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Water and nutrition supply are biologically driven

As we rediscover the contributions of soil biology to plant nutrition and soil health, the phrase “biology supersedes chemistry” seems ever more appropriate.

Jon Stika succinctly describes biology as the driver of plant nutrition and soil water supply in A Soil Owner’s Manual, (which I added to my recommended reading list):

When asked if they know how to plant nutrients become available to plant roots, producer’s answers typically include the belief that fertilizer must be added to the soil, where the fertilizer dissolves in soil water and the plants take the nutrients in. In fact, 90% of the nutrients taken up by plant roots are cycled through a soil organism before becoming plant available. Virtually everything plants need is supplied by the soil organisms that live in collaboration with each living plant.1 Less than a third of the nitrogen fertilizer applied to a field ends up in the plants grown there.2 The rest is retained by some other form of life in the soil, volatizes into the atmosphere, runs off the field or leeches down below the root zone of the soil with the movement of water. Most analytical soil testing and fertilizer prescriptions are based on the response in crop production of plants grown in dysfunctional soils. The methods and prescriptions work quite well; for dysfunctional soils.3 This should come as no surprise, since most agricultural soils in the U.S. do not cycle nutrients very well, so the corresponding methods of testing and prescribing fertilizer application have evolved accordingly.

Water infiltration and nutrient cycling are just two basic examples of what we now understand are processes that are driven by the organisms living in the soil. This change in understanding of how the soil works as a biological system is a major paradigm shift for almost everyone in agriculture. Armed with this new understanding of soil function, producers can reduce and eliminate the symptoms of erosion, runoff, nutrient leaching, drought, and poor crop performance to become truly sustainable.

The bottom line is that the plant available water in the soil becomes plant available because soil microorganisms made the soil aggregates that allow the water to infiltrate and be stored in the soil. It is also soil microorganisms that cycle and make the vast majority of nutrients available to plants.

If asked, any producer will tell you that they expect their soil to grow profitable crops by supplying water and nutrients to their crops. What many folks don’t realize is that these two basic expectations of soil function (water and nutrient supply) are biologically driven. Keep the soil microorganisms happy and the system runs at peak efficiency. A more efficient system will be a more profitable system.

1. Lavelle, P. & Spain, A. Soil Ecology. (Springer Science & Business Media, 2001).
2. Stevens, W. B., Hoeft, R. G. & Mulvaney, R. L. Fate of nitrogen-15 in a long-term nitrogen rate study: II. Nitrogen uptake efficiency. Agron. J. 97, 1046–1053 (2005).
3. Laboski, C. A. M. et al. Evaluation of the Illinois soil nitrogen test in the north central region of the United States. Agron. J. 100, 1070–1076 (2008).

2021-03-02T17:49:07-05:00March 3rd, 2021|Tags: , , |

Nutrition management for disease control

We have known how to prevent and reverse plant diseases with nutrition management for a long time. The information is not new, it has just been ignored or forgotten.

Fertilizers and trace minerals can be used to increase disease severity, or to reduce or eliminate disease entirely. Many fertilization practices today are known to increase disease. This knowledge should be foundational for every farmer and agronomist, but has largely been forgotten. Perhaps because it would eliminate the need for fungicide applications?

To illustrate how rich the literature is, here in as excerpt from the opening chapter of Soilborne Plant Pathogens: Management of Diseases with Macro- and Microelements published in 1989. For an up-to-date and more modern version I highly recommend Mineral Nutrition and Plant Disease.

