As mentioned in another post, I recently brought in a fair amount of material (containing worms) from my big outdoor worm bin. Not long after doing so, I started noticing large fruit flies flying around in my worm room. One bin in particular seems to have developed a pretty bad infestation. What’s interesting is the fact that I am now exclusively using open tub systems, and I am feeding the worms food waste paste (aka “homemade manure“) – in other words, my systems should be prime targets for serious fruit fly invasions – yet, for whatever reason, most of my bins seem to be staying free of fruit flies. The one bin that developed the bad infestation contains material collected from one of my garden worm beds (aka ‘garbage gardens‘) and a lot of partially decayed straw from my bin – not all that much actual compost material.
I have a sneaking suspicion that the reason most of my bins are fending off the fruit flies is that they contain a very diverse ecosystem, with plenty of predators. I find that aged manure in particular seems to contain a lot of different critters, with quite a few different predator species. Some of them, like the big vicious-looking beetle larvae and wolf spiders, are pretty obvious, while others fly under the radar a bit more easily due to their smaller size. Mites are one such group that I suspect play an important predatory role in manure heaps without being too obvious about it.
I once purchased predatory mites (Hypoaspis miles) to help me deal with a bad fungus gnat infestation. In comparison to the typical ‘worm bin mites’ I was used to, this species was incredibly fast moving – which makes logical sense given the fact that they need to capture their prey. Interestingly enough, I’ve noticed that manure seems to contain an incredible abundance of mites that looks exactly like Hypoaspis sp. I’m no mite taxonomist, and I’m relying on naked-eye observations – not the use of a high-powered dissection microscope – so my observations are meant to be taken as gospel. This is just a hunch.
There are of course some other potential explanations. One in particular relates to the use of the blended food waste. As I’ve written elsewhere, I suspect that the use of this material may actually help to reduce the impact of a fruit fly invasion since the worms can consume it much more quickly and easily. Chunks of food waste on the other hand, can act like little protective habitat (and food source) for zillions of fruit fly larvae – which of course quickly hatch out into the clouds of annoying adults most of us are all to familiar with.
Anyway, I’ve always been fascinated with natural ecosystems and little critters, so I definitely plan to spend more time exploring the possibility that various organisms are playing a protective role. I will certainly keep everyone posted!
Technorati Tags: mites, ecosystem, compost, compost heap, compost pile, wolf spider, larvae, predators, worms, red worms, vermicomposting, worm composting, fruit flies
Written by Bentley on November 30th, 2008 with 6 comments.
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Allison gets her hands dirty on the job
My seventh interview has certainly been a long time in coming, but I think it will definitely be worth the wait. The funny thing is that I originally asked Allison for an interview last winter, and she enthusiastically agreed. It was solely my scatter-brain tendencies that caused such a long delay in getting this to you. This fall I decided to send Allison an email to gauge her interest in giving it another shot. Thankfully she was as enthusiastic as ever, so here we are!
I first learned about Allison via an article she wrote for Vermico’s Casting Call newsletter (Volume 8; Issue #3). The article demonstrated her passion for academic vermicomposting literature (an interest I certainly share), providing a fantastic overview of the important findings in the field gathered for her Masters thesis literature review. Allison has since moved on to a PhD project, and her passion for compost science certainly hasn’t waned.
Can you tell me a little about your background? How did you become interested in compost (and the field of composting in general)?
I grew up in the San Francisco Bay Area suburbs and although my family’s house is on a sixth of an acre, my Mom is an amazing gardener. We had fruit trees (orange, Meyer lemon, lime, tangerine, plumb, apple, and apricot), berries, vegetables, beautiful flowers and of course a compost pile. So I grew up in a composting family with a “pit pot” in the kitchen. Even my pet rabbit contributed his manure to the pile!
My waste management experience started when I was 16 and volunteering as a community health worker in rural Paraguay through the Amigos de las Americas program. My partners and I helped build 40 latrines in the small town of Espinillo and educated children about the fecal / oral disease cycle. At the time Paraguay was just coming out of a long dictatorship that had a very negative effect on rural development. The second leading cause of death for young children when I was there in 1996 was diarrhea due to improperly managed human and livestock wastes. I saw first hand how important human and livestock manure management was to the overall health of rural communities.
My senior year of high school, I was the co-president of the environmental club and became intimately familiar with the trials and tribulations of running a campus recycling system with little to no support from the administration. I learned a lot about how hard it is to change ingrained behaviors. After college I served for two years as an AmeriCorps volunteer at an environmental science magnet school in Portland, OR. As the service learning coordinator, I helped students manage the composting and recycling systems including a large worm bin. I became a Master Recycler through Oregon State Cooperative Extension and was fascinated by the unit on composting. I helped the school’s science teacher design and teach several labs based on the decomposer food web in our vermicomposting system.
