- Author: Claude Wharton
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Could cactus pear become a major crop like soybeans and corn in the near future, and help provide a biofuel source, as well as a sustainable food and forage crop? According to a recently published study, researchers from the University of Nevada, Reno believe the plant, with its high heat tolerance and low water use, may be able to provide fuel and food in places that previously haven't been able to grow much in the way of sustainable crops.
Global climate change models predict that long-term drought events will increase in duration and intensity, resulting in both higher temperatures and lower levels of available water. Many crops, such as rice, corn and soybeans, have an upper temperature limit, and other traditional crops, such as alfalfa, require more water than what might be available in the future.
"Dry areas are going to get dryer because of climate change," Biochemistry & Molecular Biology Professor John Cushman, with the University's College of Agriculture, Biotechnology & Natural Resources, said. "Ultimately, we're going to see more and more of these drought issues affecting crops such as corn and soybeans in the future."
Fueling renewable energy
As part of the College's Experiment Station unit, Cushman and his team recently published the results of a five-year study on the use of spineless cactus pear as a high-temperature, low-water commercial crop. The study, funded by the Experiment Station and the U.S. Department of Agriculture's National Institute of Food and Agriculture, was the first long-term field trial of Opuntia species in the U.S. as a scalable bioenergy feedstock to replace fossil fuel.
Results of the study, which took place at the Experiment Station's Southern Nevada Field Lab in Logandale, Nevada, showed that Opuntia ficus-indica had the highest fruit production while using up to 80% less water than some traditional crops. Co-authors included Carol Bishop, with the College's Extension unit, postdoctoral research scholar Dhurba Neupane, and graduate students Nicholas Alexander Niechayev and Jesse Mayer.
"Maize and sugar cane are the major bioenergy crops right now, but use three to six times more water than cactus pear," Cushman said. "This study showed that cactus pear productivity is on par with these important bioenergy crops, but use a fraction of the water and have a higher heat tolerance, which makes them a much more climate-resilient crop."
Cactus pear works well as a bioenergy crop because it is a versatile perennial crop. When it's not being harvested for biofuel, then it works as a land-based carbon sink, removing carbon dioxide from the atmosphere and storing it in a sustainable manner.
"Approximately 42% of land area around the world is classified as semi-arid or arid," Cushman said. "There is enormous potential for planting cactus trees for carbon sequestration. We can start growing cactus pear crops in abandoned areas that are marginal and may not be suitable for other crops, thereby expanding the area being used for bioenergy production."
Fueling people and animals
The crop can also be used for human consumption and livestock feed. Cactus pear is already used in many semi-arid areas around the world for food and forage due to its low-water needs compared with more traditional crops. The fruit can be used for jams and jellies due to its high sugar content, and the pads are eaten both fresh and as a canned vegetable. Because the plant's pads are made of 90% water, the crop works great for livestock feed as well.
"That's the benefit of this perennial crop," Cushman explained. "You've harvested the fruit and the pads for food, then you have this large amount of biomass sitting on the land that is sequestering carbon and can be used for biofuel production."
Cushman also hopes to use cactus pear genes to improve the water-use efficiency of other crops. One of the ways cactus pear retains water is by closing its pores during the heat of day to prevent evaporation and opening them at night to breathe. Cushman wants to take the cactus pear genes that allow it to do this, and add them to the genetic makeup of other plants to increase their drought tolerance.
Bishop, Extension educator for Northeast Clark County, and her team, which includes Moapa Valley High School students, continue to help maintain and harvest the more than 250 cactus pear plants still grown at the field lab in Logandale. In addition, during the study, the students gained valuable experience helping to spread awareness about the project, its goals, and the plant's potential benefits and uses. They produced videos, papers, brochures and recipes; gave tours of the field lab; and held classes, including harvesting and cooking classes.
