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----- Original Message -----
From: [EMAIL PROTECTED]
Sent: Friday, March 08, 2002 5:35 PM
Subject: Re: [Fwd: Forest soil diversity, compost and
temperature] You always make me grin. I appreciate that you want clarification of concepts. Good for you. Most people aren't brave enough. Harry couches his ideas in a different terminology, one that I think most of the US public has trouble understanding, so I don't use the same verbiage as Harry. Harry talks about a biological vacuum. What is that, precisely? Not a big Hoover vacuum cleaner, right? What does he mean when he says "vacuum"? He means what I mean when I say the critters are asleep. Biologically speaking, if you aren't performing your function, then there is a vacuum there. A lack of function. Does that mean that there is no life? No. The organisms performing the function are asleep. If you add active organisms when many of the critters are asleep, the living, active, functioning organisms out-compete the sleeping organisms. The critters that are asleep are out of luck; the active, functioning ones get the food resource, multiply and grow. But you don't add the active organisms when temperature is staying hot, or the ones you add just go to sleep too. As temperature cools, then the organisms that like cooler temperatures wake up again. To give some beneficials that you know are beneficial a head-start, you add the beneficials as the pile starts to cool. The foods to feed the organisms making the high temperature have been used up, however, so the beneficials you add had better not require simple sugars, simple proteins. Cause most of that food resource has been used up. How do you know that food resource isn't there? The bacteria using it ran out of food, or they would still be growing and producing temperature. It is rapidly growing bacteria and fungi, producing metabolic heat that results in the temperature produced by a compost pile. A sterile pile of organic matter produces no heat. Once life is added, and starts growing, the heat produced is a measure of the growth of the organisms. But just by measuring temperature you can't tell whether it is bacteria or fungi making the heat. And you need to know whether the pile is fungal or bacterial to know which kind of plant to plant in that material. When people do plate counts, they don't see that in fact, there are active, living, growing organisms that survive 140, 150, 160 degrees just fine. Why don't they know about these active organisms? Because the growth conditions on their plates in lab are not the conditions that allow these organisms to grow. Think - 1. The organisms in 160 degree compost need warm temperatures, they need lots of food, they need high humidity. 2. What are the growth conditions on the agar media used in plate counts? A few kinds of sugars, proteins, and soil nutrients - yeah, soil nutrients, not the mix of nutrients in a compost pile. What is the temperature of incubation? 72 degrees. Hum, what organisms that likes 150 degrees, or 140, is going to grow at 72? There is nowhere close to the humidity in a compost pile in the lab. The media lack moisture, lack food resources, and temperature is constant. Constant! When has temperature in a compost pile remained static through the course of a single day? When have nutrients been limited in a compost pile? When was the last time those compost critters even saw 72 degrees? So ask Harry this one - How can high temperature be maintained if there is a biological vacuum? If there was no life in the compost pile? No wonder we get really bizarre ideas about compost when we use lab conditions to assess species diversity or activity. So, when Harry talks about a biological vacuum, it is a vacuum only because the species of bacteria that grow on plates in the lab are asleep. It is not really a vacuum -- there are plenty of things alive and performing their functions. So, I have to say yes to your points, "So was Hoitink underestimating the presence of beneficial organisms due to 'peak heating'? Was this because he was relying on inaccurate plate testing data?" But also realize that Harry wasn't precisely wrong about what happens in compost. The organisms that like cooler temperatures have retreated to their hammocks and are sipping mint juleps in the shade waiting for things to cool down to start growing. Are some things killed? Sure - we kill people every summer because they over-heat. But is the human species gone? Most of the beneficial species aren't destroyed, as long as there is decent structure in the compost pile. Decent structure means there are porches, cool baths, and shaded grottoes for at least some individuals of most species to survive. What about disease organisms? They are destroyed by the long duration of the heat, and by the competition for foods, and because they require low oxygen concentrations to overcome inhibition. Think about where human pathogens thrive. If you make your compost heap just like your digestive system, guess who does really well? The less your compost pile is like your gut, the fewer pathogens will remain. So, get the pile to way higher temperature than they like, get it well-aerated and grow lots of other things to compete with the pathogens. And the "good guys" make it through, the bad guys don't. Why are we so lucky? Because we evolved in this system. Luck has nothing to do with it. Would an inoculum of old growth forest soil be a good way to inoculate your compost? Yes. But you had better make sure it is a healthy forest. OK? Please feel free to distribute my responses to other folks asking the same questions. Haven't had a chance to check the website you suggested.... later today... Hope this helps! Elaine Hi Elaine,
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