The most important question in organic lawn care is:
Have you done a soil bioassay? It is imperative to know the micro/macro nutrient and biological make up of the soil. Soil bioassay's can be done by a local extention agent, university or commercial testing facility Here is some excellent information from Dr. Elaine Inghams site on how to interpret bioassay's
Bacterial balance Fungal balance Mycorrhizal balance Protozoa balance If you want to know why this works so well Keep reading Why apply compost tea The point of applying compost tea is to return the biology to the soil that should be present. This enables you to grow plants, grass or your favorite tomato with as little effort as possible. Beneficial bacteria and fungi are needed in the soil to make nutrients available to the plants. It also prevents erosion by gluing and binding soil particles together to form aggregates
What are the benefits of spraying compost teas? Benefits include increased nutrient and water aborption, nutrient mobilization, increase in feeder root longevity, accumulation of nitrogen, phosphorous, potassium, calcium, zinc and their translocation to the host tissue, minerals get mobilized in F and H horizons before they reach the sub soil system. Provide the host plant with growth hormones like auxins, cytokinins, gibberellins and growth regulators such as Vitamin B, plays a significant role in nutrient cycling and the entry of the fungai biomass into soil organic matter pool.
Application of synthetic or non organic nutrients The application of synthetic fertilizers to the soil discourages root growth and drought resistance. Think of it this way, if someone was to feed you all of your nutrients needs, eggs, steaks, french fries, etc. in the same place every day why would you ever go somewhere else? Well, OK you have a car but plant roots don't. As we apply these, immediately plant available, nutrients to the soil, they melt and drop into the top one, maybe two inches of soil. If you ever dig in your yard you will notice that the roots really do not go down that far. Why would they? All of the nutrients are in the top 2 inches of soil. During times of low moisture and high heat, which is known around here as SUMMER, the roots do not penetrate far enough into the soil to be able to reach cooler wetter soils and suffer the consequences. If we begin a program that encourages increased root mass and penetration into the soil we dramatically increase drought resistance and overall health for turf
Can compost tea supply the nutrients to the soil that plants and grasses need? The surprising answer to that question is yes. Not in the standard "fertilizer" form (nitrate) however, but as organic N, held by the biology in organic matter and microbial, biological forms.
Is compost tea a fertilizer? Most people have been told that compost tea is not a fertilizer. That statement can be made if only soluble, inorganic nutrients are used. The fertilizer industry has pushed to define N as only nitrate, possibly nitrite and maybe ammonium, the inorganic forms of N. While this is based on the soluble forms of N that most vegetable and row crops take up through their roots, it is far from the only source of N in the soil. Nitrogen enters the soil in organic forms such as plant roots, leaves, and other plant materials, in addition to dead animals, insects, and microorganisms, manure, and compost. As these decompose, the once recognizeable plant and animal materials are transformed into soil organic matter called humus which contains organic nitrogen. Living plants cannot use these organic forms of N. This is why microbes living in the soil are so important, because they convert organic N into forms of N that plants can then use. If the full soil web is present, then forms of N that are not nitrate, nitrite or ammonium will be cycled into these soluble forms by the organisms. And not just N, but any non-soluble form of any nutrient will eventually be converted from its non-soluble form to the plant available, soluble form by the organisms cycling system in a healthy soil. Natural systems do not require the additions of inorganic, soluble (and thus very leechable) forms of nutrients to maintain soil and plant health. The most productive systems on this planet are systems which do not have, and have not ever had, inorganic fertilizer applied
The good guys in the soil Bacteria There are typically 40 million bacterial cells in a gram of soil and a million bacterial cells in a milliliter of fresh water; in all, there are approximately five nonillion (5×1030) bacteria in the world. Bacteria are vital in recycling nutrients, and many important steps in nutrient cycles depend on bacteria, such as the fixation of nitrogen from the atmosphere. Bacteria occupy most of the leaf and/or root surface and thus are effective at consuming the food resource that the disease causing organisms would otherwise consume. In soil, bacteria have additional function beyond consuming; they also retain nutrients (N, P, S, Ca, Fe, etc.) in their bio-mass. Bacteria also decompose plant-toxic materials and plant residues and build soil structure. The smallest building blocks of soil structure are built by beneficial bacteria. Without these bacteria, the bricks to make the "soil house" will not occur and further development of soil structure will not happen. If the organisms are not present, water holding capacity can not be improved. Most of the bacteria in the compost tea will not be the right ones at the moment you apply the tea, so they go to sleep in the soil, and wait for the right conditions that will allow them to wake up, suppress their competitors, retain nutrients, decompose residues and build soil aggregate structure.