Fueling further research
In 2019, Cushman began a new research project with cactus pear at the U.S. Department of Agriculture - Agricultural Research Service' National Arid Land Plant Genetic Resources Unit in Parlier, California. In addition to continuing to take measurements of how much the cactus crop will produce, Cushman's team, in collaboration with Claire Heinitz, curator at the unit, is looking at which accessions, or unique samples of plant tissue or seeds with different genetic traits, provide the greatest production and optimize the crop's growing conditions.
"We want a spineless cactus pear that will grow fast and produce a lot of biomass," Cushman said.
One of the other goals of the project is to learn more about Opuntia stunting disease, which causes cactuses to grow smaller pads and fruit. The team is taking samples from the infected plants to look at the DNA and RNA to find what causes the disease and how it is transferred to other cactuses in the field. The hope is to use the information to create a diagnostic tool and treatment to detect and prevent the disease's spread and to salvage usable parts from diseased plants.
Among three cactus varieties researched by the University of Nevada, Reno as drought-tolerant crops for biofuel, Opuntia ficus-indica produced the most fruit while using up to 80% less water than some traditional crops. And spineless too.
Photo by John Cushman, University of Nevada, Reno.
- Author: Kathey Keatley Garvey
Sometimes distant relationships are better than close relationships.
Persimmons, asparagus, figs and other crops distantly related to native California plants attract fewer pests and diseases than the closer kin, and thus receive fewer pesticide treatments, according to a newly published article by two UC Davis-linked scientists in the Proceedings of the Natural Academy of Sciences (PNAS).
Co-authors Ian Pearse, research ecologist with the U.S. Geological Survey and a UC Davis alumnus, and Jay Rosenheim, UC Davis distinguished professor of entomology, analyzed the 2011-2015 state records of pesticide applications of 93 major California crops.
“We hypothesized that California crops that lack close relatives in the native flora will be attacked by fewer herbivores and pathogens and require less pesticide use,” said Rosenheim, a 32-year member of the UC Davis Department of Entomology and Nematology faculty and a newly elected fellow of the Entomological Society of America.
Rosenheim and Pearse examined the pesticide applications against arthropods, pathogens, and weed plants and compiled the data into a comprehensive analysis.
Their findings appear in the PNAS article, “Phylogenetic Escape from Pests Reduces Pesticides on Some Crop Plants,” published Oct. 12. “Phylogenetic relationship” refers to the relative times in the past that species shared common ancestors.
“It is well understood that many of the insect pests and diseases that attack our crops are often invasive species that come from overseas,” Rosenheim explained. “Almost all crops grown in California have been domesticated from wild plants whose area of origin is overseas, and many of the invading pests come from the original home of the wild ancestor of the now domesticated crop plant.”
“In contrast, our study focuses on the roughly half of all herbivores and diseases that attack California crops and that are actually native to California. These organisms originally attacked members of the native California flora, but have now shifted to attack a novel host: the crop plant.”
However, “host shifts aren't always easy,” Rosenheim said. “It's relatively easy to shift to attack a close relative of a native host plant, but it's relatively hard to shift to attack a very different host plant.”
Said Pearse: “Our study shows that crops like dates, asparagus, figs, kiwis, or persimmons that are distantly related to native California plants--and thus separated by many million years of independent evolution-- are colonized by fewer pests and diseases.”
These crop plants, the scientists said, are “too different” to be attacked readily. As a result, fewer pesticide applications are needed to protect those crops. “Thus, we can capitalize on an understanding of the evolutionary relatedness of crops and native plants to find crops that will suffer less attack, and that can therefore be grown with less use of toxic pesticides,” Pearse pointed out.
"The crops that require the most pesticide applications, Pearse said, "are those, like artichokes, blackberries, and sweet corn, that have close relatives in the Californian flora and are of high economic value per acre."
California's top agricultural crops include almonds, grapes, lettuce, strawberries, tomatoes and walnuts.
Rosenheim said persimmons are a good example “of the phenomenon we've studied: they have very, very few pests--almost zero in my experience--and that's probably because persimmons have no close relatives in the California native plant community.”
