Archive for soil food web
To understand how soils work in conjunction with plants, you really need to understand cellular biology; however, in this article, we are going to take a much simpler look at how soil nutrients, plant function and soil biology work together to form a sustainable environment.
As indicated in February’s article, most of us who are trying to “fix” or “maintain” our soils are concerned about the NPK numbers on fertilizer bags; however, knowing the nitrogen, phosphorus and potassium levels of a product is only the start to creating a sustainable soil. “Generations of gardeners have been brought up on 10-10-10 and 39-9-12, but nitrogen, phosphorus and potassium are just three of many nutrients that plants need to survive.”
Two additional nutrients to consider when evaluating soil’s sustainability are calcium (which stabilizes pH levels and biological activity, loosens soil, is a major component of plant cell walls and is a key indicator of weed growth) and magnesium (which holds soil particles together and is a major component that promotes plant growth). An equally important factor to consider is the relationship between calcium and magnesium. Evidence shows that soils low in calcium and high in magnesium tend to exhibit greater weed pressure and are prone to compaction. There are additional secondary nutrients and micronutrients to consider, but we’ll address that in future discussions.
A good soil test will provide you with nutrient levels currently in your soil. Here are a few suggestions to assist you:
- Don’t use a cheap test. Inexpensive tests are likely to paint an inaccurate picture of your soil, which can result in over-fertilization and further damage to your soil.
- Make sure your test is checking for soluble nutrient values. Our soils in the Midwest are typically heavy in clay, which binds up nutrients and makes them inaccessible to plants. Soluble values tell you the amount of that nutrient that is available for the plant.
- Make sure your test checks for the pH, organic matter percentage, cation exchange capacity (CEC) and base saturation levels. Ideally you are looking for a pH value of 6-7, 5-15 percent organic matter, CEC of 10-15 and a calcium to magnesium ratio of 7:1. Anything above or below these numbers will likely require inputs to adjust and this could take months or years.
So, now that we have a basic understanding of nutrients, how do we get the nutrients into the plants? This is where biology plays such a critical role in soil sustainability.
Plants have a symbiotic relationship with their soils. Plants give up nearly 60 percent of their energy to their roots, which release exudates. Exudates are a food source for bacteria and the start of the nutrient cycling process within the soil food web as well as the start of sustainability.
If you are applying a dry fertilizer to your lawn, garden or farm, and you have insufficient biological activity in the soil, there is no way for your grass or other plants to take up those necessary nutrients and very little defense against pests and diseases. If possible, have a bioassay test done on your soil to get a basic understanding of your biological activity.
In an organic environment, soil organisms need to digest the organic material (nutrients) and smaller organisms (soil food web) before any plant can benefit from the micronutrients. This is why synthetic fertilizers are so harmful and why we have become so dependent on them. Once the synthetic nutrient is absorbed into the plant, the runoff leaches into the ground, thus killing off the microorganisms in the soil. Once the organisms are gone, you become dependent on the synthetic fertilizer.
To speed up the nutrient cycling process, many organic farmers and land care professionals create and use custom blended compost teas. By suspending the micronutrients of quality compost in a liquid form, the plants and soil organisms can access the benefits of the compost/nutrients far more quickly and, if the soil is lacking in biodiversity, we can inoculate the soils with the necessary biology to ensure all necessary components are available for a healthy, sustainable soil.
Diversity is important because every soil is different. Having a wide variety of bacteria and fungi handles a wide variety of deficiencies. In order for the bi-products of the microbiology to be of any value, however, the soil food web needs to continue its cycle with the help of arthropods, nematodes and protozoa (the shredders, predators and grazers found in the third trophic level of the soil food web). Backyard Organics provides the necessary predators by using good quality compost, naturally rich with nematodes and protozoa, and extracting them using an actively aerated brew process. We then add a variety of appropriate nutrients that help the microbiology live and prosper until your soil is able to sustain itself.
So, if you are considering taking a healthier, more sustainable approach to maintaining your yard and gardens, consider not only the nutrients the plants need, but also the biology and the whole ecology necessary to sustain that environment.
