Although CBD oil is the prize most hemp growers currently have their eye on, there are an estimated 25,000 uses for hemp – from building materials and biodegradable plastics to rope, sailcloth, cosmetics, clothing, and paper. Hemp has been around for centuries. President George Washington grew utility hemp on his farm; the rough draft of the Declaration of Independence is rumored to be written on paper made from hemp.
In the U.S., hemp was a growing concern during the 19th and into the mid-20th century. In 1970, hemp was outlawed, and shortly afterward most of the hemp research work done by US universities was destroyed. With the passing of the 2018 farm bill, hemp was once again legalized at the federal level, so western universities such as UC Davis and Oregon State University have again formed hemp research programs. Soon there will be a vast network of land lab research results available to assist farmers in hemp cultivation.
OSU had a hemp research center from the 1880s until the 1930s, back when the university was Oregon Agricultural College. After shuttering the program for decades, a new hemp research department, The Global Hemp Innovation Center, has reorganized. The program has 10 research sites around the state, and partners with four research centers in Asia and Europe with similar climates.
OSU has also launched seed certification services for hemp. The certified seed is planted by farmers registered with the state. OSU is the only university in the nation to certify hemp seed. Currently in Colorado, North Dakota, and Tennessee, only state departments of agriculture certify hemp seed for use in each of those individual states.
Oregon’s location on the 45th parallel makes for ideal hemp-growing conditions. Hemp production is rapidly expanding in the state. In 2018, there were approximately 7,000 acres planted in hemp. In 2019 that number grew to approximately 50,000 acres, edging out Montana and Colorado. Estimates put Oregon in first place in US hemp production. Oregon CBD growers are aiming for 500,000 acres of seed sales by 2021—a $1 billion yield.
But California is closing the gap. With labor and growing costs continuing to rise in the state, many California farmers are turning to hemp as a go-to crop. And the race to be the leading state in hemp production is on.
UC Davis Research
The California Hemp Corporation, located in Oakdale and formed by Jeff McPhee and Kent Kushar, has partnered with UC Davis to study hemp growth in the California Central Valley. The team wants to help turn the Central Valley into the hemp capital of the country. McPhee predicts hemp production will “change California.”
Director of the Plant Breeding Center, Professor Charlie Brummer is leading the research project at UC Davis, which was launched in 2019. Dan Putnam is the head of field testing. The project, which is breaking new and significant ground in the UC system, aims to gather data to help farmers successfully grow hemp in the California Central Valley. The intention is to create a significant hemp breeding program, “for what may be the most important crop in a generation,” Brummer said on the research website.
Associate Professor Li Tian, Co-Director of the UC Davis Cannabis and Hemp Research Center, was appointed to the position in January 2020. She is looking forward to diving into the brand-new research and being part of the role the university can play in assisting the industry. Tian’s research focuses on how natural chemicals with benefits for human health, phytonutrients, are created and controlled within plants.
About hemp, Tian said, “This is such a new industry in California and nationally, so it’s really exciting to apply our expertise to studying this crop.”
Tian has been reaching out to the other UC campuses with shared research interests. The university system is looking at how air temperature and other growing conditions affect crop yield. Researchers are also looking into the regulation of hemp production, the agronomy, and the environmental impact.
“We still need a lot of research,” Tian said.
COVID-19 has somewhat affected the program. Tian said when Governor Newsom’s stay-at-home order came, the university team couldn’t entirely stop their research and risk losing all that work. But the researchers did reduce their activity, along with the scale and intensity, strictly following the state, local and university guidelines, she said.
Plants to Products
Another new research program through the Department of Plant Sciences at UC Davis is Cannabis and Hemp –Plants to Products. The program is led by Professor Gail Taylor. Researchers are looking into the potential of hemp and cannabis.
“We are focused on molecular and traditional approaches to genotyping, phenotyping, pre-breeding and breeding for bespoke chemical signatures that may be of value to the pharmaceutical and other industries,” the team states on their website. “We have expertise to address the environmental impact of cannabis and hemp cultivation, particularly water, pest, pathogen and greenhouse gas impacts, and can offer advice on minimizing these environmental footprints.”
The team is open to inquiries from outside agencies who wish to partner with them. One such partner is Biopharmaceutical Research Company.
“It’s really in its infancy,” Biopharmaceutical Research Company CEO George Hodgin said of the cannabis industry. “Crops like apples and strawberries and bananas have such a long history of research.”
Hodgin said the main thrust of their research business is providing federally legal cannabis to federally approved researchers, both for university and medical research. Cannabis regulatory requirements are often challenging hoops to jump through, so Hodgin’s business model assists with that.
California hemp growers are required to have a DEA-licensed laboratory test their product two weeks before harvest to make sure CBD levels are low enough. If the levels are too high, the crop must be destroyed. Biopharmaceutical Research Company provides DEA and USDA compliant hemp processing services to California hemp growers.
Even if California doesn’t bump Oregon out of the number one spot in hemp-acreage production, hemp grown in hot and dry weather regions like SoCal does tend to produce higher levels of CBD.
CBD levels were down in the Pacific Northwest and other areas around the country in 2019 crops, according to James Knox, owner of KLR Farms. KLR is a multi-state business, headquartered in Albany, Ore. Knox’s operation grows hybridized and feminized hemp seed and ships worldwide. There was a 24-35 percent depreciation in CBD content last year in most regions, Knox said. However, CBD levels in SoCal grown hemp crops were up.
Growers’ programs for hemp farmers are also cropping up. In 2019, a team of experienced researchers, growers and business professionals formed the Imperial Valley Hemp and CBD Program (IV Hemp) to facilitate the success of hemp growers in SoCal and surrounding areas.
IV Hemp is a co-op designed to help farmers successfully grow, harvest and sell hemp “from seed to sale.” The grower’s program offers special seed prices to farmers who grow through the program. Among other benefits is a partnership with a CBD oil extraction facility in the Imperial Valley and help with biomass transport, if needed.
Even though cannabis research is once again new, hemp production isn’t waiting – it continues to expand. An analytics firm called the Brightfield Group is tracking the cannabis industry. According to their data, the CBD market is expected to grow from $618 million in 2018 to $22 billion by 2022.
Soilborne diseases can cause devastating damage to strawberries. Most soilborne pathogens are lethal to this crop; fungal pathogens in the soil infect plants via roots and can impact the ability of the plant to uptake nutrients and water, causing a wilt symptom in leaves and stems in the early- to mid-harvest period. Fruit yield of infected plants is severely reduced, and the plants often die off eventually. Other soilborne pathogens, known as “root nibblers,” do not kill plants, but stunt them and likewise reduce fruit yield.
Soilborne disease management in organic strawberry production is a challenge. Unlike conventional strawberry production, no fumigants are available, tools are limited and soilborne pathogens are spreading, especially in California. However, recent studies provide some potential approaches and hints for developing agroecological management strategies.
Described in this article are three lethal soilborne pathogens commonly found in strawberry production in California. Then four approaches to managing these pathogens in organic strawberry systems are discussed.
Know Your Enemies
Table 1 shows three common lethal soilborne diseases and the responsible pathogens in California strawberries. Verticillium wilt caused by Verticillium dahliae is a classic soilborne disease in strawberries. The disease was first reported in 1932 in California strawberries and was the most widespread soilborne disease in the state until recently. Methyl bromide + chloropicrin chemical fumigation was developed to control this disease in the 1950s. In the late 2000s, however, two other soilborne diseases emerged: Fusarium wilt caused by Fusarium oxysporum f. sp. fragariae (F.o.f.) and charcoal rot caused by Macrophomina phaseolina. These pathogens were first reported in the southern production region and are now spread across the entire state, becoming a larger threat to the California strawberry industry.
These three pathogens have different characteristics (Table 1). First, the plant hosts differ between the three fungi; V. dahliae is known to infect more than 400 plant species, including 100 weed species, whereas F.o.f. and M. phaseolina (Koike et al., 2016) only infect strawberries. Second, the soil survival period varies; V. dahliae can survive in the soil without a host plant for an extended period (8-10 years) compared to F.o.f. and M. phaseolina (< 3 years.) Third, F.o.f. and M. phaseolina can survive in soil as saprophytes, meaning that these pathogens can feed not only on living plants but also can colonize dead organic matter such as crop residues and some organic amendments (e.g., rice bran, almond shell.) In contrast, V. dahliae does not have the ability to persist in soil as a saprophyte.
Understanding the characteristics of pathogens, the enemies, is crucial for developing a soilborne disease management strategy in organic strawberry production, as discussed below.
Diagnosing the Pathogen
If there are any symptomatic plants in your organic strawberry field, the first step in disease management is to determine the primary cause of symptomatic plants. Since each pathogen has different characteristics as mentioned above, it is vital to identify the specific pathogen(s) causing the wilt symptom. Unfortunately, wilt symptoms caused by these three soilborne pathogens are almost identical, and confirmation by visual observation is impossible even with the eyes of well-trained plant pathologists (see figure 1). Fortunately, recent developments in molecular approaches are making rapid and accurate determination of plant pathogens a reality.
