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If you have livestock, you have an abundant supply of materials for another compost recipe. All that is needed, in addition to barn waste, is some patience and perhaps a good microbial inoculant containing cellulose-digesters.
My horses provide me with plenty of manure, and with an average C:N ratio of 25–30:1, horse manure makes an ideal compost material. However, it is important to remember that the more bedding material you use, the more attention you will need to pay to your C:N ratio. Occasionally I’ll need to throw on some grass clippings for added nitrogen if there is too much bedding material, but my barn floor is furnished with rubber stall mats and my horses don’t often choose to sleep inside, so I use little if any bedding material. Other livestock manures generally have higher nitrogen contents, so additional carbon from bedding materials helps to balance that ratio.
Every few months an inoculant containing cellulose digester microbes is sprayed over the ever-growing pile. Microbes and worms continually digest the waste so that the size of the pile never becomes too unmanageable. Then about once a year, the newest top layers are pushed back to reveal a cache of sweet smelling compost with an amazing moisture holding capacity. According to Washington State University, only a 5 percent increase in a soil’s organic material quadruples its water holding capacity (Whatcom County Extention n.d.), an invaluable benefit of composting in our semiarid eastern Washington climate.
It is important to use only manure that is thoroughly composted and aged to ensure against possible pathogen or weed seed contamination. As mentioned earlier, do not use manure from carnivorous animals (dogs and cats), or animals on routine antibiotics or other medications that may be toxic to humans or microbes.
Two added bonuses that come with my manure compost are the huge colonies of red worms and beneficial fungi that take up residence there. A worm bin is a great way to compost kitchen scraps, and the manure pile is a good free source of red worms. The worms make short work of the kitchen scraps, and their castings make an excellent soil amendment for potted plants or spreading around bedding plants and perennials.
Classic passive (anaerobic) compost tea is made much like the manure tea my mother used to brew in her barrel. Composted materials, often held in a cloth or mesh bag, are soaked in water for a number of days until the desired strength is achieved. No mechanical aeration is applied, and the resulting tea contains anaerobic microbes.
Although passive compost tea has probably been in existence for almost as long as compost, it wasn’t until the 1970s that modernday active aerobic brewing methods were developed. Today, there is a plethora of active compost tea brewing systems available, which bubble oxygen into the solution to create an aerobic tea. Since aerobic microbes work faster than anaerobic ones, this process takes less time than the passive method.
Proponents of compost tea use it as a liquid soil-applied amendment and as a foliar spray, and claim the wide variety of beneficial bacteria and fungi in the tea combat and help prevent plant disease, along with the many other benefits that microbes provide. But like compost, any compost tea is only as good as its base ingredients, and consequently, results can be inconsistent, sometimes giving compost tea negative reviews.
Some scientists are concerned about what else can grow in compost tea, such as E. coli and Salmonella. Passive brewing systems, or even inadequate oxygen infusion in an active system can create anaerobic conditions ideal for salmonella and E. coli to grow. For this reason, some experts recommend, in the case of food crops, only using compost tea on soil and not as a foliar spray.
The opposing argument is that an oxygen-rich environment is not friendly to E. coli and Salmonella, and the beneficial microbes grown in a properly managed, oxygenated, active compost tea system should overcome any pathogens that might occur.
In a healthy natural soil environment, the various microbe species do coexist in balanced ratios, which shift as conditions and the needs of the biological community change, including the changing needs of the plants. But when brewing “microbe soup” in an artificial environment, keeping stable and consistent ratios between all the species can be difficult. Each has specific nutritional and incubational needs that may or may not suit others. More aggressive microbes can overpower weaker ones. Because of these unknown variables, the finished product can be inconsistent and lacking some desired components.
But with all of that said, there are plenty of farmers, gardeners and soil scientists who are believers in the virtues of compost tea, and use it enthusiastically and with good success. Some brewers augment their tea by adding a bit of commercial inoculant containing a broad spectrum of microbes near the end of the brewing cycle. This helps ensure each batch has the best chance for a consistently well-balanced population. Others choose to save time and effort by circumventing the whole process, and directly applying a microbial soil inoculant and a foliar spray program of microbes and nutrients, with equal or better results.
If you go this route, make sure to use quality products that have been tested by an independent laboratory for pathogens and CFU (Colony Forming Units) to be sure of what you are getting. A CFU report gives the microbial population density per gram of material. Deciding between using compost tea or ready-made biological products boils down to personal preference and what works best for your program and budget. The important thing is to protect your plants and build your soil with a healthy and balanced biological community.
Field Stubble Digestion
Corn stalks, cereal grain, seed grass stubble, or any other plant debris left after harvest can be composted right in the field. Till or disc so that the stalks are well chopped, then spray-apply a product containing cellulose-digesting fungi and bacteria. Check your soil’s carbon-nitrogen ratio (the ideal range is 20:1 – 30:1) and adjust if needed to support and speed up the soil microbes. By the following spring much of the plant debris should be digested, and any remaining debris will easily shatter, returning valuable nutrients to the soil to support microbes and plants.
About the Author:
Athena “Teena” Tainio is the president and CEO of Spokane-based Tainio Biologicals, a company that specializes in natural soil enhancing additives. She assumed leadership when her husband, company founder Bruce Tainio, died in 2009. Today, Tainio products are used throughout the United States, Canada, Central America, Australia and New Zealand. Athena continues to help Tainio lead the way in the soil health and agriculture industries.