So when I saw the announcement for the 2001 Earthworms in Ecotechnology conference, I signed right up! This even was put on by Peter Bogdanov of VermiCo and I got to meet Clive Edwards and Mary Appelhoff and learn more about the science of vermicomposting. At this point I had a BA in biology from Reed College, but I wasn’t sure which direction I wanted to take my career as a scientist. This conference really clinched it for me. Within a year I was visiting the soil science department at Cornell for a workshop on molecular techniques used to study soil microbes. I started my M.S. in soil science in fall 2002.
What is the current focus of your PhD research at Cornell?
After completing my M.S. in 2005, I moved to the Department of Plant Pathology and Plant-Microbe Biology at Cornell. The goal of my dissertation research is to understand how the microorganisms in composts can prevent plant diseases. I’m extremely fortunate to be working with one of the leaders in this field, Dr. Eric Nelson, who has been working with disease suppressive composts and biocontrol microorganisms for several decades. I’m focusing on a model system in order to uncover the microbial mechanisms involved in compost-mediated disease suppression. As it stands now, preventing plant diseases with composts is not consistent enough for commercial growers to rely on this practice. Once scientists understand how suppression works, we’ll all be in a much better position to make and use consistently suppressive composts.
The model system I’m working with involved the complex interactions between a germinating cucumber seed, seed-colonizing microbes from vermicompost and the swimming zoospores of the damping off pathogen, Pythium aphanidermatum. I want to find out how the microbes present in vermicompost prevent zoospores from finding and/or infecting their host.
Can you share some interesting/important findings from your work?
First of all, the vermicomposted dairy manure that I work with consistently suppresses Pythium damping off in my model system. When I inoculate seeds grown in soil with swimming zoospores I get a high level of disease and most of the seedlings die. However when I amend the same soil with 40% vermicompost, seedling survival is significantly higher. We’ve been able to show that this case of disease suppression is biological in nature, meaning that it relies on the microbes and is not due to the chemical nature of the vermicompost. When we heat sterilize the vermicompost and use it in our bioassays, it offers no protection from disease.
I wanted to know how quickly Pythium zoospores could find germinating seeds in my experimental set up. By removing seeds at various time intervals, I documented that zoospores had arrived at the surface of most seeds sown in soil within 24 hours. This time point is very important, because whatever interactions are taking place to prevent disease must occur within this short amount of time. Because the zoospores are motile and can “swim” towards a germinating seed using chemical cues, we can use them in experiments to find out if this chemical signaling has been disrupted. We have preliminary evidence that microbes from the vermicompost are modifying the chemical cues released from germinating seeds in such a way that the zoospores can no longer find their host. So as we understand things right now, the zoospores are not killed by these microbes, they simply end up lost and swimming aimlessly due to the disrupted signaling between the host and the pathogen. I’m currently working to document this interaction in greater detail.
Some other findings your readers might be interested in are from my M.S. I worked on a project evaluating potting media amendments for organic tomato production with Dr.’s Anu Rangarajan, Janice Thies, Thanwalee Sooksa-Nguan, and Steven Culman (2004-2005). We found that a 20% vermicompost amendment to potting media produced the largest seedlings compared to other plant and compost based amendments. This was exciting for me because we were also using thermophilic compost made from the same starting materials in the study and the vermicompost performed better in this production system. Because the seedlings in the vermicompost treatments grew so fast, if they weren’t transplanted to the field right away, they could run out of nutrients. Remember, this is a certified organic system, so no synthetic liquid fertilizers were used and all of the nutrients had to be provided in the potting media. So Anu Rangarajan and Betsy Leonard conducted a follow up study where they evaluated mixtured of composts and vermicomposts with bone meal and other amendments. Mixing vermicompost with bone meal led to the highest quality transplants. We’re following up on this finding in on farm field trials this season as part of a larger vermicompost project. We found that seedling performance in vermicompost amended potting media depends on species. So while 20% amendments were great for tomato, we had to scale down to 10% or less for cabbage and delphinium. This is all information we’re hoping will be helpful for both organic and conventional growers developing their own potting media recipes.