This advance in pathogen identification is available for strawberry plant samples. The molecular method for identifying all three pathogens mentioned above in plants is now available at public and commercial plant pathology labs. The analysis can be done in a matter of hours.
The molecular test for soil samples is becoming available as well. For soil tests, however, not only is a quick and accurate detection method needed but also an economic threshold number above which crop yield decreases. At this time, among the three pathogens, V. dahliae is the only one for which both the molecular-based quantitative method and the threshold are developed. For M. phaseolina, a quantitative molecular approach has been established but no threshold developed. For F.o.f., only a qualitative molecular test is available and no threshold has been set. Active research is in progress in creating rapid and effective soil tests for these and other soilborne pathogens.
Organic Management Practices
Once the pathogen is identified, the next step is to develop an appropriate management strategy. Described here are four organically acceptable practices that can be implemented to mitigate soilborne diseases: crop rotation, anaerobic soil disinfestation, the use of varieties resistant to these diseases and sanitation practices.
Crop rotation: Crop rotation is a traditional method used worldwide to avoid soilborne diseases in strawberries and other crops. By planting different crops sequentially in a field, the temporal crop diversity, rather than spatial crop diversity, of the field is increased. Since each crop encourages the growth of specific soilborne pathogens and microorganisms in the rhizosphere, this practice enhances diversity in the soil microbial community and reduces the populations of plant-specific soilborne pathogens. In the organic systems in the U.S., crop rotation is mandatory under the National Organic Program. In the E.U., Northeast U.S. and Canada, a minimum of a three-year break between two strawberry plantings on the same field is recommended.
In California organic strawberries, back in the 1990s, crop rotation with at least a three-year break between each strawberry planting was the only approach used to avoid soilborne diseases. This strategy works best for soilborne pathogens that only infect strawberries (e.g., F.o.f. and M. phaseolina.) Anecdotal evidence indicates that at least a two-year break is necessary to avoid or reduce Fusarium wilt in strawberries on the central coast of California.
However, the long break period itself is not enough to suppress soilborne pathogens hosted by multiple plants. V. dahliae is the prime example of this challenge. For managing this pathogen, avoiding non-strawberry host plants during the break period is essential. Table 2 provides examples of host and non-host crops of V. dahliae, which highlights some major vegetable crops in California that are hosts of this pathogen. Further, about 100 weed species, including shepherd’s purse, dandelion, groundsel, nightshade and pigweed, also host this pathogen and make weed management an integral part of the soilborne disease strategy.
The good news is that studies found some crops actually suppress these pathogens. The effect of broccoli residue incorporation on suppressing V. dahliae in the soil is well-documented (Subbarao et al., 2007). After harvesting heads, leaves and stems are flail mowed and incorporated into the soil; breakdown of the broccoli residue results in a lowering of V. dahliae soil populations. This is a long-term strategy, and two or more broccoli crops may be necessary to start reducing the V. dahliae population in a highly infested field.
Preliminary studies by two independent labs showed that a specific variety of wheat appears to suppress M. phaseolina in the soil. A greenhouse study demonstrated that when strawberries were planted after growing different wheat varieties in soil infested with M. phaseolina, the variety Summit 515 was the most effective in suppressing this pathogen (Ivors, 2015). The practice is being used by some commercial growers and observationally seems to have an effect.
Recent studies from Asian countries demonstrated that Allium crops such as leeks and onions were effective in suppressing Fusarium oxysporum in spinach (Igarashi et al., 2017) and bananas (Huang et al., 2012). The biological mechanism of this suppression was also elucidated (Nishioka et al., 2019). A preliminary field trial in California is in progress to examine the effect of this approach in suppressing F.o.f. in strawberries.
Anaerobic soil disinfestation: Another tool for organic strawberry growers is a practice called anaerobic soil disinfestation (ASD.) ASD as a biological alternative to fumigation was developed independently in both the Netherlands and Japan around the year 2000. ASD creates the acid fermentation process in anaerobic soil in which toxic organic acids, volatiles and Fe2+ ions are produced, and microbial community shifts subsequently take place. This biologically mediated process suppresses a range of pathogens and nematodes in the soil. Over the last 15 years, ASD was examined extensively in California strawberry systems and proved to be effective in suppressing a range of soilborne pathogens. Today, over 1500 acres of organic berry fields in California are treated by ASD.
The standard ASD process involves multiple steps (seefigure 2). During the ASD treatment, a total of approximately 1.5 acre-inches of water is applied via drip irrigation. After the treatment, planting holes are cut, and transplants are planted after one week. Both the level of anaerobic conditions (the stronger, the better) and soil temperatures (the warmer, the better) are keys for a successful ASD.
The three lethal soilborne pathogens each respond differently to ASD. In coastal California, ASD can suppress V. dahliae well under typical fall temperatures (Shennan et al., 2018). For F.o.f., however, ASD must be done in summer using clear plastic mulch. Using this approach, a study found a threshold of >460 hours above 86 °F at eight-inch soil depth is needed to suppress this pathogen on the central coast of California (Muramoto et al., 2020).
ASD should never be applied in the fall in coastal California to fields with a known history of Fusarium wilt. This saprophytic pathogen can grow on rice bran and result in increased populations under a lower soil temperature. This often results in higher levels of Fusarium wilt (see figure 3). Results on the effect of ASD on M. phaseolina are mixed so far, and more research is needed.
Resistant varieties: The use of resistant varieties can be the easiest and most reliable approach for a specific soilborne disease. Information on the level of soilborne disease resistance of the UC varieties is available at the California Strawberry Commission’s website calstrawberry.com/en-us/Pest-Management/Breeding. Note that there is no single variety that is resistant to all three soilborne pathogens. Also, currently there is a lack of a M. phaseolina resistant variety and a public variety with both excellent flavor and Fusarium wilt or charcoal rot resistance.
Sanitation practices: Basic sanitation practices such as washing soil off from tractors, equipment and tools are also critically important to avoid spreading soilborne pathogens. Sanitation and prevention are the key tools in soilborne disease management in organic strawberry production.
Integrated Disease Management
Soilborne disease management in organic strawberries requires an integrated approach. Based on the level and type of pathogens identified, or from the disease history of the site, a grower needs to develop an appropriate soilborne disease management strategy for the site by integrating available practices such as crop rotation, ASD and use of a resistant variety as well as basic sanitation of machines and tools to prevent the spread of soilborne pathogens from one field to another.
Well-designed crop rotation is the foundation of soilborne disease management in organic strawberry production. Diversified organic growers who grow strawberries as a core crop among many other crops may want to design their crop rotation around strawberries, one of the most soilborne disease-prone and lucrative crops. Specialized organic strawberry growers might not be able to control the crop rotation by themselves, but it is worth communicating with the vegetable grower with whom they rotate the field.
ASD is a useful tool when there is no choice but to plant strawberries after a Verticillium host crop such as lettuce. A resistant variety can be chosen as needed when it is acceptable for your market.
Tools for soilborne disease management in organic strawberries are still limited. Interactions between a crop plant and its microbiome, including pathogens and beneficial microbes, need to be better understood, and differences in microbiomes between varying crops need to be discovered. Armed with such science-based information, improved suppressive crop rotations may be able to be developed as well as ways to use microbial amendments more effectively. This soilborne disease management approach is knowledge-intensive and location-specific, which is in contrast with fumigation practices that are characterized by chemical-intensive and location-general approaches.
Acknowledgements: The author would like to thank valuable comments from Steve Koike, Kelly Ivors, Mark Bolda and Erin Foley to the previous version of the manuscript.
Igarashi, C., Asano, Y., Nishioka, T., Suga, H., Hyakumachi, M., Shimizu, M., 2017. Suppression of spinach Fusarium wilt by intercropping with Allium plants. Japanese J. of Phytopathology 83, 87-94.
Koike, S. T., Arias, R. S., Hogan, C. S., Martin, F. N., and Gordon, T. R. 2016. Status of Macrophomina phaseolina on strawberry in California and preliminary characterization of the pathogen. Int. J. of Fruit Sci. 16: 148-159.
Muramoto, J., Shennan, C., Mazzola, M., Wood, T., Miethke, E., Resultay, E., Zavatta, M., Koike, S.T., 2020. Use of a summer cover crop as a partial carbon source for anaerobic soil disinfestation in coastal California. Acta Hort. 1270, 37-44.
Nishioka, T., Marian, M., Kobayashi, I., Kobayashi, Y., Yamamoto, K., Tamaki, H., Suga, H., Shimizu, M., 2019. Microbial basis of Fusarium wilt suppression by Allium cultivation. Scientific Reports 9, 1715.
Shennan, C., Muramoto, J., Koike, S., Baird, G., Fennimore, S., Samtani, J., Bolda, M., Dara, S., Daugovish, O., Lazarovits, G., Butler, D., Rosskopf, E., Kokalis-Burelle, N., Klonsky, K., Mazzola, M., 2018. Anaerobic soil disinfestation is an alternative to soil fumigation for control of some soilborne pathogens in strawberry production. Plant Pathology 67, 51-66.
