Cover Crop Secrets – Interview with Jeff (Part 2)

Welcome back to our Nutrition Matters readers for the second half of this interview. There was a tremendous response to Part 1, so there is obviously a hunger for this information out there. Thanks again to Jeff Rasawehr for sharing this valuable advice, and I hope you all enjoy the rest of this interview.

Graeme: Wheat is Australia’s largest crop and I was wondering if you had some tips and strategies to improve both wheat soils and the profitability of this crop?

Jeff: Here's something that works well. In my fall seeding of winter wheat, I will add 2 or 3 pounds of daikon radish. The daikon radish will not get much bigger than pencil-thin in this limited time frame before winter, but the first nutrients it will mine at this young stage will be boron, calcium and zinc. The radish will die over winter, but in the spring, as the wheat breaks dormancy, those key starter nutrients will be there to kick off the crop. The spring release point is simultaneous to the wheat breaking dormancy.

Graeme: You mean you have actually created your own DIY seed or seedling treatment?

Jeff: That is the goal. These micronutrients become available exactly when they are most needed and there is research out of Michigan State to back that up. There is a large amount of yield data demonstrating that the radish will bump wheat yields.

Graeme: So your total wheat cover crop might involve a blend of peas to push the protozoa, three pounds of daikon radish and a sprinkling of fava beans. What is the total amount of seed involved?

Jeff: It depends upon whether it is a forage harvest where I need the plant material and then I will go higher. In general, it will vary between 10 – 12 pounds up to 30 – 40 pounds per acre. What we find is that you have to modify the amount based on conditions. For example, I will always go higher in dry soils where I want to protect moisture and cool soils. I will lower the seeding rate in heavy clay, wet soils.

daikon cover crop

Dave De Vries, NTS Canadian distributor, with a Daikon radish – note the planting rate was way too high in this crop.

Graeme: It almost seems counterproductive to seed heavily on dry soils. Can you explain the logic behind this strategy?

Jeff: It is common to assume that the higher plant numbers will compete for moisture but, in actual fact, it is just the opposite that happens. The higher plant rate will prevent the sun and air from hitting the soil and the cover crop will also provide the capillary action to bring that banked moisture back up. At 70% soil temperature [relative to air temperature], there is 100% moisture utilisation. At 100% soil temperature, which is often achieved in drier areas, you are losing way over half of your moisture each day. In two days you're dried out!

Graeme: That's such an important message for our dryland farmers. So many misunderstand that cover crops can conserve, rather than steal, precious moisture.

Jeff: In the American Southwest there is a serious problem. If we are going to take a proactive stance to prevent desertification as global warming bites, then there is one critical essential. They need to go back to "green". If they could start creating condensation with appropriate cover crops, then weather events could pick up some moisture and create some rain. They are inadvertently causing desertification, an ecological disaster, because they do not understand this basic principle.

Graeme: Increasing desertification is a global disaster, because huge areas no longer house photosynthesising plants. Carbon sequestration grinds to a halt when there is no glucose (carbon) from photosynthesis pumped down to the roots and out into the soil. All is not lost though, even when we have overstepped the mark and created deserts. CAM plants are succulents that thrive in these conditions. They are designed to provide carbon to soils where there is none. They photosynthesise in a different way, where they open their stomata at night. These plants are so easy to propagate. Each leaf produces a new plant and it can simply be poked into the soil. We could have massive nurseries producing mother plants and we could be planting out the desert – this would sequester some serious carbon and should be part of our planet-saving strategies. Don't even get me started about the potential of the Moringa tree as the ultimate cover crop.

Jeff: That's fascinating stuff. Tell me about this tree.

Graeme: It is a rare, non-succulent, CAM plant that ranks amongst the most nutrient dense plants on the planet. The leaf powder is currently difficult to source because it is in so much demand as a superfood. Like all CAM plants, this tree can be planted in very ordinary, barren soils, where it will improve those soils significantly, while providing a substantial cash crop. You can plant at a rate of 1100 trees per hectare. It grows at up to 15 ft per year and yields around 6 kg of leaf powder per year. The current price in Asia for this powder is around $5 per kg, but it can obviously be value-added elsewhere. At $30 per tree, that equates to $33,000 per hectare, while you are improving your soil with this longer-term cover crop. I am planning to plant out a hectare on my new research farm. This crop can also be an amazing fodder crop for cattle. A 50 m2 plot, densely planted, can yield 6 tonnes of fodder per year.

