John Kempf

Elementary discussions of plant pathology describe the disease triangle almost without fail. It has become a standard inclusion in many presentations, and a quick image search will find hundreds of graphical designs that have been developed to describe the idea. The foundational idea appears quite simple at first glance. For a 'dise-ease' to express itself requires a combination of three elements: a susceptible host, a potentially pathogenic organism, the proper environment, This seems like an obvious and simple explanation. We accept it without much question and move on to the next part of the discussion, which usually revolves around controlling 'pathogens' when the combination of these three elements is met. Rather than moving immediately to the control conversation, and assuming an infection has occurred that we have no influence over, we might dig a bit more deeply into each of the three elements. When we understand these three elements fully, they will give us all the information we need to prevent any 'dis-ease' from expressing in the first place. Prevention is often easier and more effective than a cure. Read the full article

It is possible for plants to become completely resistant to disease when we manage nutrition well. On the surface, this sounds like a bold statement. When you dig deeper to understand the enzyme interactions and infection pathways of different infectious organisms, it becomes clear how nutritional imbalance is a foundational cause that allows these organisms to express themselves and produce active infections. In this discussion, I ask Don Huber how to develop disease resistance to airborne pathogens. To dig deeper into this subject, the best reference book available is Mineral Nutrition and Plant Disease. It is a very inexpensive book for the money it can save growers. John: You and I have spoken before about the capacity of nutritionally sound plants to become resistant to soilborne pathogens and organisms residing in the soil. We haven’t spoken about airborne pathogens, such as bacterial and fungal pathogens. How can we develop plants that are resistant to those organisms? Don: You’ll see the same thing there. Pathogens are looking at the plant and they’re attracted to it as a food source―a nutrient source. Also, some of them actually require specific nutrients in order to cause disease. Several of the rusts, for instance, require an exogenous source of zinc on the leaf―an available source of zinc―before the spores will germinate and produce an infection. Read the full article

For many perennial fruit crops, we can use shoot growth as an indicator of overall plant energy and vigor. It is common for shoot growth to slow down, and sometimes even stop completely, setting a terminal bud, during the fruit fill period. When this occurs, it is an indicator that the plant is not producing enough photosynthetic energy to both fill fruit and develop growth, so it will sacrifice the new growth to be able to reproduce. When we manage plant nutrition to optimize photosynthesis, it is possible to restart healthy new shoot growth, without the addition of nitrogen. On these apple trees in Michigan, the trees set terminal buds on new growth tips in late June, during early fruit fill. We started working with this block this year and recommended foliar nutrient applications designed to increase photosynthesis to increase sugar production for the heavy fruit load. Incredibly, the shoots that had set 'terminal' buds began regrowing! Perhaps terminal buds aren't so terminal after all when supported with enough energy and the needed nutrition. These shoots continued to have healthy growth with tightly spaced nodes through the fruit fill period. When trees have continuous healthy shoot growth with tightly spaced nodes, it is indicator they have enough energy to also set fruit buds for the following year, and we can effectively prevent biennial bearing. Read the full article

We are recognizing that liquid manure often has a very negative effect on soil biology and soil health. It may deliver nutrients, but it comes with a long list of possible negatives. It is often in an anoxic state (deeply anaerobic), where the organic residues contained within it are putrified rather than fermented. (which is the source of odor and microbial toxins) The microbial activity which might be present in the liquid manure has often been suppressed or even shut down completely as a result of this anoxic state, along with the presence of antibiotics. Liquid dairy manure generally contains quite a high salt content, which has a negative effect when applied to the soil. In some cases, cleaners and antimicrobial chemicals from milking parlor waste wash-water are also put into the lagoon or pit. (Which is a very, very bad idea, and will increase weed pressure of velvetleaf and other weeds dramatically where this is applied to soil). Often, when liquid manure is applied, dead earthworms can be found on the soil surface the next day. Might this be a signal that this product is harmful to soil biology? The odor is also an indicator of fermentation and decomposition gone wrong. It doesn't need to be this way. It is possible to turn liquid manure lagoons into fermentation tanks that turn this valuable nutrient source from something that is harmful to soil biology to a fermentation broth that is very beneficial to soil biology. Read the full article

Some apple varieties are quite susceptible to apple scab, while others are resistant. Plant sap analysis indicates the resistant varieties are much better at absorbing cobalt than the susceptible varieties in the same soil conditions. They will often show 2-3x higher cobalt levels. When we balance all the other nutrients and apply foliar applications of cobalt to susceptible varieties, apple scab is not present.  We have implemented this treatment successfully on enough different apple varieties on enough different orchard blocks to be confident of its success. Many other diseases have similar correlations to nutritional imbalances and can be managed effectively by managing nutrition. Preventing and reversing scab infections can occur very quickly. We expect to see reduced pressure within weeks of the first application. In several cases, we have been able to eliminate all the later scab treatments after cobalt was applied in the spring, within several weeks of beginning to work with a block for the first time. This reduced the pesticide budget requirements by $500.00-$600.00 in the first year. Like any trace mineral, cobalt can easily be overdone. Don't attempt treatments without using sap analysis to evaluate progress and nutritional balance. Not all diseases respond this quickly to nutrition management, but many do. When we begin managing nutrition differently, we can dramatically reduce fungicide and insecticide applications on most crops. Read the full article