Written by Arthur Englehard:

A large volume of literature is available on disease control affects provided by macro- and microelement amendments. Huber and Watson in 1974 in “Nitrogen Form and Plant Disease” reviewed and discussed the effects of nitrogen and/or nitrogen form on seedling disease, root rots, cortical diseases, vascular wilts, foliar diseases and others. They summarized work from the 259 references in four tables in which they list crops, diseases and citations. McNew in the 1953 USDA Yearbook of Agriculture discussed effects of fertilizers on soilborne diseases and their control. He reviewed briefly specific diseases such as take-all of wheat, Texas root rot, Fusarium wilt of cotton, club root of crucifers and common scab of potato. Many other diseases were mentioned, as well as how macro- and microelements effect host physiology and disease. Huber and Arny in “Interactions of Potassium with Plant Disease” summarized in three tables the effect of K (positive, negative, neutral) on specific diseases. They listed 267 references in the bibliography.

The Potash and Phosphate Institute is dedicated to research and education and celebrated his 50th anniversary in 1985. It is a source of information on the use of K and P in the production of plants and the effects on plant disease. The Institute promotes a systems approach to crop production; disease control is one of the factors in the system.

Leath and Ratcliffe described plant nutrition and diseases in forage crops production. They indicated that fertilizers affect pathogens in the soil and on the host, and also can affect the pathogenicity of an organism. Presley and Bird reviewed the effect of P on the reduction of disease susceptibility of cotton.

In 1983, Graham, in Australia in “Effects of Nutrient Stress on Susceptibility of Plants to Disease with Particular Reference to the Trace Elements” discussed under the heading “Macroelements,” the effect of six essential elements on disease; and under “Micronutrients,” seven essential elements and 15 others as having been reported to influence a host-parasite relationship. He gives 305 literature citations.

Another review by Huber entitled, “The Use of Fertilizers and Organic Amendments in the Control of Plant Disease” contains a wealth of information. He indicated how the severity of 157 diseases was affected by N in table 1. In table 2, a similar listing is given for nitrate and ammonium forms of N. The effects of P, K, Ca and Mg are given in tables 3, 4, 5 and 6 respectively. Tables for S, Na, Mn, Fe, Zn, B, Cu, Si and other elements are also presented.

A literature research of the CAB ABSTRACT database utilizing the DIALOG Information Retrieval Service and using some keywords: soilborne disease, macroelements, microelements, soil fungi, Fusarium, Pythium, and Phytophthora, yielded 1500 citations published during the past 14 years.

The Future

Obviously a virtual flood of literature is available regarding the effects of macro – and micro element soil amendments on the level of soilborne disease in plants. What is lacking is the correlation of the positive factors into integrated production systems. The biggest problem now is how to organize and comprehend the mountain of available and often conflicting data. We have entered an era in which computer-aided analysis and other sophisticated tools are needed to integrate information and develop systems approaches is to growing healthy, productive plants.

One of the most rewarding approaches for the successful reduction of soilborne diseases is the proper selection and utilization of macro- and microelements. Since virtually all commercially produced crops in the developed world are fertilized, it is extremely important to select macro- and microelements that decrease disease. This is an important and viable alternative or supplement to the use of pesticides which usually only gives partial disease control.

Remember, this was published in 1989. What other things have you heard about that deserve to be generally known, but aren’t?

Interplanting sweet allysum for aphid control

We might ask the question, “What is the root cause that allows aphids to feed on this plant?”

When we pursue the wormhole of information needed to answer this question, we can develop a description of the carbohydrate profile within plant sap that aphids are dependent on. The carbohydrate profile changes dependent on the critical minerals plants require as enzyme co-factors to develop functional enzyme systems. The mineral profile is determined by the soil biology’s capacity to supply specific nutrients. These are layers of empowering answers which indicate the management tools needed to prevent aphids from becoming a problem. You can find my previous blog posts related to aphids here.

We might ask a similar question at a different level of thinking, “Why are aphids showing up in this ecosystem?”

When we ask questions at a different level, we arrive at very different answers. How are we managing the field ecosystem that allows the aphids to proliferate unchecked? When we have a continuous mono-crop of plants with an incomplete carbohydrate profile, it is a near-perfect environment for aphids to proliferate. We are supplying them with an abundant food source, and no habitat for their natural predators. When we spray an insecticide, we improve the environment for the aphids even more, because now we have removed all the predators, and weakened the plants even further.

