Category Archives: science

2019 Native Plant Field Season Update

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I’m thrilled to announce that this summer I completed the third field season of my study. This is slightly bittersweet – while I’m excited that we are done with hot fieldwork, I will miss chasing bees around the farm and the view of Mt. Hood. I’m incredibly thankful for this third season of data, as it will help account for some of the temporal variation inherent in ecological studies. In fact, pollinator communities in particular tend to be highly variable both within and across field seasons. Having three seasons of data will hopefully allow us to identify more reliable patterns of pollinator visitation between my study plants.

Lots of lab work remains, as I’m tackling the insect samples that we collected with the bee vacuum. With the help of a dissecting scope, I’m attempting to identify the each specimen to at least the taxonomic level of family to get a sense of the broader insect communities associated with each flower species in my study. It will be several months before I can share this species-richness data, but in the meantime I have bee abundance data to share with you!

Aaron and Lucas in the native plant study site, in 2017. You can see the 1m by 1 m plot in the foreground by Aaron, a second one near Lucas, and a few more in the distance.

As a refresher, we performed timed pollinator observations at each plot. This consisted of observing each blooming plot for five minutes and counting all the insects that landed on open flowers. Bees were sorted to “morpho-type” (honey bee, bumblebee, green bee, and other native bee). Though this doesn’t give us species-level information on the floral visitors, it allows us to understand which plants attracted the most pollinators overall, and allows us to detect any patterns of visitation between honey bees, bumblebees, and solitary native bees. Below is a summary of some of the highlights.

2019 overall bee abundance by plant species:

  • Origanum vulgare, Lavendula intermedia, and Eschscolzia californica were top five bee plants in 2019, just as they were in 2018.
  • In 2019, Phacelia heterophylla and Solidago canadensis jump into the top five, while Nepeta cataria and Gilia capitata fall out of the top five. It should be noted that Nepeta was the sixth most attractive plant, with about the same visitation level as Solidago.
  • Again, similar to 2018, it appears that honey bee visitation was driving the high visitation rates of the popular exotic garden species (marked with a red asterisk), while native wildflowers were being visited more frequently by native bees.
  • I’ve included the 2017 and 2018 overall abundance graphs as well, for comparison. You can see that the overall abundance was higher in 2019 for the two most popular plants, at about ~25 bees per observation period!

2017 overall bee abundance by plant species:

2018 overall bee abundance by plant species:

Since honey bee visitation drove the high abundance of many of the top pollinator plants, I took honey bee visits out of the data set and made a new graph, to compare which plants were most attractive to native bees.

2019 native bee abundance by plant species:

As you can see above, honey bees are excluded from the analysis, the top five most popular plant species completely reshuffles.

I’ve included that 2017 and 2018 native bee abundance data below for comparison.

2017 native bee abundance by plant species:

2018 native bee abundance by plant species:

Please stay tuned for more updates on the bee species richness we collected in 2019, as well as data on the other insects (pests and natural enemies) that we collected!

Unpopular Opinion: Saving Honey Bees Does Very Little to Save the Bees

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Although I have been studying garden bees for the past three years, I was never focused on honey bees. From a biodiversity point of view, they are not very interesting to me. They are non-native and abundant. In fact, honey bees were the most abundant bee species that we collected in Portland-area gardens (332 individuals collected), even though we took great care not to collect more than one individual per visit, when hand-collecting.

Some of the 300+ individual honey bees that we collected from Portland area gardens, even though we took great care to not hand collect more than a single individual honey bee per garden, per site visit.

Honey bees, which hail from Europe, are only one of 20,000 bee species, worldwide. In North America, there are 4,000 species of bee. In Oregon, we have between 400-500 species of bee. From Portland area gardens, we have documented 86 species of bee (with our 2019 bees still awaiting identification).

Unlike some native bees, honey bees are not at risk of extinction. Compare this to bumblebees. We found 17 species of bumblebee in Portland gardens, two of which (12%) are at risk of endangerment or extinction, due to declining populations: Bombus fervidus and Bombus caliginosus. Across North America, more than 25% of bumblebee species are thought to be at risk of extinction.