The popular narrative is that healthy soils produce healthy plants.  This is correct but incomplete. We need to ask the question, what creates healthy soils? "Healthy plants", is the right answer.  Without the contribution of plants, soil is just decomposed rock particles; sand, silt, clay. Plants contribute the carbon, the sugars, the energy that serves as a fuel source, and substrate to develop microbial populations that build organic matter and mineralize nutrients and make them available to plants. The humic substances and humus clay complex are the result of plant contributions to the ecosystem. Healthy plants create healthy soil. The key adjective in this statement is ‘healthy’. Unhealthy plants do not create healthy soil. In fact, the opposite.  Unhealthy plants create unhealthy soil.  In this post a few days ago, Robert Kremer described how the root exudates of GMO crops can increase the virulence of soil-borne pathogens. But wait, root exudates are supposed to be a good thing, no? The influence of root exudates on soil microbial communities is determined by the complexity and quality of the compounds they transmit through the root system, not the quantity of exudates.  Unhealthy plants will transmit simple carbohydrates, non-reducing sugars, amino acids, and other compounds in ratios that enhance the virulence of pathogens, by providing them with a ready food source.  Healthy Read the full article

When fungal activity looks like this beneath the tree row, how long do you suppose leaf residue will be around to carry over disease to the next season? How will this fungal activity compete with Armillaria and other potential pathogens in the rhizosphere? How will it influence nutrient availability? From our observations and experience, soil biology can deliver essentially all of a plant's macronutrient requirements without any added fertilizer, provided that the nutrients are already present in the soil's native geological profile. When we farm the biology, we no longer need to import fertilizers that are generally already locked up in our soils. It may not be wise to simply discontinue fertilizer applications if the soil biology is severely compromised. They need to deliver whatever does not come from imported fertilizers in order to maintain or increase yields and quality, and in challenged soils they are often unable to do so. Read the full article

On several occasions, we have observed GMO corn crops and GMO corn stalk mulch produce a soil environment that enhanced disease, sometimes dramatically. Why would it be the case that GMO crops produce a disease enhancing soil environment, where non-GMO corn produces a disease suppressive environment? Other research has identified that GM plants have altered carbohydrate and amino acid profiles in the root exudates, which seems to be a probable mechanism for producing an altered rhizosphere microbiome. Robert Kremer and I approached this conversation in our podcast interview: John: Earlier you mentioned the impact of genetically modified plants themselves, apart from glyphosate and AMPA. How do GMOs impact the soil’s microbial community? Robert: Well, there’s not a lot of information. We found with soybean, for example, that genetic modification can have what are called pleiotropic effects—indirect effects due to the genetic modification that are in addition to the intended effect. In other words, effects that are in addition to the effect of making the plant resistant to glyphosate. And so there are things that can happen in the root system—with some of the early genetically modified soybean varieties, anyway—that even without being treated with glyphosate, the roots seemed to release a lot more carbohydrates or soluble carbon and amino acids. Read the full article

Plants with abundant energy produce flower clusters with uniform size and fruit with uniform maturity. Nutritional integrity has at least as big, if not a bigger impact on harvest timing and quality than genetics. Read the full article

How is it possible for a high Brix plant to be resistant to insects and not provide them with an abundant food source when insects are attracted to sugars? The key insight is that plants contain different concentrations of different carbohydrates at various levels of plant health. The goal for optimal plant health is to have all photosynthates and soluble sugars such as glucose and fructose converted to non-reducing sugars in each 24-hour photoperiod. This means a healthy plant will have a high Brix concentration and very low levels of reducing sugars. From the podcast interview with Don Huber. John: Are there any negative health consequences of plants having high levels of fructose and glucose? Don: Yes and no, depending on what other stresses there are present. If you have a deficiency of manganese, for instance, it can’t store the reducing sugars―glucose and fructose―that are being produced through photosynthesis. It can’t store them as sucrose, and so they become very attractive reducing sugars, and they become very attractive to insect pests and to a number of plant pathogens. Manganese is a critical factor for that sucrose-phosphate synthase enzyme that converts glucose and fructose into sucrose for storage. If you’re deficient in manganese, you’ll have high reducing sugars―glucose and fructose. Read the full article

There is a story of a personal visit between Carey Reams and William Albrecht, both pioneers in soil mineral balancing and the human health implications. Carey Reams was in private consulting, based in Florida, while Albrecht was focused on Missouri and the Midwest. Albrecht asked Reams, "What is the soil like in Florida?" Reams responded, "Well, it would be a good place for some." The soil in this seed onion field reminded me of this story. It is probably true that this location is an optimal environment for onion seed production from a climate perspective. It is also likely that onion seed production is a very profitable crop for the grower. It seems worth asking the question, is this use the highest good for the landscape? Luther Burbank said, "Heredity is nothing more than stored environment." Would you prefer to buy seed grown in soil of this quality? Read the full article

