define for us what resilience means here?
SPEAKER_04:That's a great question. I mean, it it I would suggest resilience means the ability to withstand shock, right? In terms of an ecological definition. It looks at how a community or a system recovers after after some type of turbulence or some type of shock event. And usually what we see in an ecological system is that the more ecosystem services that are functioning in that system, the more resilient it's going to be, or the more it's going to be able to recover quickly after a shock. And so if you just kind of take that theory and say, well, if you have more ecosystem services available on an agricultural landscape, then you could correlate that to a more resilient system. And I think that was kind of the rationale behind it. Um, taking a step back a little bit more, I think originally we were looking at this really more from a I don't know, a reductionist lens where we were thinking, well, let's take let's look at this from a weeds standpoint or from a soil health standpoint, or just one or two of these things. And and as I, you know, was kind of building in my PhD world grad school, I I said I don't want to just to myself, I've said I don't want to just like take that reductionist standpoint. I'm interested in the full-on picture of the trade-offs across all these different dimensions, looking at agronomic, looking at environmental, looking at soil health, many different things.
SPEAKER_02:So yeah. You did mention the trade-offs. Can you tell us some of the trade-offs that can be expected when increasing the number of functions within a system?
SPEAKER_04:Certainly. So it's kind of based on I guess a few different ways of talking about it. Generally speaking, the more ecosystem services you're going to have, the more resilient you are, but the less likely you are to maximize any one of those services. Right. And so that's the trade-off. So if you're really looking at maximizing one service, like maximizing yield, which of course many, you know, growers are really in their business, you're you're going to likely see a reduction of other ecosystem services. That's kind of what the literature tells us. But at the same time, the more ecosystem uh services that you can enhance, the less trade-offs you have between them. So what we can talk about is like ecosystem service evenness. So you have an even amount of expected services across all of the different outcomes that you're trying to achieve.
SPEAKER_01:Thank you. That really that was a really good way of tying that all together, by the way.
SPEAKER_04:Okay, good. I know these things can be a little bit, you know, I don't know what the word is, nuanced or theoretical, I guess, sometimes, and trying to tie it to the applicable and is is difficult.
SPEAKER_02:I mean, we're talking about a pretty complex subject as a whole. How did you and your team design this experiment to study this concept? What was your, I guess, basic design and methods for undertaking this project?
SPEAKER_04:Yeah, so this was an on-farm field experiment, meaning we I sampled across like many different farms that have been under different management regimes for long term. So every farm was sampled from once in order to capture what we call the legacy effect of that management regime over time. In comparison to a trial that might be replicated on a research site, and you're doing those research trials year after year after year to assess change. We just sampled from a large number of farms in the Sacramento Valley. Each farm was sampled from once for soil health. We got survey data from growers for management. We just assessed that those farms that were continuously cropped with rice compared to those farms that were under some form of crop rotation, delineated from conventional versus organic.
SPEAKER_02:When you talk about you've sampled in the Sack Valley, you probably were able to encompass a wide variety of soil types. Did you see a lot of change in the sampling sites?
SPEAKER_04:Yeah, I mean, in general, that's going to be, you know, a control issue. And most rice in the region, as you know, they're gonna have pretty high clay content, pretty much in the clay or silty clay loam texture. They're also gonna have attributes like soil that's poorly drained due to floodplains or impervious clay pans or hard pans, things like that. Um so what we do to try and control for that variability is if I have we had like 46 sites that we sampled from, we tried to get comparisons of the rotated field in proximity to the continuous rice field, geographically speaking, with similar soil types. Sometimes that was difficult to find, which is why you get more, you know, you can just get more field samples that kind of overshadow that uh variability in the analysis. The other part about this is that the majority of locations are happening in certain regions, right? And so if you look at the field selection on a map that we had, most of the rotated fields were bound south, which will also skew certain things. So we had a high density of sites that we sampled from in the y in the Sutter YOLO Palooza region. And that's just a product of where rotations are happening in Sacramento Valley.
