Second part of #9418
I have many different sources of organic "waste" and I create different compost piles depending on the season. Sometimes I have access to fallen leaves only. At other times I can mix it with grass clippings and other higher N material. Some of my piles have only leaves and have no added water at all. They decompose much slower and some never heat up over 30 C. In terms of beneficial organisms is this material inferior to a properly prepared compost with sufficient water and C:N ratio at the start? What might be the difference? Can beneficials deal with pathogens at lower temps? How can I see the difference between pathogens and beneficials on a microscope?
I put the basic recipe for good aerobic compost that will reach high enough temperatures for long enough, if the high N is actually high in nitrogen. Water is important for microorganisms - if there isn't enough water, the organisms won't do their jobs, part of which is to decompose the plant material. So, no decomposition, no killing of the disease organisms, pests, parasites, and the product can't really be called compost then. Moisture needs to remain around 50% for thermal compost, and around 70% for a worm compost. Otherwise, the organisms won't do what they need to make good compost.
There are beneficial species that are selected at every temperature, usually hundreds of species, if not thousands of species. Scientists didn't have a good way to assess bacteria or fungal species until just a few years ago, when DNA analysis improved. Now we're focused on trying to decide what change in DNA base actually means a new and different species. Lots of discussion but I don't think it is worked out or agreed on yet. But, no matter what is decided, it is clear that in a gram of healthy soil there should be 50,000 species of bacteria, maybe more. There should be 25,000 species of fungi present, maybe more. there should be hundreds of species of protozoa, and 20 or more species of nematodes.
Unhealthy soil ---- well there we go again with what is soil and what is dirt exactly ---- so ----
Soil where the sets of organisms have been reduced, and the plants growing in that..... ah......soil (?).... are not able to get the soluble nutrients they need, and thus are susceptible to disease and pest attacks, clearly have many fewer species of bacteria, fungi, protozoa and nematodes. Use of pesticides lowers the number of species found by a serious amount. Use of inorganic fertilizers at high levels do the same. There is a dose relationship of course.
Tillage reduces diversity, but not as badly as the toxic chemicals. It is when farmers start tot till more than once a year that we start losing many species, and health is compromised. When the entire field is tilled, instead of just where the seeds are dropped in, then loss of species is significant.
Once the soil is healthy, there are hundreds of species that grow at each temperature, but not outside that temperature range.
Plate count methods cannot even begin to assess diversity, and so much of the older literature used that human-pathogen method of growing bacteria or fungi to assess total diversity. such a mis-leading method, and so mindlessly used for so many years. Chemical companies have published absolutes lies about how their toxic chemicals didn't kill any beneficial organisms in soil, based on no reduction in bacterial diversity as assessed by plate counts.
So, if DNA shows 50,000 species of bacteria per gram in healthy soil, what would a plate count show you? NO SPECIES PRESENT AT ALL, typically. Remember, I said healthy soil, and plate counts are for growing human pathogens.
So, back to the question (grin)....... can the microscope differentiate bad-guys from good-guys? Depends on which group we are talking about.
Bacteria - not at all close to being 100% able to ID good versus bad. Instead, we look for indicators like Spirilla, or Spirochetes or Vibrio, which are usually bad guys. If we see their very distinctive shapes, we know we're in trouble. But we can't differentiate E. coli, for example, from a 100,000 other species of good or bad guys. So, if your question is, do I have bad guys like human enterics, you do plate counts, because ..... plate methods are good for growing pathogens. If your question is, do I have too few, good, lots or too many bacteria, microscope works great.
Fungi - the beneficial fungi are usually wide diameter, have cross walls, and are colored. the skinny clear fungal hyphae are the scary ones. Not a perfect match, but close enough that you know you are likely in trouble if you only have the not-so-good present.
The bad-guy protozoa are the ciliates; good guy protozoa are the flagellates and amoebae.
Nematodes are pretty easy to distinguish based on mouth parts. Not 100% perfect, and of course we aren't trying to get to genus or species. but useful when we're trying to get an idea of really bad, ok, or really good.