A natural followup to the previous question is, “How can we manage the ecosystem differently so that aphids are no longer present?

Thanks to Klaas Martens for pointing me to Eric Brennan’s research on inter-planting sweet alyssum in lettuce and broccoli as a biological control for aphids. As I followed the wormhole of published research on biological control for aphids at an ecosystem level, I was pleased to discover that adding relatively few insectary plants per acre like sweet alyssum can attract enough hoverflies to provide complete control of aphids.

I estimate that additive intercropping with about 500 to 1000 alyssum transplants per acre, distributed throughout the field should provide sufficient pollen and nectar for hoverflies to control aphids in transplanted romaine lettuce. ~ Eric Brennan

This limited population of sweet alyssum has no negative impact on lettuce yields, and seems unlikely to have a negative impact on yields of other crops. Sweet alyssum can be direct seeded, and seed is inexpensive. This seems like an imminently practical and scalable solution for other crops with aphid pressure.

What other practices or plants  provide control of different diseases and insects? This is a topic I am would like to learn  more about.

 

1. Brennan, E. B. Agronomic aspects of strip intercropping lettuce with alyssum for biological control of aphids. Biol. Control 65, 302–311 (2013).

2. Brennan, E. B. Agronomy of strip intercropping broccoli with alyssum for biological control of aphids. Biol. Control 97, 109–119 (2016).

3. Ribeiro, A. L. & Gontijo, L. M. Alyssum flowers promote biological control of collard pests. Biocontrol 62, 185–196 (2017).

4. Harris, A. S. Integrated Organic Management of Cabbage Aphid on Brussels sprouts. (University of New Hampshire, 2019).

5. Quinn, N. F., Brainard, D. C. & Szendrei, Z. Floral Strips Attract Beneficial Insects but Do Not Enhance Yield in Cucumber Fields. J. Econ. Entomol. 110, 517–524 (2017).

6. Mollaei, M., Fathi, S. A. A. & Nouri-Ganbalani, G. Effects of strip intercropping of canola with faba bean, field pea, garlic, or wheat on control of cabbage aphid and crop yield. Zhi Wu Bao Hu (2020).

2021-02-13T12:28:21-05:00February 16th, 2021|Tags: , , , , , , , |

Environment determines genetic expression

Prior to the human genome project, the popular expectation was that understanding the structure of DNA, and being able to edit or manipulate it’s structure would enable us remove the cause of degenerative illness.

As this project approached it’s concluding stages, it became obvious that DNA did not contain enough information to describe all the variability found within a given population. From this insight emerged the concepts of genetic fluidity and the science of epigenetics.

Epigenetics is the study of heritable changes in gene expression that do not involve changes to the underlying DNA sequence — a change in phenotype without a change in genotype. A foundational premise of epigenetics is that changes in environment result in changes of how an organism expresses itself.

“Heredity is nothing more than stored environment.” Luther Burbank

As farmers, we recognize this as an obvious truth. We know that we can plant the same seed in different fields with different soil types, and the crop will express itself differently. This effect is compounded as multiple generations are grown in different environments.

It is easy to recognize this process in plants, and also in animals.

We may not have appreciated enough how fundamental this process is in determining the pathogenicity or infectious capacity for the organisms we call ‘diseases’ or ‘pests’.

When we plant a blueberry plant into soil that is optimally balanced for alfalfa, we have placed it in an environment where it is unlikely to do well.

If we were to plant lambsquarter seeds into forest soil that is undisturbed, they will not even germinate, because they are not in the proper environment.

If we were to plant foxtail seeds into soil that is aggregated and well aerated, they also will not germinate, because they are not in the right environment.

Each of these examples is a case where the environment has determined genetic expression.

Soils can contain fusarium populations that are able to cause disease, but instead develop a symbiotic relationship with the plant, when there is a healthy soil microbial environment present. The DNA of the fusarium remains unchanged, but it’s expression is completely different.