Subbarao, K.V., Kabir, Z., Martin, F.N., Koike, S.T., 2007. Management of soilborne diseases in strawberry using vegetable rotations. Plant Dis. 91, 964-972.
Managing arthropod pests with pesticides is a common practice in crop production. Managing arthropod resistance to pesticides is an important part of integrated pest management (IPM.) Under natural circumstances, plants, insects, mites, natural enemies and beneficial or harmful microorganisms continuously co-evolve and adapt to the changes in their environment. When there is a higher selection pressure, such as the indiscriminate use of pesticides, mutations in arthropods enable them to resist the pesticide and increase their chances of survival. Since there are fewer pesticides for organic crop production, there is a higher chance of their repeated use and increased risk of resistance development.
Arthropods, such as insects and mites, develop resistance to chemical pesticides through genetic, metabolic, or behavioral changes resulting in reduced penetration of toxin, increased sequestration or excretion, reduced binding to the target site, altered target site that prevents binding of the toxin, or reduced exposure to the toxin through modified behavior. Through one or more of these mechanisms, arthropods can also develop resistance to biopesticides. When the active ingredient of a biopesticide is a toxic molecule and acts more like a chemical compound, arthropods are more likely to develop resistance even though it is of biological origin. When the mode of action is due to infection by a microorganism, rather than a toxin, arthropods are less likely to develop resistance.
Botanical Pesticide Resistance
Botanical insecticide pyrethrum, extracted from the flowers of Chrysanthemum cinerariaefolium and C. cineum, contains insecticidal esters known as the pyrethrins. Pyrethrins are nerve poisons disrupting the sodium channels in neurotransmission and are commonly used for controlling pests in agricultural, structural and public and animal health sectors. Arthropod resistance to pyrethrins and their synthetic analogs, pyrethroids, is very common and has been reported for several decades. Insect mutations that reduce the penetration of the toxin through the cuticle, reduce its binding to the target site, or alter the properties of the sodium channels, and other mechanisms impart pyrethrin resistance.
Another botanical insecticidal compound, azadirachtin, is a tetranortriterpenoid limonoid from neem (Azadirachta indica) seeds, which acts as an insecticide, antifeedant, repellent and insect growth regulator. While neem oil, which has a lower concentration of azadirachtin, has been used in the United States as a fungicide, acaricide and insecticide for a long time, several azadirachtin formulations in powder and liquid forms have become popular in recent years. While there was a report of artificially induced resistance to azadirachtin in the green peach aphid, several studies demonstrated the efficacy of azadirachtin against various pests and recommended it as an option in IPM and for managing resistance to other pesticides. Azadirachtin is also thought to reduce the production of detoxification enzymes and known to improve the efficacy of other biopesticides. While arthropod resistance to botanical pesticides other than pyrethrins is not commonly reported, it is known that plant allelochemicals (e.g. alkaloids, phenolics, terpenoids, etc.) can contribute to cross-resistance to certain chemical pesticides. It is important to monitor the potential risk of resistance development and cross-resistance when botanical pesticides are used.
Bacterial Biopesticide Resistance
Bacillus thuringiensis (Bt) is a gram-positive soil bacterium, which contains crystalline toxic protein that is activated upon ingestion by an insect host, binds to the receptor sites in the midgut, and eventually causes insect death. Bt pesticides are used against a variety of lepidopteran (Bt subsp. aizawai and Bt subsp. kurstaki), dipteran (Bt subsp. israelensis and Bt subsp. sphaericus) and coleopteran (Bt subsp. tenebrionis) pests and are very popular in organic farming. Since the mode of action involves toxins rather than the bacterial infection itself, resistance to Bt pesticides or transgenic crops that contain Bt toxins is also very common. Some examples of resistant insects to Bt include the beet armyworm, the cabbage looper, the corn earworm, the Colorado potato beetle and the diamondback moth. Mutations in insects that regulate the immune system or interfere with the activation of Bt toxins and their binding to the target site led to insect resistance.
Spinosad is a mixture of macrocyclic lactones, spinosyns A and spinosyns D, derived from Saccharopolyspora spinosa, an actinomycete gram-positive bacterium, and is used against dipteran, hymenopteran, lepidopteran, thysanopteran, and other pests. Although naturally derived, some spinosad products are not registered as biopesticides. Insect resistance to spinosad later led to the development of spinetoram, which is a mixture of chemically modified spinosyns J and L. Both spinosad and spinetoram are contact and stomach poisons and act on insect nervous system by continuous activation of nicotinic acetylcholine receptors. The American serpentine leafminer, the beet armyworm, the diamondback moth, the tomato borer, the onion thrips, and the western flower thrips are some insects with spinosad resistance. Production of detoxifying enzymes (metabolic resistance) and changes in the target site are the most common mechanisms of spinosad resistance in insects. Cross-resistance between spinosad and some chemical insecticides has also occurred in some insects.
Viral Biopesticide Resistance
Baculovirus infections in Lepidoptera have been known for centuries, especially in silkworms. Currently, there are several commercial formulations of nucleopolyhedroviruses (NPV) and granuloviruses (GV). When virus particles are ingested by the insect host, usually a lepidopteran insect, they invade the nuclei of midgut, fatbody, or other tissue cells and kill the host. Baculoviruses are generally very specific to their host insect species and can be very effective in bringing down the pest populations. However, variations in the susceptibility of certain insect populations and development of resistance to viruses has occurred in several host species. Mutations in one or more genes with complex mechanisms are involved in insect resistance to viruses.
Fungal Biopesticide Resistance
There are several fungi that infect insects and mites. The fungal infection starts when fungal spores come in contact with an arthropod host. First, they germinate and gain entry into the body by breaching through the cuticle. Fungus later multiplies, invades the host tissues, kills the host and emerges from the cadaver to produce more spores. Entomophthoralean fungi such as Entomophthora spp., Pandora spp., and Neozygites spp. can be very effective in pest management through natural epizootics, but cannot be cultured in vitro for commercial-scale production. Hypocrealean fungi such as Beauveria bassiana, Isarea fumosorosea, Metarhizium brunneum and Verticillium lecanii, on the other hand, can be mass-produced in vitro and are commercially available. These fungi are comparable to broad-spectrum insecticides and are pathogenic to a variety of soil, foliar and fruit pests of several major orders. Since botanical, bacterial and viral biopesticides have insecticidal metabolites, proteins, or viral particles that have specific target sites and modes of action, insects have a higher chance of developing resistance through one or more mechanisms. Although fungi also have insecticidal proteins such as beauvericin in B. bassiana and I. fumosorosea and dextruxin in M. anisopliae and M. brunneum, their mode of action is more through fungal infection and multiplication, and arthropods are less prone to developing resistance to entomopathogenic fungi. However, insects can develop resistance to entomopathogenic fungi through increased melanism, phenoloxidase activity, protease inhibitor production and antimicrobial and antifungal peptide production. It also appears that the production of detoxification enzymes in insects against fungal infections can also impart resistance to chemical pesticides.
These examples show that insects can develop resistance to biopesticides in a manner somewhat similar to chemical pesticides, but due to the typically more complex and multiple modes of action, at a significantly lesser rate depending on the kind of botanical compound or microorganism involved. Resistance to entomopathogenic fungi is less common than with other entomopathogens. The risk of biopesticide resistance is much higher in organic farming because of the widespread use and limited biopesticide choices. Avoiding the repeated use of biopesticides reduces the risk of resistance development and can reverse the resistance mechanism in some cases. IPM recommends the use of host plant resistance, biological control, cultural control and other management options before using pesticide applications. When pesticides (both biological and synthetic) are to be considered, using them only when needed, applying at recommended rates and alternating/rotating with other modes of action can reduce the selection pressure on arthropod populations and resulting mutations.
Farmers and ranchers in the West have confronted considerable challenges with the COVID-19 pandemic. They have been dealing with rapidly changing markets, supply chain slowdowns and shortages. Strongly shifting consumer behaviors and dramatic drops in demand from restaurants and schools required them, as well as farmer organizations, to respond quickly and creatively. This has required a lot of hard work and long hours. Along with this hard work, producers still face uncertainty about the future.
Western SARE conducted a survey of its stakeholders in April to get a better idea of the impacts of COVID-19 on the food system. The survey also demonstrated strategies undertaken rapidly to adapt to new situations. A report based on the survey results was developed and can be found here. Given the valuable information shared, Western SARE followed up with producers and farm organizations who shared their stories in more depth.
Larry Bailey, owner of Clean Food Farm, was well-known at local farmers markets for providing organic blueberries and pastured eggs for consumption within a 100 mile radius of Pierce County, Wash. But when COVID-19 hit, he had to quickly pivot from farmers market and wholesale restaurant sales to on-line direct-to-consumer sales. As a small farmer, finding on-line platforms to use was challenging. So, he created his own system and now is sold out of pastured eggs until September.
The typical online ordering platforms have been designed for farmers and ranchers with approximately $1 million-plus per year in revenue and don’t provide discounts for small producers. Larry has 135 customers, enough for him, but not enough to effectively use and pay for these platforms.
“I bootstrapped my system using a WordPress website to get me through this year. I have to add and track my product manually and use it for shipping. It does work and I’ve sold subscriptions two months in advance,” Bailey said.
