Episode 158: Reducing Weeds and Pests with Regenerative Mulching Systems with Erwin Westers

Hi, friends. Welcome back to the Regenerative Agriculture Podcast. This is John Kempf, and today I'm here with a guest who I've wanted to have a conversation with for a long time, Erwin Westers. Erwin, you know, it's so easy for us in agriculture. We all understand that we have our own unique local context, and our local context is different. We have to adapt practices from different areas to our own areas. But I've been really intrigued by the direction you've taken your operation and the number of practices that you've incorporated that I don't see quite often. I don't see very commonly in production scale agriculture here in North America. I don't see people spreading mulch on a scale of hundreds of acres, for example. So I've been looking forward to our conversation, to learning more about your operation and to seeing what we can learn from you. Tell us a little bit about your context and the scope of your operation, the work that you're doing today.

Yeah, thanks for having me, John. We have a biodynamic seed producing farm in the north of the Netherlands, all at the border of the sea. So we own a part of the dike that holds the Netherlands dry from the sea. And we own a part of land that is outside the dike, which is a salt marsh. And it is in that climate that we, we have developed a seed production system under biodynamic certification in which we try really to go some steps further in putting a lot of quality in the seed.

What are the various crops that you're producing seed for?

We are producing seed for potatoes, so which is a tuber, but it's a seed potato. We're producing for radish, for kale, for turnips, for nasturtium, a lot of wildflowers also, and lupins and a couple of others. And that ferries every year because we have a couple of seed buyers, some of them in the German part of Europe. So in Germany, Austria and Switzerland, two in the Netherlands and even one in North America.

You've mentioned a couple of pieces that I'm interested in. You made mention of trying to produce higher quality seed. What does higher quality seed look like exactly for you? What are some of the parameters that you're trying to achieve and how are you approaching that?

Yeah, if you buy a seed, most people look at the germination rate, and that is one of the most easy to research quality parameters of a seed. But figure is also one that most seed companies research, but they don't always put that on the label. And what we have seen is that by giving the seeds a very well life on our farm, they that the farmer or gardener that buys the seeds has a better plant the second year. And we have seen that too. And it was kind of aha moment, so to say it was 10 years ago, 2015, when we produced seed potatoes and we had of this one variety, not enough from one farmer. So we went to two farmers to deliver us the, which was in this case, a conventional untreated seed potato in the same amount, about three bags that we put on the same amount of land next to each other. And the seed potatoes were optically all the same, they were fine, they were without optical disease. And they were checked in the laboratory and the field was treated all the same. And then we, when we harvested, we harvest in crates. And I myself am on the harvester. I saw that the one part of the field where the other seed potatoes from the other farmer were used, there were much more rhizoctonia, the seeds on disease on the tubers. So these black spots which have to be thrown out, all because they damage the next sprout next year. And the yield was 25% less, which was just. And it's very easily because we could count the boxes and we just. There were 25% less boxes of that field. And I was like. So that farmer of who I bought these seed potatoes did something with that seed potato crop that gave me a better or a worse harvest. And if that holds true for a seed potato, which is a big storage canister of nutrients and it's got a lot of reserves. Yeah, but then that must also translate to smaller seeds. You know.

How. How do you measure vigor.

If you have. I think they do it. I don't know it exactly, but I think they do it like that. If you have different seed lots and you put them next to each other, you can clearly see what the difference is. And I don't know how you score it by then, but the one who grows really rapidly or develops best at the first two, three weeks, when most of the energy is coming still from the seed, that one, I think will have the most vigor.

I had an experience several years ago and I related the story, and I'm a bit fuzzy on the details at the moment, but a friend of mine purchased arugula seed from a mainstream seed supplier, planted most of what he had purchased and had some leftover. And that arugula seed that he planted, he harvested most of it, but some of it he let go to seed. And he had worked for years to build up his soil, to build up his soil microbiome and soil mineral balance. And he harvested seed from some of the arugula that he had planted. And he had much larger seed size. He had about a third of the seeds per pound as the original seed that he had purchased. And then he planted what he had left over side by side with his own seed for the next crop. And his seed that he had saved from the larger seed size reached harvest size 11 days earlier than the seed that he had purchased.

