Posts Tagged: Sustainable Agriculture
Powers of microbes: UC Davis graduate students get creative to teach farmers about soil microbiology
If you grew up in the 1980s or 1990s (or were a child at heart during that era), the famous Powers of Ten film likely left an indelible mark in your mind.
The film starts with a couple lounging on a picnic blanket and zooms out to the outer reaches of the universe, then back in to peer into the microscopic world of the human body: from white blood cells to DNA, and finally down to the proton of a carbon atom.
In its short 9-minute run time, Powers of Ten manages to inflame an existential angst about the size of a single human life while at the same time connecting the viewer to the beauty of the universe and the human body.
As a high school student watching the video, it filled me with the same sense of awe that I felt the first time I heard Carl Sagan's famous quote that “we are all made of star stuff.”
Powers of Ten reminds us that looking at the world from different perspectives, from the very tiny to the immensely large, helps create a better understanding of the natural world, our place within it, and how we can impact it for good.
Had Powers of Ten returned from outer space by zooming into a piece of soil rather than a the human body, it would have explored the billions of living creatures in one handful of soil, slowly scaling down from millipedes to earthworms to ants to nematodes to protozoa, and finally down to the soil's bacteria and fungi that make up the base of the soil food web.
The video might then have looked a lot like the recent workshop at the Russell Ranch Sustainable Agriculture Facility, which served as a science fair for farmers and researchers to learn about the minuscule but powerful soil microbe.
While farmers often have a baseline knowledge about soil microbiology and its importance on the farm, “the science is evolving so quickly at this point, that it can be hard to keep up,” said attendee Margaret Lloyd, UC Cooperative Extension advisor who works with small-scale farmers in Yolo and Sacramento counties.
The workshop coupled foundational principles of soil microbiology with practical on-farm management situations, making the case for farmers to actively consider soil bacteria, fungi, and other micro organisms in their decision-making process.
Jessica Chiartas, a fourth-year graduate student in soil microbiology and one of the workshop organizers, is somewhat of a soil science evangelist.
Her hope was to help workshop attendees better understand that “soils are not just physical, chemical systems. A majority of the processes that take place underfoot are biologically driven. Soils are living and breathing bodies and much like us, they need to be fed, covered, and protected from disturbance” in order to function in the long term.
The scale of microbial activity in soil makes it challenging to help farmers dig into just what scientists are talking about when they talk about microbes.
“It's important to talk about the scale of microbes,” Chiartas said. “So much of what goes on in soils is mediated by microbes and the scale that they operate on is far different than the scale we measure them at. Our typical method of soil sampling and analysis is analogous to harvesting whole fields of crops, chopping them up, throwing them in a heap and then trying to glean information about the individual plants.”
The presenters at the soil health workshop used vivid analogies to translate the abstract results of scientific research and hard-to-imagine scales into concrete, relatable concepts.
A single gram of soil may contain a billion bacteria, and several miles of fungal hyphae, the web-like growth of fungus. Translated into human scale, the numbers are mind boggling.
If a single microbe were a 6-foot-tall person, then a single millimeter of soil would be as tall as the empire state building. A typical soil bacterium contains as many DNA letters in its chromosome as two copies of “War and Peace.” A stack of copies of “War and Peace” equivalent to bacterial DNA from a single teaspoon of soil would be larger than the Great Pyramid of Giza.
A soil information revolution
The metaphors of scale are a fun thought experiment, and they could provide a jumping-off point for a discussion between farmers and scientists essential for improving our current understanding of soil as a living system. Climate change is expected to amplify the effects of soil erosion, compaction, nutrient leaching and other issues common in our current agricultural systems.
“We need improved management that works with the soil ecosystem to increase crop production while enhancing soil health,” said Radomir Schmidt, a postdoctoral researcher and workshop organizer. ”That's going to take a concerted effort and open dialog between farmers, scientists, and citizen scientists to discover, test, and implement these methods in the real world.”
We are now in the era of “soil information revolution," Schmidt said. As our knowledge of the soil microbiome expands, implementing this knowledge in agricultural practice is more and more possible.
This graduate student cohort is well-positioned to make the necessary connections, learning from farmers while helping them zoom in to see the essential lifeforms that impact their farm, then zoom out to help make decisions that are good for the farmer, good for the crop, and good for the microbe.
Farmers in the Davis area will have another opportunity to learn soil health fundamentals at a workshop this fall hosted by the UC Sustainable Agriculture Research and Education Program and Russell Ranch Sustainable Agriculture Facility. Details about the workshop will be posted here.
Recently, it seems we have reached a plateau of production with current planting materials and management methods in the San Joaquin Valley vineyards. Making a vineyard less variable with more uniformly productive grapevines regardless of their location within a given vineyard is the most important question to the viticulturists.