Jeff: That sounds exciting. There are whole regions in the U.S. that simply don't need to become deserts if they just understood cover crops.

Graeme: In Australia, we have a farmer/consultant called Colin Seis, who has pioneered a concept called “pasture cropping”. Many Australian farmers are now direct drilling multiple species into their pastures. Sometimes, they might harvest forage or a cereal crop from this planting after grazing them off a couple of times. Are you familiar with this concept?

Jeff: It is huge! I have had to leave your awesome course a number of times this week to do prescriptions for graziers in the American South, who are wanting to begin this practice. We do "diversity by design" in pastures all of the time. If you can get your clover blends to account for 40% of the plant species, things really change. The urine and faecal droppings go from being "piss and shit" (excuse the phrase) to fertiliser. In a grass environment, your utilisation of those materials is very low. As soon as you bring in the fungi from the clovers, you see some serious change. One of the gentlemen who called me yesterday was having gut issues with cattle. Part of the problem was that he was feeding only dry grass while the other issue was that he was feeding genetically modified corn, which is renowned for creating gut problems. We got him to drop the corn and build more protein into his pasture. He desperately needed more species in the pasture. We added four species of clover and beefed up the grass species. However, the most important additive was leaf chicory. I think this is pretty common on your side of the world. Leaf chicory is something special for the gut biology of cattle. It is like a prebiotic that really stimulates the rumen.

broad bean cover crop

Cash crops can serve as a cover crop, as is the case with these broad beans in the iconic Cullen Wines vineyard in Western Australia.

Graeme: Do you add plantain as well? It is a deep-rooted nutrient accumulator that is also anti-parasitic for the livestock.

Jeff: No we don't, but it sounds like something we should be looking at. We are always looking for new ideas at Center Seeds. That’s how we discovered Balansa clover. It has given us a tremendous advantage over other suppliers, because we are the only ones with this tremendous plant. I promise that we will now be looking at plantain, because it is not commonly used in the U.S. at present.

Graeme: You also mentioned the use of winter oats in the fall with wheat crops. What is the rationale for this?

Jeff: Winter oats are really cheap in the States and they are a fascinating and productive additive. The first exudation of winter oats serves to make phosphorus (P) and potassium (K) available. However, it does not make P and K available when it is in full growth. At 2 – 3 inches tall, it will be slobbering exudates all over the soil and really kicking in some P and K. I will plant it on many occasions with winter wheat knowing that it is destined to die. I know that it will get just 1.5 – 2 inches, then die. Other farmers think I am wasting my time planting something that is dead a few weeks later, but I know otherwise.

Graeme: What sort of seeding rates would you use with the oats?

Jeff: I would use 5 – 10 pounds and it only costs about 7 cents a pound. I get a good delivery of P and K for much less than a dollar an acre. It’s a great investment! I also include a sprinkle of a non-winter-hardy, annual rye in with the oats. I am adding some seasoning like this all of the time. Annual rye pours out the exudates to stimulate soil-life, even if it only lasts a short time.

Graeme: So you have been walking the talk for some time on your own farm with the widespread use of cover crops. What has it meant to you? Has it increased production or profitability? Have your soils improved?

Jeff: My neighbours are always checking to see what insecticide they may have to use this week. This is not an issue for me. They are all using fungicides as we speak. My plant health is so good I simply do not suffer these pest problems.

Graeme: How do your fertiliser rates compare to others in your region?

Jeff: I am using very low rates, but after attending your conference, I understand that I can use humates to magnify and stabilise the fertilisers I am using. I can foliar spray urea and really get efficient with my N. I am excited about foliar spraying urea on my corn at 4 1/2 weeks and again at 8 1/2 weeks, [timing is dependent on crop growth stage]. It makes perfect sense and I am confident I can move my corn yields to a new level.