  • Frontal view of Bombus fervidus, a threatened bumblebee species that can be found in Portland area gardens.
  • Dorsal view of Bombus fervidus, a threatened bumblebee species that can be found in Portland area gardens.

By focusing ‘save the bee’ campaigns on honey bees, we may be neglecting the bee species that really need our help. In fact, researchers have started to call out organizations and advertising campaigns that promote feel good stories about honey bee conservation as a form of ‘bee washing’. You can visit www.bee-washing.com to learn more about companies that promote their product or organization as being bee-friendly, in a less than genuine way.

Researchers have documented at least seven different ways that honey bees may harm native bee species (summarized in Cane and Tepedino, 2016):

  1. Honey bees monopolize and deplete nectar and pollen from local plant communities, which can reduce native bee reproduction.
  2. By depleting local plant resources, native bee females have to devote more time and energy to fly and find new resources, which also reduces native bee reproduction.
  3. Unlike honey bees, most bees are solitary, which means that they do not live in colonies and they do not have a queen. Solitary females who have access to fewer floral resources produce fewer daughters and more sons. Since female bees are needed to maintain a population, this skewed sex ratio can slow population growth and recovery in native bees.
  4. When females collect less nectar and pollen, they have less food to feed their young. These bees grow up to be smaller, and are more likely to die over winter, compared to well-fed bees.
  5. The longer a solitary bee mom is away from her nest, the higher risk that parasites and predators will attack her unguarded young.
  6. Honey bees can physically block native, solitary bees from preferred pollen hosts.
  7. Honey bees have many diseases. Some honey bee viruses have been found in native bee communities. Researchers think flowers that are visited by both native bees and honey bees are analogous to an elementary school water fountain: a place where repeat visitors can pick up a pathogen.

Please note that I am not suggesting that you extinguish honey bees from your garden. What I am asking, instead, is that you take the time to learn about and to notice some of the other 80+ species of bee that you might find in your garden. My group is creating a ‘Bees of Portland Gardens’ guide that we hope can help you in this journey. In the meantime, there are some great guides that are currently available. One is Wilson and Carrill’s ‘The Bees in Your Backyard: a guide to North America’s bees’. This book is available at Powell’s City of Books, as well as on Amazon. The second is August Jackson’s ‘The Bees of the Willamette Valley: a comprehensive guide to genera’. This free guide can be found online.

The first step to saving something you love is to be able to recognize it and to call it by name.

References

  • Cane and Tepedino. 2016. Gauging the effect of honey bee pollen collection on native bee communities. Conservation Letters 10: 205-210.
  • Jackson. 2019. The Bees of the Willamette Valley: A Comprehensive Guide to Genera. Self-Published, Online: https://tinyurl.com/y4qfssrl.
  • Wilson and Carrill. 2016. Bees in Your Backyard: A Guide to North America’s Bees. Princeton University Press.

How Alan Alda Helped Me to Become a Better Teacher

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A few weeks ago, I tweeted about the difference that the Alda Center for Communicating Science has made in my teaching. To my sincere surprise and delight, Mr. Alda, himself, quoted my tweet, in one of his own. It made my day.

And today, after my last lecture of the term, the lab instructor sent me this note:

“I have students here putting in extra time (!!) on their [insect] collections, and they’re talking about how much they loved your class, and the applause you got at the end of class today. One of them is saying how it’s about time she had a class that was 100% relevant to Ag. I’m so happy for you, Gail, . . . I wish you could hear their conversation 🙂 “

To fully appreciate how much these comments mean to me, you have to understand how much of a struggle it is for me to teach. I score very high on the introversion scale. I hate the idea of teaching as performance (why do I have to entertain them?). I’m a stickler for academic rigor. My classes have a reputation for being difficult. And, I teach a required course that all majors must take (whether they are interested in entomology, or not), that is scheduled for M/W/F at 8am. All of these things, added together, make me a fairly unpopular teacher.

