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Organic Facilitators |
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Most of the companies which sell Liquid Nutrients and soil Bio Amendments utilize some type of carbon based liquid in the mixture. Basically they are used in two ways, either to add carbon to the rhizosphere or to help nutrients get
into the plant as a root feed or a foliar feed.
Health of the Rhizosphere
The rhizosphere is defined as the soil which is under the influence of the roots. The roots absorb water and nutrients in that area. This area of the soil is rich in microorganisms which increase nutrient availability, immobilize nitrogen in the root zone and reduce nitrate leaching. This biological fraction in the rhizosphere conserves nutrients and is responsible for organic material breakdown and nutrient cycling. The soil microorganisms are responsible for formation of soil structure, improved aeration and improved drainage.
During photosynthesis; sunlight, carbon dioxide and water thru the action of the chloroplasts and chlorophyll yield carbohydrates, oxygen and water. These carbohydrates are both utilized by the plant to sustain growth and life functions as well as be stored in the roots for reserve.
The roots are not photosynthetic and are 100% dependent on the photosynthetic energy captured in the leaves and shoots. The amount of energy captured depends on such things as the duration of light, the extent of stress, and the amount of leaf surface. Modern day superintendents in order
to satisfy the wants of their golfers for green speed simply cut their greens so low and so often that there is very limited leaf surface.
In an ordinary situation a plant will store ½ of all the carbohydrates produced in the root and utilize ½ for sustaining life functions. Around ½ of that carbohydrate reserve in the root is then excreted back into the rhizosphere as a microbial substraight called exudates. These exudates are a combination of protein, carbohydrates and sugars. These exudates sustain the life of the complex micro-community and the microbes in turn make nutrients available to the plant. Great teamwork.
On a modern putting green mowed at 1/8 inch or less, regardless if it is a warm or cool season grass, simple can not produce enough photosynthesis to make enough carbohydrates to go around. The turf is trying to survive and does a
poor job of storing reserve and an even poorer job of producing exudates.
Since the roots are largely responsible for the organic matter in the soil via exudates, then managing for maximum root growth becomes very
important. Anything we can do to improve either the physical properties of the soil or the chemical conditions of the soil are important agronomic practices.
There are many companies that have the philosophy that because your turf can not produce enough exudates to build the needed microcommunity, then they will produce and sell to you products that will assist in the health of the soil.
And while there is very little scientific evidence that these products work, the philosophy behind their development is backed by science.
These products may contain various types of carbohydrates, protein, glucose, sea weed extracts, organic acids, organic humates such as humic acid, amino acids, and simple organic extracts of composed manure or lenordite. These
may be alone or mixed in combination. With everyone making claims and little research going on pick products made by those companies which have good science behind them and make quality products and are willing to stand behind them. You have to be the judge of whether or not they are helping.
Organic Facilitators for Nutrients
Many humic and organic materials have the capacity to bind substantial amounts of metals and other cations, and they can therefore exert
considerable control over the supply and availability of nutrient elements to plants and in water.
When the metal ion or cation combines with an electron donor, the resulting substance is said to be a complex or coordination compound. If the donor atoms are attached not only to the metal ion but also to each other as well forming a ring, it creates a chelate.
There are good complexes and bad complexes and there are good and bad chelates. Some of the organic agents used in these products are: humic
acids from many sources, fulvic acids, ligno sulfates, amino acids, sugars and carbohydrates, hydrolyzed protein mixes and derivatives from the wood pulp industry. Many of these have low stability constants and when mixed with anions such as phosphates may result in precipitation. Once again, select your products wisely. When added to the nutrients, organics are biodegradable
and available to the plant and the soil micro community as an energy source.
Since the 1950’s synthetic chelating agents have been used as aids in plant nutrition. Among the more popular ones are EDTA, HEDTA and EGTA, and others. They are cost effective and can be effective if used properly but they are generally not biodegradable or very slowly biodegradable. Synthetic chelates are used extensively in many turf products. Many researchers have reported that they may remain as a residue in the plant tissue or in the soil tying up other nutrients and providing no additional energy source.
Both the synthetic chelating agents and some natural organic agents are intended to be root uptake. In the soil the synthetic agents can be effective. The intent of having a chelating agent is to prevent the negative charge on the soil colloid from attracting the nutrient and thus tie it up and make it unavailable to the plant. Complexing agents do not do as good a job of holding these bonds as do chelating agents but again there are many variables. The organic agents can duplicate becoming both a microbial feed as well as a
nutrient carrier.
Several of these chelates are also used to make nutrients available to the plant through direct absorption into the leaves and shoots. Once in the plant the act as any other nutrient would.
Absorption is only one aspect of a foliar fertilizer. In addition, the absorbed nutrient generally must be translocated throughout the plant. While absorption is a key process in selecting a foliar applied nutrient, the extent of redistribution or mobility of each nutrient in the plant is an important consideration also.
Buyer Beware
There is little regulation over the complexing and chelate industry.
- The presence of an organic or synthetic chelating agent in the formulation legally makes the product a chelate.
- It does not matter whether there is enough chelating agent in the mixture to chelate all the metals in the formulation or not to be considered a chelate. Many products contain only a few percent. Ask how much active ingredient is in the container.
- Any agent that can be shown to cause chelation is considered a chelate, without regard to whether it is stable or not.
- Unstable chelates that precipitate when mixed with anions, such as phosphorus, are poorly absorbed by the plants and are not translocated well in the plant.
- The concentration of these complexing and chelating agents in the various formulations need not be on the label.
I personally believe that the best chelating agents are those that are natural components found in the metabolism of the plant and my personal observation is that they need to compose a high concentration within the formulation.
Gary holds a BS degree in Agriculture and Entomology from Utah State University and a Master of Science degree in Agronomy from Michigan State University. After a 34 year career as a golf course superintendent
he retired to become co-founder of Grigg Brother Fertilizers.
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release 1/19/2011 |
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