A laboratory founder discusses the importance of testing and how carbon was forgotten in the NPK revolution
David Knaus is the founder and president of Apical Crop Science. Apical is a regenerative agriculture consulting service that assists farmers in developing non-toxic production systems and in transitioning to organic production.
David spent about a decade working on and managing organic farms before beginning to teach agriculture and horticulture at the university level. He founded Apical in order to help growers improve crop quality and nutritional content and to minimize the amount of harmful chemicals in our food systems — all with the purpose of feeding people healthy food.
Acres U.S.A.: You’ve spoken at a couple Acres U.S.A. events lately; how did those go?
David Knaus: Really good. I just got back from Wisconsin the other day. It was really nice to go and see Gary Zimmer and his farm and to get to take in a little bit of the local charm up there. It’s a really pleasant place to be this time of year.
And then Sacramento [the Acres U.S.A. Healthy Soil Summit] was a lot of fun. I got to see a lot of people I haven’t seen in a couple of years, since COVID. The conference was really well attended in terms of the knowledge base — the level of knowledge and the skill set that was included at the conference was quite high. It’s been a fun month getting to go to a few Acres U.S.A. events.
Acres U.S.A.: That’s great. Is most of your business on the West Coast?
Knaus: On the lab side, we accept samples from across the country and seven or eight countries internationally. On the agronomy side, we mostly do consulting locally and on the West Coast.
Acres U.S.A.: What’s your background? Are you an agronomist by trade or more of a lab scientist?
Knaus: I’m a certified crop advisor. I spent about 10 years teaching agriculture at various colleges. And prior to that I had approximately 10 years of organic farm management experience as well. I did a lot of farm management when I was really young, and that was a lot of fun. I continued to teach as an adjunct all the way up until COVID. We started Apical in 2017.
Acres U.S.A.: What kind of operations did you work on?
Knaus: Organic fruit and vegetable farms primarily, in the Oregon-Washington area and a little bit overseas.
Acres U.S.A.: And where have you taught?
Knaus: I taught for Pacific University for a number of years, and for Willamette University — as well as Clark College, in their horticulture department. And then I worked closely with Washington State University Extension for about four years developing a number of different small farm programs for them. That was a lot of fun. It exposed me to a lot of different farming systems and cropping systems — the nexus of production agriculture, where academia and the government get involved in terms of technical support.
I’ve been really fortunate to have had a lot of experiences that were really supportive — through universities and various programs. All government agencies and universities — large organizations in general — have limitations of scale. My personal experiences as a grower and as a farm manager, combined with the academic experience that I had, made me acutely aware that there are a variety of ways to farm that work.
I left the college and moved on to start Apical for a combination of factors. One was marketplace demand. Two, the ability I thought we had to make an impact. And three, I would say also just my own personal interest in having a larger footprint in agriculture from a long-term perspective.
Acres U.S.A.: Apical has a lab testing side and then an agronomy consulting side. On the lab side, are you doing leaf tissue tests and soil tests as well as the leaf extract tests?
Knaus: We do. Our version of the plant sap analysis, which we refer to as leaf extract analysis — it’s our own method that we’ve developed from the ground up. I was personally researching and developing it with a number of interested parties all the way back to about 2013, and we released it commercially in 2017. Then in 2018 we released our proprietary soil analysis method as well.
To develop those two methods, we went through a number of different trial and error periods to see what was actually making an immediate impact on the plants and crops — to allow growers to make positive adjustments in real time. We started with the plant analysis method and then worked our way back to an accurate soil method.
We’ve found plant sap analysis information in the academic literature dating all the way back into the 1920s. So we don’t necessarily consider plant sap anything new — it’s just the way that we’re optimizing it and using the data itself. In every step of the process there are things that we’ve thrown into the mix that we feel provide value. So, the time of day of sampling; how samples are taken; how they’re preserved in transit; how they’re preserved; once they get to the lab, the extraction component; how the extraction component is turned into viable data through analytical methods, and so on. And then how that data is delivered to the grower — how that data is utilized in terms of providing recommendations, from the short-, medium- and long-term perspectives for the grower.
Every step of the way there’s been further engineering that was needed. Looking back through all of the literature, there was a framework, but it needed to really be systematized into a way that could be accessed for your average grower to have repeatable results.
Acres U.S.A.: What’s keeping growers from using sap analysis? If people are reluctant to do it, why are they reluctant?
Knaus: I don’t necessarily see a lot of folks being reluctant. We definitely see it as a growing tool.
But why is it not the dominant test? Number one, the tissue analysis that was developed in the mid-60s and 70s and was popularized in the 80s and 90s was all about standardization — how to get standardized results for standardized varieties. Sap analysis was actually developed in tandem with tissue analysis. But tissue analysis started to dominate in the 60s and 70s due to standardization protocols. At that time, it was just easier to do a standardized method.
