BONUS: Regenerative Farming, Irrigation Efficiency, and Agroforestry Tips from Kevin Rost

After wrapping up Episode 284 on SGMA, Kevin Rost (Apollo Ag Technologies) and host Craig Macmillan kept the conversation going—and it was too good not to share. In this bonus episode, Kevin dives deeper into the benefits of maintaining irrigation distribution uniformity, selecting cover crops based on grower goals, and how agroforestry and silvopasture can revolutionize water retention and soil health. Learn how regenerative practices can reduce water use, pesticide inputs, and fertilizer needs while improving soil biology.

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Transcript

[00:00:00] Craig Macmillan: So you've talked about different technologies. I'd like to hear more about that in terms of technologies for water savings and, and improving quality and, and taking care of your farm, basically. Tell me more about some of those things.

[00:00:12] Kevin Rost: Yeah, definitely Craig. So, you know, when I, when I do like a discovery on a farm and, and kind of just focused on water usage, , there's some main parameters I'm looking at that cause me to overuse water. Maybe just be inefficient at different phenological growth stages of my crop.

[00:00:29] You know, I'm looking at , the irrigation system itself. , When a manufacturer installs an irrigation system, let's say double line drip or micro sprinklers, and an orchard, for example, that system is gonna have. On the specifications, what we call a distribution uniformity percentage. So at install it should be 85 to 95%.

[00:00:54] I think it's very imperative that my system stays at that manufacturer install specifications, the duration of its life cycle, because it's, if I start decreasing my du over time, I'm gonna be running my pumps longer. Crop performance goes down, nutrient uptake goes down. All those things start to subside, and it's all directly re related to the system performance.

[00:01:18] Keeping that system absolutely as clean as possible is important. That's done through periodic flush outs, whether it's manually or chemically. That's something I specialize in. So we wanna keep that system running at manufacturer specs.

[00:01:34] We also want to, you know, be able to, like you asked earlier, monitor water levels, monitor flow rates.

[00:01:40] It's not just to record how much water I'm using, but to to gauge the performance of my system. And like I said, like I always said, I want my entire system from the well to the filter station down to the last emitter running at manufacturer install specs because that is the most efficient way it was designed to run. And anything less than that's gonna cost me more money.

[00:02:02] Craig Macmillan: How difficult is it for a grower to perform a basic distribution uniformity for themselves? Or do they need to have somebody from the outside come in?

[00:02:09] Kevin Rost: I think any grower can do it. Definitely it takes time. There's a lot of resources, including myself that'll come out and do one for free. So I know the uc they have programs to do very thorough DU exams for free. So I, I would look for those resources, contact me, I can help with that , or get you in the right, right place to do that.

[00:02:27] Let's say our drip tape out, there's Netafim, Netafim, iss a good manufacturer. They recommend flushing your system every 200 to 300 hours of use. So it's like changing the oil in your tractor. You're just not gonna let that go, you know, blow a turbo or something. It's the same concept. So that's the system itself.

[00:02:42] There's plenty of ways, whether you're dealing with algae or bicarbonates that's plugging up your system. Maybe it's nutrient usage over time that's plugging up your system. It's everywhere. It happens everywhere. It's just natural for that drip tape to get plugged up with something, you know?

[00:02:56] So we got, you know, different techniques, organic, non-organic chemicals. There's a, there's a lot of opportunity to flush that system out and to maintain it, to keep it clean, the duration of its life. So that's sort of the system there, you know. Then the next step I like to look at is the water quality.

[00:03:11] What type of water are we using? What risk does that water pose to efficiency, whether it's plugging up the system or plugging up my soils, for example. You know, if I have really high salts and bicarbonates, I'm probably gonna be using a lot more water. Yeah. I'm gonna have to have like a 30% leaching infraction to push the salts out of the soil.

[00:03:30] Well, you know, like here at Apollo we specialize in soil remediation. We can help mitigate that and if not, eliminate salt and bicarbonates in the water, in the soil, which over time also allows us to be more efficient and use less water. Just meet the crop's demand. That's kind of what we're after looking at soil chemistry.

[00:03:48] I, I personally specialize in regenerative agriculture. That's my passion. So I'm always trying to do a lot more with nature and a lot less with inputs. And so I've been doing cover cropping for over 12 years now. Multi-species cover crops, anything from a four species to a 18 species cover crop, depending on the goals.

[00:04:08] Primarily a lot of, for me, it's been building organic matter and reducing things like sodium and chloride and bicarbonate in the soil , through annual and pre annual. Cover crop rotations, and there's a lot of strategy. We get really scientific into that. But ultimately, what we're trying to achieve there is better water holding capacity in the soil and better infiltration rates in the soil.