SPEAKER_02:In a way, it's it's more realistic, at least. Yeah, absolutely. How many years did you collect data for this project?
SPEAKER_04:Uh so about three years. But again, every site was sampled once, so we didn't go back to those farms and sample, you know, consecutively every year. It was just about like finding new sites every year for three years. And we sampled between 10 and 22 fields per year.
SPEAKER_02:Mm-hmm. And I guess in terms of the fields that you were sampling, I'm interested in some of the management practices used in these fields. Are there records of some of your rice farmers doing winter practices like winter flooding, or is there a certain percentage of organic or conventional fields that you were able to uh get a history of?
SPEAKER_04:Yeah. So I guess the first question is management practice around the winter flooding, which as we know is extremely common in uh most the Sacramento Valley for continuous rice farmers. And so the majority of those who were continuously cropping rice also did winter follow following and winter flooding. Sorry, to be more concise, winter flooding. Those who were doing rotations were not doing a winter flood because it would impact their ability to come in in the summer and do an upland crop that wasn't rice for a a lot of different reasons. So but oftentimes those farmers, and this gets out of our time sampling horizon of when we were looking at some of the soil health stuff, but oftentimes the growers that were considered like they were in the category of like rotating rice with summer crops, when they were in their rice system, they would be in that system for anywhere for like two to five years, sometimes more. And during that time frame, they would winter flood if it was once it was rice back to back to back. So you know, not clear-cut, yes, they did, no, they did not, but during the rotation phase, they did not winter flood. And then what your question about like organic versus conventional numbers, I think. Was that that was it? In total, we had the majority of the sites were conventional, 34 were conventional and 12 were organic. And so that's a disparity. That is that is something that was recognized throughout the study, where we said anything, you know, that we're able to pull from this as like an organic effect is is a trend because the population size was so small. Of the 12, eight of the organic fields were under some form of rotation, and four of them were continuous rice practice. And the organic rotated fields they were the ones that were the most diversified outside of rotation practice, meaning they also implemented a lot of cover cropping, soil amendments, chicken manure mostly. Uh huh. Sometimes Uh compost, I believe, but um most or if not all of them did some form of organic amendment and cover cropping regime along with that rotation.
SPEAKER_02:Great. And that's like that is a lot of work. That's a lot of differences in fields. But what I wanted to ask is about the soil samples that you were taking from these fields. And so I when I was reading your paper, I wanted to ask how you were taking your soil samples in each of these fields, just kind of the methodology for that, and then how you analyze them later.
SPEAKER_04:So the methods for sampling was quite fun, actually. We were able to get into the fields in spring, right after first or second tillage pass and before any inputs were put in place. So that'd be between May. And I would be out there with myself or a team or a few people, and we'd, you know, I'd be driving around and kind of scout the field and take a representation number of soil samples from each each farm. So anywhere from 10 to 22 plus soil samples were taken. You know, these are sites that are 30 acres to 150 acres that you're driving around on. Pretty rough soil has been tilled up and it's kind of like driving on a moonscape sometimes, don't like. But yeah, we'd sample down about six inches, just down to the annual cropping system roots level recommendation, and aggregate everything, mix it all up together, and then we put soil samples in storage based on how they needed to be preserved for the type of sampling that we were doing. I sent out all of my samples to labs, thankfully, so I didn't have to do the in-house work of all of that analysis. I was more focused on the in-field sampling and getting the survey results from the farmers and then doing the beta crunchy on the other end.
SPEAKER_02:And one of those analysis methods that you talked about was phospholipid fatty acid or PLFA. And that's not one that I'm terribly familiar with. Can you explain how you use that analysis to provide information on microbial biomass diversity?