Another interesting finding from the 2004-2005 tomato study was that the choice of potting media amendment impacted the bacterial community living on the tomato plants’ roots. We expected the different amendments to impact root-zone bacteria in the transplant plugs where roots were in direct contact with these materials. However, we tracked root bacteria after the seedlings were transplanted to field soil and were somewhat surprised to find significant treatment differences a month later. This means that even as the roots grow out of the original transplant plug and into the field soil, the bacterial communities continue to be influenced by the tablespoon or so of amendment that was in the plug. We found that in this case, tomato root bacteria were different depending on if they were grown in dairy manure that was thermophilically composted vs. vermicomposted. I found this interesting, but we would a lot more information before we can draw definitive conclusions about what effect the composting process has on the microbial communities present in these materials. Overall, we found that growers can influence the root zone bacteria for the life of the tomato plant just by choosing one type of potting media amendment over another. Once we understand more about how these changes in bacterial communities can translate into plant growth, yield and health, then we have the possibility of actually managing the rhizosphere, or root zone of our crop plants for optimum production.
You’ve worked with both thermophilic composts and vermicomposts – are there any consistent differences between these two end products in terms of disease suppression?
It’s really too early to draw these kinds of conclusions. There have been very few studies that effectively compare the different composting processes. Many of the scientific papers available say that they make this comparison, but then use a food scrap vermicompost and a sheep manure thermophilic compost. So this is like comparing apples to oranges. This is a great question, and I hope to provide some useful data in this area, but we need a whole team of compost scientists working on this one!
How important a role does the staring material play in disease suppression? (ie would a manure compost offer different disease fighting ability than a compost made from food waste?)
I’m only working with one type of feedstock, but I have seen some good comparisons in the literature. Polish scientist, Magdalena Szczech, and colleagues found that vermicompost made from cow, sheep and horse manure suppressed disease caused by Phytophthora infestans in tomato, while vermicomposted biosolids did not. There is a large body of scientific literature on disease suppressive thermophilic composts that deals with a range of feedstocks. However, it’s difficult to compare between studies because experimental methods can differ widely.
It’s my understanding that you’ve collaborated with RT Solutions (Worm Power). Can you tell us a little about that?
Sure. Scott Subler (now of Environmental Credit Corp. and previously a vermicomposter) introduced me to Tom Herlihy of RTS right after my talk at the U.S. Composting Council conference in Las Vegas in 2003. At that time Tom was a consulting engineer and the facility was just a gleam in his eye. Tom and I corresponded throughout my M.S. and we ended up using his material in our tomato study when his facility was up and running in 2005. Since then we’ve done a lot of grant writing together, successfully and unsuccessfully of course, which is how it goes! Right now Tom is on the advisory board for our NY Farm Viability Institute funded project “Potential use of vermicompost as a substitute for synthetic inputs to horticulture and nursery production”. My advisors, Eric Nelson and Anu Rangarjan are co-PI’s (principal investigators) on the project and Chuck Nicholson from Applied Economics and Management and Jean Bonhotal from Cornell Waste Management Institute are also involved. This season we put in 7 on-farm field trials with RTS’ “Worm Power” vermicompost and I’m continuing my work with disease suppression for this two year project. Tom, Eric and I also applied for the USDA’s Small Business Innovation Research (SBIR) program and were funded to develop biocontrol products out of vermicompost and non-aerated vermicompost extracts. We received matching funds for this project through Cornell’s Center for Biotechnology and the NY Science to Achieve Results Center for Advanced Tecnhology (NYSTAR CAT).
When I started my M.S. I was making my own vermicompost in the barn at Dilmun Hill student farm, so having the opportunity to collaborate with one of the largest vermicomposting businesses in North America is very exciting! Now I don’t have to say “Hey, it would be neat if someone would produce this material on a large scale so growers have access to it and we can learn more about how it performs in different systems.” Because that’s exactly the situation right now! It’s been a pleasure collaborating with RTS, because Tom and his team really value rigorous scientific inquiry. We’ve all learned a lot from each other. I can talk with confidence about sub-surface injecting liquid manure with a chisel plow and cap and trade carbon incentives for dairies, and I think you’d be impressed if you asked Tom about Pythium aphanidermatum zoospores!
Is there anything else you’d like to share?
As part of the NYFVI funded vermicompost study we’ll be hosting a workshop summer ’09 geared towards growers who are interested in learning more about vermicompost in different plant production systems and the results of ours and other studies. More information TBA!
Also, I have to say that I’m incredibly proud to live in Tompkins County, which has one of the highest home composting rates in the country thanks to the Tompkins County Cornell Cooperative Extension Compost Education Program. I took the Master Composter training in 2003 and have been involved in the program one way or another since then. It’s a great program run by my friend Adam Michaelides that has a huge impact in our community. I would encourage all hobby composters to talk to their county extension offices about starting up a Master Composter program if they don’t already have one. It’s a great way for composters to pass on their knowledge to people in the community who may be interested in composting, but don’t know how to get started.
I’d like to take this opportunity to once again thank Allison for her participation in this interview. If you would like to learn more about Allison’s work, be sure to pay a visit to the Cornell Vermicompost page.