Today we’ve developed a standardized method for sap analysis, and a few other labs across the world have done the same thing. But the sap analysis method that we are now using is much more geared toward customization and variability and outcome driven in the field. In other words, we’re not looking to standardize nine different types of blueberries to one tissue analysis methodology. We use sap analysis to pick up the strengths and weaknesses of each one of those varieties in a plant-soil environment.
Acres U.S.A.: Was the technology even there in the 70s and 80s — the ICP [inductively coupled plasma mass spectrometry]?
Knaus: Some of it was, but there were some limitations. Mass spectrometry methods have evolved over the years. We’ve been able to get down to lower and lower detection limits and to analyze more elements in tandem. Those are some significant advancements that had never really been applied to plant analysis, or raw analysis of plant fluids. That really hadn’t been done on-scale in commercial applications. There’s just a handful of labs around the world that are doing similar things in the past 10 or 15 years.
Acres U.S.A.: The consulting side of your business — what does that look like?
Knaus: Our consulting is primarily lab based. We do support a lot of other agronomy firms — a number of independent consultants. Personally, I do have a large array of long-time clients that I’ve served here locally for quite a few years.
And then we do a fair amount — a growing amount — of work with larger-scale firms — consulting for them on the lab side and then working with their in-house agronomist. We help them to develop regionally appropriate customized crop plans with customized crop inputs that we determine from looking at their data over the course of six months to a year or so. So, we’re engineering these regenerative agriculture systems from a pretty high level, which is really exciting for us. We can approach, for instance, the California almond market or the Pacific northwest apple market, or our regional berry markets, from a fairly high level using the expertise and partnerships that we have in the marketplace.
Acres U.S.A.: Can you go through some of the nutrient interactions that you’ve observed through testing? It seems like it’s often nutrients that are in excess that are tying up other nutrients.
Knaus: Sure. It’s interesting, because if you really dig through the academic literature — if you dig to the very bottom of the barrel — you’ll see that across the world — and I’m slightly over-generalizing — that loose soils are generally limited by too many salts, and in heavier soils your limiting factor is mostly aluminum — too much aluminum.
When we first got into doing plant analysis through leaf fluids, we didn’t really understand what we would end up looking at — we didn’t know what the data sets were going to be. Our first foray into it was very limited in terms of number of analytes. We were looking at pH and Brix and sodium — maybe some calcium numbers and things like that. It wasn’t until we really started digging into the full data set that we started to see these commonalities pop out — which revalidated some of the academic texts.
So, salt is an issue in light soils, but then there’s a whole plethora of situations where regionally, for example, there’s an over-application of one nutrient — nitrogen, or phosphorus, or calcium, or sulfur, or whatever it might be. And that’s causing larger bioregion-specific problems.
You have to take a step back when you start looking at those sorts of data sets. It circles back to what we do as a company — we’re really trying to work through these regenerative systems at a fairly high level with our partners in these locations.
Acres U.S.A.: I grow in a sandy loam; why is it that I would tend to have excess sodium?
Knaus: It goes back to the parent material of loose soils versus heavy soils — how that breaks down into soil texture. Sand, silt and clay make up the physical, chemical and biological balance of soil. Heavier soils have a tendency to actually hold a lot more soluble organic matter in the soil structure itself — between the clay particles.
We’re getting ready to release a soluble carbon test on our soil analysis. We’ve been testing soluble carbon on clay soils versus, for instance, potting soils — which have a large amount of non-soluble carbon but very little soluble carbon. In a sandy loam soil, there’s even less soluble carbon. Carbon is what drives organic farming. It’s really the missing nutrient in terms of plant growth.
Carbon was forgotten in the NPK revolution. Now it’s the thing that people circle back to from one way or another — through humic acids or fulvic acids or some other form of carbon-based crop input. Then all of a sudden you get these great plant responses, and it allows the plant to develop higher-level molecules and plant defense compounds and deeper root structures — a whole host of benefits.
NPK systems are not engineered to produce foods that have those higher-level compounds in them at all. Carbon has been forgotten; the soluble carbon is not there. And the excesses have a tendency to dominate, in a regionally specific way.
That used to be addressed a little bit with regional soil testing labs, but over time the soils have been depleted. And that really puts more and more pressure on these regional soil testing labs. Growers just aren’t getting the results that they want; they’re continuing to use the regional soil method — which maybe once had a really good basic framework back in the 60s or 70s, but now the soils have been depleted, and so that method is continuing to produce results that require an increasing amount of pesticides, or genetic modification — or that aren’t capable of supporting as many crops per region economically.
The NPK methods were developed in tandem with soluble conventional fertilizers, so the analysis methods match the system itself. It’s only as carbon has been depleted that the system has become unsustainable, or uneconomical in certain ways — or has other externalities.
