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Effect of Worm Type, Storage Time, and Composting System on Vermicompost


I wanted to update everyone on a few things since I've been taking the summer off to recover from grant proposal writing.

NC State Vermicompost Conference

First, I am going to be attending the 21st NC State Vermicompost Conference this year and will be presenting on this project. I hope to see a lot of familiar faces there, and if you haven't been, I would highly recommend it!

Grant Statuses

Over the past year I applied for a couple of grants, a small business seed fund grant and a research and education grant centered around vermitea. Unfortunately, both of these grants were not selected for funding :(. This outcome is about how grant writing goes, but rejection never feels very great.

The vermitea grant was rated "above average" with a primary strength being strong support for the project. So thank you all who submitted letters or emails of support. The vermitea grant will be modified and resubmitted this November. I will also continue applying for more vermicompost and soil health grants as they become available. I am always looking for vermicomposters and farmers to work with so stay turned for more opportunities.

Small DNA Sequencing Business

On the upside of this summer, Prof. Pankaj Trivedi, a world leading plant microbiome expert at Colorado State University, is graciously allowing me to use his lab space to continue vermicompost research and start this small business. My good friend and former lab mate during grad school, Dr. Chris Trivedi, will be joining me on this venture and undertaking most of the bioinformatic analysis. If you are looking to have any samples sequenced in the near future please reach out via email ( or phone (650) 837-6525. I should have a website up soon with more details!

Now on to the fun stuff...

Effect of Worm Type and Storage Time

I had a question on the effect of worm type and storage time on the microbiology of vermicompost. These results aren't conclusive and more of a hypothesis at this point due to the huge number of variables we are dealing with in this study. However, we are not seeing a big difference between African Night Crawlers and Eisenia Fetida or storage time.

Above, is principle coordinate analysis (beta diversity) that condenses the microbial communities down to a single point. The closer the dots to one another, the more similar the communities are. You'll see the African Night Crawler samples in pink and blue is Eisenia Fetida. We see most of the blue and pink dots clustered very close in the middle indicating there are no major differences between the two microbial communities.

If we look at the same plot but labeled by storage time after sampling you'll see about the same thing.

The light blue shows samples were stored for 120 days or 3 months. They fall pretty close to other producers samples sampled immediately from the composter. I'm pretty sure the samples stored for 3 months were in an airtight container and were not dried out.

Ideally, to get a better grasp on the question of storage time we would do a time series sampling of a single vermicompost. There could be some minor community changes overtime but it appears pretty stable.

Composting Systems

Alright lets take a look at these outlying points on the right side of the graph. Is there any variable that might be driving a difference in their microbial communities?

If we re-label the point again by composter type, and you look at the pink and purple dots outside of the main cluster you'll see that they are both windrow based systems. This means the composting is done directly in the ground. Perhaps some of the native soil microorganisms are colonizing the compost? Or it could just be a different environment all together shaping a different community. It's also interesting that these windrow systems are different from each other as well demonstrating that a single producer can have somewhat of a unique communities.

Please let me know if you have any more questions, and I'll be happy to answer as best I can.

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