SPEAKER_04:Yeah, sure. So I wanted to look at the mic, the microbial biomass differences between the sites, but I also wanted to look at the diversification of the different groups of microbes across each site. And PLFA is one way of doing this. It's going to give you the total living microbial biomass, whereas a lot of times a soil analysis on microbial biomass is necromass and living. Necromass and both necromass and living are good in things to know about. But this one is going to look particularly the living microbial biomass. And that's because of the way that it extracts. Those would be things like different types of bacteria, different types of fungus that is in the soil, your different types of I mean, those two big, those are the two big groups, right? And then and then within that giving you the fungal to bacteria ratio, and you know, there's just like a lot of information that you can get. So it's a breakdown of who's in my soil rather than just how much is in my soil.
SPEAKER_02:That is a really, really neat. Um, before you got the results back, did you have any kind of hypothesis or idea of what type of microbes you were expecting to see?
SPEAKER_04:I mean, you know, as far as like hypothesis is concerned, we kind of went based on literature that said the more diversity you have above ground, the more diversity you have below ground type of logic. But generally, I was like going into this more of a kind of just an unknown exploratory lens because it's not apples to apples. You're looking at a system that is semi-aquatic, the biogeochemistry is completely different under standing water for many, many of those months, versus an aerobic cropping system that is dominated in oxygen. The amount of biomass is different across the systems when you're talking about you know turning over the last year's crop. Um and all of that's gonna affect who's eating what and when and how. So I was just kind of more of taking that exploratory view of um what's what's the difference between these two systems.
SPEAKER_02:I mean, I think that's really neat, though, because you I mean, to keep it simple, you kept an open mind as you were going into it. You didn't have any preconceived ideas. And part of that is because, like we said earlier, this is kind of a landmark study. This is the first study to assess soil health and agronomic outcomes in these kinds of systems. So not a lot to go off of in terms of literature.
SPEAKER_04:Yeah, well, I think also, I mean, to to be fair, not a lot to go off of in the context of California. There's a lot of there's a lot of literature that has been studying drop rotations with rice in subtropical environments, you know, and the kind of paddy environments up in the parts of Asia that have two seasons, or you know, just there's but those systems are so different compared to what we have going on here in our rice realm. So yeah, there was a lot of unknowns going into this paper in the context of California agile ecosystems.
SPEAKER_02:So I did notice in your paper, you noted there were higher carbon and nitrogen mineralization rates in rotated rice fields. And you mentioned that the differences in the bacterial communities between these systems may have contributed to the shift. Can you walk us through that statement?
SPEAKER_04:Certainly. So just a little kind of like breakdown of what we found along the soil microbial differences. Generally speaking, there were two groups that differed within the rotated fields and the continuous rice fields. And it wasn't that there was more diversity between one type or the other, it was more that there was a shift in the communities that existed, which really starts to make sense when you think about it, because you're changing the diet, you know, of these microbes pretty vastly when you move from a rotated system to a continuous rice system. So in the rotated fields, the dot which were dominantly conventionally rotated fields, we saw a higher, a significantly higher rate of a group of bacteria called ectinomycetes. And these are beneficial bacteria that promote soil health as secondary decomposers of organic material. They are really known for their role in cycling nutrients and mineralization, particularly of secondary decomposition of things like cellulose, omicellulose, lignin. And they are also known, you know, for like oh it's a very, very large phylogroup. So getting into the nitty-gritty and what types were there, we didn't get that far. But these this group is also known for suppressing plant pathogens. You know, actinomyocetes are previously known as the actinobacteria or uh classes of bacteria that we know are and are kind of world as like antibiotics, so to speak. So they're the good bugs in in some way. So that's what that that kind of like correlation to higher carbon and nitrogen mineralization, because we did see we did see a reduction in POX C, which is kind of an indicator for that labile carbon in that easily degradable carbon bank. We saw a reduction of that in our rotated fields. We also saw a high reduction of our ACE protein, which is the indicator of our readily available organic pool of nitrogen in our rotated fields. And so there we we saw the correlation between those reductions of those carbon and nitrogen pools and the higher amounts of actinomyocetes, as you know, perhaps these types of bacteria are driving that reduction or that mineralization of carbon and nitrogen.
