Crop Health Transitions:
Identifying Key Stages of Plant Resilience
By John Kempf
Our vision and our mission is to help farmers produce healthy crops which are insect and disease resistant and have no need for toxic insecticides and fungicides. We can accomplish this goal by providing farmers with knowledge of how diseases and insect pests interact with growing plants, tools to monitor crop health in the field, and information and materials which can be used to increase and enhance plant health.
The degree of plant health and immunity is based on a plant’s ability to form structurally complete compounds such as carbohydrates and proteins. Complete carbohydrates, proteins, and lipids are formed by healthy plants with a fully functional enzyme system, which is dependent on trace mineral enzyme cofactors.
So-called plant pathogens, bacterial and fungal diseases, and insect pests have less complex digestive systems than higher animals and lack the needed enzymes to digest complete plant compounds. In his book titled Healthy Crops: A New Agricultural Revolution, Francis Chaboussou has documented a fair amount of research on plant-pathogen relationships, protein formation in plants, and the plant immunity connection. Chaboussou’s theory of plant health which he calls “Trophobiosis” is founded on the premise that insect and disease pests cannot utilize complete proteins and carbohydrates as a food source.
We work with a broad variety of fruit and vegetable and broadacre crops in many regions with different soils and different climates. On many of the farms we work with we have noticed some interesting transitional stages of plant health and energy levels as soil and plant health improve over time, frequently over a period of a few months to several years, depending on the crop and previous soil conditions. These stages of improving plant health have been based on our own experiences and in-field observations. Over time and experience on many farms a successful pattern of plant health stages is becoming clearer.
As charted in the graph (above), efficient photosynthesis and the formation of complete carbohydrates is the foundation of plant health and immunity. Without efficient photosynthesis plants will not achieve any level of immunity or performance.
With functional photosynthesis and adequate levels of minerals and trace minerals to serve as enzyme cofactors, formation of complete proteins is initiated. As photosynthetic capacity and plant energy increase, plants begin to store surplus energy in lipids, plant oils. These lipids are the building blocks used to build plant protection compounds, called plant secondary metabolites (PSMs) or plant essential oils.
Phase 1 In this foundational phase of plant growth and health, a plant’s needs for adequate sunlight, air, water and minerals are all being met, an efficient photosynthetic process is absorbing carbon dioxide from the air, water from the soil, and with the energy input from the sun, begins producing plant sugars, carbohydrates. Initially the sugars formed during this process will be monosacharrides; simple sugars such as fructose, sucrose, and dextrose. As the process evolves more complex sugars called polysaccharides begin to develop. Cellulose, lignin, pectins, and starches are structural and storage carbohydrates produced in greater quantities as plants become healthier.
In our experience, as long as plants are photosynthesizing properly and producing pectins and other complex carbohydrates, these plants do not seem to be susceptible to soilborne fungi — known as “pathogens.” Saprophytic fungi (fungi which decompose dead plant residue) such as alternaria, fusarium and verticillium only become a problem when plants are unhealthy to the point where they no longer develop complete carbohydrates. As long as we have active photosynthesis and energy transfer these “pathogens” cease to be a problem.
PHAsE II As photosynthetic energy increases, plants begin to transfer greater quantities of sugars to the root system and to the microbial community in the rhizosphere. This increase in energy and a food source for the soil microbes will stimulate them to mineralize and release minerals and trace minerals from the soil matrix and provide them in a plant-available form. Plants then utilize these essential minerals as enzyme cofactors which are needed to form complete carbohydrates and especially proteins. Soluble sugars — monosacharrides — when partnered with nitrogen are the base materials used to form amino acids.
Through the action of enzyme catalysts these amino acids are bonded together to form peptides, from which complete proteins are formed. Thanks to their rapid metabolism, insects need large amounts of protein for growth and reproduction. They can source their protein requirements from plants, which have elevated levels of soluble amino acids in the plant sap. Many insects have a simple digestive system which lacks the digestive enzymes needed to digest complex proteins. In our experience, plants which are forming complete proteins and have low levels of soluble amino acids are not susceptible to insects with simple digestive systems. This would include insects such as aphids and whiteflies, and especially larval insects such as cabbage loopers, corn earworm, alfalfa weevil, tomato hornworm and many others.
Phase III As photosynthetic energy and efficiency increases plants develop a surplus of energy beyond that needed for basic growth and reproduction. Initially, large quantities of this surplus energy in the form of sugars is translocated to the root system, as high as 70 percent of the total sugar production. Later the plant begins to store this surplus energy in the form of lipids (plant fats) in both vegetative and reproductive tissue. In vegetative tissue these fats are primarily in the form of Omega 3s, whereas Omega 6s and 9s are mostly found in the storage organs of the fruit.
Plants always maintain a minimum baseline of lipid levels since they need these compounds to help form the phospholipid cell membrane. As energy and lipid levels increase this cell membrane becomes much stronger and more resilient enabling it to better resist fungal pathogens. It appears as though once plants achieve higher lipid levels and stronger cell membranes they become more resistant to the airborne fungal pathogens such as downy and powdery mildew, late blight, scab, rust, and others as well as some bacterial invaders, notably fireblight, bacterial speck and bacterial spot, among others.
It should be noted that plants must have a functional digestive system (the microbial community in the rhizosphere) before they will develop to this stage of plant health, otherwise they will lack the energy needed to develop higher levels of lipids.
Phase IV The elevated lipid levels developed in phase III are then used to build complex plant protectant compounds. The plant builds these PSMs, or essential oils, to protect itself from would-be parasites, UV radiation, or overgrazing by insects or herbivores. Many of these compounds, which include terpenoids, bioflavonoids, carotenoids, tannins, and many others, contain anti-fungal and anti-bacterial properties, as well as digestion (enzyme) inhibitors.
Once plants achieve this level of performance, they become immune to insect attack from insects possessing a better-developed digestive system, primarily members of the beetle family such as cucumber beetles, Colorado potato beetles, and Japanese beetles. At this point, plants have a tremendous level of stress tolerance and can cope with weather extremes reasonably well.
Again these phases of plant health are based on our observations and experiences in the field. Transitions in the field are not always clearly delineated as in the chart, however over time a clearer picture begins to emerge as crops and soils become healthier and healthier and “pathogens” become less and less of a problem.
John Kempf is the owner of Advancing Eco-Agriculture (440-632-1012), Middlefield, Ohio, an eco-agriculture consulting and solutions company. Kempf along with Jerry Brunetti and Lawrence Mayhew will be leading a pre-conference intensive workshop on Comprehensive Eco-Growing Systems as part of the Acres U.S.A. Eco-Ag University in Columbus, Ohio. For more information on attending visit www.acresusa.com.
Healthy Crops: A New Agricultural Revolution by Francis Chaboussou is available from Acres U.S.A. For ordering information visit www.acresusa. com or call 800-355-5313.
This article has been reprinted with permission from the November 2011 issue of Acres U.S.A. visit the www.acresusa.com website.