Pearse, a 2005 Fulbright scholar who received his doctorate in ecology from UC Davis in 2011, studying with Professor Rick Karban, joined the U.S. Geological Survey in Fort Collins in 2016. He focuses his research on invasive species and plant-insect interactions. Rosenheim researches insect ecology, with a focus on host-parasitoid, predator-prey, and plant-insect interactions, with direct applications to biological control.
“Pesticides are a ubiquitous (found everywhere) component of conventional crop production but come with considerable economic and ecological costs. We tested the hypothesis that variation in pesticide use among crop species is a function of crop economics and the phylogenetic relationship of a crop to native plants, because unrelated crops accrue fewer herbivores and pathogens. Comparative analyses of a dataset of 93 Californian crops showed that more valuable crops and crops with close relatives in the native plant flora received greater pesticide use, explaining roughly half of the variance in pesticide use among crops against pathogens and herbivores. Phylogenetic escape from arthropod and pathogen pests results in lower pesticides, suggesting that the introduced status of some crops can be leveraged to reduce pesticides.”
- Author: Ben Faber
Craft breweries aren't just a fun place to meet up with friends. They may be fueling an unprecedented geographic expansion of hop production across the U.S., according to researchers at Penn State and The University of Toledo. Their findings suggest that as more craft breweries emerge around the country, so may new opportunities for farmers.
Hops are a key ingredient in beer production, providing aroma and bittering characteristics. Before 2007, hop production in the U.S. was limited to only three Pacific Northwest states--Oregon, Washington, and Idaho--according to Claudia Schmidt, assistant professor of agricultural economics in Penn State's College of Agricultural Sciences. Citing a report released this year by the Hop Growers of America, she said that 29 states are now engaging in hop production.
"Our study is the first to systematically show that the number of hop farms in a state is related to the number of craft breweries," said Schmidt. "It suggests that in areas where hop production is possible and not cost-prohibitive, breweries are expanding markets for farmers and providing an opportunity to diversify farm income."
Using data from the U.S. Census of Agriculture and ReferenceUSA, the researchers found that from 2007 to 2017, the number of breweries in the U.S. more than quadrupled from 992 to more than 4,000, and that the number of breweries in a state is associated with more hop farms and hop acres five years later. The number of hop farms grew from 68 to 817, and hop acreage expanded from 31,145 to 59,429 acres.
"This growth has not only led to interesting changes in the locations of hop farms across the U.S., but it has positioned the U.S. as the largest producer of hops globally, both in terms of acreage and production," said Elizabeth Dobis, a postdoctoral scholar at the Penn State-based Northeast Regional Center for Rural Development, and lead author of the study.
Working with farm, brewery, and climate data, the researchers developed a statistical model to determine whether new craft breweries in a state between 2007 and 2017 resulted in a larger number of hop producers and hop acres planted, by both new and existing growers in that state. They built a time-lag into their model to identify the effect of new breweries over time. They also controlled for other variables that may influence farmers to start growing hops, such as average farm size, average net farm income, and climate.
Their findings, which were published recently in the Journal of Wine Economics, are correlational and do not point to a clear cause-and-effect. However, the time-lag built into the model indicates that the growth in breweries preceded the growth in hop farms, said Dobis.
One possible explanation for the trend is that the growing consumer demand for locally sourced food and beverages encourages craft brewers to seek out locally grown ingredients, said Schmidt.
"While most craft breweries serve a local market, they haven't always sourced local ingredients for their beers," Schmidt said. "But if you're a brewer looking to differentiate yourself in an increasingly crowded market, sourcing ingredients locally is an approach that some brewers have found to be effective."
For example, in a project unrelated to this study, Penn State Extension's Kristy Borrelli and Maria Graziani conducted focus groups with Pennsylvania craft brewers, who reported that sourcing ingredients locally helps them connect with their customers' sense of place and preference for a flavor profile that is unique to the region.
If more brewers are looking for hops grown nearby, then more farmers may be willing to try growing them, even if only on a small scale. For instance, in Pennsylvania only 17 farms reported hop production in 2017, and their combined acreage is small--only 21 acres in all, according to the U.S. Census of Agriculture.