[00:04:31] I have an example. I have a, an a's a 5-year-old pistachio orchard now, I helped develop and plant that orchard, it was walnuts. Previously conventionally grown walnuts . We tore those out, planted pistachios, and from day one, I had a cover crop in that orchard.

[00:04:46] And still to this day, it's been five years. We have not put down any fertilizers. We haven't done one pesticide spray. And I have documentation that we've u we're using 30% on average, less water than the industry standard or industry uc recommendations. We've improved the water holding capacity of the soil.

[00:05:06] Craig Macmillan: soil. You, you, you mentioned like different types of coverage for different kind of goals. I would really like to hear more about that. So you've got water holding capacity, you've got infiltration, you've got probably fertilization in terms of having some legumes in there. Tell me about some different styles or different kinds of mixes and what they are appropriate for or what cropping systems they work best in.

[00:05:29] Kevin Rost: Yeah, I would definitely, you know, be wanting to meet with a, you know, a cover crop specialist or an agronomist that, that's in the cover crops. For that, we like to look at the water and the soils. Typically I'll set like four main priorities. Let's say it's salinity management,

[00:05:45] let's say it's also. It's Building organic matter in the soil, for example. You know, so I take my top four priorities and I, I have some tools that I use, like there's a tool online free resource called the seed calculator. And so when you set your priorities in there it's gonna give you species of cover crops and then we have local experts as well that are, you know, far greater than the calculator at this. But it's gonna give you species that target that. Specific things.

[00:06:14] What recently we've gotten even more advanced in that we're doing, like in orchards for example, we're doing a specific blend. So , growing plants like clover for example, that don't grow very high, we're using those on the berms, you know, 'cause we, we don't want to have to use a ton of herbicides or try to. Control the, the vegetation around the emitters and stuff like that. So using prostrate, really low growing cover crops on the berms.

[00:06:38] And then, you know, I like to focus on personally in the, in the center rows, you know, closer to the berm, let's say. You know, things that are, have an aggressive tap root, for example.

[00:06:49] I'm really focused on what's happening below the soil. So if I can get things to grow downward, I'm creating a lot of variation and microbial activity in the soil downward, closer to the berm. We can look at species that are gonna grow laterally to provide. You know water and nutrient movement towards the berm and towards the root zone of the plant, they then you have different, different thought patterns around management.

[00:07:12] You know, it does pose a different set of management when you're, when you're growing cover crops versus controlling weeds, for example. Like in a pistachio orchard, I'm looking for species that won't grow taller than the bottom of my canopies. Because I'm hosting bug pressure in there as well, both beneficial and pest.

[00:07:29] And so, you know, if I can keep it below the canopy, then it's not as big as a management threat where I gotta go in there and mow it. You know, I wanna keep it growing as long as possible. And then, you know, when I go in there to chop it, for example, I might leave 10 to 14, 18 inches of the, of the cover crop.

[00:07:46] I don't chop it all the way because I want to keep stimulating root growth below. It's really about what's below the soil. But even recently, I've, I have where I'm doing on like say the first five outside rows of an orchard, and then every fifth row in the orchard, I'm doing specific cover crops, like anything with a yellow flower.

[00:08:03] For example, mustards and stuff to, to act as sort of a catch crop for my beneficials and unwanted pests. And we've seen reduction in sprays definitely, you know, drastically by doing that. I'm managing 500 acres of pecans right now in Visalia. And there is no budget for a cover crop there, but I just let the weeds grow.

[00:08:21] I let the weeds grow. I just cut 'em a couple weeks ago and I skipped two aphid sprays. From, you know, what's typical in that pecan orchard? I've skipped two aphid sprays. Now, once I cut my, my, what I call a cover crop, it's weeds, but I, I like it, it's a cover crop. Once I cut it, I had to spray for aphids, so it's an example of how keeping the. The bugs in the catch crop, you know, can benefit the, the system as well. It's kind of an endless list of species we can choose from, but basically we have four categories of cover crops and we, we want to choose some species from each one.

[00:08:56] Craig Macmillan: What are some examples you mentioned? Mustard is one that's got a nice tap root. Now it's also a trap crop, which is pretty cool. What are some examples of like the lateral growing root systems? What's, what are some other examples of the tap root type or trap crop type? What, what specifically are your, like your favorites?

[00:09:14] Kevin Rost: Yeah, we're using a lot of like fava beans you know, different types of beans and peas, even snap peas, for example, sugar peas, hemp, summer hemp. Can be really good. Vetch is a good one there. There's a lot of different blends and like guys like Silas Roso for example, at California Ag Solutions in Madera.