But this term was different. In January, I spent two days in New York City for the Alda Center for Communicating Science STEM immersion program. This workshop could not have come at a better time in my professional career. I was burnt out, in part because of: (a) the corporatization of higher education, (b) students who increasingly take a customer-centered approach to their education (where the customer is always right), (c) attacks on and rollbacks of scientific progress at Federal Agencies, and (d) public distrust of science. These things have all taken their toll on me and on my love for my profession. I was looking for something to re-ignite my love for science and teaching, and to stave off my growing cynicism.

The Alda immersion program did all of these things, and more. The premise of the workshop is that ‘Connection is the Key’ to effective science communication. The workshop instructors (including Alan Alda) use improv exercises in small groups and with partners to teach storytelling, message design, and how to really listen to, empathize with, and engage with your audience. Key messages were embraced over the recitation of hypotheses and theory. A heavy focus was put on connecting with your audience, so that even if they were not ready to listen to you in that moment of time, you might be able engage them at some point in the future.

There were two turning points to the workshop, at least for me.

The first was when we partnered up with someone to explain our science in 2 minutes, then 1 minute, then 30 seconds. Between each round, our partner gave us feedback on how to refine our message. When we came back together as a group, each person had to explain their partner’s science, rather than their own. In almost all cases, folks did better explaining someone else’s science ~ because we didn’t get bogged down in details. This really helped me to limit how much information I present in my classes. Instead of teaching *everything a person should possibly know* about a topic, I focus on key points, and how those points relate to students’ lives.

The second was when Mr. Alda demonstrated how he would discuss science with someone who believes the earth is flat. There was such a genuine kindness in the ‘conversation’ he had with the flat-earther ~ acknowledging their experience (the earth looks flat to them) while adhering to the science that demonstrates that earth is a sphere. It made me realize that I had become so accustomed to being right and defending my interpretation of science, that I rarely listened to others who disagreed with me. I was too busy formulating my retort, to truly listen to and understand their perspective.

This revelation was coupled with an exercise that was called ‘My Dear Friend’. In this exercise, you spend a few minutes ranting at your partner about something that drives you crazy. I ranted about the state of higher education, today. Your partner then has to share your rant with the group, by saying something like ‘this is my dear friend, Gail, and she cares passionately about the education that her students receive.’ I use this exercise, nearly every week. In fact, when I returned to the office from the workshop, there was an anonymous letter in my mailbox that was signed by ‘a disgruntled Master Gardener’. I reread that letter, and instead of feeling attacked, I could see how much the person loved this program that I help to coordinate, and how they wanted to share their passion for the program.

In terms of my teaching, the Alda workshop helped me to slow down, focus on key messages, and truly care for my students. This term, I am 6 classes behind where I would normally be. But, I think my students learned and retained more than they have in the past.

I stopped worrying about students who missed class, or who might try to cheat. Instead, I designed my class so that students who had to miss class (for whatever reason) had built in buffers that could help them absorb or make up lost points. These included things like dropping your two lowest quizzes, or earning extra credit points for lecture participation. I built an array of assessments into the class, including TopHat clickers from mobile devices, and adding ample short answer and essay sections to my exams. These things both made it more difficult to cheat, but also offered students with different learning styles different chances to do well.

I started bringing in breakfast on Fridays. I did this because Thursday is the traditional ‘party night’ on a university campus. In the past, my 8am Friday classes often had 15 or fewer people in attendance. (There are 50 enrolled in the course). I wanted to bring a small breakfast to say ‘thank you for showing up’. Over the course of the term, more and more students started to show up, and not just on Fridays. They went out of their way to thank me. Some told me that they were hungry, and that the small meal made a big difference to their day. Being a Filipina who loves to feed people, by nature, that’s all I needed.

There were a few other things, as well . . . students who shared some difficulty that they were going through that made it difficult for them to do well in class. Instead of my past approach of ‘not my problem’, I tried to help where I could.

Mostly, when I stopped feeling like I was there to serve as some sort of academic guardian . . . keeping all but the most-worthy students out . . . that’s when everyone (including myself) became invested in learning.