Bailey’s eggs are rated high due to having three times the typical vitamin E and four times the Omega-3s of regular eggs. As important as that is, Bailey markets on flavor, not food chemistry. With the change in how customers find Clean Food Farm and purchase its products, Bailey is finding new ways to connect with people about his values and the quality of his food.
“I did my research and identified who my ideal customer is. She’s female, around 44 years old with children and a full-time career,” Bailey said. “This was important to learn as previously my customers knew me from the farmers market and I had no way to contact them. I’ve started a blog with a one-minute read and created a short video that addresses my ideal customers’ concerns. I’m being me and I’m connecting.”
Like Clean Food Farm, Mountain Roots Produce in Southwest Colorado quickly changed its markets. Farmer Mike Nolan has been working hard to shift from wholesale markets to CSA boxes, change cropping plans and build new caterpillar tunnels. It’s all working for him, but it’s tough.
“I’m as tired now as I should be in August,” said Nolan in late May.
Farming in Southwest Colorado was already challenging with an ongoing drought, and the market channeling changes came close to “the straw that broke the camel’s back.”
Before COVID-19 hit, Nolan had seven acres in production along with cover crops. He is now fallowing some acres, reducing production acres to 3.5. Because he hadn’t yet planted due to snow, he was able to quickly change the farm’s cropping plans. The majority of the crop goes to CSA boxes, with wholesale picking up some as restaurants are slowly opening. The number of CSA subscriptions increased from 70 to 150, with a waiting list.
“The CSA program will let us make it through the summer,” Nolan said. “We have 2.5 acres of storage crops that will also let us get through until restaurants fully open and we get back to normal.”
With the increase in CSA subscriptions, the farm’s high tunnel was “about to burst at the seams.” Nolan and his crew built two more caterpillar tunnels for cucumbers, peppers, and tomatoes.
Supporting Farmers and Ranchers
Making Connections. As a leading farmer organization in California, the Community Alliance with Family Farmers (CAFF) quickly changed how they assisted producers as they found their normal supply chains disrupted.
According to CAFF’s Director of Membership and Communications, Evan Wiig, their Farm to Market team already had connections with both buyers and sellers. In March, they worked to get an idea of what the new needs were and to then use existing relationships to make connections. These efforts included making one-off connections, doing some matchmaking themselves, or sending distributors a list of farmers when asked.
“This is the work we do on a regular basis, but now on steroids,” says Wiig.
That was the first wave. A second wave hit in May with the increase in food box programs, specifically federal, state and local emergency food boxes. These programs are purchasing product from small farmers and farmers from socially disadvantaged communities.
CAFF has been working for years to get local foods included in disaster relief efforts.
“There’s typically a disconnect, such as when local farms were hurting and trying to off-load product during the Santa Rosa fires but emergency relief programs were buying from large distributors,” Wiig said.
Some COVID-19 emergency programs have panned out better than others, but overall, CAFF saw a huge demand. Suddenly the Farm to Market team was scrambling to meet the demand.
“The team is working hard helping the farmers who need it the most,” Wiig said.
Technical Assistance. The farm training and incubator organization for limited resource and aspiring organic farmers, Agriculture and Land-Based Training Association (ALBA), spent March trying to make sense of rapidly changing conditions, both for their programs and for their farmers, according to Education Program Director Nathan Harkleroad. As an essential service, staff was still coming on-site to help farmers with production, food safety, infrastructure and marketing. The staff shifted to meeting farmers outside, requiring masks and setting appointments rather than accepting drop-ins.
Most challenging was changing ALBA’s training model. They had to very quickly move to online training using Zoom and Google Classrooms.
“Farmers really grabbed the opportunity to learn online,” Harkleroad said. “We asked them to use the app and provided a little training on Zoom, and it has gone very well.” Almost 100% participated in the first Zoom training.
“I’m so impressed their ability to learn the technology with such short notice,” said Nancy Porto, Community Relations and Environmental Education Officer.
Financial Assistance. California FarmLink provides loans to farmers and ranchers, focusing on small-scale, sustainable entrepreneurs. The organization has made 353 loans to farmers and ranchers in 30 of 58 California counties since 2011.
FarmLink leveraged their investment and expertise in lending and business support to quickly assist farmers in need when COVID-19 impacted markets. Since March, they have provided 102 forgivable Paycheck Protection Program (PPP) loans totaling more than $2.3 million. They also have provided special emergency loans at 0% interest for two years with no payments for six months.
“Starting in April, we quickly geared up to decipher government relief programs and create new loan products to meet the farming community’s challenges. As we move forward, we are determining how much capital is needed and how to manage such a quick outflow of capital so we can maximize our impact,” said Executive Director Reggie Knox.
Porto at ALBA has also been helping farmers take advantage of financial assistance with on-line applications. Since the farmers are busy and need to make money by staying in the field, they don’t have time to sit on hold with an 800 number. There are also language barriers and paperwork hurdles, which Nancy helps mitigate.
Bailey is going to continue his blog and online system, adding more products, until he grows large enough for a commercial platform. He plans to return to selling to local restaurants and an upcoming local online store. He believes catering and value-added products, such as with a future blueberry crop, will allow him to be more profitable. Due to the amount of work, he will likely drop farmers markets.
“I get my time back with the online sales as I move the same amount of our pastured eggs in half the time,” said Bailey.
Nolan is watching the demand for CSA subscriptions and attempting to plan for the future. It’s challenging as it’s uncertain where the region will be with COVID-19 and shifting consumer patterns in the fall. He is staying in conversation with the local Farm Bureau and Farmers Union about planning for and meeting local demand.
However, for Nolan, the CSA model is not working. He finds it stressful and challenging work. It works for the farm now, and he wants to meet his commitments to local customers so the farm is continuing with the program. In the future the farm may get rid of the tunnels and cut back on the number of crops grown. The future may be in growing storage crops and going back to selling wholesale to restaurants. He’s beginning to have conversations with chefs, working out the cash flow, and will start making changes in October and November.
“We’ll be all right and survive all of this, but it’s been a bit much to handle with extra labor and new protocols while out in the field and making deliveries,” Nolan said.
As for everyone else, it’s hard for CAFF to predict the future impacts on their farmers and their programs. Some crops haven’t come in yet, like apples. If the supply chain is still disrupted with restaurants, employee cafeterias and schools closed, those growers could be hurt.
“It’s not about a lack of demand for food but how people buy it, and are the markets nimble enough,” Wiig said.
Wiig believes CAFF is positioned well to be nimble: Large and organized enough to provide the resources and support needed, but small and grassroots enough to shift quickly to meet priorities.
“Whatever happens next we’ll be able to pivot to what is needed in the moment.”
Like all farm organizations, CAFF has other programs that they need to focus on. The organization needs to work on both what is going on today and also focus on other issues like climate change. Getting people’s attention back to these issues is the challenge.
ALBA would like to return to in-person courses, but will adjust to shifting Shelter in Place regulations. The courses are accredited by Hartnell College so ALBA will follow their guidelines in the fall. Harkleroad says that they have seen an increase in interest for farmer training due to job losses.
“The benefit of online courses is that they have been recorded so we can use them to meet future needs,” said Harkleroad. “Zoom also includes translation so we can offer bilingual online recordings.”
Urban farming is more than just producing food. It also includes agritourism producing projects and activities on the farm. Urban farming is becoming more popular because it focuses on sustainability, affordability, health and convenience.
Stacey Givens, owner, farmer and chef of Side Yard Farm and Kitchen (thesideyardpdx.com) has a one-acre farm in northeast Portland, Ore. She feels strongly that urban farms are important because of their accessibility.
“We’re near bus lines, we’re really easy to get to, and we host a lot of schools,” Givens said, from grade school, to college, to culinary schools.
Givens’ ground is farmed from the end of February to November. She and her crew work long hours and take a break in the winter to regroup and rebuild the soils.
“We interplant and do intensive farming practices,” Givens said, and what she gets out of her small plot of land is the equivalent of two to three acres.
“When we’re planting lettuce, we’re plopping in Cipollini onions or Japanese leeks in between,” Givens said, adding it’s all planted very close together.
“We host a lot of events out here,” Givens said, and they are a main revenue stream. Some of the events from the farm include:
Lost Table Grief Group
Yoga on the Farm
Bike In Movie Night
Bike In Movie Night is popular with about 120 attendees, and outside vendors are invited to participate, Givens said.
One of Givens’ favorite events is the Lost Table Grief Group started after her father died nine years ago. The group meets monthly, and it has grown from five to 300 to 400 people, but each session is limited to 25 people. Attendees bring a dish to share that is usually a favorite that their loved one enjoyed.
“We just eat, and we cry, and we laugh, and share our grief, which is really beautiful,” Givens said.
Community Sponsored Agriculture (CSA)
With the COVID-19 outbreak and shutdown, Givens saw many of her restaurant customers disappear, so in response, she immediately ramped up her CSAs and started an online farm store that’s been doing extremely well.
“We just pivoted really fast, and we have an online store which we sell all our produce,” Givens said.
