Advanced Seminar on Soil Mineral Nutrition:
Techniques for Raising Yield and Quality
by Ben Grosscup with gratitude to Dan Kittredge
On February 5-7, 2009, NOFA/Mass will host a three-day seminar in Barre on advanced biological farming techniques that can improve yields, decrease disease and insect pressure, and improve the taste and nutritional content of crops. The presenter, Arden Andersen - an agronomist, osteopathic physician, and international leader in the field of biological farming - says big changes are coming in agriculture: Quality standards like nutrient density will gain in importance alongside process standards, such as organic.
To learn how this approach works and what growers might gain from the seminar, I spoke with Dan Kittredge, a leading practitioner of biological farming in Massachusetts and an alumnus of Andersen's seminars. I was happy to learn that the basic science behind this approach is not mysterious, and growers can begin to implement it in the short-term.
Kittredge says that the approach of biological farming is managing the soil to create an optimal environment for soil life. To maximize yield and nutrition, crop plants require soil with sufficient biologically available minerals in ratios appropriate for feeding the fungal, bacterial and other soil life communities that have symbiotic relationships with crop plants. By understanding what environmental conditions are optimal for what we're growing, we can make informed management decisions about what we need to add to the soil. Kittredge says the approach involves a few basic steps.
Step 1: Testing the Soil
First, we need to understand what is going on in the soil, biologically. Typical university soil tests use a strong acid to dissolve and then analyze the mineral components of soil. However, these tests don't tell us how much of the minerals are biologically available, because they don't reproduce the plant's acidic conditions. To determine what mineral and biological amendments are needed, we need a soil test that uses an acid with similar intensity to that of the exudates from plant roots, fungi, and bacteria.
Step 2: Amending the Soil with Minerals
By weight and volume, the most deficient minerals in Northeast soils tend to be calcium and phosphorus. These basic deficiencies can be remedied by adding calcium carbonate (limestone), calcium sulfate (gypsum), and soft rock phosphate to the soil. Once these macro minerals are in place we can begin remedying trace mineral deficiencies such as manganese, iron, copper, cobalt, boron, and selenium.
Step 3: Providing Biological Companions with the Minerals
These minerals need to be accompanied with an appropriate microbiological regimen, because plants cannot directly digest crystaline mineral compounds such as calcium carbonate; they require microbiological organisms to do it for them. Microbiological soil communities involve both bacteria and fungi. Bacterial predominance tends to favor weeds, and fungal predominance (especially mycorrhizae) favors crop plants, so inoculating with mycorrhizael spores is almost always beneficial.
Step 4: Feeding the Microbiological Companions
Once the mineral and biological components are physically present in the soil, the next step is to facilitate the reintroduction of the minerals into the biological system. This is done by ensuring that the microbiological organisms can access sufficient energy to digest the minerals, thereby making them available to the crops as nutrition. This process requires energy, similarly to human digestion. To illustrate this, a person may feel tired after a large meal due to the energy the digestive system expends.
In fields where the symbiotic relationship between mineral-digesting microbes and crops is compromised, we need to add materials that provide readily available energy for microbes such as fish emulsion, molasses, and/or kelp. Without this "feeding," adding otherwise beneficial minerals can actually decrease crop growth in the short-term, because the microbes begin expending energy to digest minerals into a biologically available form without enough energy to complete the process. The soil eventually absorbs the minerals and becomes healthier, but waiting is unnecessary.
Step 5: Monitoring your Progress
Over-applying or under-applying any components to the soil can pose certain problems. Finding the happy middle is the real art of this approach. To inform these decisions, Kittredge suggests monitoring both soils and crops with a variety of diagnostic tools, each revealing different parts of the picture.
In addition to the pH test, the refractometer is a key tool in the biological farmer's toolbox. This simple device measures dissolved solids (e.g. sugars, amino acids, oils, proteins, flavonoids, and minerals) in the sap of plants. This measurement, known as brix, correlates with the crop's nutrient quality and vitality.
Another important tool is the electrical conductivity meter. By measuring the electrical conductivity of the soil, we can perceive the availability of energy to the microbiological organisms, so necessary for soil health. By taking pH, brix, and conductivity readings, we can gain a sophisticated understanding in real time of what mineral and biological deficiencies are present and amend our fields accordingly. These tools are no alternative to regular visual, tactile, olfactory and taste monitoring of crops, but can enhance our ability to discern what our crops need.