When I said goodbye to my students today, I heard the applause . . . but I was so confused. Was someone watching YouTube videos, in the back? It honestly makes me tear up to think that it might have been because they loved the learning environment that we built, together.

Native Plants and Pollinator Survey

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Aaron Anderson is repeating his original survey on native plants and pollinators. This time, he is trying to understand how knowledge of a plant’s ecological function may alter impressions of native plants.

The survey takes about 25-30 minutes to complete. Folks who have taken the survey thus far have commented on how much they learned from taking the time to answer the questions.

If your time and interest allows, we would be extremely grateful if you could take the time to respond to this survey. The direct link to the survey is:

http://oregonstate.qualtrics.com/jfe/form/SV_9Alhv961rZX8Vs9

If you have friends or acquaintances who also might be interested in taking the survey, please feel free to share it with them.

A syrphid fly pays a visit to a California poppy at the North Willamette Research and Extension Center.

A bee visiting one of the Canada goldenrod plots in our Native Plant study.

Gilia capitata

Lotus unifoliolatus

Is the Insect Apocalypse Upon Us?

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With all due respect to Beyonce, insects were recognized as ‘The Little Things that Run the World‘ by entomologist E.O. Wilson, decades before Beyonce’s 2011 hit song. As Wilson wrote in his iconic perspective piece:

The truth is that we need invertebrates but they don’t need us. If human beings were to disappear tomorrow, the world would go on with little change.

In fact, Wilson noted, the Earth ‘would set about healing itself‘. But if invertebrates were to disappear, Wilson predicts that ‘I doubt the human species could last more than a few months‘.

 

California Tortoiseshell, taken in a Portland-area garden on August 22, 2017.

Insects, the most abundant and numerous of all invertebrate animals, play a particularly important role in our world and in our life. Not counting the enormous contributions of non-native honey bees, which annually help to bring $235 and $577 billion dollar worth of food to the global market, native insects contribute $71 billion dollars (inflation adjusted to 2019) worth of ecological services to our economy and to our society.

So what are we to make of the recent NY Times article entitled ‘The Insect Apocalypse is Here‘, or the Atlantic article entitled ‘Is the Insect Apocalypse Really Upon Us?’.

These articles covered recent science papers that have caused a lot of concern, and generated a lot of attention. In the ENT 518 class that I am teaching this term (Current Topics in Entomology), our class spent time dissecting and discussing the science papers, as well as popular press coverage of each study.

The first paper, published in 2017 by Hallman and colleagues, documented a 76% decline in insect biomass over a time period spanning nearly three decades. In the peak summer season, the decline was even larger (82%). These researchers had been sampling protected areas in Germany using Malaise traps. This group is working to identify the insects that they collect ~ but, because it takes so much time and specialized expertise to identify most insects to species ~ they also took data on the collective weight of the insects that they collected. This is how they were able to show a 76% decline in insect biomass, between 1989 and 2016.

Mardon Skipper taken in a Portland-area garden on August 22, 2017.

What caused this massive decline in insect biomass? To address this question, They constructed a series of models to try and identify what factors might explain this precipitous drop in insect biomass (which is being used a proxy for insect abundance). They did not find evidence (from their mathematical models) that climate factors (e.g. temperature, precipitation, wind speed), habitat factors (e.g. site conditions, plant species), or habitat factors (e.g. amount of forest, grassland, water) were responsible for insect declines. Because they did not find evidence that climate change, landscape conversions, or habitat changes reduced insect biomass, they concluded that factors which they did not measure were responsible for insect declines. Specifically, they hypothesize that agricultural intensification (pesticide use, year round tillage, increased use of fertilizers) was a plausible cause.

Students taking the ENT 518 class were mostly convinced that the researchers had documented a large and significant decrease in insect biomass over the time period of the study. Students agreed that the loss of biomass reflects a loss in insect abundance, and probably reflects a loss of insect diversity. Students were more reserved in their assessment of the authors’ suggestion that agricultural intensification was the cause of the decline. Although they agreed that it is a plausible explanation, they wanted to see data to address this hypothesis, rather than having the authors arrive at this conclusion because they eliminated other potential causes of insect decline (e.g. climate change, landscape conversion, habitat change).