There is a full produce menu online from lettuce mix, to radishes, to turnips that are continually updated. Farmer chef boxes are created depending on what’s available that week.
There are also value-added items made on the farm including salad dressings, jams and canned vegetables. Some of Givens’ favorite vendors in Portland are highlighted with a variety of items to choose from.
Givens recently purchased her farm with a loan from USDA. She reached out to USDA 18 months ago about buying the one-acre property that has no house onsite that she’d been farming for more than a decade. They turned down her application because the property is zoned residential, but Givens kept applying and getting turned down.
“I thought I’d never be able to buy it,” Givens said.
Givens persisted and finally reached out to her congressman, an advocate for urban farming and local food. The congressman made some calls, and after a few months, she reapplied and was granted a loan.
“I’m the first urban farm in the nation to ever get a loan that is residentially zoned to buy an urban farm, which is pretty cool,” Givens said.
“Our goal is to preserve the land because Portland’s changing so much,” Givens said, adding many urban farms have closed because the landlords have decided to develop the property into condos.
“I wanted this for future generations to come. It will never be developed, and that’s the deal I made with my landlord as well. It will always be a farm,” Givens said.
The Urban Homestead
Anaïs Dervaes is the co-owner of Urban Homestead (urbanhomestead.org), a family farm in Pasadena, Calif.
Dervaes said her family turned their front yard into edible plants in the late-80s.
“If an acre is a dollar, we’re farming on ten cents,” Dervaes said.
“When we moved here in ’85, our neighbors had chickens running around, they had corn growing in their front yard so we took out the lawn and started growing food,” Dervaes said.
“We did worry what the city of Pasadena would think because, oh no, we’re growing food, and we didn’t have a lawn. Actually, it’s been a really wonderful relationship with the city,” Dervaes said, adding the city now pays residents to remove lawn and put in food or native plants.
When the restaurant and catering clientele completely dried up due to COVID-19, the farm box program/CSAs tripled in size, Dervaes said.
“Now, we’re doing more farm boxes, so we’re trying to see how we can bring back in the restaurant and catering clientele, just slowly,” Dervaes said.
With the shutdown, Dervaes missed their busiest, most lucrative season which is spring—Mother’s Day, graduations, weddings—events where edible flowers and all the nice little accouterments that go along with catering platters, she said.
“That was a wash this year,” Dervaes said.
Urban Homestead also canceled all their workshops and tours on the farm that included their popular Elements of the Homestead tour that features farm production, growing soil, animals, energy outpost and water conservation.
The tours were monthly and open to the public. Scouts and students came through on an almost weekly basis.
“Everybody wants to see how we do it, and we would also go out and teach at the local library and interact with the community, too, through offsite workshops,” Dervaes said.
Urban Farming Challenges
“There are challenges to growing in an urban setting. “
We’re dealing with close proximity of things. It’s not really open space. We have our neighbors’ trees, our house shade—actually things that grow too well,” Dervaes said, and as the shadow circle expands, it limits what can be grown in a small space.
“It’s ever-changing. Things grow well, things don’t grow well,” Dervaes said.
It’s a challenge to stay on top of things farming in a small space.
Agritopia is a homestead that morphed into a thriving village centered around an urban farm in Gilbert, Ariz. The original farm was converted from desert in 1927, according to Joe Johnston, self-titled “visionary” of the community.
Johnston’s father bought the farm in 1960 and raised cotton, wheat and other row crops. The Agritopia community started in 2000, which includes the farm, a residential park, school, assisted living, community garden, Joe’s Farm Grill and a group of businesses.
Out of the 160 acres, 12 acres are farmed organically in row crops, community gardens and orchards—citrus, date palms, olives and peaches. The climate in Gilbert allows crops to be grown year-round. “Arizona has got a fantastic climate,” Johnston said.
The farm grows about 80 different crops that go into spring mix that goes to the restaurant and the orange juice that is fresh-squeezed from the orchard, CSA customers, farm store and about five different restaurants.
Farm to Table
While some restaurants completely center their menu around the produce of the day, Joe’s Farm Grill maintains a consistent menu, which means they use only a percentage of produce from the farm, and it varies over time.
“Certain things we’re able to run almost eight months of supply from here (the farm), and other things, they’re just short windows,” Johnston said.
“For example, onions are harvested in May, and then maybe there’s a two or three month window where we can use those,” Johnston said, adding he tries to use as much as he can that’s in-season within the confines of the menus that he creates.
Joe’s Farm Grill opened in 2006, and the restaurant was doing well, then it was featured on Diners, Drive-Ins and Dives (DDD). DDD first aired about 12 years ago, and at that time the restaurant was on a nice growth curve. Being on DDD really catapulted it into solid profitability, Johnston said.
On the 10-year anniversary of that airing, the show did a DDD Nation where it came back and revisited the restaurant to see how they were doing.
DDD is the gift that keeps on giving, Johnston said. Johnston estimates about 10 percent of its customers are vacationers. Many will mention they saw the restaurant on DDD. There’s also a lot of people who do specialty travel and visit the DDD locations in the Phoenix area, Johnston said.
Johnston said Agritopia does its CSA a little differently. “It’s almost like going to the grocery store. The sign says you take two of these, take three of these, so they assemble their own box,” Johnston said.
Half shares are available for couples, and there are add-ons like eggs and bread. A friend provides the eggs they sell, and a local vendor provides the bread.
Agritopia also has “you-pick” citrus and peach orchards. All the lower fruit in the orchards is you-picked, and the upper sections of the trees are harvested by workers for the restaurant and CSAs.
The farm manager is planting a tomato you-pick section. Tomatoes are a good opportunity because they grow low to the ground, Johnston said.
The farm harvests during the week, Johnston said, “But on weekends, we’ll do you-pick.”
“For us, as farmers, it’s great because we don’t have to then have harvesting labor because they’re doing it,” Johnston said.
The California Department of Pesticide Regulation (CDPR) approved the use of BotaniGard Maxx (pyrethrin + a fungicide, Beauveria bassiana) to control insect pests in hemp. Pyrethrins are broad-spectrum insecticides that are toxic to honey bees and other pollinators. Best Management Practices (BMPs) should be followed to reduce the risk of bee exposure to BotaniGard Maxx when producing hemp.
While most cultivated hemp are non-pollen producing female plants, seed feminization is never 100% true and males (picture at right) will be present in the field. Males shed a lot of pollen, making them attractive to native bees and honeybees.
How to Protect Bees when using BotaniGard Maxx in Hemp:
Rogue male plants before flowers open to avoid attracting bees. Male hemp plants are distinct and can be identified by walking the field. Females (left) have stigmas (that looks hairy and are sticky) at nodes between leaves while males (right) have stamens that look like round balls and are filled with pollen. Plants can be left to dry in the field if pulled before stamens are open but should be removed from the field if pollen is present.
Use IPM (Integrated Pest Management) practices to manage pests. Scout fields for insect pests and damage and spray only when needed.
Don’t spray when males are producing pollen and bees are active.
If it is necessary to spray when males are present and producing pollen, or if you don’t know if males are present, reduce risk by only spraying when bees are not active (dawn, dusk, night.) This will reduce bee exposure but will not eliminate it. Pyrethrins can stay on the pollen and be transported back to the hive where they are harmful to bee larvae.
Contact local beekeepers within a mile of the hemp field, 48 hours before application.
Turn off spray booms at row edges to avoid drift or direct sprays to hives. If possible, apply BotaniGard by ground to minimize potential drift.
Report suspected pesticide-related honey bee incidents to the county agricultural commissioner’s office as soon as possible.
Buying or trapping blue orchard mason bees may be a good plan for your spring-blooming orchards’ pollination needs. Mason bees are affordable, low maintenance and improve crop yields. The little bees work well in conjunction with honey bees in almonds, cherries, pears, early raspberry varieties and blueberries. Researchers are starting to also look at mason bees’ pollination effectiveness in strawberries, too.
Unlike the European honey bee, mason bees are native to the US. They emerge in early spring, with males emerging first. They set about pollinating while keeping an eye out for females. Females emerge several days later. Males live two to four weeks, while females live six to eight weeks.
Retired entomologist Rich Little, a former county deputy agricultural commissioner in California, suggests farmers place 20 to 30 mason bee boxes per three acres. That many, he says, is manageable for one person.
“You have to scatter these boxes throughout the grove,” Little said. He keeps 15 to 20 mason bee boxes at his home in Sweet Home, Ore., and gives educational programs on native bees through the Oregon State University Extension Service.
As far as what the little iridescent blue-green mason bees require: “There needs to be food and there needs to be mud,” Little said.
Steps for Mason Bee Success
Watts Solitary Bees, located out of Washington state, offers the follow steps for success with mason bees. The company sells bees to farmers with commercial customers in Idaho, Washington, Oregon and California. Almond growers are one of the company’s biggest clients and Watts estimates almond growers can replace one hive of honey bees per acre with 1,000 mason bees.
“We did 1,000 acres of almonds last year with mason bees,” said owner Jim Watts. “The almond growers are paying huge amounts for pollinators. Honey bee prices are going up every year.”