Todd and Tara Rockweit are owners of Backyard Organics, LLC, Wisconsin’s first organic land care business accredited by NOFA, one of two organizations in the country that accredit Organic Land Care Professionals (AOLCPs). Since 2004, Backyard Organics has been supplying natural and organic products and services for people, pets and property, including a complete do-it-yourself program. To read more about our products and services, or if you would like to submit a question, please visit us at www.backyardorganics.net, email firstname.lastname@example.org or call 920.730.3253/888.200.0446.
Jan. 06, 2013 |
In a series of articles that will be written throughout this years growing season, I will try to walk you through the process of converting a non-productive and/or chemical dependent lawn, garden, and/or farm into a safe, sustainable environment that requires less time, money and effort to achieve fantastic results. This month, however, we are going to focus on the basics of soil and help you understand how sustainability starts.
Soil is typically made up of 45% clay, silt, and sand; 25% air; 25% water; and 5% organic matter (if you’re lucky). Understanding your soil profile is the start to achieving sustainability but we are not done yet.
The conventional view of the soil looks at three “independent” factors which make up soil and they are structural, chemical and biological. The emerging view of soil and soil health is looking at the same three factors; however, rather than looking at each component independently, soil health is achieved when all three are working together, not autonomously. Lets consider the three factors independently and then how they should work together.
Soil Structure tells us the size and portion of the particles within a sample, in other words the percentage of sand, silt, and clay found in the soil sample. Understanding soil structure is the start to better understanding the soil’s ability to retain nutrients, its holding capacity for water retention, and its tendency to become compacted. For a quick and easy way to test soil structure, try the ribbon test. Here is a link to the ribbon test instructions, http://www.backyardorganics.net/faq/
Understanding the chemical make up of soils is the typical benchmark used by most land care providers. This will give you a better understanding of the macro (Nitrogen (N), phosphorus (P), potassium (K)) and micro nutrients found in the soil. Chemical testing will also uncover the “blood count” and “blood pressure” of the soil, in other words the pH of the soil. This pH is a critical factor in determining nutrient availability, especially if the soil is lacking biology, but we’ll get into that in later articles. Depending on the test, a chemical test should also give you the holding capacity of nutrients (C.E.C.), organic matter percentage, and soluble values of macro and micro nutrients, which are the nutrients actually available to the plants. Again, the chemical component to soils is certainly a key factor and one that should be understood but by itself will not achieve a healthy, sustainable soil.
The biological component to a healthy soil is probably the least discussed and perhaps the most influential factor in achieving sustainability. The biological component is made of bacteria, fungi, protozoa and nematodes in addition to a variety of other insects. Why is it important to understand the biological make up of your soil? Because without good soil biology, pH alone will determine nutrient availability to your plants and manual inputs will then be required to retain the appropriate nutrient levels to feed those plants.
Here is a closer look at the microbes found in healthy soils; Bacteria are mostly decomposers which feed on plant exudates and fresh organic matter. They immobilize and retain nutrients in their bodies and are very nitrogen dense. Bacteria have six times the nitrogen than the microbe which feeds on them. Think of them as little bags of fertilizer! Fungi are also decomposers, feeding on more complex organic matter. Fungi thread-like growth habit improves soil texture, transports water, and nutrients, and protects against pathogens. Protozoa, nematodes and other insects are the preditors to bacteria and fungi and the carrier of the value which comes in the form of natural, slow releasing fertilizer. The biological component to soil is the difference between “dirt” and “soil”. Without biology, over time you would simply have sterile “dirt”.
“The nation that destroys its soil, destroys itself”, President Franklin D. Roosevelt.
Soils require a balance between structural, chemical and biological components to be sustainable. If you are lacking one component, your soil will require manual inputs in the form of fertilizers (either organic or chemical based) or mechanical soil manipulation. The greater the balance, the more sustainable the soil.
This article will also appear in the February, 2013 edition of Nature’s Pathways
In the months ahead we will talk more about how soil components should work together and how to build and maintain soil fertility.