Yeah, I think I know who you're talking about. I heard the same story. And it's exactly that, you know, and we have that in, in, in a few cases only. There's only this one seed company that also lets us produce the stock seed. And that's nice because then we can also replant that as, how do you say, the next generation seed. And we see that from our own seed, which has had one year at our farm, does it much better the second year than the seed that we get provided otherwise. Which is also a problem with the big seed companies, that a lot of the stock seed is produced in greenhouses under very hygienic conditions because they're afraid for every kind of virus, disease, whatever. But that means it's. It's a monoculture always. It's a conventional managed crop.

Excuse me, is it grown in sterile media?

Dead soil? Is that sterile media? I think almost, yeah. Dead soil is a sterile media.

That was awesome.

You know, and actually it might be worse than sterile, probably. So we get that seed as a stock seed, and then you have to make best of it, you know, and, and that's, that's not always easy because if you have this first phase of the plan, then especially with all these brassicas that we grow the first two weeks, that the energy comes from the seed and also the microbiome, we must have a very strong plant. But when it has had that life previously in a greenhouse on a sterile medium, that's hard. And we have a lot of, you know, these, these infant pests are in the infant states, like a flea beetle that come in. And we can. We tried helping the seeds with nutrition and with compost extracts and stuff like that. And that's still a hard one we now try to solve. And that seems pretty effective by putting it in a companion crop. So we have a mixture of the brassica with the buckwheat, a fenugreek and a. And a flaxseed. And that seems, if that comes out as a mixture, it's a very common thing they do in the UK and in France with the rapeseed in August when they sell it. But it seems to be working pretty effectively in spring in our region too.

So are you actually harvesting seed from that combination?

Yeah, but since we pick the seeds in that size, that is very easy, separable. It gives no problem for us. And that is what we do with, with all the seed crops that we do. We most of them we try to sow in a combination, but they have to ripen at the same time. And all of them we sow together with an under sowing. So that means in most crops we go in spring to the field with about 5-10 kg per hectare of the actual seed crop, which can be a mustard or a garden cress or a radish, and then about 15 to 20 kilos of an under sowing. So you go with more seed relatively to the field that is not there for a harvest then that you are with your cat scrub. And we have chosen those plants in the last 20 years that we developed this system very wisely so that they do not when they get harvested with the seed, that they have a seed size that's very easily separable. But most of these seeds are perennials or biennials like grass and clover. So they won't produce seed the first year. They will stay vegetatively. And that is the main goal of this understory. Because all of our seed crops will have a generative or a vegetative in a reproductive state. As you know, some of them have that in year one and then in year two, and a couple of them have that in one year, the annuals. But it means that there is a big part of the season that there is no forest synthesis products really flowing to the soil life. And there is where this under sowing takes over. So when you see that it is mostly in June and July that these crops turn to flower, they, they make buds and they turn flowers then in, in and they, they ripen in August, September and then you harvest. It means that the most photosynthesis intensive period of the year, if you look at your photocells on your roof, you. You do not have photosynthesis growing in a vegetative plant through the soil life. And as if you, you have explained that previously, as Christine Jones that is a very important food source, you know, and of course it's about the harvest of that year, but the harvest of this year is the prerequisite of the harvest of next year, you know.

Yeah. So you are trying to optimize your, your understory so that it is in a vegetative state and photosynthesizing while you're. The seed that you are primarily targeting and growing is in the reproductive state and is not at optimal photosynthesis.