SPEAKER_02:And that does make sense, given what you've said about the what that population, what those can do and how they act within the soil depending on the various types of food that they're getting into their diets. Exactly. Now, when you're looking at the soil microbial communities, was there a noted difference between the different management methods? So, say a difference between the organic rotated fields, the conventional rotated fields, and the conventional non-rotated fields?
SPEAKER_04:Yes, yes, and that's a great answer. Or yes, but I'm not sure. I like yes and so I I mean you did, you did see it. But in as far as this the like what we call the significance statistically speaking, it was less of a significance, and that is because honestly, we just like I said didn't have enough organic fields, right? We had a very small amount of organic fields. But you do see a trend in organic rotated fields and organic non-rotated fields to have higher amounts of fungi present compared to the conventional fields, and this is a particular type of fungus that is the saprophytic fungus, which is another group, a phylogroup that is recorded in the phospholipid fatty acid analysis, the PFLO. And this also, you know, the sort of higher saprophytic population in our organic fields compared to our conventional fields, makes a lot of sense when you think about it because this population is really sensitive to things like herbicide applications. It's really sensitive to pH change. These are primary decomposers, these are our funguses that really help break down our organic material at the higher level. And so when you think about all of the different organic matter amendments that organic farmers are using, like chicken manure and cover crops, this is gonna be a big kind of like feast, so to speak, for our saprophytic groups of of fungus. There's also some evidence around these particular primary decomposers being really good at breaking down lignin. You know, this this is a like really woody type of material. And even thinking about on the organic continuous rice fields and on the conventional continuous rice fields, the amount of rice straw that's going into that input, right, is uh is going to need a starting point to break down before the actinomyces can come and break it down further. And so those those funguses, those saprophytic communities are going to be the primary stage colonizers at that amount of biomass uh compared to like a conventional rotated field that's gonna just have less of that type of biomass circulating in the system.
SPEAKER_02:And so because maybe a conventional uh continuous field might have exposure to more chemicals that may hinder the population of the saprophytic fungi, that might indicate why there were higher populations of those in the organic fields. Is that accurate to say?
SPEAKER_04:Correct. Right. Yeah, yeah, I would say so. I mean, all of this is correlation, not causation, right? And so we looked at some, we looked at these results in terms of getting significant indicators across population sizes. We put them through what's called a multifunctionality analysis and lens in a uh multivariable assessment, and we saw correlations between these two. And then, you know, we can we can interpret some of these findings through our understanding of the mechanisms behind them. Yes, correlation, not causation. These are these are important differences.
SPEAKER_02:Yes, very, very much so. I'm really glad you keep mentioning that because oftentimes research like this does get distilled down a little bit too much, but there's a there's a lot of variables at play here. And I guess one of those interesting variables was the difference between rotated and non-rotated fields in terms of total microbial biomass. So not just microbial diversity, but the diff was there a difference in numbers of total microbial biomass between these rotated and non-rotated rice fields?
SPEAKER_04:We expected there to be, but there wasn't. There wasn't a significant difference between the two. So, like I said, it wasn't like a complete difference in terms of diversity, it was just a shift in community. And when you change the community, you're not necessarily changing the entire biomass of microbes. So that again is at a time point sensitive sampling event. So we don't know how things might change later in the season or a different time frame, but at the time that we sampled in spring, when rotations are coming are are and I did not mention this in the methodology of of the of the study, but um at this time that we sampled all farmers that were rotating with rice were going to be going into a rice crop the following year. Coming out of a rotation crop for you know three to five years or whatever. I think actually it was some of them or even one to six years or something. So at that time point when we were sampling, you did not see any differences in total microbial biomass.
SPEAKER_02:And so that that could be different, I guess, than what people might expect. Some may think that a flooded rice soil may be because of the anaerobic environment having less of a microbial biomass. But can you say why the flooded rice soils might contribute actually to microbial biomass?