Feb. 09, 2012 |
For the past year you have read our articles that described what is happening in the soil and the potential problems that can occur if that “life cycle” is disrupted either chemically or through our own use of the land. Today I would like to talk to you about a tool that homeowners and gardeners can use to help get back your healthy soil – compost tea.
Brewing high-quality compost tea with consistent results is a challenge (much like brewing good-quality coffee or beer), which is why it’s critical to source the highest-quality compost and nutrients as well as utilize the best equipment and processes that will not harm the biology. Brewing compost tea can be as simple as a five-gallon bucket and compost processed from home or as complex as a 250-gallon brewer, bio-assay tested compost, and an assortment of nutrients and soil additives, which is the approach that Backyard Organics™ takes. In addition to the technical design of the equipment and the science behind the formulations, timing of the applications is critical. Compost tea is a live, active, aerobic blend of microbes, which are rapidly expanding and can become unfavorable if they run out of nutrients and become anaerobic. Applying compost tea with the first 48 of a finished brew cycle is critical to receiving a quality product.
A good-quality compost tea has a quantity and diversity of microbes. Compost teas that achieve high quantities and a good diversity of bacteria, fungi, nematodes and protozoas are able to combat a larger variety of symptomatic issues. Each community, each neighborhood and each yard have unique soil needs. Having a high count and a diverse group of microbes ensures consistent results. Also, applications within a yard can vary, which is why it’s important to be able to understand the differences between a fungal-dominated need versus a bacterially dominated need. For example, certain grasses prefer a more bacterially dominated compost whereas certain trees and shrubs prefer more fungal activity. This is why it’s always important to test your soils prior to applying amendments.
Verified benefits of compost tea
- Improves soil structure and porosity – creating a better plant root environment
- Increases moisture infiltration and permeability, and reduces bulk density of heavy soils – improving moisture infiltration rates and reducing erosion and runoff
- Improves the moisture holding capacity of light soils – reducing water loss and nutrient leaching, and improving moisture retention
- Improves the cation exchange capacity (CEC) of soils
- Supplies organic matter
- Aids the proliferation of soil microbes
- Supplies beneficial microorganisms to soils and growing media
- Encourages vigorous root growth
- Allows plants to more effectively utilize nutrients while reducing nutrient loss by leaching
- Enables soils to retain nutrients longer
- Contains humus – assisting in soil aggregation and making nutrients more available for plant uptake
- Buffers soil pH
In addition to the numerous biological benefits, compost tea also has a practical side that can greatly benefit the homeowner. Compost tea, whether you brew it yourself or have someone apply it for you, can be applied as a foliar feeder. Feeding the leaves of plants, shrubs and trees, efficiently uptakes nutrients, stimulates the plant rhizosphere and acts as a protector against harmful leaf diseases. Also, compost tea is much easier to spread and faster acting than compost with the same biological benefits of a compost top dressing application (we would still recommend compost application if your soil is lacking organic matter).
Here is what a few experts in the field have to say about compost tea:
“Aerated compost teas are the latest in scientific organic research today. In many ways, aerated teas offer greater immediate benefits than classic compost, manure or other homemade foliar teas” – The Garden Web
“Compost tea is one of the inputs on the horizon that will change the way we deal with several of the management aspects of growing high-quality turfgrass, either in your backyard, on your town’s parks and athletic fields, or on commercial and institutional properties” – Chip Osborne, Osborne Organics
Dr. Elaine Ingham, a leading researcher and founder of the Soil Food Web organization, sums the benefits of compost teas up best … “The use of actively aerated tea, when applied under a proper management regime, returns beneficial biology to the soil. This in turn rebuilds a soil food weed which, reduced dependency on fertilizers and pesticides, improves plant growth and reduces disease, significantly reduces water use, reduces toxicity and encourages the healthy establishment of healthy biology” – Dr. Elaine Ingham, President and Director of Research at Soil Foodweb, Inc.
Backyard Organics™ firmly believes in the benefits of organic land care and agrees with Chip Osborne and experts in the field who believe that compost teas will be one of those “tools” that will change the way we deal with land care in the future.