Aphids will die in minutes, and become ‘candied’ when the sugar profile within plant sap they are feeding on changes. A change in the environment determines whether they live or die.

Not all insects in a given population serve as a vector for viruses. If an individual insect benefited from an optimal diet and environment, it will resist viral infections and not spread viruses from one plant to another. (Disease resistance is as real for insects as plants or animals)

Powdery mildew infections can decimate one variety, and leave another variety in close proximity completely untouched. The powdery mildew organism is present in both varieties, but one variety does not present a hospitable environment, and the organism never expresses itself as a ‘disease’.

We could continue this list until we included every ‘disease’ and ‘pest’ that is known.

The concluding point is simple: Every ‘pest’ requires a certain environment to be able to express itself. Change the environment, and the ‘pest’ ceases to be a problem.

If our crops are susceptible to disease or insects, it is because of our management practices that have created a hospitable environment. Change the environment with nutrition and microbial management, and you change the susceptibility.

 

How to reduce herbicide application rates

The soil health challenges of glyphosate use are becoming well known. Don Huber has reported that even a single application of ten ounces per acre is enough to alter the microbial community in favor of oxidizing – disease enhancing organisms.

I am not aware that any other herbicide is known to have the strong antibiotic effect of glyphosate, though each has it’s own set of environmental and public health challenges.

Some growers have figured out how to eliminate herbicides altogether. Other growers are still on the pathway of figuring it out.

Robotic weed control technologies are being developed that may make herbicides obsolete in the future, but they are not here yet.

Given this state of affairs, it would seem wise to figure out how we can apply the smallest amount of active ingredient possible and maintain or improve effectiveness.

When we describe designing nutrition applications, we find that we get the greatest performance when we use synergistic stacks of products from different categories, for example: bacterial inoculant, fungal inoculant, microbial stimulant, microbial food source, plant nutrients, plant stimulants.

We can use this same concept to reduce the required rates of herbicides. Some growers have reported reducing rates by upwards of 80% and maintaining effectiveness using a combination of different strategies.

The practices which are known to improve herbicide performance include:

  • removing all minerals from the water, particularly carbonate and bicarbonate
  • acidifying the water
  • premixing the herbicide with a vegetable oil
  • adding sugar to the spray solution
  • adding fulvic acid to the spray solution
  • structuring the water

Each of these practices increases the effectiveness of any material added to a spray solution (including foliar sprays). When we stack practices together, the improvement in results can compound.

When we stack these practices together, they need to be added in the right sequence, much the same as products should be added to a spray tank in the correct sequence. Here is the sequence that I have observed to be the most successful:

  1. Demineralizing the water, most commonly using reverse osmosis (RO). RO is very inexpensive for the reduction in active ingredients it can produce. This step alone can account for a reduction of 30-40% in product required.
  2. Structuring the water after it has been through an RO device and demineralized.
  3. Premixing the herbicide with vegetable oil 50/50 on a volume basis, and then add to the tank. The theory is that coating the compounds with vegetable oil will improve their absorption by the crop. I have some question marks about how this might work, and how much it actually does, but growers are reporting observable improvements.
  4. Add any acidifying agents to tank, such as ammonium sulfate. This may require much less than you expect when you use RO water to reach a low pH.
  5. Add fulvic acid to improve leaf absorption.
  6. Add sugar to contribute stickiness, and improve leaf absorption.

Exercise caution when using this approach with selective herbicides. The applied products will be much more effective, and can easily damage the non-target species. Test how much application rates need to be reduced, they will almost certainly need to be reduced to avoid burn.

I have observed complete weed control with 8 ounces of RoundUp per acre, roughly 4 ounces of active ingredient glyphosate per acre.

What practices have you used to reduce application rates while improving effectiveness?