Watts offers the following advice:
1) Trap or purchase wild mason bees.
2) Set out nesting material throughout the orchard, including football-sized balls of wet clay.
3) Incubate the bee cocoons until time for release.
4) Provide forage for food and mud for nest building.
5) Check on bees during the active season.
6) Remove bees from the orchard after pollination.
7) Sanitize cocoons and bee boxes.
8) Store the cocoons over the dormant season.
Protecting Bees from Spray
Mason bees are more susceptible to sprays than honey bees, according to Watts.
“Tank mixing sprays together is really detrimental,” he said, adding that it’s important for farmers to learn how to protect their orchard without killing the bees. “It’s really more about what you spray, when you spray and how you spray it.”
Watts said they put the nests inside totes. Before farmers spray, they can simply put the lids on the totes if they choose.
Pests of Mason Bees
Pollen mites hide out in flowers and hitch a ride on mason bees back to the nest. That’s why cleaning the cocoons before storage is important.
Houdini flies are also a serious pest to mason bees. They came in from Europe. Watts cautions growers to buy their mason bees from reputable and preferably certified bee farmers. Otherwise, he said, growers could accidentally buy tubes full of Houdini flies and spread them to native bee populations.
Watts Solitary Bees has its bees and equipment inspected as part of the certification process.
“We’re getting better and better at it,” Watts said of his family’s operation. Even so, he knows there is still room to learn more. “Ten years from now it may be way different.”
Watts also predicts the current price for mason bees–which started out at $1 a bee and has since dropped to 30 to 40 cents–will eventually fall to about a nickel a bee.
There was a definite learning curve involved in farming mason bees, Watts said. His family has another division of the business called Rent Mason Bees, which rents bee kits to backyard gardeners. In June, the gardeners ship the filled bee boxes back, where the cocoons are cleaned and stored for the following year.
It took eight years, what felt like forever, to get production to 1 million bees, Watts said. “Then it started snowballing.”
Watts’ advice to growers who want to try mason bees for the first time? “Get help. It’s not hard, but what we do has a lot of science behind it. You need to get help early,” he said. Watts provides on-site consultation, a service that is built into the price. “It’s actually not too early now to get started,” he added.
It’s helpful to the bees to have other blooming plants in the orchard. In almond orchards, for example, Watts suggests growers plant a mustard mix every row or every other row. “It will bloom along with almonds, and about a month later.” The bees prefer the tree blossoms, so they’ll head there first. The mustard will give them enough to sustain them after almond bloom. Planting native shrubs and flowers around fields and orchards also helps.
Food pollinated with mason bees can be marketed as “pollinator friendly” or “pollinated with native bees.”
“The future of mason bees, I think, is really bright,” Watts said.
Mason Bees vs. Honey Bees
According to Watt, it takes fewer mason bees to pollinate a crop. It takes only 400 mason bees to do the pollination work of 40,000 honey bees. Honey bees are a more advanced bee. It takes about five contacts with a honey bee to fully pollinate a bloom. Mason bees are more primitive.
“Mason bees are messy like a kindergartner,” Little said. A mason bee isn’t elegant at landing—she sort of belly flops into the flower. “She gets pollen all over her body. One contact with a flower and it’s pollinated.”
Little said honey bees are fair weather workers and don’t like to fly during wet or cold weather. Mason bees work in cooler temperatures and even during light rains. They often also work longer hours from early morning until late in the day. While honey bees will fly several miles to reach food, mason bees only work close to home. They travel in a 300- to 400-foot radius from their nest, about the distance of a football field.
Unlike honey bees, Mason bees rarely sting. They have an ovipositor for laying eggs, and although the females can sting with it, they rarely do. If you smash a mason bee or get one trapped in your shoe or clothing, it will likely sting. Otherwise, they are harmless, safe even around children and pets. They may bump into someone standing in front of their bee box, but most of the time will simply fly around you. Honey bees, on the other hand, have a communal hive and a queen to protect. They will sting if roused or disturbed.
Mason bees don’t make honey. They collect pollen and nectar, which they leave in a ball with a single egg per cell. It’s just enough for the larvae to survive on before chewing their way out of their cocoon the following spring. They also have a short lifecycle. The males survive only a couple of weeks. Females live six to eight weeks. Their lifecycle matches well with early blooming crops. Mason bees aren’t around to pollinate summer-blooming crops. Honey bee workers generally live from six weeks to six months and work a longer season from springtime until cold weather sets in.
Recently, two types of evidence have emerged to indicate that farmers must make substantial changes in their crop production systems in the future. The first is economic; If farmers want to preserve their markets, they must use farming practices in alignment with buyer preferences. This concept appears front-and-center in the YouTube video, “How to future-proof your farm (and not become obsolete!),” by Pennsylvania farmer Steve Groff.
“Is your farm becoming obsolete?” Groff asks. “There are changes coming over the horizon in our industry that have ripple effects and are forcing farmers to make difficult decisions about how they manage their soil. The reality is that you will come face-to-face with the supply chain that you are a part of.”
As Groff points out, if you don’t improve the way you’re doing things, your markets will disappear.
This economic point was further driven home in the opening keynote address by Nestle vice president Patricia Stroup at last fall’s Sustainable Agriculture Summit in Indianapolis, Ind. Stroup spoke to over 650 of the world’s major food brand and market representatives. “If you want to sell your food to us, you’ll meet our specifications,” was her stern admonition.
Nestle, by the way, is the world’s largest food company buying and selling food in every country on the globe.
All About Health
Now, just what are these “specifications” for how crops are produced? Where do they come from and what are they based on? The answer is simple. It’s all about HEALTH – soil health, farm health and human health. Strengthening connections between these three dimensions of planetary health are now gaining momentum in the public, markets that farmers rely upon, but also increasingly by medical health experts. There is now a growing recognition that human health is intimately connected to the nutritional quality of the food we eat, which in turn is connected to the health of farms that produce the food, and ultimately to the health of the soil in which crops grow. These converging values lead to the recognition among a growing sector of society that ‘food is medicine,’ and that nutrient-dense food comes from healthy farms with biologically active soils.
There are now several visionary physicians and healthcare administrators on the frontlines of this emerging arena calling for farmers to build bridges between human health, farm health and soil health. ALL IN Alameda!, a collaborative initiative led by Alameda family physician Dr. Steven Chen, M.D., is a shining example of integrative medicine. Recognizing the value of high-quality food, county clinics in Alameda are partnering with local organic urban farmers and writing vegetable prescriptions for patients. They are making remarkable positive impacts on a number of health indicators, including diabetes and hypertension, conditions that frequently afflict the largely low-income populations in urban “food deserts”.
Dr. Chen is fond of quoting writer and environmental activist Wendell Berry: “People are fed by the food industry, which pays no attention to health, and are treated by the health industry, which pays no attention to food.” Dr. Chen adds, “and both the food and health industries pay no attention to the agricultural industry.”
The evidence that supports new food and crop production paradigms is growing stronger. Markets are leaning toward supporting farmers who use practices that contribute to a healthier food system and ultimately, healthier people, and, in turn, lower-cost healthcare. Focusing on an “agricultural revolution” will compensate farmers for cultivating the land and delivering “public goods” in terms of climate change mitigation, ecosystem conservation and public health outcomes. Governments, including Great Britain, are moving to scale up incentives to farmers employing such practices.
There is also strong ecological evidence in support of a farming revolution. Overall soil health is directly affected by reducing disturbance, keeping the surface covered and encouraging biodiversity both above and below ground. Research shows that farmers who use ‘natural systems’ gain a host of important benefits, including the ability to use less fertilizer and water, capture and store more carbon, and require fewer inputs overall. The authors’ research in California’s San Joaquin Valley, for instance, has demonstrated that the combination of no-tillage (reduced disturbance) with cover crops reduces water applied over the course of the season by 13%, the equivalent of about 4 to 5 inches. In addition, no-till cuts dust emissions from the field by over 75%, and combining no-till with cover crops leads to increases in soil carbon, water infiltration, soil aggregation, water holding capacity and biological diversity. The ecological evidence from many other sources around the world support these soil care and conservation agriculture practices.
The early-generation pioneers who have become successful using these techniques tend to be organic farmers who seek to emulate natural systems. A group of California farmers who have been leaders in soil care, worker health and farm health are now working together through an NRCS Conservation Innovation Grant (CIG) project to develop crop production system alternatives for vegetable crops. (Insert Photo 2). More information about this group is available at the Conservation Agriculture Systems Innovation (CASI) website and by joining the authors’ project’s Collaborative Tools network at casi.ucanr.edu.
It’s now time to work together to scale-up improved farming systems across the board. We should no longer view food as just a substance to be bought and sold as cheaply as possible, but rather as medicine. Paul Muller, a Guinda organic farmer and member of the CIG project, puts it this way: “We are at a point where many people are asking how our farming systems can do more for the common good. Long-term soil stewardship and healthy soil is a common good; thinking through water stewardship in healthy soils enhances the common good; finding strategies to support and nurture those who grow our food and tend or steward our resources for the long-term is a common good; putting more carbon through cover crops and reduced tillage of the soil and keeping carbon as a food for a teeming microbial universe there is a common good; growing more nutrient-dense food is a common good. It is all related and companies can invest in this supply chain and support its growth and create a supply chain of value where all parts are rewarded for doing something good for consumers. The question is, ‘Who pays for the defense and enhancement of the common good?’”