Written by Bentley on November 27th, 2008 with 4 comments.
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Happy Thanksgiving, everyone!
We already had our ‘Turkey Day’ back in October (in Canada, that is), so I’m afraid it’s just a regular dinner for me today!
Anyway, I just wanted to let everyone know that I have decided to extend the Christmas sale. For one thing it seemed a little odd to me to have a Christmas sale before December even arrived (during Thanksgiving week no less). I also figured the timing might not have been great for a lot of people who might be traveling a lot this week, and not thinking too much about vermicomposting!
That being said, we’ve definitely had a busier week than usual so far, so I guess some people are in a vermicomposting frame of mind!
As you can tell, I have also decided to get rid of my ‘sticky’ announcement post up top (it will now move down with the rest of the posts) – and have replaced it with a banner instead. I know I don’t feel like staring at that post for two weeks, and I’m sure all of you feel the same way as well. We have some good stuff coming your way very soon, so I want it those posts to be featured front and center where they belong!
Written by Bentley on November 27th, 2008 with no comments.
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From Marlee:
Hello. 
I want to start my own compostat home with food
scraps, but I don’t have a back yard I can make a pile in. I was told
to by a big container with a air tight lid and start putting vegetable
scraps in it. I was wondering if the lid was a good idea, becaue I
looked up actual composting containers and they all have air
circulation. I wanted to keep a lid on it because it will have to be
in my house and I dont want to be able to smell it.
Also, I was wondering if I could dig up some earth worms and put them
in my container. Will they be able to live in it if the lid is air
tight?
Thank you so much for your time and answering my qustions.
Hi Marlee,
I’m glad you wrote in! I’m sure there are plenty of newcomers with similar questions on their mind.
You are absolutely right – air circulation is very important! I have started tiny worm bins in plastic tubs without any additional air holes added – but the small size of the system, along with the somewhat loose-fitting lid and small holes in the handles made it not so much of an issue. I should mention also that when I DID finally decide to start adding air holes to those small bins, the performance of the system (and overall health and welfare of the worms) definitely seemed to improve.
If you were to simply pile up food scraps in a tightly sealed container, you would end up with a monumentally nasty, smelly mess on your hands! Aside from the issue of air flow, there would also be the important ‘carbon-to-nitrogen ratio’, and moisture content of the bin to consider. Wet, n-rich wastes piled up without any absorbent, carbon-rich materials will definitely go anaerobic (thus creating an awful stench) and potentially produce ammonia gas (also a nasty smell – not to mention being toxic).
Interesting enough, if you provide lots of air circulation and mix your food materials with even more absorbent bedding materials (such as shredded cardboard/newsprint etc), there shouldn’t be any bad odors coming from your bin – even before the worms are added! Once you have composting worms (more on that topic in a minute) in the system, and your are able to provide them with their basic requirements, bad odors should be even less of a concern!
Ok – back to the worms. Unfortunately, you can’t just dig up some garden worms and put them in your bin (especially not the bin you’ve described). Worms suited for composting are specialized species that don’t really burrow in soil – they are adapted to live close to, or above the soil surface in rich, organic matter. This explains why they can sometimes be found naturally occurring in compost heaps and aged manure piles! The variety you are likely looking for is the Red Worm (Eisenia fetida) – this is the most common, and also the most versatile of the composting worms.
If you want to learn more about setting up and worm bin, I highly recommend that you check out my ‘Getting Started’ page. You should also check out my ‘Setting Up a Worm Bin’ videos found at the bottom of my ‘Worm Composting Videos’ page.
Hope this helps!
Written by Bentley on November 24th, 2008 with no comments.
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Last week I wrote about adding a lint ball to one of my worm tubs. I just thought I would provide a quick update to let you know the decomposition process is coming along.
One thing is becoming abundantly clear – it is going to take a LONG time for this lint to fully decompose! Even though I soaked it in yummy ‘homemade manure‘, I was only able to find a few worms burrowing into it – unlike the situation I wrote about with the Natura Eco cloth some time ago.
The important thing to remember however, is that a week hasn’t even passed yet. I suspect that over time, more worms will move into the lint ball as it breaks down further.
There do seem to be a lot of springtails associated with the lint (they are the small white flecks in the photos above), but there are loads of them in my bins in general so it’s hard to say if they are particularly attracted to the material. Even if they are, it is almost certainly due to the coating up blended food waste!
Anyway, while I certainly won’t bother to provide updates very often (since they will getting really boring REALLY fast), I’ll definitely keep tabs on the lint ball and let you know how things are coming along from time to time!
Written by Bentley on November 24th, 2008 with 3 comments.
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