SPEAKER_04:Yeah, and it was sort of a point, like as far as you know, literature is concerned, you could have gone either way. You could have suggested like that there would be more microbial biomass in the rotated fields. There's a lot of in a lot of really good studies out there that actually just show how efficient patty soils and rice systems are at building carbon reserves, and this is directly correlated to microbial biomass, and so in general, you could expect a higher microbial biomass in the rice fields. I I do think that is still prevalent in California systems, right? Like the rice systems in California are a major carbon contributor in general, net carbon contributor, because of the high biomass turnover of rice stock and the flooded environment. And the flooded environment slows down decomposition. So those two kind of mechanisms are going to differ from an anaerobic system where you are rotating with annual crops that may not have as much biomass turnover, and and perhaps like the type of biomass is not as difficult to decompose like rice straw is. So you may not have as much biomass, but you're also under an anaerobic environment which is very inefficient, and so you have a lot of CO2 respiration happening and loss of carbon through that CO2. So I I do think that is one kind of like in general, you know, that's that's knowledge that we knew, and that's something that this study backs up. But there was kind of this other side of the coin, which is that, well, then why wasn't the rotated, why did the rotated fields not show a drop in overall microbial biomass? And you know, there wasn't a there's again, there's some interpretation there, but there's not a whole lot of causation. But but generally speaking, the sites all had a pretty high level of carbon to begin with. California agriculture is is intensive, and so you know, even in the annual cropping system, you're still getting a pretty good turnover of of organic material after the season. And that kind of amount of high amount of organic matter in the soil across the sites just could not have any substantial decretion over time or decrease over time based on how stable the carbon levels are in the soils.
SPEAKER_02:It's a complicated topic, and there's a lot of different factors, but it's it's so interesting just to see the output of this work, and especially when you're able to kind of illustrate it through these studies into microbes and the microbial communities. Now, one more thing, and this is a bit more rice related, but with the talk about how the straw takes a long time to break down and how that can affect depending on the different management situations. Let's talk about straw incorporation effects. Anything that we can maybe extrapolate from this study on how straw incorporation into the soil might have an effect on microbe communities?
SPEAKER_04:This the simple answer is yes, right? Straw incorporation can affect microbial communities. As far as the implications of that and what that means, the study does suggest a strength of the rotations is that you have. More efficient niconutrient cycling events happening. Mineralization was occurring at a higher rate in the uh rotated fields compared to the continuous rice fields. And so, you know, if you wanted to, we also did see a pretty distinct increase in rice yields coming out of rotation. And that could be an effect of the weeds support that the rotations were having, or it could be an effect of the nutrient cycling support that the microbes were providing, probably a combination of both, you know. This project brought up more questions than solid answers, as any good research will do. And for me, a part of that was well, what would happen later on in the time series in the rotation sequence? So at the time of coming out of rotation, we saw this shift in microbes, right? Actinomyocedes are really helping with cycling your nutrient level and breaking things down, but you're also getting a dearth in your labile carbon pools and your retention of nitrogen overall because you're cycling it through. But what happens like three to five years down the line when the rotation has been in rice for three to five years? Do those pools recover in some way? Is there this kind of like push pool lever effect that happens in a rotated field in terms of nutrient cycling that may be a little bit more sustainable than just saying, oh, you're gonna have a reduction of carbon and a reduction of nitrogen compared to your continuous race fields? You know, those were kind of questions that came up out of this. Generally, you know, continuous race fields are going to have some immobilization issues, and there's a lot of work from, I believe, Bruce Linquist's lab that's talked about this. And so the rotated fields might perform better because it doesn't have those immobilization issues. But as far as climate mitigation is concerned, if you just take it from the standpoint of what you sample from, you're losing that carbon day, which is affecting a lot of different things. So I know that wasn't like a direct answer to like how does rice straw affect microbes, but it's just like the microbes are an indicator of so many other things, you know? And so it's more like how does the rice straw affect all these other things? I hope that was kind of a a good way to think about that.