Graeme: It is so interesting talking with you. I guess we had better finally get back to your five secrets. I think we are up to number three.

Jeff: Yes, number three is to try to avoid or minimise tillage. I strongly believe that we need to restore the integrity of the soil biology. I used to say that I wanted 2 tonnes of soil-life per acre in the Midwest but recent research has revealed that a truly active biological soil should have up to 20 tonnes, particularly when you factor in the earthworms. I have found that you can’t restore the integrity of the soil with tillage. You are constantly giving with one hand and taking with another.

Graeme: Unfortunately, this is also a problem with no-till. In light of all the recent findings about the toxicity of glyphosate, it is hard to support a system where you are blanket herbiciding with this chemical. You are literally destroying some of your good work each season. How do you feel about this issue?

Jeff: I agree that it is the thorn in the side of the no-till philosophy, but I am constantly moving away from these chemicals. I am using less and less each season. In fact, I have sold my sprayer.

Graeme: How are you managing the weeds?

Jeff: Well, we have managed the weeds in soybeans by simply having a high enough rate of cereal rye under the crop and then we roller crimp the cereal rye.

Graeme: I see. I didn't realise you were crimping. Do you direct drill into the crimped mulch cover?

Jeff: I actually direct drill and then crimp immediately afterwards. I know that in some regions the growers use a crimp roller and then direct drill. I have tried both strategies and the "drill before you crimp" technique has always worked best on my farm.

Graeme: Crimp rolling is a relatively new technology. Are there any drawbacks? What’s your feeling about this technology?

Jeff: I love it. The only real concern I have relates to corn. I am still using some chemical termination with the corn, but I am trying. I am non-GMO, so that reduces the glyphosate.

Graeme: So you have realised that the GMO option is not the most sustainable?

Jeff: I think that the recent studies on the toxicity of glyphosate are a real issue that responsible agriculture must confront. I am personally moving away from this chemical completely.

Graeme: What is your fourth key to cover cropping?

Jeff: My fourth strategy is to embrace viable biologicals. It is part of the reason I am at your course. I am constantly seeking to learn more about these inputs. I have been using mycorrhizal fungi and Trichoderma as seed dressings with good results, but I think I can do better.

Graeme: Have you recognised the potential of making your own inexpensive living fertilisers by setting up a brewing tank and multiplying the organisms?

Jeff: No, I have not, but after your course I am realising that this is something I should be looking at.

Graeme: Sometimes farmers think the idea is so foreign and it sounds like creating more work for yourself, but it really is remarkably simple. You can set up a 1000 litre brewing tank for a few hundred dollars, and that opens up several doors. You can take 10 kg of a good compost and 10 litres of our Liquid Microbe Food (LMF™) and add them to 1000 litres of water in the brewing tank. After 24 hours of aeration, you have a tank full of a new, biodiverse workforce that can be applied at 20 litres per acre. The total cost is less than $2 per acre and there can be so many benefits.

Jeff: What about specialist microbes. Can they also be brewed?

Graeme: Not many suppliers will admit to it, but yes, many of these inputs can be successfully multiplied. Our biggest selling microbial inoculum is Nutri-Life 4/20™, which can be brewed to produce a bacterial or fungal dominated brew. This means that 50 grams becomes 100 litres of microbe concentrate, at the end of the 24-hour brewing process. You can also brew Pseudomonas fluorescens to give you very cost-effective frost control.

Jeff: I remember the looks of disbelief when you mentioned that frost is caused by a microorganism.

Graeme: Yes, that one rocks a lot of boats. I usually suggest that people google "ice-nucleating bacteria YouTube" and they can watch this phenomenon happen in front of their eyes. The good news here is that a species called Pseudomonas fluorescens likes to eat ice-nucleating bacteria. These organisms can live on the leaf for four weeks and provide some remarkable frost protection during that time. As I mentioned, you can brew our product Nutri-Life Sudo-Shield™ and apply these organisms to any crop cost-effectively.

Jeff: A 250 gallon purpose-built brewer is quite a large investment in the States.

Graeme: That needn't be the case. We currently have a system you can use with a 1000 litre shuttle that costs around AUD1000. We will soon have a kit available for half of that price. Anyway, let’s move on to your number five strategy. What is this one?