This is not going to be an easy question to answer. Fortunately, innovators are beginning to put the pieces together. (Insert Photo 3). One such effort involves the National Cotton Council, the U.S. Cotton Trust Protocol, Cotton Incorporated and cotton farmers, such as John Teixeira of Firebaugh, who has many years of experience with soil health management systems. The organizations are working with companies like Wranglers, Levi-Strauss and Walmart, and researchers with experience in both soil and human health domains. Read more about this effort on the CASI website.
Federal and state government agencies are also involved in similar soil health initiatives. In 2012, the USDA’s Natural Resource Conservation Service launched “Unlock the secrets of the soil,” a major national education and awareness campaign about the core principles of conservation agriculture and soil health. This initiative will have a broad impact in many regions of the country. CDFA’s Healthy Soils Program, started in 2017, is now also having similar impacts and benefits. Indeed, CDFA has invested over $50 million and supported 307 projects incentivizing adoption of core soil health management practices.
However, it is ultimately the pioneering visionary farmers who are leading the movement. As renowned author David Montgomery puts it in “Growing a Revolution – Bringing our soil back to life,” “the movement is growing bottom-up, fueled by individual farmers rather than governments, universities, or environmental advocacy groups.” The excitement and the future of our food system is now in the hands of farmers who see a better way forward and are working hard to get there.
There are now clear roles that professional crop consultants can play. Imagine contributing creatively to the development of a completely new paradigm for farming systems that emphasize soil, farm and human health. Imagine becoming part of the effort to push far beyond IPM strategies that have been developed over the past 50 years. The economic and ecological evidence suggests that we have a commanding mandate to do so.
Few soils in the world tend to have the correct amount of magnesium for providing the highest yields and the highest nutritional value. Crops need adequate magnesium to sufficiently utilize both nitrogen and phosphate. Along with potassium, it also helps against frost resistance.
Areas with sandy soils tend to have the greatest problem with levels that are too low in needed magnesium. Yet, there are specific regions based on detailed testing for magnesium availability that do not have characteristics that would be considered sandy soils that also prove to have severe magnesium deficiencies for growing plants and crops. Far more soils used to produce food throughout the world have a high magnesium content, and yet the crops are lacking the magnesium they require for the best performance and highest nutritional values.
Why is this problem being overlooked even by organic growers? How can it be verified? And what can individual growers do to determine and remedy magnesium deficiency in food and feed crops?
If or when soil needs magnesium, how much is enough and how much is too much? And how can you know? This second in a two-part series will further explore the role of magnesium in improving crops and yields.
Magnesium in Soils
In the first article about soil magnesium printed in June/July 2020 Organic Farmer, the example of magnesium deficiency in carrots was discussed. When the soil does not have enough magnesium, carrots serve as an excellent indicator crop to tell at exactly what point soils are magnesium deficient. Carrots consistently show the accuracy of a soil test for predicting precisely when there is or is not a magnesium deficiency in the soil where they are growing. Based upon responses right in the field, an accurate test will show when and exactly how much magnesium is needed to correctly solve such a problem.
Another crop that shows how much the correct percentage of magnesium matters is cotton. When cotton ridges are hipped up in the autumn and allowed to sit until spring, even when a ripper-hipper is used to successfully break up any compaction layer in the aerobic zone, the more the magnesium level exceeds 12%, the harder it will be for the taproot of each cotton plant to correctly penetrate that soil after being planted the next spring. Again, 10-12% is ideal (which can vary up or down from these established acceptable fig-ures on tests from other labs,) and cot-ton roots have no penetration problems in such soils unless they are worked when too wet or something has caused a compaction problem. But once the numbers go above 12% for magnesium (on sandy soils this figure will vary from 13% to as high as 20% depending on its exchange capacity,) cotton roots which should have one tap root that goes straight down into the soil will have two smaller ones that fork out and begin curving to the side instead.
When cotton farmers have this much magnesium in the soil it is causing a yield reduction of at least three-fourths of a bale of cotton per acre. But growers only get that back once that excess is reduced to below 12% and kept above 10%.
All types of legumes are very sensitive to the soil’s magnesium content. At whatever magnesium percentage level carrot tops start to die prematurely on a particular soil test (below 10% on the test Kinsey Agricultural Services (KAS) uses,) at that same point legume yields will be seriously impaired until corrected and kept above that critical level. When the testing method for magnesium accurately reads at 10 to 12%, then magnesium poses no problem for the best production of legumes. Other labs’ soil tests may report these numbers as being more or less. But use of this exact analytical testing method will correctly show either too little (less than 10%) or too much (more than 12%) magnesium on legumes and will begin to reduce yields. Legumes are some of the most sensitive crops to either too much or too little magnesium. Either situation will reduce both quality and yield potential.
Understanding Soil Tests
Just be careful not to assume that all soil tests will provide those same readings. In fact, most generally do not. Actually, when a true Albrecht soil test shows 10%, other soil tests generally do not agree. Most farmers and growers never learn this because they do not make direct comparisons.
Perhaps using an example here will help growers to better understand this important point. On medium to heavy soils, all crops will respond best to soils with magnesium levels between 10 to 12%, as long as other needed nutrients are present in sufficient amounts. Upon hearing that KAS specialized in dealing with soils that had serious magnesium problems, a farmer growing corn to sell as grain who had not been using KAS’s services called to ask about applying more magnesium to his soils.
During the call it became apparent that he had some exceptionally good soils as based on his proven yield averages; he was producing more grain corn on his dryland operation than many farmers in the area were making under irrigation. Including the nitrogen supplied for the corn-based on the previous year’s soybean yield, his nitrogen efficiency was just right (supplying one pound of actual nitrogen to produce each bushel of corn) to indicate that magnesium was not a limiting factor. Under the circumstances, it seemed the best advice was to send some samples for analysis to see what the magnesium levels were at present before adding any more.
Samples from his fields were tested, but copies of the lab reports from a repu-table lab used by the other consultant were also sent for comparisons. The other lab recommended a minimum of 10% magnesium saturation just as KAS’s tests do. But the samples from that lab showed 8% magnesium which on KAS’s test would mean that with-out adding enough magnesium to get to 10%, it would require 1.5 pounds of actual nitrogen to grow a bushel of corn. This would actually be 1/3 more nitrogen than the farmer was current-ly using to reach the desired yields. He was already making those yields without adding the normally required extra amount of nitrogen for soils that actually shows 8% on the testing KAS uses.
When the results from the samples he sent for analysis from each field came back, the magnesium saturation showed to be between 11 to 12%, which is barely below the high side of the ideal for field crops, not at all like soils from the 8% level shown on the other test would indicate. Applying more magnesium on this land would not have been money well spent to make a better crop. In fact, it would have contributed to at least two more problems that happen with corn when you push magnesium levels above 12%.
These problems occur whether grow-ing organically or conventionally, and this is true for any type of corn crop, whether corn for grain, silage corn, sweet corn, or popcorn. First consider that the higher the magnesium level rises above 12%, the more nitrogen it will require to grow the very same yield of corn. Once above 12%, growers will need to apply 1.25 pounds of nitrogen to grow one bushel (52 pounds) of corn. Once above 15%, that number changes to 1.35 pounds of nitrogen per bushel of corn produced, and above 20% or below 10%, it requires 1.5 pounds of nitrogen per bushel of corn. Of course, this will only happen if you have sufficient levels of the other needed elements for achieving that yield, but many times, especially on organic farms, nitrogen tends to be the most limiting fac-tor for better yields. Adding too much magnesium to the soil can also result in a shortage of some other nutrients—generally potassium, sodium, calcium, or some combination thereof as well as reducing trace element availability. And depending on the source, using dolomite lime for example, that problem will not become completely evident for a full three years from the time it is applied. So, it is important to be sure that what you add is only what the soil actually needs.
Adding too much magnesium to the soil can also result in a shortage of some other nutrients—generally potassium, sodium, calcium, or some combination thereof as well as reducing trace element availability. And depending on the source, using dolomite lime for example, that problem will not become completely evident for a full three years from the time it is applied. So, it is important to be sure that what you add is only what the soil actually needs.
Mark this and do not forget it when you strive to grow nutrient-dense foods: When there is too much magnesium in a soil, the crop growing there will not get enough. Yes, crops growing on soils that contain an excess of magnesium will not get enough and will be short of magnesium that is actually needed to supply the best nutrition, the most efficient use of fertilizer and the best growth.
For proper results, growers should test the plants and add foliar magnesium until it reaches at least what is shown to be the high range for the crop. Sufficient or mid-range is not enough, especially when magnesium is above 12% in a medium to heavy soil. Adding more magnesium to a soil that is already too high in magnesium does not solve such a problem, it only makes the problem worse. In such cases, foliar applications are recommended, but it usually requires multiple applications to move magnesium into the specified high range on plant or tissue tests.