Looking forward, the researchers said that they will collaborate with Penn State Extension to identify the specific attributes and price points that Pennsylvania craft brewers are looking for in order to help inform farmers' production decisions.
The Role of Craft Breweries in Expanding (Local) Hop Production
- Author: Ben Faber
The common question comes up all the time – “What can I grow here that will make money?” Why not lemons or avocados. The coastal California area is generally well adapted to these crops and infrastructure and markets are developed. Still people want to diversify and do have serious concerns about ACP and other problems that might affect these two big coastal crops.
A recent class of Cal State Channel Islands students was asked to identify crops that would make a difference if introduced to the Ventura/Santa Barbara agroenvironment and would make money based on the exceptional climate here. The crop had to fit into the rules:
1) Something that could be grown here, or only with difficulty somewhere else where it was too hot/cold, or that it is out of sync with production somewhere else
2) Or the corollary, that it couldn't be grown somewhere else more cheaply or processed or stored, somewhere with cheap land/water/labor/laws. Cheap
3) It needs to be fresh and even delicate to make it hard to ship distances.
4) Or if it doesn't meet rules 1-3, it can be marketed so that it takes on the specialty of the locale. “It really cant be grown anywhere else, but here, because it can only be found in Ojai.” Or something of that nature.
So, the proposed perennial crops were:
Pitahaya – Hylocereus undatus or ‘dragon fruit' is already being grown in the county, has a good market and potential and has some drought tolerance although it can have problems in full sun, even along the coast.
Azerole – Crataegus azarolus or ‘Mediterranean medlar'. Does best where not too cold, but with those thorns its going to be a tough crop to pick and will require a lot of marketing even though it can take drought.
Yuzu – Citrus junos is a high demand fresh fruit that grows similar to standard lemon, although a bit more cold hardy. Demand is primarily from Japanese and Korean restaurants. And being citrus might be susceptible to huanglongbing.
Jaboticaba – Myrciara caulifora, a new crop, well adapted to the coast, very tasty and fits in with the locavore trend. And Fresno cant grow it unless in tunnels. And you cant eat just one.
‘Santa Rosa' plum – this is the standard Prunus salicina stone fruit, but because it is early along the coast and can be picked “just so O, ripe” for shipment to LA restaurants that would welcome an alternative to the standard tasteless store-bought fruit
Persimmon – Diaspyros kaki – one of the flat ‘Fuyu' varieties, because they crop earlier along the coast than the Central Valley. And there's nothing more satisfying than that crunch.
Moringa – Moringa oleifera or drumstick tree is often produced for oil, hence the botanical name. It can also be grown for cattle food, but the deal here is it's grown for fresh market for its spinach-like leaf and it's a perennial which you just keep on cutting and cutting and cutting and there's not replanting. A money machine.
Mulberry – Morus alba and nigra. Nothing could be more sweet, but ever so delicate than a mulberry fruit. Harvested off tarps (to comply with food safety) and shipped immediately to farmers markets and to the finest LA restaurants, you can make a bundle or a lot of permanent stain if it doesn't get to the consumer in good shape. Drying is an option, but the Turks have that market.
Tamarillo – Solanum betaceum or ‘Tree Tomato” really like coastal weather and depending on the variety can be quite sour (red) or sweet (yellow). This is one that will take some market development, but could take off as the new fruit on the block.
Hops – Humulus lupulus is a crop that most adults know about it. The grow local/drink local crowd could really get into this. There are so many small breweries looking for a distinguishing mark, and what better than a “Big Piru Pilsner with Priu Hops”. There was a small hop industry along the coast before Prohibition.
Yellow oleander – Thevetia peruviana is an unusual choice for the coast here, but it seems there's a black market for the beads and hard to get. It could be legally grown here to supply a specialty market.
Papaya – Carica papaya. This is one of those crops that has a developed market and already a lot of import to fill the demand. Growing this to go after a new consumer willing to pay more for a high-quality piece of fruit. This is going to take some market development.