Jeff: Number five is choosing the right soil amendments. I am a big fan of zeolite. I am not that keen on gypsum though.

Graeme: There is an issue with using gypsum in acidic soils and there is also an issue when you use too much. Gypsum is often used to help remove excess magnesium and sodium because it forms highly leachable magnesium sulfate and sodium sulfate in the soil. However, it can also form leachable sulfate forms of other minerals and, as such, it can have a demineralising effect if overused. What amount of zeolite do you use?

Jeff: I use about 100 lbs per acre, and it is really effective. It is the gift that keeps on giving because it never breaks down in the soil. In this country, that costs about $US14 for 100 lbs. I find with our system that P and K levels will rise each year with my cover crop strategies, but some of the trace minerals need to be addressed. We have seen good results with boron in particular.

Graeme: Have you had any experience with liquid micronised minerals, as fast-food soil amendments? We have found that you can achieve impressive results with a few litres of micronised lime, or gypsum, or magnesium carbonate, right in the root zone. We have had tremendous results with liquid micronised guano that delivers phosphorus, calcium, silica and trace minerals directly into the root zone.

Jeff: I have not had experience with these kinds of products but they sound very interesting. My sixth and final cover crop pointer is this: you must stick to the system to succeed. I look at cover crop systems all over the country and it is so common to see a situation where the farmer is doing several things right, but at year three, he misses the cover crop and the wheels fall off quite quickly. The integrity of your microbes is quite short. They need to be fed or they simply cannibalise each other and the system collapses. You need to provide the exudates to feed the microbes. One year without this food is a long time in a dynamic, interrelated system. It is so important not to miss a year. I have met cover croppers who say it doesn't work and so often you will find they collapsed the system by missing a year. Ray Styers from Carolina is a very astute biological farmer. He had his system really cycling with minimal inputs and maximum results. He missed one year through health issues and his wonderful win/win system suffered immediately. His completely self-sufficient system collapsed. You must stay in the system and not miss a year.

Graeme: Did you have any other concepts you would like to share?

Jeff: Yes, it is very important that we do not overdo the seeding rates in cover crops or it can be counterproductive. Always remember that "less is more and more is too much". I see cover crop mixes all the time where some of the components are just way, way, way too high. There have been many failures in the States totally linked to horribly high seeding rates.

Graeme: Perhaps you could give a rundown of the kinds of amounts that you think are appropriate in different situations.

Jeff: Well it is really quite complicated. If I was using 70 lbs of cereal rye per acre as my base and I decided to include winter barley at 10 lbs per acre then I would reduce the cereal rye at a rate of two-to-one. I would cut the cereal rye down to 50 lbs per acre. This ratio is essential because of the thick roots at the surface. However, if I was adding triticale, then it’s a one-to-one ratio. You really need to know the root dynamics. Triticale has a long skinny root, so if I add 10 lbs of triticale, I subtract 10 lbs of cereal rye.

Graeme: You have your spaghetti and you add your sauces. If you were using winter oats as your spaghetti base, what kind of seeding rates are suitable?

Jeff: I would usually use 30 – 50 lbs of oats per acre. In a wet environment, oats stimulate saprophytic fungi. I think we need much more emphasis upon both fungi in the soil and surface fungi. This is a ridiculously cheap way to look after your fungi in the soil. Oats offer so much, so cheaply, that sometimes our customers only want to do that. They miss out all the other benefits that come with the seasoning. Building biodiversity can deliver an average increase of $200 profit per acre and we have quantified this in cropping soils all over the country. Dairy farmers usually see a bump of around $500 per acre. They feed the cover crop species to their animals. If you do it right, we see a bump of over $1000 per acre in dairy.

Graeme: Yes, I have seen some wonderful examples of multiple benefits with pasture cropping in the NZ dairy industry.

Jeff: An increasing number of growers are recognising that they don't need to keep expanding. They can make more money by getting smarter rather than getting bigger.

Graeme: Have you noted good gains in building humus with your cover cropping?