[00:09:33] They've got it dialed in, you know, specific to your crop, your soil type, your goals, and your water quality. So we're getting really specific and then what, what we like to do is like, you know, you plant a cover crop, there might be some species that don't perform very well. So what we're gonna do is take those out and replace 'em. We look for the ones that naturally want to be in that environment.

[00:09:53] Craig Macmillan: When you talk about regenerative ag, are you including animals in your system? Do you have sheep or goats or anything grazing?

[00:09:59] Kevin Rost: A lot of growers are. Yeah. We're seeing sheep and goat grazing for sure. Mm-hmm.

[00:10:03] Craig Macmillan: are you a fan?

[00:10:05] Kevin Rost: I am a fan. Yeah, I am. Yeah, I know, I know. It's been challenging getting the sheep and the goats 'cause there's a lot of guys doing it now. But. I think there is some huge benefits to it as, yeah, definitely if you look at like permaculture or agroforestry, for example, civil pasture.

[00:10:19] If, if anybody's heard of that you know, yeah. Rotating animals in the system is, is definitely part of what nature does already. ,

[00:10:26] Craig Macmillan: Let's go back and touch on that. Tell me a little bit about Agroforestry and Silva Pasture. 'cause those are concepts that I think are not super widely known

[00:10:34] Kevin Rost: yeah.

[00:10:35] Craig Macmillan: I think they're gaining, I think they're gaining some momentum from folks that I'm talking about. Tell me a little bit about what those are and what the benefits are.

[00:10:42] Kevin Rost: That's really exciting to hear you say that because I don't, I, I've been talking about that for a while and I've never heard anybody that even knew what it was. So that's really fun to hear you.

[00:10:51] Craig Macmillan: WW we interview a lot of people, Kevin.

[00:10:54] We talk to all kinds of people on this, on this podcast.

[00:10:57] Kevin Rost: gonna have to find that episode, man. That's exciting. Yeah. Yeah, I love agri forestry. It's something I'm personally study. I'm a, I'm a certified agri forest designer. , I like to say it like this, you know, if we drive up the mountain we go up to our favorite you know, mountain range or snow park or whatever, right?

[00:11:13] I get up there. I, I've done this so many times. You know, even in the mid-summer you go up into the mountains, right? When everything starts to turn green and lush and you get out and just kind of like go, go to the soil and pull back all the mulch and debris from the, from the forest canopies. And I don't care how deep you dig down, that soil's gonna be really moist, really carbon rich and cool to the touch, even cold.

[00:11:38] That's the kind of the thinking of agroforestry is like. Who is up there irrigating all year long? Who's up in the mountain range or the forest fertilizing the orchard floor? Nobody, right? It doesn't exist. We don't need to irrigate it. And so you come down into the valley and you see a bunch of bare dirt it's just scorched earth in essence.

[00:11:59] The soils are pulverized. They're really dusty, they're really hot. And so we, we have to continuously water, water, water, water, water, because. We're trying to supplement for evapotranspiration

[00:12:11] Craig Macmillan: supplementation,

[00:12:12] Kevin Rost: know, up there on the forest floor, that's not, that's not necessarily the case. What annual rainfall it gets up there is quite sufficient to sustain annually.

[00:12:22] And so in agroforestry, we're trying to mimic that. We're trying to add layers into our, our farm situation and mimic what the forest nature already does. So you have tall trees, mid side trees, you have. Smaller trees, bushes and shrubs down to your ground vegetation. And if you get really strategic about that, what happens is just like the forest at all different times of the season, you have leaf fall.

[00:12:48] , And decomposition and different types of litter hitting the floor, which creates a layer of natural compost and natural soil retention, soil moisture retention, soil temperature, retention. I've seen, I, I love to take, do this. I take like a infrared heat gun. Out into an orchard setting or a tomato farm, for example.

[00:13:08] And, you know, you could test soil in the furrow or in the middle of the, the orchard floor compared to where there's weeds or where a tomato canopy is growing over the soil. It's night and day difference. In an orchard where let's, let's say pistachio orchards where it's clean, bare floors, it's spotless in there.

[00:13:26] Aesthetically it looks wonderful, right? And you, it's 105 degrees outside ambient temperature I've seen where that soil, and then you, I'm looking at soil moisture probes. The temperature readings that soil in the top 18 inches is 135 degrees. In 105 ambient temperature, whereas where you look at where there's a cover crop and it's 85, 90 degrees, so that, that adds a lot of benefit.

[00:13:50] Your microbials don't like heat. You know, there, there's one of the things I talk about a lot when we're battling salts is every time we dry down our soils in those bare soil situations, all those salts like to precipitate up and accumulate, and so the problem becomes worse and worse and worse. You know that's, so that's another reason why, you know, covering your ground floors is so important.