2021-02-08T11:08:40-05:00February 10th, 2021|Tags: , |

Replacing expensive inputs with free inputs

Farming is about taking three free things – sunshine, water, carbon dioxide, running them through a catalyst called soil, and producing things to sell. ~ Ben Taylor-Davies

The magic of photosynthesis is that it takes abundant free resources we can’t otherwise easily capture, creates incredible ecosystems that sustain millions of organisms, which are used as food, clothing, and housing. Photosynthesis is the source engine that drives everything else.

Photosynthesis is the only way to bring new energy into the ecosystem. It makes sense to optimize the efficiency of this photosynthetic engine as much as possible, particularly when we consider that modern agriculture commonly realizes only 15-20% of an average crops photosynthetic potential. This means our use of these free resources is only 15%-20% of where it might be.

We choose to pass up these free inputs whenever we use products or management practices that limit photosynthesis and soil microbial activity, restricting carbon cycling.

Modern agronomy does not emphasize capitalizing on the things we are given for free, instead focusing on the supposed need to buy more things which are not free. Not free to the farmer, and expensive to the environment.

Contemplating additional inputs which may or may not be free –

Does nitrogen qualify? The air is 78% nitrogen, and vigorous healthy microbial populations have been measured supplying 300 units of N per acre with no legumes and no manure applications. Is biological nitrogen free? If not entirely free, it certainly costs only a fraction to grow as compared to buying it, both to the farmer, and to the environment.

What about soil minerals? Are they really free? What is the true value of soils that contain more phosphorus, potassium, calcium, and trace minerals than will be used by crops for centuries or millennia? Should we account for the additional value of soil’s mineral and humus fertility on our balance sheets when we improve it? Should we account for investments in regenerating soil fertility as an operating expense, or as a capital improvement? And most importantly, how expensive are purchased inputs that prevent us from accessing these resources in our soils?

What about the free consulting advice of sales agronomists who advocate the continued use growing practices and products which limit the potential of the ecosystem to tap in to these free inputs? How much does ‘free’ advice actually cost?

What do you think is perceived as free that actually isn’t?

What other things do you think are free that we are not considering or optimizing for?

2021-02-06T13:22:07-05:00February 9th, 2021|Tags: , |

Managing nutrition for control of aphids and flea beetles

Tom Dykstra and I discussed the concepts of plant health, nutrition management, and insect resistance in a rapid fire, intense one hour webinar, with a specific emphasis on controlling aphids in sugar beets and flea beetles in canola.

While the conversation was fairly high level, and didn’t get into the nuts and bolts of implementation, Tom’s knowledge of insect metabolism and the type of food sources they require to survive is unparalleled.

If you want to learn how to grow insect resistant crops, this webinar is a must listen. You kind find the recording on KindHarvest.ag here.

Tom uses a refractometer as a research tool, and describes a brix index of plant susceptibility to to different groups of insects at different brix levels. There is a big difference between using using brix as a research tool and using it as a crop management tool. You can read my thoughts on using brix here.

Cobalt to inhibit ethylene production, increase yields, and improve storability

Cobalt is an under valued and under used nutrient. If you are not managing cobalt, it is costing you yield and storability. It is likely costing a lot of yield.

When plants contain adequate levels of cobalt ethylene production is inhibited(1). This is a really big deal. You may not know about the many effects of ethylene in influencing growth, node elongation, and speeding up senescence. Here is a story, and short list of some of the impacts cobalt has.

When we worked with an organic green bean grower, in the first season, yields increased from a prior four year average of 3.7 tons per acre, to over 10 tons per acre. Almost a 3x yield increase. While all the other nutrients also had to be managed well, (and were, using plant sap analysis) I attribute much of the yield increase to managing cobalt.

Green beans set flowers over an extended period, but are usually concentrated into different ‘sets’. It is common for processing green beans to only have the first and second set be in the optimal size range when harvested. The third set is still too small, but if harvest is delayed until the third set is large enough, the first set is too mature with the seeds beginning to swell.