Western Tiger Swallowtail, taken in a Portland-area garden on July 27, 2017.

The second paper, published in 2019 by Sanchez-Bayo and Wyckhuys, was a review of other papers that studied insect declines. The authors searched science databases for the words ‘insect’ AND ‘decline’ AND ‘survey’, and then reviewed the hundreds of papers (653!) that they found to limit their survey to 73 long-term studies that took place for 10 years of more. The authors then summarize the details of each study, according to major insect groups (e.g. butterflies, bees, beetles, flies). Ultimately, they report that 41% of all insects are in decline, and that across all insect species, the annual rate of decline is 1% per year, and the annual rate of insect extinction is 1% per year. Like the Hallman et al. paper, Sanchez-Bayo and Wyckhuys suggest that agriculture is to blame:

‘Overall, the systemic, widespread and often superfluous use of pesticides in agricultural and pasture land over the past 60 years has negatively impacted most organisms, from insects to birds to bats . . ‘.

The students in ENT 518 honed in on the fact that the authors searched for the words ‘insect’ AND ‘decline’. Accordingly, there was a level of bias in their search procedures. Students seemed convinced that many insect groups are in decline, but were less willing to agree that the overall level of decline, rate of decline, and rate of extinction reported by the authors were accurate estimates. In addition, although students agree that pesticide use is likely to blame for insect declines, they would have been more convinced, if there were better data tying the two together.

Students then discussed how the science papers were translated into a narrative for the NY Times and Atlantic articles. We talked about the elements of a story, and how as scientists, we don’t worry about setting the scene, developing characters, or of conflict in a plot. But, many of us are also science communicators via our work in Extension or through other outreach efforts. If we can paint a picture that people can relate to ~ if we can get them to notice and to share their experience with noticing fewer insects in their yard or their town ~ will they care more about insect conservation?

One of the major reasons that we do the work that we do in the Garden Ecology Lab is because we believe that how we manage our gardens can truly make a difference to insect conservation. If we can take better notice of those ‘little things that run the world’ and share these experiences with our friends and family . . . will that make a difference? I believe that it will. In fact, it is the reason that I come to work, each and every day, excited to learn more about how we can make this world a better place through gardening.

Isabella Featured on Pollination Podcast

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Isabella Messer has been a member of the Garden Ecology Lab for more than two years, where she primarily assists with the garden pollinators study, but will is also developing her own research project. Her independent research project will look at bee visitation to some of the plants we are studying in controlled research trials, when these same plants are in a mixed garden setting. Controlled research trials are important, because they let us document the attractiveness of plants to bees, in a setting where study plants are not competing with other plants for pollinators. Controlled research trials are also valuable, because they let  researchers have better control over environmental conditions, such as irrigation. Isabella is going to see whether and how bee visits on plants in a garden context is different than what Aaron is documenting in his controlled research trials. This will be one of the first, if not the first time, that we will have direct and contemporaneous measures of bee visits on focal plants in each situation: in a research field, and in a garden.

In addition to her work in the lab, Isabella is also a member of the ‘Research Retinue’: a group of Oregon State University undergraduates, who review and discuss papers on the PolliNation Podcast.

In this episode, the retinue discusses two papers that look at the impact of a common herbicide (glyphosate) on bees, via indirect impacts of glyphosate on the microbiome (bacterial community) that can be found in honey bee guts.

The paper that they discuss is linked, below:

 

Pollinator Survey

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Lauren Bennett, a Master’s student at OSU, is doing her capstone project on pollinators She has a short survey (10-15 minutes) on pollinators and pollinator plants.

If you could spare a few moments of your time, we would appreciate your participation in this study. More information this study can be accessed, by following the link, below.

http://oregonstate.qualtrics.com/jfe/form/SV_bw2OqokCObh83rv

FYI ~ this study was deemed ‘quality improvement / assessment’ and not ‘scholarly and journalistic’ by the OSU IRB. Thus, we do not need or have IRB oversight for this study.