Jeff: I most certainly have seen good increases across the country. However, I now think that we can do even better with the use of humates. Humic acid can give a further kick to stimulating the fungi who create the all-important aggregates and stable humus.

Graeme: Yes, they are the missing link in so many soils. It’s almost time that I got back on stage. This has been an invaluable interview and I am really grateful for your time. Did you have any remaining cover cropping principles to share?

Jeff: Yes, there is one important last thing. I think a lot of people don't understand the concept of an in-ground effect preparing for the above-ground event. So many farmers are concerned about the visual – the above-ground effect – when, in fact, that is often not the main benefit. It depends what you are seeking from a cover crop. If you are wanting forage for baling or grazing above all else, then that concern for the visual is relevant. However, a huge reason to consider cover cropping relates to the wonderful effect on soil microbiology, soil fertility and associated production. Most of the exudates that feed up that in-ground army are released early on in the crop. When the crop is in full growth mode it is often taking more than it is giving. Cover crop blends are designed in accord with this understanding. We might want to boot the biology with the young cover crop or perhaps soak up some mineral excesses to stabilise leachable minerals with the more advanced cover crop. I am sure that my neighbours drive by thinking "his cover crops never get very big", but I am happy with that because they are delivering this all-important in-ground effect.

Graeme: The herbicide cowboys need to wrap their heads around the simple fact that Nature always wants the soil covered, and she loves biodiversity. We saw a perfect example of this misunderstanding in the Australian cotton industry a few years ago. Cotton farmers with their mantra that "the only good plant is a dead one, unless it was cotton" developed a practice where they left the soil bare and herbicided often during long periods of fallow. This was somehow supposed to be restorative but, of course, it backfired. The cotton crop planted after a long fallow became stunted with small leaves and a tiny root system. It was found that the plants were screamingly deficient in phosphate and zinc, hence the small roots and leaves. These deficiencies could not be corrected with fertilisers and then it was realised that the mycorrhizal fungi had died off in these soils. These creatures must always have a host, even if it is a weed. In the prolonged absence of hosts, their numbers seriously dropped. One of the major roles of mycorrhizal fungi is the improved access to, and delivery of, phosphate and zinc. We can so easily shoot ourselves in the foot if we do not understand basic biological principles.

mycorrhizal root growth

The simple use of humates and mycorrhizal fungi generated this great root growth in a new pasture crop.

Jeff: Same story over here. The Western states developed this insane strategy called chemical fallow, where they came up with bright idea (supported by the chemical companies no doubt) that you would spray all summer, you would cook the soil, dry it out and overheat the biology and somehow the moisture would restore. Well, it is an absolute failure. In Kansas, we are replacing this bankrupt system with cover crops, including summer sippers (plants with low moisture requirements) and plants like brassicas that will droop over, and the third component is plants that are very active to provide quick stimulation before they die with frost. This might be buckwheat or sorghum-sudan type species. The wheat growers want to spray, spray, spray but we point out that they need to direct drill into the cover crop. They need to let the existing plants transfer their stimulated biology to the wheat crop.

Graeme: One last comment. There is a huge issue with the use and abuse of glyphosate out there. We now know it is a carcinogen and I have only recently become aware of the fact that it is sometimes sprayed directly over food crops like wheat and soy to kill off the crop before harvest. Potatoes are the Western world's favourite vegetable and they are sprayed off before harvest with either glyphosate or paraquat. It is ridiculously irresponsible. We are working to develop a harmless desiccant that may even add some benefits to the soil. However, it is difficult to find something viable because of the very low price of glyphosate and you can use just a litre of this herbicide to kill off 20 tonnes of organic matter.

Jeff: It’s only because the farmers and chemical companies have not yet been made responsible for the real cost of glyphosate. They do not have to bear the cost of the damage it is doing. If they had to compensate for the damage to our human population, our animal population, our water, our environment and our planet, this herbicide would be radically expensive.

Graeme: Thanks so much for a great interview. I think I need to bring you out to Australia to share more of your cover cropping wisdom at some point soon.

Jeff: That could be a lot of fun. I have thoroughly enjoyed this interview and I hope I have given your readers something of value.

To read Part 1 of this interview, please click here.

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