[00:14:13] But yeah, in agroforestry, we're, we're taking that a step further. We're building sort of that environment. I've seen studies like in subset Sahara Desert areas where those agroforestry systems, even a 40 acre system was actually creating its own micro climates and bringing in it in its own rain. You know, so we, we we're, I, I don't wanna say we're doing it wrong, but there's other ways to do it.

[00:14:34] And, and I think we can mimic that. Not only does it, it, it provide a healthier environment, but in an agri forest setting, we should be able to capture even more income streams as well, because what we're planning is not a monocrop. Everything in that crop, everything in that agri forest setting is gonna be usable and hopefully profitable to the farmer.

[00:14:54] Craig Macmillan: So you're actually planting trees in an orchard that are not crop trees.

[00:15:01] Kevin Rost: Correct. And we do see that. You see growers who have been practicing agro force techniques, maybe they don't know that's what it is, but we see hedge rowing, for example, hedge rowing to block out winds or you know, unwin. Contaminated dirt, different things like that. Those are all agri forestry techniques.

[00:15:17] Yeah, you can use hedge rows. I see hedge rows all over with different types of trees or oleander, for example. You see a lot of that around the valley. But yeah, that, those are kind of, ain't even cover cropping, but those are basic agri forestry techniques. You really need to somehow create an environment where it mimics the forest, for example.

[00:15:36] Craig Macmillan: I'm just, I'm trying to envision a pistachio orchard with another type of tree planted in.

[00:15:42] Kevin Rost: Yeah, we haven't seen that yet.

[00:15:44] Craig Macmillan: Okay. Okay. There.

[00:15:45] Kevin Rost: we haven't seen that yet.

[00:15:46] Craig Macmillan: All, okay, that makes sense. All right.

[00:15:47] Kevin Rost: The reason I really got into the Agri Forest. Kind of concept is because, you know, years of going to water compliance meetings, and then most recently I sit on the Tulare County Board of Supervisors Ag Advisory Committee.

[00:16:01] The hot topic right now is alternative land use 'cause SGMA is causing farms to, to not be able to farm anymore, especially small and mid-size farms. You look at Tulare County, our board of supervisors is anticipating that by 2030. We'll lose 50% of our farmland in Tulare County permanently retired.

[00:16:21] Craig Macmillan: Wow.

[00:16:22] Kevin Rost: So this is the first time we've had the actual board of supervisors sitting on the Ag advisory committee because obviously that's a huge impact to Tulare County. Right. And so alternative land use, that's the hot topic it keeps coming up. I forget his now. I was gonna say John Doherty, same thing.

[00:16:37] He had a big talk at the water lines meeting about alternative land use. What are we gonna do with our land if, if it's zoned agriculture? It's zoned agriculture because of the soil characteristics. It doesn't matter what crop is available to it. It doesn't matter if there's water available to it that's not included in the zoning laws.

[00:16:54] The zoning law is protecting the soil. And there's some very strict laws that protect that soil, which means if it's zoned agriculture, you may not have the opportunity to build houses on it or have a developer do something with it. It has to benefit agriculture. And so we're, we're kind of in a scenario where we need to start thinking about alternative land use.

[00:17:14] Craig Macmillan: That's actually an interesting question. Are there crops. And let's a place like Tulare County, for instance or, or Kerns, another one I can think of. Are there alternate crops that might be better suited for the coming environmental stresses other than pistachios, almonds, stone fruit, citrus, things like that.

[00:17:38] Kevin Rost: That's kinda what I'm actively working on right now. Building scenarios out that, you know, is what can we look at that could potentially produce income for a landowner that you know, maybe is not traditional, it's not gonna be a monocrop system, obviously. Specifically what I'm looking at is that could probably survive on native rainfall only and no, you know, no substitute irrigation needed. So you know, that's not gonna be the same type of farming we're looking at now, where we have contracts with processors. I think it's gonna be more direct to consumer, direct to market type thinking, and at least from the research I'm doing. So I don't know, there's, there's probably an endless amount of species like I.

[00:18:18] Yucca plant, for example. You know, different types of oak that can be used for timber maybe, or it, it is gonna take some creative marketing and, and kinda looking back historically even into ancient farming practices like.

[00:18:32] Craig Macmillan: Mm-hmm.

[00:18:33] Kevin Rost: What worked before, what type of diets did we have before? What type of timber were we using?

[00:18:38] So that's kind of my objective. Personally. I wanna, I wanna get more involved in maybe not non-traditional contracted commodities, but there, there is a lot of species that survive in our climate with native rainfall.

[00:18:51] Craig Macmillan: that is really fascinating.