I think that system probably could have worked 50 years ago if carbon was included with NPK. But it wasn’t, and so the massive amounts of NPK have depleted the carbon from the soil. So now, when guys are adding carbon back into the soil, they’re seeing a really nice, visual plant response. But that doesn’t necessarily build the framework for the entire regenerative space. What we need is a laboratory whose methods are appropriate for the type of growing we’re trying to achieve.
So that’s the basic thesis behind Apical — it’s what we’ve been working out since inception. We’re really lucky to have some really strong advisors and partners who have worked with us, from a scientific perspective, to take what we identified as limitations and work step by step backwards from an analytical method to say, “This is a method that’s going to give us the right outcomes from where we are today.”
Acres U.S.A.: Do you have a basic recommendation or process for dealing with excess?
Knaus: We do. We have some pretty straightforward protocols nowadays for dealing with excesses in the plant, and also in soil environments. Every plant-soil environment is completely different. We offer detailed recommendations on any sap or soil analysis, and the interesting thing is that the more you test, the more progress you’ll make. If you do a sap analysis, you’ll have decent results, but you’ll probably have even better results if you do a soil analysis too. But then sometimes that will still leave questions, and that’s where you can go to a water test, and then all of a sudden everything makes sense, because maybe the water is full of a toxin or something.
From a methodological perspective, we have the ability at this point to address pretty much any excess. How that unpacks for the grower can be tricky. The excesses in water are definitely the hardest to solve. Soil would be second and the plant would be third. There are differences and nuances with every farmer and soil type and even delivery method of fertilizer — the equipment and applications the grower can manage and their appetite for dealing with rock powders or bulk humates or bulk soil amendments. Budget is a huge factor oftentimes. Or if they’re going for organic certification. Each is a different layer that needs to be worked through in order to get the appropriate outcome. That’s really what we’ve tried to build with Apical — a system that’s flexible to handle the challenges of modern agriculture, but also extremely precise and that can move the needle.
You can run a leaf test, get a recommendation, make an application, and see visual response in seven days. That’s tough to do with shipping, but we’ve been able to achieve that on a pretty repeated basis now, which is really exciting. A lot of the growers we work with have those types of experiences, and that just snowballs and gives them confidence to either transition more acres to organic or start using less nitrogen or adding more carbon. The outcomes really have a way of evolving on their own, once they have some really good results from an analytical perspective that’s driving it.
Acres U.S.A.: Do you make a lot of recommendations for foliar feeding as opposed to soil feeding?
Knaus: It depends on if the grower is looking for a recommendation from a soil analysis or a leaf analysis or a water analysis. If it’s a leaf analysis, and the grower orders recommendations, they get a liquid foliar and a liquid soil application to make an immediate plant impact. If they send in a soil analysis, they get a long-term soil-building recommendation as well as a short-term, immediate-impact soil-building recommendation — put on a half-ton of lime or 500 pounds of biochar or something like that. And then the liquid application is four quarts of potassium and three quarts of carbon — something like that.
Water recommendations are the most nuanced, because oftentimes you’re dealing with a system that’s pumping ounces or pounds of a potential toxin on a day-to-day basis into a system. Those need to really be worked through over two to three months, but generally, when we make a base recommendation from a water analysis, we’re addressing whatever the base toxin is. It might be, say, to apply two pounds of raw carbon per week or one pound of phosphorus per week, in order to deal with excess iron in the water, or aluminum, or something like that.
We try to make the recommendations as potent as possible and as real-time as possible, because we know that every dollar counts for growers. They have to move the needle quickly as soon as they start doing anything organic or regenerative, because there’s apprehension, for a lot of reasons, with organic and regenerative growing. The solutions that we present have to be successful — otherwise we’ll lose the opportunity to make a positive impact for these guys.
Acres U.S.A.: No pressure!
Knaus: Well, you talk about pressure — we’ve had some really extreme case studies over the years where a lot of chips were on the table. We’ve been working with a lot of bonsai growers, which has really pushed the boundaries and the limits of what sap analysis could do. There’s a lot of limitations in the bonsai community. We’ve basically hammered out basic organic, regenerative bonsai cultivation methods with some of the more aggressive bonsai cultivators here in the Pacific Northwest.
Acres U.S.A.: That’s fascinating — specializing in providing support to bonsai growers.
Knaus: It was the most random thing. We got an emergency customer who said he had some major issues — his garden is extremely valuable, and he didn’t know where else to turn, so he came to us and we worked with him for about a year and basically remediated his garden, which is worth millions of dollars.
That’s just one non-crop example. But on the crop side, on a daily basis we’re working with either our local customers or other agronomists from a distance who are dealing with very acute issues that affect growers’ dollars and cents — their livelihoods, the viability of their farm long term — with all kinds of different issues. It’s really remarkable the pressures that are being put on agriculture right now. There are a lot of tools out there to help them, but it does take a lot of energy to make sure that things go right and that we all have healthy food to eat.