Protozoa Protozoa eat bacteria, releasing nutrients that stimulate growth of bacteria, fungi and plants, if plants are present. So, when scientists say "bacteria mineralizes N in soil", what is really happening is that protozoa mineralize N as they consume bacteria.
Nematodes Nematodes play a number of different roles in the soil, and it is important to recognize that while one group of nematodes is detrimental to plant growth, most nematodes in the soil are beneficial for plant growth. There are four major functional groups of nematodes in soil. 1. Plant-feeders are the "bad guys", and consume root material , reducing plant growth 2. Bacterial-feeders consume bacteria, releasing N, P, S, etc. which are then available for plant uptake 3. Fungal-feeders consume fungi releasing N, P, S, etc. which are available for plant uptake 4. Predatory nematodes consume other nematodes and keep the population numbers of the bad guys, and the good guys, under control. Too many bacterial feeders could reduce bacterial populations below the level needed to suppress disease, retain nutrients, decompose residues or build soil aggregates. Thus predators are important controls on the soil food web.
Soil Testing Healthy soil contains the proper balance of organisms, minerals, nutrients, organic matter and other essential components. Soil sampling is used to determine depth, structure and texture of the topsoil layer and basic characteristics of the subsoil layer. A standard soil test is used to determine soil PH, the percent of organic matter contained in the soil, any nutrient or mineral deficiencies, excesses or imbalances and recommendations for corrective measures. For these reasons soil testing should be mandatory when amending the soil with nitrogen, phosphorous, or potassium. A more comprehensive soil bioassay can evaluate the presence and balance of soil organisms such as fungi, bacteria, nematodes and protozoa.
The organically maintained landscape In natural systems, organic matter generally cycles in place, added to the soil through root and stem decay of winter killed annuals and leaf decay. A thriving microbial community digests and breaks down this organic matter to release nutrients back to the soil. Organic soil amendments may be needed to help balance the soils chemistry, stimulate its biology, and restore its physical composition. Such amendments may also be needed to feed turfgrass in a lawn, which has extraordinary nutrient needs because it is grown in an unnatural way, perpetually mowed and kept green as long as possible.
NPK and Inorganic Fertilizers Lawn and landscape care methods which directly feed the plant with synthetic nitrogen-phosphorous-potassium (NPK) lead to damage to the soil and a weak root system, making the turfgrass or plants in the landscape more susceptible to insects, disease and drought. Over fertilizing the turfgrass or plant will also inhibit the development of mycorrhizae, a symbiotic fungi growing on or around the plant roots that help gather nutrients beyond the range of the root themselves. Eventually the soil structure collapses and becomes infertile.
Leaching Like the negative end of a magnet, nitrogen in the form of nitrate is negatively charged and is not attracted to soil's negatively charged clay and humus. Negatively charged clay repels negatively charged nitrite ( NO2- ) and nitrate ( NO3- ) so they will not be absorbed by the clay and are left to move down through the soil and into the groundwater, where streams and drinking water can become contaminated.
Reviving collapsed soil structure To revive dead, compacted soil, it will necessary to apply compost and compost tea to improve and build soil life. A well balanced soil fertility program that increases humus content, organic matter and beneficial microorganisms recycles nutrients, improves water retention, balances minerals and buffers PH. In addition to compost, organic matter (manure) and compost tea other amendments may be indicated based on soil test results. These include natural surfactants to aerate soil, root stimulants and developers, rock dust, secondary and micronutrients, flocculants, vitamins, beneficial microbes, enzymes, organic humus, fulvic acid, kelp or dextrose.