A pepper field had Phytophthora problems. Ridomil Gold treatments were known to be completely ineffective. Instead of anti-biotics, we applied pro-biotics, microbial inoculants of mycorrhizal fungi, a range of bacterial species, and biostimulants through the drip irrigation system. Within weeks the soil is filled with these thick strands of mycelium/plant roots and the crop recovered completely. The phytophthora symptoms disappeared. What have you seen something similar to this in the soil? What do you think this might be? Read the full article

Several years ago we worked with a greenhouse grower where crops were being grown in the soil continuously for over a decade. The soil was quite sandy and became quite tired as you can imagine. The large investment in the greenhouse made it worthwhile to invest in regenerating soil health. The grower green chopped cover crops grown in the field, applied them to the soil surface to a depth of several inches, sprayed Rejuvenate and Spectrum on the residue, and incorporated it into the soil. In 3 weeks the soil had noticeably darkened in color and had developed good aggregation. The following crops grew better than they ever had in recent memory, and without any disease or insect pressure. Biology can regenerate soil health quickly and provide all the nutrition a crop requires when given a food source. The soil sample on the right is from an untreated greenhouse bay, taken at the same time. Read the full article

Leaf residue can carry potential disease pathogens from one season to the next. The best short term solution to solve it is to apply Soil Primer to have the residue be rapidly digested and broken down. The midterm solution is to cover the naked soil and provide the existing biology a food source so they can thrive and accomplish the job on their own. Stop the continuous herbicide applications. This picture was taken in the dormant season, but I don't need to see these trees during the growing season to know they are immune-compromised, susceptible to insects, susceptible to diseases, and biennial bearing. I can know this to be the case because it obvious this soil is not capable of delivering the nutrition the crop needs to be healthy and high yielding. Read the full article

Cotton is commonly grown with high rates of nitrogen and multiple aggressive PGR applications to keep internodes tight and increase yields. If you think that is a bit like driving by holding both the accelerator and the brake to the floor, you would be correct. In this podcast episode on vegetative vs reproductive nutrients, I describe how to manage nutrition to produce rapid vegetative growth and tightly spaced nodes at the same time, producing high yields and high-quality fiber at the same time. The nutrition on this field has been managed differently than the mainstream. Instead of having excessive vegetative growth, this field has almost too little, partially because of cover crop residue tying up nitrogen. No PGRs have been applied, node spacing is tight, and the crop is on track for an exceptional yield. And isn't the photo just beautiful? Life in agriculture is just awesome, isn't it? P.S. I am hosting a Book Discussion on the questions and ideas you raised from Quality Agriculture, tomorrow, August 28th, at 12:00 EDT. You can register here and bring your questions! See you then. Read the full article

Providing enough water to our crops is the one thing we stress about more often than almost anything else. We joke that we worry about drought when there is nothing we can actually do about it. Actually, we can, if we want to. There is a lot we can do about providing a crop with a season-long water supply in the soil reservoir. We forget that water infiltration and percolation are two very different things. There is no correlation between the quantity of water that falls on an acre of soil, the amount of that water that is held in the soil,  and the amount of the held water that is actually available for plants to absorb. Some soils can deliver almost 100% of the annual rainfall to the crop as available water during the growing season, and other soils may deliver less than 40%. This explains why we have drought-stressed crops in regions that receive 30 inches of annual rainfall. In a new course titled How Soil Health Determines Crop Available Water Supply that is being released from the Regen Ag Academy today, Jerry Hatfield describes soil and atmospheric water dynamics we should keep in mind to help us manage water better and ensure our crops get the benefit of the rainfall the land receives. You don't want to miss it. Read the full article

Copper is known to provide flexibility to plant structures. Stems become flexible, plants can bend in high winds, and stand back up afterward, without any breaking or lodging. Twigs and branches become more flexible and don't break as easily. Spurs and fruit clusters become less fragile and breakable. Crops that are sometimes known for 'brittle' leaves like broccoli don't have the leaves snap off as easily. Fruit skin becomes more flexible and very slightly stretchable, allowing for fruit expansion right at maturity with additional moisture without cracking and splitting.  Copper provides all of these benefits because it enhances the formation of lignins in the structural tissue. We have observed all of these benefits occurring in the field. When grain crops have adequate copper, they develop very flexible stems. A corn plant should be able to bend when gripping the stalk immediately above the ear until the tassel brushes the ground, with no strain, and stand right back up again. This gives grain crops a lot of resilience to severe weather stress and physical abuse. This also means plants do not need so-called 'brace roots'. At least not to 'brace' themselves. 'Brace' roots only show when the plant's vascular tissue is plugged immediately below the node. As soon as the vascular tissue begins plugging, plants quickly send out emergency bypass roots at the node, above the plugged transport pipeline. Read the full article