Seeds mature faster in response to ethylene. When we supplied this crop with cobalt, it delayed seed maturity on the first set, and permitted the harvest of the first, second, and third set,  all being in the appropriate size range at once.

Ethylene increases node length. When you have adequate cobalt, nodes will be much shorter. This means plants are short, stocky, and sturdy, have more nodes per inch of crop height, and can carry the heavy crop load.

Ethylene decreases the number of flowers/buds/fruit. When you have adequate cobalt, there are more flowers set per node, and higher fruit count. On soybeans, you can have as high as 10-12 pods per node (or higher) instead of only 2-3.

These are three significant contributing factor to increasing yields 3x.

When we store fruit for extended periods, such as apples, one of the challenges with degrading fruit quality while in storage is because of continued senescence and ethylene production. This can be inhibited with cobalt, which will improve storability. Any fruit or vegetable which gets stored or shipped will find its shelf life improved when it has adequate cobalt.

Cobalt is needed as an enzyme cofactor by rhizobium bacteria for nitrogen fixation. Many legumes fix only a fraction of the nitrogen they are capable of, because they lack adequate cobalt.

Cobalt is one of those elements that exist in the soil in different oxidation states. Plants use only the reduced form, and the reduced form is in very limited supply because of historical exposure to glyphosate and other management practices on most agricultural soils. Because of this, we often apply to the plant in the early stages of regenerating a soil system.

Cobalt is considered an essential plant nutrient. Why don’t we begin managing it as though it were as important as nitrogen?

1. Lau, O. L. & Yang, S. F. Inhibition of ethylene production by cobaltous ion. Plant Physiol. 58, 114–117 (1976).

2021-02-05T07:42:55-05:00February 5th, 2021|Tags: , , , |

Frost resistant seedlings

We have consistently observed that plants are able to tolerate freezing temperatures without damage when they are supported with balanced nutrition. It is particularly important that they not have excessive nitrogen.

These seedlings were grown in two different types of soilless media. The seedlings on the left are grown in media from Keystone BioAg, which has compost, biology, and soil amendments added to balance nutrition. The seedlings on the right are in standard peat moss based growing media.

Temperatures dropped to 27 degrees F (-3 C) one morning and the plants with balanced nutrition show no impact, while the plants on the conventional media are obviously burned.

What if we balanced row starter fertilizer nutrients with the intention of developing freeze resistance, how might the blend be different. Liquid N and P would certainly be excluded from the mix, and microbial populations and plant health would improve.

PS If you have read this far, you are invited to an Ask Me Anything session tomorrow afternoon at 1 PM EST on Zoom. You can register here. See you there!

2021-02-03T12:27:44-05:00February 4th, 2021|Tags: , , |

Nutrition helps cut fruit stay fresh longer

We expect a cut apple to  turn brown within a few hours if left exposed to the air.

Some people have noticed that occasionally apples turn brown only very slowly, taking a day or longer.

The change from white flesh to brown is result of polyphenol oxidation.

Common advice for people who want to avoid  browning while cooking with apples at home is to coat them with lemon or pineapple juice. Both of these juices provide antioxidants, which slows or stop the oxidation process, and prevent the polyphenol breakdown.

This begs the obvious question, what if the apple contained high levels of antioxidants to begin with?

When plants have nutritional integrity, they will produce much higher concentrations of antioxidants, which might be part of the explanation why some apples do not turn brown quickly.

This half eaten apple (grown with good nutritional balance) was deliberately left to see how quickly the polyphenols would oxidize. This photo was taken 96 hours after it was left on the counter.

Apples browning quickly is a nutritional imbalance problem, not a genetics problem that we should try to solve with genetic engineering.

PS If you are not on social media (wise choice) you may not have heard about RegenRev, a virtual regenerative ag conference taking place later today, that you can attend for free. You can find the details and sign up here. I personally know all the other presenters, and I can promise you don’t want to miss it.

2021-02-02T20:47:55-05:00February 3rd, 2021|Tags: , , |

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