Vineyard variability was first studied in Australia, and the yield variation within-vineyard is typically of the order of 8 to 10 fold . The fruit quality variation might follow the similar pattern as yield variation under or over a certain crop load window. Differential harvest was first applied in Australia with yield monitor installed on the mechanical harvesters to separate the low yield zone and high yield zone for high quality and low quality fruit for different wine programs. It was an improvement from the winemaking point of view. However, differential harvest still didn't solve the problem of vineyard variability for both yield and quality. Then viticulturists started to think of differential management or even differential planting may provide a solution to variation in vineyards.
Then the question becomes: is the variation pattern always consistent? Unlike annual broadacre crops, e.g. corn or soybeans, grapevines are a perennial crop and the yield variation carry-over effect is always something important for viticulturists to keep in mind. Initial research results suggested the variation pattern can be consistent in 2 years' period. However, different site location may contribute to vineyard variation as well. Soil texture, water holding capacity, and soil mineral nutrient content were believed to be the main cause of the variability. Further investigation is needed to confirm that the variation pattern is somehow consistent and manageable to make the vineyards produce uniformly.
Once it is assessed vineyard variability can be managed. Defining vineyard variability becomes the next question. Assessing vineyard variability visually may not be possible for large vineyards. Yield monitoring, on the other hand, is only suitable to define the variability at harvest and might be also financially difficult for small growers. Early detection of the vineyard variability in order to manage the vineyard differentially is an active area of research. Currently, different sensors have become available for vineyard managers to tell how much variability is in the vineyard through measurement of canopy reflectance through use of NDVI, thermal images, irrigation scheduling using sap flow sensors and availability of soil moisture through measurement of soil matric potential. UAVs and satellite imagery are also available to assess vineyard variability at an economical cost, as they may provide larger data sets with relative cheap cost. However, ground-truthing is needed to make sure how accurately these data from different sensors define the variability in the vineyard.
Recently, Cornel University, Carnegie Mellon, and UC Davis were awarded a $6 million grant from the USDA's Specialty Crop Research Initiative (SCRI) to further study the proximal sensing, crop estimation, and soil mapping to develop tools for variable rate management in table and wine grape vineyards. The goal of the project is to increase/optimize yield and quality within a vineyard by spatially tuning (a) vine balance and (b) canopy light microclimate.
The challenge for San Joaquin Valley grape growers is to make grape growing more economically sustainable for future generations. Optimizing yield per acre with less labor and energy inputs should be the goal of growers. Reducing the vineyard variability to have more uniform production might give growers more profit per acre by increasing the yield per acre without adversely affecting fruit quality. Ultimately, new breeding materials will be the long term goal to increase the yield potential and profitability for vineyards.
The prestigious award, given each year by the Agricultural Sustainability Institute (ASI) at UC Davis, will be presented at a ceremony at UC Davis on April 23. UC Agriculture and Natural Resources, with its Sustainable Agriculture Research and Education Program, is a partner with ASI.
The keynote speaker at the awards presentation will be Navina Khanna, a UC Davis alumna and leader for food justice in California.
The Bradford–Rominger award honors individuals who exhibit the leadership, work ethic and integrity epitomized by the late G. Eric Bradford, a livestock genetics professor who gave 50 years of service to UC Davis, and the late Charlie Rominger, a fifth-generation Yolo County farmer and land preservationist.
Former students describe Fujimoto as a prophet and “energizer bunny of social change.”
“Isao began advocating for more socially just and environmentally sustainable forms of agriculture over 40 years ago,” said Mark Van Horn, director of the Student Farm at UC Davis. “At the time, it made him quite unpopular in some quarters, but he remained true to what he knew was right.”
In his early days at UC Davis, Fujimoto used the campus's signature red, double-decker buses to transport children of farm workers to school when public bus service was canceled. The incident sparked conversation about the need for the university to focus on California's rural communities, and led to creation of the Community and Regional Development Graduate Program at UC Davis in the mid-1970s.
Fujimoto was also instrumental in starting the Asian American Studies program on campus, and was mentor to many students who have become sustainable agriculture leaders in their own right. Throughout the 1970s, Fujimoto's home served as a local hub for community activism, with projects such as the Davis Food Co-op and the Davis Farmers Market starting out at his kitchen table.
“He has helped countless students understand the world around them and clarify their personal values and principles,” Van Horn said. “Most importantly, his actions have provided lessons and inspiration for those wanting to act upon their values and principles to bring about positive change in the world.”
Like Eric Bradford, Isao Fujimoto is a respected mentor and a consensus builder. Like Charlie Rominger, Fujimoto has consistently stood up for his beliefs, regardless of their unpopularity, and has done so with a kind heart and humble nature.
“The kind of commitment and sense of responsibility that Eric and Charlie had is a pretty remarkable trait,” Fujimoto said. “I find this award set up by the Bradford and Rominger families as a pretty significant marker of change in terms of broadening the scope of agriculture to include being conscious of the environment and using agriculture as a tool for building community.”
Past winners of the award include UC Agriculture and Natural Resource's advisor Rose Hayden Smith, specialist Ken Tate and advisor Mary Bianchi; and UC alumna Kelly Garbach.