Governors plum – Flacourtia indica, a new fruit to the area, although it grows as a weed in Florida. It's gonna take some marketing to get this into the mouths of consumers
According to the group of students who proposed these crops, the most likely to succeed in one year's time (immediate acceptance) was hops because of the drink local move happening here and around the country, but it would be limited to consumers in this area probably. The most likely to succeed in the long term, with market development, would be moringa. It would be a new perennial vegetable crops that could be mechanized and might come to rival spinach itself, because of it perennial nature.
Almost all of these crops could have various health benefits associated with them – longer life, improved vision, springier step, snake-bite remedy, etc. So, they all have promotion potential, aside from their ability to grow here. There are lots of other possible crops here that might rival what is currently commonly grown here. Something or things will rise to replace those that are.
At one-point Oxnard was the sugar beet capital of the world. The world's largest walnut growing area in the country was Ventura Co. and Lima was Rex here. They are all good crops, but their importance has been eclipsed many times by other crops gown here.
- Author: Aubrey Thompson
Blue elderberry, a California native plant with clusters of small bluish-black berries and a sweet-tart flavor, have long been eaten by Native Americans in the western states and are used today in jam, syrups, wines and liqueurs. And while elderberry orchards are popping up in parts of the Midwest, California's elderberries are usually just grown on field edges, and elderberry products sold retail rely mostly on foraged crops or imports.
Farmers at The Cloverleaf Farm near Davis are already selling elderberry products from plants grown on their farm, alongside their blackberries and stone fruits. And they find that customers love them. The farmers want to understand the viability of growing elderberries for market beyond their nascent effort, bringing some of the out-of-state production home.
The UC Sustainable Agriculture Research and Education Program (SAREP) launched a project in collaboration with the Cloverleaf Farm, the UC Agriculture Issues Center, UC Davis Department of Food Science and Technology, and four Central Valley farmers to assess the farm management practices, nutritional content, and market potential for elderberry and elderberry products in California.
“I think a lot about the long-term systems sustainability of our food system,” said Katie Fyhrie, one of the farmers at the Cloverleaf. “I keep thinking about how much we focus on production of blackberries and blueberries, when the elderberry also achieves that dark berry color and flavor people like with much fewer resources.”
Elderberries are typically grown on farms as hedgerows for their ability to attract beneficial insects, act as a windbreak, and sequester carbon, benefiting the overall health of the farm, but not providing direct benefit to a farmer's bottom line. Despite long-running federal cost-share programs for planting hedgerows, the number planted in California is still quite small relative to the large expanses of farmland in the state. Adding a financial incentive to planting elderberries may help increase the popularity of hedgerows amongst farmers.
“When we think about building sustainable farming practices, we can think about the whole farm as being a site of both conservation and profitability,” said Sonja Brodt, the project's principal researcher at UC SAREP. “Elderberries may have the potential to combine crop production with environmental conservation functions in a way not typically seen on California farms. This model would enable small- and medium-scale farmers to receive a direct income from a farm practice that benefits the ecosystem as well.”
As climate change impacts California with heat and unpredictable water availability, some studies suggest farmers may need to consider diversifying the crops they grow to adapt to changing local climates.
Elderberries, which grow in arid California regions along the coast and into the mountains, have the potential to grow in a range of climates and adapt to changing California ecosystems in the future. It is unlikely that farmers would plant entire orchards of elderberries, in part because of restrictions on pruning elderberries that may be home to the Valley elderberry longhorn beetle, a federally threatened species. But for small- and medium-scale growers looking to diversify their income sources, elderberries may provide a boost.
The two-year elderberry project now underway will conclude with a growers' production guide, cost of production study, an assessment of market demand and nutritional contents, and workshops to help link growers with buyers interested in elderberry products. The project will also address issues related to the Valley elderberry longhorn beetle and generating income from hedgerows.
“Elderberry juice is already in so many products,” Fyrhie said, “so building a market for locally grown elderberries seems like a no-lose situation.”
For farmers interested in learning more about incorporating perennials into annual crop farms and similar agroforestry practices, check out this webinar recently hosted by UC SAREP.