 

Master Gardener Input Needed!

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We are soliciting Master Gardener feedback on the attractiveness of the native wildflowers that Aaron Anderson is studying for pollinator plantings. More detail on the study can be found at:

http://blogs.oregonstate.edu/gardenecologylab/native-plants-2/

As we mention, not only are we interested in finding plants that support ecosystem services; we also want to find plants that gardeners find attractive, and that they would want.

This is where you come in. If you are willing, please let us know which ones you would like to see in your own garden, based on their looks, alone. Below is the recruitment letter, with further information about participation. Thank you for your consideration!

*******************************************

Study: Screening Willamette Valley Wildflowers for attractiveness to Pollinators and Natural Enemies

Graduate Research Assistant: Aaron Anderson (andeaaro@oregonstate.edu; 503-860-9286)

Principal Investigator: Dr. Gail Langellotto (Gail.Langellotto@oregonstate.edu; 541-737-5175)

Dear Master Gardener,

You are invited to take part in a survey that will generate useful information on the ornamental value of pollinator-friendly native wildflowers.

Previous research has shown that urban greenspaces, notably gardens, can provide excellent habitat for pollinators and other invertebrates. The inclusion of pollinator-friendly plantings in gardens has the potential to improve habitat quality and connectivity in otherwise inhospitable landscapes. However, research on which Willamette Valley wildflowers are best to use for these plantings is lacking. Thus, I am conducting a research project to assess the relative attractiveness of 23 wildflower species native to the Willamette Valley (Oregon) to pollinators and natural enemies. Additionally, I would like to assess the aesthetic value of these plants to identify native flowers that are also attractive for ornamental use in home gardens.

As a Master Gardener, I am asking your help with my study, “Screening Willamette Valley Wildflowers for attractiveness to Pollinators and Natural Enemies”.  If you are aged 18 or older, and are currently a Master Gardener, or have been a Master Gardener in the past, I would appreciate it if you could take 10-15 minutes to respond to this survey:

http://bit.ly/OSUNative

Your survey responses will be recorded as a group. Thus, your response will be anonymous.  If the results of this survey are published, your identity will not be made public. The security and confidentiality of information collected from cannot be guaranteed.  Confidentiality will be kept to the extent permitted by the technology being used.  Information collected online can be intercepted, corrupted, lost, destroyed, arrive late or incomplete, or contain viruses.

Your participation in this study is voluntary and you may refuse to answer any questions(s) for any reason.  There are a limited number of Master Gardeners in Oregon, so your participation in this study is important. If you do not want to participate and do not wish to be contacted further, do not fill out the online questionnaire. There are no foreseeable risks to you as a participant in this project; nor are there any direct benefits. However, your participation is extremely valued.

If you have any questions about the survey, please contact me at 503-860-9286 or via email at andeaaro@oregonstate.edu.  If you have questions about your rights as a participant in this research project, please contact the Oregon State University Institutional Review Board (IRB) Human Protections Administrator at (541) 737-4933 or by email at IRB@oregonstate.edu.

Thank you for your help. I appreciate your consideration.

Sincerely,

Aaron Anderson

First Publication from the Garden Ecology Lab!

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Our paper on the potential for bee movements between gardens and urban/peri-urban agriculture has been published in a special issue on Agroecology in the City, in the journal Sustainability.

Langellotto, G.A.; Melathopoulos, A.; Messer, I.; Anderson, A.; McClintock, N.; Costner, L. Garden Pollinators and the Potential for Ecosystem Service Flow to Urban and Peri-Urban Agriculture.Sustainability 2018, 10, 2047.

In this paper, we estimated how far the bees we collected from our Garden Pollinators Study could move between gardens and pollination-dependent cropland. We found that when pollination-dependent crops (commercial-scale or residential-scale) are nearby, 30–50% of the garden bee community could potentially provide pollination services to adjacent crops.

But, we currently know so little about bee movements in complex landscapes ~ if and how bees move across roads or through gardens embedded in housing developments. This question will be a focus of our future work.