Todd and Tara Rockweit are owners of Backyard Organics, LLC, Wisconsin’s first organic land care business accredited by NOFA, one of two organizations in the country that accredit Organic Land Care Professionals (AOLCPs). Backyard Organics also supplies a variety of natural and organic products for people, pets and property. To read more about our products and service, or to submit a question, please visit us at www.backyardorganics.net, e-mail us at email@example.com or call us at 920.850.7450.
Dec. 01, 2011 |
Very little customization can be done with dry applications (early spring and winter applications), so they will remain the same for 2012. However, I have asked our agronomist to re-evaluate our wet applications in an effort to improve on the effectiveness of the application. The result of his findings and numerous conversations with professionals in the industry is new equipment, new products, and a new process.
We will continue to apply products based on soil type; however, the rate of the application will now change, depending on your specific soil type. For example, soil types A and C will get a slightly higher rate of products (perhaps 1 to 3 gallons/1000 sq.ft vs. 2 gallons/1000) applied because of their lack of certain microbial activity. More product = more microbes which is lacking in soil types A and C.
Compost Tea Brewer
We have purchased a Greater Earth Organics compost tea brewer and will be setting that up in the shop during the off season. The brewer will allow us to formulate a tea that is more specific to our clients’ needs and is rich in numbers and diversity of bacteria, fungi, protozoa, and the more complex nematodes. “As these organisms eat, grow, and move through the soil, they make it possible to have clean water, clean air, healthy plants and moderated water flow,” according to Elaine R. Ingham. Each day of applications will start with a freshly brewed batch of extract and, when combined with our custom nutrient blend, will form the most diverse and active blend of microbial activity offered.
Click the link above to see how Harvard is using the same equipment that Backyard Organics uses.
Modifications will be made to our compost tea application equipment in order to “protect” the microbes as they are being applied.
In 2012 Bio Humus will be used as a standard nutrient to all soil types. In 2011 we added Bio Humus only at certain times during the year or to certain soil types. We have since discovered that Bio Humus can benefit all soil types, depending on the application rate.
We will continue to work with our agronomist, local professionals, and the Soil Food Web professionals throughout the country on the optimal biology and nutrient combination that is best for our soil types. Certainly, this is a science and a number of variables go into healthy productive soil; the key for us is to live, learn, and apply as we go.
Natural Thatching Additive
We will continue to use an additive in our final, early fall wet application that naturally expedites the decomposing of dead plant material (thatch) into organic matter; however, we have been told that with our new brewer we should no longer need the additive. We will keep a close eye on the wet applications and make necessary adjustments as we go. Please email me to let me know how your thatch looks in 2012. BYO’s Email Address
Testing Products for 2012 – We will be experimenting with a product called Cedar Gard, an insect control product we can add directly to our Summer applications. We would apply it at a preventative level, and an added bonus is that it would add a cedar smell to the tea. Initially, we’ll be exploring client interest and will experiment with it on a few yards during the summer applications.
Chemical Free Insect Control - Testing Phase only
Our Summer 1 and Summer 2 applications will include Cedar Gard to drive non-beneficial insects from the area. The aroma of cedar oil is lethal to non-beneficial insects which are driven by pheromone (odor) and heat stimuli. Cedar oil stifles the ability of the insect’s receptors to detect food and mates, and the oil disrupts its reproductive habitats. The affected insects are grasshoppers, mosquitoes (adults), springtails, and ticks.
Garden applications of Compost Teas. Following the success at Gardens of the Fox Cities and the feedback we received from this years clients that received garden applications of compost teas, we have decided to add the application to the services offered. Pricing will vary depending on garden size and will only be available during the early spring and late fall applications.
Tree and Shrub applications. Our new brewer and application equipment is now allowing us to provide the same benefits to trees and shrubs as we do with soils and turf. Pricing will vary depending on size and quantity. Application can be done throughout the growing season.
What They Are and A Few Interesting Facts
Bacteria are minuscule, one-celled organisms that can only be seen with a powerful light (1000X) or electron microscope (we’re talking TINY). They can be so numerous that a pinch of soil can contain millions of organisms. Bacteria are tough—they occur everywhere on earth and have even been found over a mile down into the core of the earth.