Yeah, exactly. And that's mostly in the summer months when it's. It's not as here hot here as in some regions of the world, but it has gotten a lot hotter and drier last years. But still, though, our main photosynthesis gift that we get for free is in those summer months. And in a normal situation, a seed crop would be harvested in August and the soil would be tilled shallowly and a cover crop would be sown. That would mostly be a freeze, frost, vulnerable cover crop. So that means in November or at first frost that would be killed again. And if you add up all the vegetative photo energy that you get in a year like that, it will maybe be maximum three, four months of the total 12 that you harvest. Photo energy. And it's not the most photo intensive months of the year that you do that. So not in middle of summer. And when we have a system, when we have a seed crop after a seed crop, which is an annual. Annual with an under sowing, we have about 48 to 50 weeks of the year, a vegetative growing crop.

Wow. So if I'm understanding you correctly, you have kind of three, three different strategies that may overlap. You have a strategy of planting an annual intercrop, if you will, an annual into a biennial seed crop or vice versa, where you're planting biennial intercrops with an annual seed crop or, and, or you are planting seed crops that have two very different seed sizes that you can easily separate. Did I correct that correctly?

Yeah, you correct that correctly. And I said the under sowing is actually it's a biennial, but it is often a perennial. And that is one you could also let stand the next year. But then we terminate it again and the next crop comes in and it can be a potato or carrot or a next seed crop. And it is this. It is pretty constant in our farm. And it's also in spring, it's pretty constant. What you have to do, you have the same situation to start from. And it has not been easy figuring out what plants to put in the understory and how to manage that because we have a lot of different seed crops and, and we are trying to, to find a little bit, one size fits all. So in the olden days, we had a lot of different mixtures put under it. And now we have actually one which we vary a very little bit. And this mixture consists of one third of grasses, one third of clovers. These clovers must not be trifolium clovers, but Medicago species, because those according to deep moneser, which we will talk about later, I think have a different nitrogen root profile which have more of an ammonium root profile instead of a nitrate root profile, which is important because we have accounted a lot of thistles which seem to be coming from there in our organic system. And the third part is herbs. And these herbs are actually all the other plants that don't fit in the first two categories. And if you look at it like a diet for the soil or you look at what the dietary values are on the other side of a product from the supermarket, it is this carbohydrates, the proteins and all the other stuff, you know, and that's the same which you would give to the soil. And I think it's this three compartmentalization that gives a very nice full palette of food source to the soil.

Can you tell us a little bit more about this combination of a third grasses and clovers and herbs or forbs? What are the things you found to work?

Well, yeah, the grasses that stay pretty low will be the ones who are biannual. So if you saw them in spring, the first year, they must not go to bloom in that year. Those are the ones that can maybe give a leaf of like a feet or something, which is okay because we swath, mow everything for harvest. And there are a lot of these, how do you say these really perennial, short, short above ground biomass grasses and high root biomass like timothy grass. And how do you say special rye grasses that are, say it rightly in, in Dutch it is the English rye grass and in Germany it's a, it's a German ryegrass. So I don't know, I don't know what's in the state, but different rye grass, they're like. I think there are seven species we have which comprise a third of the mixture. Then these clovers is, as I said, the Medicago species, which is alfalfa is one of them. I must look what the names are in English of the other ones. I think I made a list for you a while back. It's black medicine, it's birch food trefoil, sweet clover. Those are the compartments of the legumes, the clovers. And then as for herbs, that compartment it is the plantain, chicory, poppy seed, cornflour, caraway, cilantro, coriander or burnet and those are more like the spices spices on the, on the plate so to say. And they comprise about 15% of the seeds that we sow but they are very important and for diversity and you know the insects and also the next year that you don't have grasses, cloves but these herbs and since we do not feed this grass clover herbal mixture to an animal we can also have stuff like sweet clover in it you know which has otherwise this blood thinning thinning compound that cows can pellet. Yeah.

All right. I don't want to lose sight of your comments about nitrate and ammonium because this is such an important concept and it's still it's becoming more widely known. But this, this understanding of redox reactions in soil and what that means for soil's disease suppressiveness or disease enhancing characteristics. I really like to dig into this a little bit more and you made mention of changing the Canadian thistle population which is a very important topic for me.