AgNet DEMO

Category: Organic

  • Shade Nets Show Benefits for Peppers

    Figure 1. Shade nets can prevent crops from receiving too much light.

    By Juan Carlos Díaz Pérez

    Vegetable growers know well about the importance of light to plants. Light is necessary for the process of photosynthesis through which plants convert light energy into chemical energy (sugars) needed for plant growth and development.

    LIGHT AND HEAT

    Light is electromagnetic radiation that comes from the sun. The portion of the electromagnetic spectrum that can be seen or perceived by humans, the “visible light,” is within 400 to 780 nanometers (nm). (A nanometer is a billionth of a meter.) Photosynthesis also occurs within this visible range.

    In addition to the visible light, infrared is an important region of the electromagnetic spectrum that is for plant growth. The infrared light covers the range from 780 nm to 1 millimeter. A little more than half of the electromagnetic energy received from the sun is in the form of infrared radiation. Objects such as plants, animals and the soil emit heat as infrared radiation.

    Heat is energy that flows because of differences in temperature. Although visible light and other electromagnetic radiations may produce heat, the majority of heat at the Earth’s surface is associated with infrared radiation. Thus, plant heat stress due to excessive light and temperature are related to high exposure to infrared radiation.

    Although not all scientists agree with the concept of global warming, most climate experts believe that Earth’s temperature has been increasing since the time of the Industrial Revolution. The rise in temperature affects agricultural crops and may increase incidences of pests and diseases. New pests and diseases have been detected in the last decades that have been linked, at least partially, to changes in climatic conditions.

    Vegetable crops are particularly sensitive to high temperature and high light intensity conditions. Vegetables typically require soil moisture availability to reach high fruit yield and quality. Under conditions of high light and high temperature, crops such as pepper plants show drought stress, reduced fruit yields and high incidences of fruit physiological disorders such as fruit sunburn and blossom-end rot.

    PROTECTIVE TOOL
    Figure 2. Bell pepper plants are grown under shade net supported with a metallic cable and posts forming a pyramidal structure at the University of Georgia in Tifton.

    Shade nets are a type of technology used extensively to protect vegetables and other horticultural crops from damage by high solar radiation, wind, birds and hail. Black nets are the most common and the least expensive (Figure 1).

    Shade nets help reduce the heat load on crops by absorbing a portion of the solar radiation (visible light and infrared) and may reflect or refract some of the radiation, depending on the color and chemical composition of the net. The percentage of the solar radiation reduced by the net (called the “shade factor”) may vary from as low as 15% to as high as 80%. The type of net shade factor to use depends on the crop.

    RESEARCH RESULTS

    A study at the University of Georgia (UGA) in Tifton was conducted to determine the response of bell pepper plants to nets with different shade factors. Bell pepper plants (cultivars Camelot, Lafayette, Sirius and Stiletto) were grown in the field following the recommendations of the UGA Extension Service. Plants were planted in the field during the spring season of two years.

    Table 1. Bell pepper fruit yield under field conditions in Tifton, Georgia, as influenced by shade factor of black nets. Values are the means of four cultivars (Camelot, Lafayette, Sirius and Stiletto).

    Plants were grown in unshaded conditions (0% shade factor) and under nets with 30, 47, 63 and 80% shade factors (Figure 2). Results showed that fruit marketable yield of the four cultivars was highest under nets with 30 and 47% shade factors (Table 1). The yield of nonmarketable fruit decreased with increasing shade factor, indicating that reduced light levels were associated with diminished incidences of fruit physiological disorders (sunburn). The fruit size also increased with higher shade levels. See doi.org/10.21273/HORTSCI.49.7.891 for a more detailed report of this study.

    In conclusion, shade nets with shade factors between 30 and 47% resulted in the following benefits:

    • Increased fruit marketable yield
    • Improved fruit size
    • Decreased incidences of fruit sunburn

    Juan Carlos Díaz-Pérez (jcdiaz@uga.edu) is a professor in the Department of Horticulture at the University of Georgia in Tifton.

  • Regenerative Agriculture on the Rise

    By Sarah Bostick

    Regenerative agriculture is fast becoming a buzz phrase in America. You may have heard about it on the news, in feature films or in farmer forums online. You may have seen the words “regeneratively grown” on a box of mac and cheese, a tub of yogurt, a container of oatmeal or even a case of beer.  

    DEFINING THE TERM

    But what is regenerative agriculture? There is not one single working definition of regenerative agriculture, but at its core is the idea that virtually all agricultural farmland in the world has been damaged over time and that growers can actively improve the health of the land.

    Regenerative agriculture is best thought of as a collection of land management practices that restore soil health. The list of land management practices generally includes the use of diverse cover crops, managed grazing, the creation of on-farm fertility, no or minimal use of pesticides and synthetic fertilizers, and no or minimal tillage.

    INSIDE THE SOIL

    We often think of soil as simply soil, but soil is actually a very complex system. If you pick up a handful of healthy soil, approximately 45 percent of the volume is mineral (sand, clay or silt), 25 percent is water, 25 percent is air, and 5 percent is organic matter. Organic matter is a small part of most soil, but the services it provides to your farm are vast.

    Organic matter is anything that is or once was alive. Organic matter is the part of soil that most effectively captures and holds nutrients, prevents erosion and lessens the impacts of both flooding and drought. Organic matter is what makes soil the most biologically diverse ecosystem on the planet. It is also the part of soil that captures and holds carbon.