SPEAKER_02:Absolutely, absolutely. And it's it's not just that we're interested in the microbes for the microbes' sake, but they are, I guess, an indicator of all of that's going on underneath the soil surface. And so it's it's been such a treat to read this, honestly. One of the actually, I copied this down because I was really interested in it. It's one of your final remarks on the results of the study. And it's and I'm gonna quote this while soil microbial biomass was similar among cropping systems, microbial communities under diversified rotations trended towards higher bacterial abundance associated with mineralization processes. And I feel like that really sums up what we've talked about here today. I I think probably one of the coolest things I've read coming out of this paper, and I don't want to take all the time to talk about it. This is your project, but any anything here you want to add on this?
SPEAKER_04:Well, I think that was a very concise way of saying what I was, you know, trying to articulate. And and yeah, I do think that was a really cool finding that came out of this project. You know, there's so much more depth that can happen in any any one, any number of the dimensions that were analyzed in this paper. And that's one of the strengths of this paper is there's a breadth of knowledge here, and then one of the weaknesses is that it is, you know, it's a breadth, not a depth. So, you know, so much more work that that needs to be done.
SPEAKER_02:Well, and since you're in extension yourself, I am gonna ask you these results, how would you say they might apply to growers or producers or people who are interested in crop rotation?
SPEAKER_04:I would suggest, you know, looking at this as a body of knowledge that can display benefits and trade-offs. It's not like a best practice approach, it's not like do the study and then say the best management practices therefore are two X, Y, and Z. This is more of a displaying all of the like the benefits of this type of system and the relevant trade-offs of this type of system, and all of the benefits of continuous rice systems and some of the trade-offs of that system. And then as a grower, you can be informed and make decisions based on your your own personal sustainability goals of what you might want to do to, you know, improve upon sustainability outcomes. Um, I understand and knew growing into this project that rotations for rice growers in Sacramento is not a it's not something that's going to become common and it's it's not a super feasible practice. But you know, in our changing climate and in our changing environments, um having a tool belt that allows you to adapt is really important and um rotations are just one of them among many.
SPEAKER_02:Well said. Well said. Well, with that, Sarah, I just want to ask you, well, first, thank you for your time and ask you if there's anything you'd like to share concerning your program or your work here with our listeners.
SPEAKER_04:Well, if you want to follow my program easily without much need for like deep diving and reading right now, you can follow us on Instagram and Facebook at BCCE Regenerative Agriculture. And uh that's gonna give you some good highlights under the different projects that's going on. I'm really excited to see uh the research unfold in some of the arenas of integrative livestock management and tree crops in the San Jacobin Valley. And while I don't have anything firm to share with you, following us on Facebook is definitely a good way to see how that that carries out. We do have a lot of really fun events up in the foothills in Mariposa. If anyone is interested in learning more about the type of ad that's going on up here and the local food systems that are growing out in this region as well. So yeah, that's that's the best I can give you right now. UCCE regenerative ad, follow us on Instagram and Facebook.
SPEAKER_02:Serious being modest, but absolutely I've been watching their work there and especially the venture that they put forth about a month ago with the agro-tourism, that was really impressive to see. So please stay tuned, go check out that. And if you're in that area, if you're touring around Yosemite, come on by. Oh man. Well, Sarah, thank you so much for coming back on. I know this is no longer technically in your program area, but we really appreciate you taking the time to talk about the time you spent with us up here in the North region. So it's really a treat to see you again.
SPEAKER_04:Thanks, Sarah. And I do have one more small announcement that I totally blanked on, which is the third aspect of this dissertation work will be published quite soon. And that is an entire paper on the economics of proper teams with race systems. So that's the third lens of this project, right? And that looks at comparing a rotation over a period of 15 years to continuous race and looking at profitability outcomes. So stay tuned for that, I suppose.
