A Scientific Aroma

*We are continuing with Farmer  Al’s presentation entitled “Compost: the new rage in sustainability”. This presentation describes all the facets of on-site composting at Frog Hollow Farm. This slide shows a table that summarizes how the compost (also compost tea and soil samples) are analyzed using light and fluorescent microscopy. We will analyze this slide in two parts (1st part in this blog, 2nd part in next weeks blog).
*Several compost samples are collected from a windrow and are mixed together. The samples are then diluted appropriately with water. The diluted samples are then spotted on a glass slide that is divided into a pattern of 20 fields (a field is the round circle of light that is seen when looking through a microscope).  Using a professional microscope, we count the number of bacteria (we also assess their diversity), we count the number of fungal strands (we also assess the width and color of the fungal strands), we count the number and types of protozoa and we count and identify the nematodes. The analysis of the samples by microscopy takes several hours and does not include the preparation of samples (collection, shaking, dilution).
*We covert some of the data to biomass and we compare the results to past samples (in our database). We also measure the activity of the bacteria and the fungi (more on this topic in future blogs). Periodically, we cross-check our results by sending our samples to a soil foodweb  analysis lab (Earthfort-SFI). Based on our data and data supplied by a soil foodweb lab, we establish ranges for what constitutes good compost, good tea or good soil. Each microbe described here gives us a wealth of information as to quality or condition of our material. For example, if we see a lot flagellates and amoebae (protozoa) and very few ciliates, we can assume that our compost is aerobic. If we see a lot of ciliates, we have to check the compost very thoroughly because it could be anaerobic and that is not the type of compost we want to apply in the orchard.
*In future blogs, blogs we will continue this discussion.
*Last week, we described a compost windrow that was found to have an odor (anaerobic) that was not normal, that was not the usual “earthy” odor of our compost piles. It was not practical to find out why the problem occurred. Rather we decided, to “save” the pile by returning it to a aerobic state. We assumed that some of the problem was compaction (pile for some reason was too “high”) which maybe stimulated an abnormal growth of anaerobic bacteria. The first thing we did was to spread the volcano shaped pile into a flatter (plateau-like) pile. The purpose of the re-shaping was to introduce more air into the pile. We then vigorously watered the pile with a fungal compost tea (analyzed using the methods described above). After a couple of days, the pile became aromatic rather than “odorous”: the “earthy” odor returned and the compost was applied to the trees in the orchard.

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