Fujimoto will receive the award at the annual Bradford–Rominger Agricultural Sustainability Leadership Award Ceremony which begins at 5 p.m. in the Multipurpose Room at the Student Community Center at UC Davis. Khanna's keynote speech will address, “Claim Your Superpower: Meeting the Moment for a Winning Food Movement.” On April 24, Khanna will meet with UC Davis students to further discuss leadership in the food movement.
This event is free and open to the public. Students are encouraged to attend. Learn more about the award on the Agricultural Sustainability Institute's web site.
For more information, contact Aubrey White at 530-752-5299, firstname.lastname@example.org
The UC Sustainable Agriculture Research and Education Program is working to build an online community for growers facing challenges and trying innovative approaches to how they manage nutrients on the farm. With the help of FarmsReach and Sustainable Conservation, we've been working to build up an online group based on nutrient management to discuss a wide array of practices. For two weeks in January, we hosted a discussion on nutrient management for vineyards, particularly in times of drought.
In a recent Capital Public Radio story on winemakers struggling with groundwater shortages this year, winemaker Chris Leamy said “the drought has helped to spur change and innovation.” When business as usual is not an option, farmers get creative. Through discussion, informational videos, and a tool kit of resources, farmers and UC advisors shared some of the creative ways that growers are adapting to water limitations and building healthy soil in their vineyards.
One discussion to rise to the surface throughout was the use of animals in vineyard systems. Farmers with experience running animals through their vineyards chimed in with valuable insights.
Some thoughts repeated by several growers were:
- Short breeds like babydoll sheep and tall cordons on vines make sheep less able to graze on the canopy. Some growers use electrified deterrents running parallel to the trellis to allow sheep to stay in the vineyard into the summer with no leaf damage. Growers who kept sheep in vineyards year round described eliminating mowing completely.
- Drip lines need to be tall enough to be out of reach from sheep.
- Move sheep frequently to prevent soil compaction.
- One grower runs chickens through the vineyard at the end of the season, but says to avoid the practice if shoot growth has been too vigorous — the added nutrients from the chickens may give vines an unwanted boost in the spring.
- Growers who use sheep in their vineyards describe significant nutrient inputs from sheep, some to the point of eliminating other fertilizers altogether.
You can follow more of the conversation here. The group of participants is growing (94 strong now!) and we'll be hosting future discussions on different topics. This project is hosted by UC SAREP as part of the Solution Center for Nutrient Management. You can join our mailing list to stay up-to-date with our activities, online discussions, and updates to our website./a>
Writing on Earth Day, I am reminded of one of the world's major successes in environmental protection, the Montreal Protocol. Originally signed in 1987, it works to phase out ozone-depleting substanc
Twenty-seven years later, the realities of enacting the Montreal Protocol are still taking shape, and strawberry growers are, with each harvest year, a step closer to a complete phase out of the fumigant and increased restrictions on alternative chemical fumigants used for disease suppression.
UC research has focused on how to make an economically viable and effective transition away from the soil fumigant. Initial alternatives include replacement chemical fumigants as well as biological fumigants such as anaerobic soil disinfection (such as putting tarps over fields to decrease oxygen), mustard seed meal amendment, or steam disinfestation.
But what if a practice many growers already use could also serve to suppress soil-borne diseases? What if growers could use a substance that provides multiple on-farm benefits?
Many conventional and organic growers alike use compost to boost soil fertility and organic matter. But compost's potential to serve other purposes, including suppressing disease, remain largely unexplored.
Ph.D. student Margaret Lloyd and Tom Gordon, professor in the Department of Plant Pathology at UC Davis, are hoping to close the gap in that knowledge. With a grant from the National Strawberry Sustainability Initiative, a program administered by University of Arkansas and funded by Walmart Foundation, and funding from UC Sustainable Agriculture Research and Education Program, Lloyd's research seeks to understand whether compost can contribute to disease suppression on a commercial scale, and how growers can best incorporate compost into their farm management to see its benefits.
“Compost is part of the production system that has potential as biological control,” says Lloyd. “Historically, we've only focused on it as a source of organic matter or soil nutrients. I'm trying to characterize its role in root health and soil health.”
The study evaluates the root health of strawberry plants, and compares plant yield and disease suppression across a number of research sites and compost types.
“In general, we talk about compost just as compost,” Lloyd said. “But it has drastically different qualities — soil fertility characteristics, physical properties, and microbial profiles. By focusing on different compost sources, the study will help growers better assess their available compost options to m
Alternatives to methyl bromide have been a long time coming. “The research suggests that it won't be one technology replacing another, but a package of tools to help growers manage disease suppression in the soil,” Lloyd said. If some of those tools are already in a grower's tool kit, the transition away from fumigants will be that much smoother.
The research suggests a powerful Earth Day message for me: use what you have, but seek a deeper understanding of just how to use it.
Lloyd's research findings will be completed in 2014, with results available for growers in 2015. Visit the project's website for more information.