Why does it work?
These techniques work by creating environments that are highly conducive for the expression of crop DNA and inhospitable for weeds, insects, and diseases. By applying the relevant scientific understandings of each species' preferred environmental conditions, we can skew the forces at work in our fields to favor crops.
The appeal of a plant to pest insects depends much on whether it is undergoing protein synthesis or not. A plant that is, produces complete proteins, non-reducing sugars and complex carbohydrates - all of which constitute nutritious food for mammals. But insects can't digest these same molecules. Farmers who successfully implement biological methods report insects do not eat their crops, even while infestations ravage neighboring fields. When a plant is not in protein synthesis, it is in proteolysis, meaning that the plant is degraded at the cellular level - a condition that correlates with low-brix. This is caused by environmental stresses such as nutrient deficiencies, drought, and chemical fungicides, pesticides, and herbicides. Pest insects sense degraded plants, whose proteins they can digest, and feed on them.
The success of weeds in our fields indicates nutritionally imbalanced soil for our crops, and particular weeds provide clues about which nutrients are not available enough. For instance, broad leaf weeds grow where the potassium to phosphorus ratio is out of balance, sour grass weeds grow where the calcium to magnesium ratio is off, and succulent weeds grow where biologically available carbon is deficient.
Soil compaction - another factor undermining crop health - occurs in large part due to excessive ratios of magnesium to calcium in the soil. Adequate biologically available calcium flocculates the soil, whereas excessive magnesium compacts it - with or without heavy tractors riding over it.
What's at Stake?
Arden Andersen writes on his blog, "USDA and UK Ministry of Agriculture statistics show that food grown today has 30-70% percent less nutritional value than the same foods grown 50 years ago. Eating all the right foods today still leaves us short of needed nutrition." Industrialized agriculture denudes soils of biological diversity and essential minerals, generating foods whose nutritional deficiencies cause health problems for those surviving on them.
With degraded nutrition comes degraded taste. Japan has begun demanding high-brix kiwis from New Zealand, because the higher nutrient quality corresponds to improved taste. The mealy, flavorless, low-brix kiwis are segregated and sent to the United States, because quality standards have dropped so low.
Finally, the same practices that produce healthy food regenerate our environment. Recent Midwest floods would not have been so devastating had biological methods been widely used on cropland. Sufficient calcium and biological activity expands the water retention capacity of soil, preventing run-off that ruins both crops and low-lying town centers, while replenishing much depleted aquifers. Moreover, growing plants in protein synthesis sequester atmospheric carbon by incorporating it into the biological system.
The February Seminar
Complex soil science underlies the basic principles of biological farming, but putting it to work in the field doesn't require academic expertise. It does, however, require understanding soil components and their importance. The 3-day seminar gives farmers a unique chance to become conversant with these exciting and eminently practical conceptual tools.
Arden Andersen has contributed enormously to the field of biological farming by compiling and interpreting the work of some of the 20th Century's brightest soil scientists, including Dr. Carey Reams, Dr. Dan Skow, Dr. William Albrecht, Dr. Phil Callahan, and others. For decades, these researchers have demonstrated the effectiveness of biological techniques through hard science.
The organic movement, despite its many innovations, remains heir to some misguided legacies -- such as managing pests with implements that kill rather than on managing soil with implements that provide nutrition. The potential of biological farming for completing what the organic movement has begun are truly exciting.
NOFA/Mass is actively seeking funding to provide on-the-farm technical assistance for farmers adopting these methods, so that after this seminar they will have access to trained knowledgeable help to implement their biological crop nutrition program. Registration for the seminar is $195. With both the NOFA member discount and the early-bird discount (must sign-up before January 17), it is $165. Get full info about this event, including registration: click here. Pre-registration is required and seminar enrollment is capped at 150 people -- first come, first served. Direct questions to: Ben Grosscup, Event Coordinator, ben.grosscup@nofamass.org, 413-658-5374.
This page was last modified on December 09, 2008 at 1:06:02 PM.
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