What is nitrogen (N)? Nitrogen is an essential macronutrient because it is required to create amino acids and proteins, genetic material, chlorophyll and other important biochemical molecules. Nitrogen is the most abundant gas in the atmosphere (78%) but the gaeous form (N2) is inert and unavailable for use by animals and most plants. Turning N2 into available nitrogen or "fixing" it, requires breaking the bond between the nitrogen atoms which requires energy. Under natural conditions nitrogen is fixed by lightning strikes through the atmosphere and by the work of a few species of symbiotic bacteria and some free-living bacteria and fungi in the soil or water. As part of the symbiotic relationship, the plant subsequently converts the ammonium ion to nitrogen oxides and amino acids to form proteins and other biologically useful molecules, such as alkaloids. In return for the usable (fixed) nitrogen, the plant secretes sugars to the symbiotic bacteria.
What is Phosphorous? (P) Phosphorous, in the form of phosphate, is an essential macronutrient – it is a vital part of the cellular energy transfer. Phosphorous is added to soils in natural systems by rock weathering. Leaching and runoff removes phosphorous from the soils, where it is carried to aquatic systems like aquifers, streams, lakes and bays. In fresh water aquatic systems excess phosphorous can substantially increase plant productivity and lead to eutrophic conditions (lack of oxygen), causing increased phytoplankton and bacterial growth, loss of dissolved oxygen and loss of animal life in the system.
What is Potassium? (K) It is primarily used in fertilizers as either the chloride, sulfate or carbonate - not as the oxide. Potassium is an essential component needed in plant growth and is found in most soil types. Potassium has two roles in the functioning of plant cells. First, it has an irreplaceable part to play in the activation of enzymes which are fundamental to metabolic processes, especially the production of proteins and sugars. Only small amounts of potassium are required for this biochemical function. Second, potassium is the "plant-preferred" ion for maintaining the water content and hence the turgor (rigidity) of each cell, a biophysical role. A large concentration of potassium in the cell sap creates conditions that cause water to move into the cell (osmosis) through the porous cell wall. Turgid cells maintain the leaf's vigor so that photosynthesis proceeds efficiently. Plants are apparently unable to regulate the uptake of potassium; and if the soil supply is high enough, a so called luxury consumption may result. Under such conditions, the high potassium content in the grass plant may cause an excessive amount of stiffness in the stems and leaves as well as other undesirable or harmful effects.
NPK note: Commercial preparations of fertilizers have a somewhat misleading labeling system. It is often said that the three main numbers listed is the amount of Nitrogen, Phosphorus, and Potassium in the product. This is NOT the case. You must read the label carefully. If you read carefully, you will find that the last number is the percentage of Soluble Potash – NOT Potassium – expressed as K2O.
THE MYSTERY RATIO by Paul Tukey — Here's something you won't hear from most soil testing agencies outside of the Soil Food Web: The relationship between calcium and magnesium is among the most important in lawn care. For years, especially in the East where soils are inherently acidic, folks have applied limestone to raise the pH. Often times, that limestone has been dolomitic in nature, meaning it contains a high percentage of the heavy metal magnesium. Although soils do need magnesium to grow grass, too much magnesium will leave soils overly compacted. The result is often a high percentage of weeds. If your soil test result from the Cooperative Extension Service tells you to add limestone at a specific rate, you'll almost always be better off adding high-calcium or "calcitic" limestone rather than dolomitic limestone. In soil, the ideal ratio is seven times more calcium than magnesium. Since calcium moves through the soil slowly, it's almost impossible to add too much A lot of credit needs to go to Dr. Elaine Ingham for some of this, her Compost Tea Brewing Manual is very comprehensive and full of great information to understand the inner workings of soil.