How much magnesium is enough in the soil? Whether a soil has too little magnesium, or the correct amount, or too much is not determined by how many pounds that soil contains. The only way to determine whether magnesium is helping or hurting the soil and/or the crops that grow there is by measuring what percentage of each soil’s nutrient holding capacity is occupied by available magnesium. If the base saturation is less than 10%, that soil is magnesium deficient and as the percentage drops lower, the signs that indicate magnesium deficiency will become more and more apparent. Adding enough to achieve 10% magnesium saturation to these soils will solve the problem.
Yet on medium to heavy soils, the higher the magnesium saturation goes above 12% the harder it will be for the crop to take up a sufficient amount of magnesium. This is a type of hidden hunger which means you do not see observable signs of deficiency in the crop. Such a need can only be established by plant or tissue testing while the crop is growing. On such soils, adding more magnesium to the soil will only prolong the problem or make it worse. In such cases, test the plants and use a foliar application every three or four weeks until the plant tests show the magnesium level to be at least slightly above the high range. If the tests never get that high, then keep spraying every three to four weeks until the crop is made. Just keep in mind that as long as the crop needs nitrogen or phosphorus, it also needs magnesium.
Establishing the correct magnesium content for the soil is accomplished by determining the amount of colloidal clay and humus each soil contains. Both have negative charges and attract and hold positively charged elements such as potassium, magnesium and calcium. Once the amount of negatively charged particles are determined for a specific soil, then 12% of those need to have magnesium attached to them.
The desired amount of magnesium can be established in pounds per acre by multiplying the soil’s total exchange capacity (TEC) times the atomic weight of magnesium in milliequivalents (240) times the desired percentage of magnesium. This allows for converting and expressing the amount of needed magnesium in pounds per acre. Farmers and growers need only to understand the concept, as the conversions are already done on the soil tests that use this method.
Once the needed amount for a particular soil has been established when deficient enough for available magnesium to be needed quickly, materials like Sul-Po-Mag, K-Mag, or magnesium sulfate can be applied. For long-term buildup of magnesium, dolomite lime is usually most economical and works well as long as the soil can also tolerate the calcium it contains.
What if your soil has too much magnesium? Can you get rid of the excess? Excess magnesium levels can be corrected. When necessary, excess magnesium can be removed from the soil, but there are specific requirements before that can happen.
First, calcium levels must already be above or increased to reach 60% or higher in any soil before magnesium can be leached out. Once that is accomplished and a 60% or higher calcium saturation can be maintained, it then requires two pounds of sulfur over and above soil and crop needs to remove one pound of excess magnesium. So, once the amount of excessive magnesium has been established, double that to see how much sulfur will be needed to remove it. That will be the minimum cost to remove magnesium from that soil. Enough lime to keep the calcium saturation above 60% may also be needed, and though all soils need that 60%+ level to be most productive, some may still want to include that as a cost for driving out an excess of magnesium.
On soils with too much magnesium, does the increased income justify the expense required to remove the extra magnesium from that soil? How much is adding an extra three-fourths of a bale of cotton per acre worth? How much is the savings from not having to add an extra one-third more of required nitrogen to grow the same yield of corn worth? How much is 10 more bushels of soybeans per acre worth?
Is it worth the time and the effort? That answer depends on the amount of the excess and the cost of the materials it will take to remove it. Remember this point: As long as you have an excess of magnesium in your soils, the production capabilities are constantly being impaired, and top efficiency from even certified organic sources of soil nitrogen and phosphate materials will not be achieved, nor will the crops being grown there ever contain the ideal amount of needed magnesium for truly nutrient-dense foods. Such great costs to our feed and food supplies cannot go on ignored when the technology is there to prove what is needed and provide for the greatest positive responses.
Soil microbes, or microorganisms, are the mediators that convert the bigger organic pieces, such as plant matter, insect skeletons and worm castings, into the ammonium and phosphate that the plants can take up and use.
“Soil is a living being, and it’s filled with microenvironments and niches,” said Kate Scow, UC Davis Professor of Soil Science and Microbial Ecology.
Plants and microorganisms are involved in important symbiotic relationships. The roots of plants release chemicals and slough off cells, providing food such as sugars, starches and amino acids for microorganisms. In turn, microorganisms decompose organic matter, which allows plants to more easily take up nutrients. Mycorrhizal fungi concentrate phosphorus and other minerals at the roots of plants.
The rhizosphere, or area immediately around the root zone of plants, is teeming with microorganisms. Many times, these microbes are single-cell organisms, but they also may group together to form colonies of cells.
“Soil is very diverse,” Scow said. “It is home to a variety of communities that do a tremendous amount of work.”
Scow compares these various soil communities to guilds whose members specialize in different skills—the silver smith, the candle maker, the black smith. In the case of soil, these groups are defined by their ecological functions. Some of these groups include:
Decomposers of organic materials—Without the decomposers, such as microbes, along with earth worms and arthropods (centipedes and millipedes,) all the rich organic material would just sit there. It wouldn’t break down into components that plants can utilize.
Nitrogen mineralizers—help turn organic matter into the minerals that plants need. Nitrogen mineralization is the process of microbes decomposing organic N from organic matter into ammonium that plants can then use.
Plant growth promoting bacteria (PGPB)—These organisms live in close association with plants and can enhance plant growth and protect them from disease and other stresses.
Scow compares healthy human bodies with good immune systems to what’s going on in healthy soil. Both support beneficial microorganisms that are good at boosting immunity and defeating disease.
“If we’re healthy, we’re less likely to get disease. Healthy organic soils have a lot of capacity to suppress diseases in plants. They don’t give diseases much of a chance to get a foothold,” Scow said.
Conventional Soil vs. Organic Soil
With conventional farming, the grower is giving the plant what it needs as far as Nitrogen (N), Phosphorus (P) and Potassium (K), most often with the use of chemical fertilizers. But that doesn’t provide all that is needed by the soil and the microorganisms that live in it. The soil can starve if organic matter isn’t going back in, because it’s missing the carbon.
“An important part of organic inputs is the carbon,” Scow said. “Like our bodies, soil needs to eat, or be fed.”
“Soil in intensive agricultural systems, i.e. growing food, loses carbon in the plant material that is removed during harvest and which is often not replaced,” Scow said.
Adding back the organic matter with compost, manure, blood meal etc., gives back to the soil the nutrients and organic material that is taken away with harvest. Continually feeding the soil with organic material supports the beneficial bacteria, fungi and nutrients plants need and use. A “bank” of nutrients, organic matter is like a continuous smorgasbord for growing plants.
Organic material also rights a lot of wrongs. It not only helps the soil microbes, but it tends to regulate soil acidity levels. It also helps problem soils: clay soil with drainage, and sandy soils with retaining moisture and nutrients. Organic matter helps feed the organisms that create aggregates—sand, silt and clay joining together to form larger-sized granules. Larger granules create crumbly soil, which improves root growth and provides a beneficial habitat for soil organisms.
Organic soils have much higher microbial mass than equivalent conventionally managed soils, according to Scow. If you could actually weigh the microbes, you might find twice the weight in organic than in conventionally-farmed soil, she said.
Organic farmers have long relied on microbes and their symbiotic relationship with plants to get their fertility.
“Growing organically requires you to think about the life in the soil and to take care of it,” Scow said.
For both organic and conventional growers, cover crops are beneficial. They add nutrient-rich organic matter back into the soil. The cover crop collects the rays of the sun, powering photosynthesis. The plants take in carbon dioxide from the air, which produces food for the plants, as well as for the microorganisms living in the root zone. During this same process clean oxygen is released back into the atmosphere.
Facts About Microbes
There are 50-billion microbes, give or take, in one tablespoon of soil.
Soil microorganisms are the source of many antibiotic medicines humans use to treat infections and disease.
Food sources for microorganisms are plentiful in topsoil and more microorganisms live there than in the deeper subsoil.
Growers often add supplemental organic phosphorus fertilizers to the soil to adjust for crop needs. Treating seedling roots with endo-mycorrhizae helps increase the plants’ ability to absorb phosphorus in the soil.
The hair-like hyphae of fungi can spread for hundreds of feet underground. In undisturbed forests, these hyphae can stretch for acres and acres.
The largest living organisms are fungi. Underground fungal networks can transport nutrients throughout the hyphal system.
Microbes can help plants send signals to other plants, warning about pests or disease.
Additional Benefits of Microbes
Mycorrhizal fungi help extend plant roots so they can access a much larger volume of the soil. Hyphae, which are tiny hair-like fungi strands, can reach into the tiny nooks and crannies in the soil to reach pockets of nutrients that plants couldn’t get to by themselves.
Microorganisms also help rid soil of toxins. If there are organic toxins in the soil, such as gasoline, and some of the pesticides, there are microbes that can actually utilize them as food.
“Some of these chemicals are toxic to higher organisms like humans, but not to microbes,” Scow said. “Through bio degradation, microbes eat them, grow new cells and release harmless by-products. Microbes, such as fungi, can also accumulate heavy metals and hold them there in their hyphae.”