Bacteria can be classified into five functional groups. Autotrophic (literally, self-feeding) bacteria are photosynthetic. They are the primary producers. Decomposers consume soil organic matter, plant litter, and simple carbon compounds, releasing the nutrients in these substances for use by living plants. Mutualists, such as nitrogen-fixing bacteria, form associations with plants and help them absorb nutrients. Pathogens are the bad guys— they cause disease in plants. The last group, the chemolithotrophs (literally, chemical and rock-eating) obtain energy from minerals rather than from carbon compounds.
Bacteria are common throughout the soil, but tend to be most abundant in or adjacent to plant roots, an important food source.
Actinomycetes are a broad group of bacteria that form thread-like filaments in the soil. They are responsible for the distinctive scent of freshly exposed, moist soil.
Why They Are Important
Bacteria are important in the carbon cycle. They contribute carbon to the system by fixation (photosynthesis) and decomposition. Bacteria are important decomposers in grassland environments. Actinomycetes are particularly effective at breaking down tough substances like cellulose (which makes up the cell walls of plants) and chitin (which makes up the cell walls of fungi) even under harsh conditions, such as high soil pH. Some management activities, particularly those that change nutrient levels in the soil, can shift the dominance of decomposers from bacterial to fungal. When one group becomes dominant where it shouldn’t be, there is also a shift in the rest of the system. The shift from bacterial to fungal dominance, for instance, can enhance the conditions favoring weed invasions on rangelands.
Bacteria are particularly important in nitrogen cycling. Free-living bacteria fix atmospheric nitrogen, adding it to the soil nitrogen pool. Other nitrogen-fixing bacteria form associations with the roots of leguminous plants such as lupine, clover, alfalfa, and milkvetches. Actinomycetes form associations with some non-leguminous plants (important species are bitterbrush, mountain mahogany, cliffrose, and ceanothus) and fix nitrogen, which is then available to both the host and other plants in the near vicinity. Some soil nitrogen is unusable by plants until bacteria convert it to forms that can be easily assimilated.
Some bacteria exude a sticky substance that helps bind soil particles into small aggregates. So despite their small size, they help improve water infiltration, water- holding capacity, soil stability, and aeration.
Wait! Aren’t there also “bad” bacteria? Yes, there are, but some soil bacteria suppress root-disease in plants by competing with pathenogenic organisms. The key is in maintaining a healthy system so that the good guys can do their work.
Bacteria are becoming increasingly important in bioremediation, meaning that we (people) can use bacteria to help us clean up our messes. Bacteria are capable of filtering and degrading a large variety of human-made pollutants in the soil and groundwater so that they are no longer toxic. The list of materials they can detoxify includes herbicides, heavy metals, and petroleum products.
The process that Backyard Organics uses to cleanse and enrich the soil, focuses on the quality, quantity and diversity of the microbiology that goes into our applications. Diversity is important because, (depending on your soil conditions) every soil is different. Having a wide variety of bacteria handles a wide variety of deficiencies. In order for the bi-products of the microbiology to be of any value, however, the soil food web needs to continue its cycle with the help of arthropods, nematodes and protozoa’s, (the shredders, predators and grazers found in the third trophic level of the soil food web). Backyard Organics provides the necessary predators by using good quality compost, naturally rich with nematodes and protozoa, and then extracts them using our brew process. We then add a variety of appropriate nutrients that help the microbiology live and prosper until your soil is able to sustain itself.
“BLM NSTC Soil Biological Communities – Learn More.” BLM – The Bureau of Land Management. Web. 29 Nov. 2011. <http://www.blm.gov/nstc/soil/learn/index.html>.
Ingham, Elaine. 1998. The soil biology primer, soil bacteria. USDA, Natural Resources Conservation Service, Soil Quality Institute.
Kennedy, A.C. and R.I Papendick. 1995. Microbial characteristics of soil quality. Journal of Soil and Water Conservation 50 (3) 243-248.
Vollmer, A.T., A. Au, and S.A. Bamberg. 1977. Observations on the distribution of microorganisms in desert soil.Great Basin Naturalist 37 (1) 81-86.