Some of the bees collected from our 2017 Garden Pollinators study.

Urban Soils Update, May 2018

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garden ecology lab

Urban agriculture has received a lot of attention over the past decade, as more folks are looking to localize their food supply, reduce food miles, and/or exert greater control over their food. Urban agriculture, however, brings a distinct set of challenges from farm systems in more rural regions. For example, urban farms tend to be relatively small and diverse (which can make it challenging to rotate crops), and are often close to neighborhoods and housing developments (which may make urban farms more prone to nuisance complaints). Urban farmers tend to be younger and to have less experience in agriculture, compared to rural farmers, and in need to high levels of technical assistance from Extension and other providers (Oberholtzer et al. 2014). However, many of the resources that Extension has to offer are focused on traditional growers, rather than new urban farmers.

Our lab group wanted to examine an issue that is specific to urban growers, and for which we could find very little information: urban agricultural soils. Soil scientists have prioritized research on urban agricultural soils as a key priority for the 21st century (Adewopo et al. 2014). Yet for his thesis work, Mykl Nelson could only find 17 academic papers that looked at urban agricultural soils in the United States. Most of these studies focused on

residential-scale or community-scale urban agriculture (in home or community gardens). Only one paper looked at soils on an urban farm.

Still, residential- and community-scale gardening is an important type of urban agriculture. In Portland, a conservative count of 3,000 home gardens collectively covers more than 20 acres of land (McClintock et al. 2013). In Chicago, residential food gardens cover 29 acres of land, and represent 89% of all urban agriculture (Taylor and Lovell 2012). In Madison, WI, more than 45,000 food gardens cover more than 121 acres of land (Smith et al. 2013).

For Mykl’s thesis, he looked at urban soils from 27 Master Gardener-tended gardens, in Portland and Corvallis, OR. Even though all gardens were tended by OSU Extension trained Master Gardeners, they were incredibly diverse: 74 different annual crops, and 58 different perennial crops were grown across these gardens. Unique crops included kalettes, papalo, thistle, savory, paw paw, quince, sea berry, and service berry, among others.

In terms of the soils, Mykl found that soils were within the recommended range for physical parameters, such as bulk density, wet aggregate stability, and soil compaction. However, home garden soils tended to be over-enriched in soil organic matter. Growers generally aim to foster soils that are between 3-6% organic matter. However, Mykl’s tested soils were on average 13% organic matter! Raised beds were on average 15% organic matter. In ground beds were a bit better: 10% organic matter, on average. So to put this another way, Master Gardener vegetable garden soils had 2-5X the recommended level of organic matter for productive agricultural soils. We suspect that Master Gardeners were annually adding organic matter to their soils, without necessarily knowing the baseline levels in their soils. Adding more organic matter, without knowing where you’re starting from, encourages over-applications.

Does that matter? Afterall, for years, we have been preaching that if you have sub-par soils, ‘just add organic matter’. Biological activity in these soils was great! But, the excess in organic matter promoted excess in several soil nutrients. Garden soils were over-enriched in phosphorus (mean phosphorus across all gardens was 2-3X recommended levels. Potassium in some gardens was 5X recommended levels! Gardens were over-enriched in magnesium and manganese, too. Nutrient excess was worse in raised beds, compared to in-ground gardens.

Unexpectedly, Mylk found the highest lead levels in raised beds. Often, we tell gardeners to grow their food in raised beds, to avoid heavy metal contaminants. Why would there be high lead in raised beds, if we weren’t finding elevated lead levels in nearby in-ground beds? We suspect that the lead might be coming in from compost waste that can be purchased on the retail market. If a compost product makes no nutritional claim, then it is exempt from analysis and contamination limits.

We can’t wait to finalize this work for publication. In the meantime, I wanted to share a brief update on this work.

Mykl will be defending his thesis on May 31st. We’re trying to arrange an online broadcast of the public portion of his thesis defense (1pm-2pm, May 31st). I will update this post, if we are able to get an online link for his presentation.