SPEAKER_02:Yeah, we're definitely going to please beg you to come back on to talk about that when that comes out. We're really excited about that one. Great. Thank you so much for your time, and we hope to see you again soon. All right, thanks, Sarah. Take care of the question. We will be holding an IPM Rice Workgroup meeting concerning drip irrigated rice and tomato rotations on December 12, 2025 at the UCCE Sutter Yuba office in Yuba City. The time will be from 9 a.m. to 12 p.m. and lunch is included. All are welcome for this meeting. We are soliciting feedback, experiences, and opinions about rotating rice with tomatoes, with a focus on drip irrigating rice. As lunch is included, we would like to encourage people to register for this event in advance. The registration form will be available in the show notes, as well as available at the UC Rice website, which is agronomy-rice.ucdavis.edu. Hope to see you there on December 12, 2025 at the UCCE UPA Center office, 142 Garden Highway A, Uba City, California from 9 a.m. to 12 p.m. We've also got a bunch of save the dates coming up, so bear with me as I read through these. We're gonna call these save the dates because we are still finalizing the locations for these meetings, but once we have that information, it will be available on our UC Rice website. We have announced the dates for our UCCE Winter Grower meetings. And the first meeting as a reminder, these are five meetings across a stretch of three days. Two of the days will have two meetings, one in the morning, one in the afternoon, and the final day will have just one meeting. So the first set of meetings will be the Richvale and Willows meetings, and those will be Wednesday, January 21st, 2026. The next day, January 22nd, 2026, which is a Thursday, will be the Calusa and Yupa City meeting. The final day of our meetings will be Woodland, January 23rd, 2026. As a reminder, do not go to every single one of these, pick one, whichever one's the most convenient for you, and attend that. Hope to see you there. And as a reminder, as we firm up locations, that information will be available on our UC Rice website as well as sent out in our mailing lists. We also have some events that are further out in our calendar, and one is the rice production workshop, which will take place March 18th and 19th, 2026 at the Lundbergs in Richvale. This is a two-day workshop and registration will be required. This is a meeting that's devoted to the basics of rice production. Our final Save the Date will be the Rice Quality Workshop, which will take place July 30th, 2026. As a reminder, if you're interested in learning more about any of these events or save the dates, they will all be posted on our UC Rice website, which is once again agronomy-rice.ucdavis.edu. For more information about these and other upcoming events, feel free to check out our resources, which include the UC Rice blog and the UC Agronomy Rice website. In terms of other resources you might want to take advantage of, you can also look at our newsletters, which include Rice Briefs, which covers Clusiolo, Rice Notes, which covers Jupister, Rice Leaf, which covers Buton Glen, and Field Notes, which covers rice in the Delta region of California. Thanks for listening to Thoughts on Rice, a University of California Cooperative Extension podcast from the University of California Agriculture and Natural Resources. You can find out more about this podcast on our website, thoughtsonrice.bugsprout.com. We'd love to hear from you, whether it's from using our text link in the show notes, a survey submission in our feedback form, also in the show notes, or in a comment or rating in your podcast streaming service of choice. We are excited to announce that after several months of trying, we are finally on YouTube. So if that is your podcast streaming service of choice, you can now listen to us on YouTube. You can also email us with any comments, questions, or concerns at smarchuanr.edu. For almost all of us, rice harvest is finished. Fields are flooding up, and the migratory waterfowl are beginning to arrive. Remember, like the growers like to say, have a rice life. Mention of an agrochemical does not constitute a recommendation, merely the sharing of research findings. Always follow the label, the label is the law. Find out more at ipm.ucanr.edu. The views, thoughts, and opinions expressed are the speaker's own, and do not represent the views, thoughts, and opinions of the University of California. The material and information presented here is for general purposes only. The University of California name in all forms and abbreviations are the property of its owner, and its use does not imply endorsement of or opposition to any specific organization, product, or service.
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