    It is this last bit — carbon capture and storage — that has caught the attention of people from every walk of life and recently put agriculture on the big screen.

    In the book “Soil as World Heritage,” soil scientists estimate that since the start of agriculture, approximately 320 billion tons of soil carbon have been lost worldwide from clearing land for agriculture. That is equal to the weight of 107 billion standard-sized pickup trucks.

    According to the book, most agricultural soils worldwide have lost 12 to 16 tons of carbon per acre. That’s equal to 25 to 75 percent of what existed before the land was first cleared.

    Where does soil carbon go when it is released? It goes back into the atmosphere in the form of carbon dioxide.

    Tillage releases carbon stored in the soil back into the atmosphere. By minimizing tillage and focusing on building organic matter, soil can store the huge quantities of carbon that plants pull out of the atmosphere through photosynthesis.

    The higher the organic matter level in the soil, the more carbon it is storing. According to Paul Hawken’s book “Drawdown,” for every 1 percent increase in soil organic matter, about 8.5 tons per acre of carbon are stored.

    Most of the attention that regenerative agriculture is receiving boils down to the idea that agriculture can be a powerful force in removing the top greenhouse gas (carbon dioxide) from the atmosphere.

    Farmers are clearly seeing the benefits. An estimated 108 million acres of farmland worldwide currently practice regenerative agriculture, according to “Drawdown.”

    If you are interested in learning about regenerative agriculture directly from farmers who practice it, here are a couple videos to get you started:

    REGENERATIVE ORGANIC CERTIFIED

    As of fall 2020, there is a new certification: Regenerative Organic Certified (ROC; regenorganic.org). The certification is overseen by a nonprofit organization called the Regenerative Organic Alliance. Rather than creating a different set of rules and regulations, ROC certification is based primarily on ensuring that a farm has a collection of other certifications.

    The three pillars of ROC are soil health, animal welfare and farmworker fairness. The soil health pillar requires that farmers be U.S. Department of Agriculture Certified Organic. The animal welfare and farmworker fairness pillars are proven through certifications such as Animal Welfare Approved and Food Justice Certified.

    CONCLUSION
    Regenerative agriculture doesn’t have a clear-cut definition, but it does have a growing following amongst both farmers and consumers. Regenerative agriculture is not an all-or-nothing concept. As you learn more about it, you might start with giving just one of the ideas a try. Regenerative agriculture is a process of learning what works on your unique piece of land.

    Sarah Bostick is a University of Florida Institute of Food and Agricultural Sciences sustainable agriculture Extension agent in Sarasota. 

  • Choosing Cover Crops for Nematode Management

    Sunflower in the foreground and sunn hemp in the background

    By Johan Desaeger

    Cover crops are one of the more practical options for nematode management as their use is already common practice for many growers. The subtropical climate in Florida and the southeastern United States allows growers to plant crops year-round, and cover crops have been an important component of Florida’s agro-ecosystems since its early days of agriculture.

    Until the 1930s, velvetbean was a popular summer cover crop in Florida due to its nitrogen contribution. However, around the 1950s when chemical fertilizers and pesticides became widely available, cover crops became less common. Currently, the most planted summer cover crops in Florida are sorghum-sudangrass hybrids, sunn hemp (Crotalaria juncea) and cowpea (Vigna unguiculata). 

    SUMMER COVER CROPS

    Sorghum-sudangrass is a tall annual grass that is quite competitive against weeds. Leaf tissue of sorghum-sudangrass contains dhurrin, a cyanogenic glucoside that releases hydrogen cyanide upon degradation in the soil. While many varieties suppress root-knot nematodes (RKN) — by far the most damaging nematodes in Florida vegetables — sorghum-sudan is a good host to sting and stubby root nematodes. Sting nematodes are a major problem in Florida strawberries.


    Sunn hemp is a tall, rapid-growing legume that is widely grown in tropical regions as a green manure. In Florida, Tropic Sun sunn hemp produces high amounts of biomass. Its ability to fix nitrogen permits vigorous growth, even in sandy soils with low levels of nitrogen. Sunn hemp is well known to be a poor host to RKN and also to sting nematodes. However, it is a good host to lesion nematodes. Sunn hemp also contains alkaloids in its tissue, and both its leaf and root residue have nematicidal activity.


    Cowpea is a good fit as a summer cover crop for Florida growers. Unfortunately, cultivars like Iron Clay, which is the most common in Florida, is a good host to most species of RKN. Cowpea nematode susceptibility is greatly influenced by cultivar and composition of the nematode population. For example, while Iron Clay is a good host to most RKN species, California Blackeye No. 5, Tennessee Brown and Mississippi Silver are poor hosts to RKN. Both Iron Clay and Mississippi Silver can be good hosts for sting nematodes. In addition, cowpea is susceptible to southern blight, to which many Florida vegetables are also susceptible.

    WINTER COVER CROPS

    Common winter cover crop species include winter rye, oat, crimson clover, hairy vetch and several Brassica species such as mustard. These have varying effects on nematodes, but generally, when a susceptible crop is grown after them, nematode numbers quickly rebound.  Brassica plants like mustard and radish are also known to have biofumigant properties. This is due to the glucosinolates (sulfur-containing compounds) that they contain. Upon degradation, glucosinolates hydrolyze into several volatile compounds, including isothiocyanates (the active component of metam-based soil fumigants) and mustard oils.

    MIXING AND USE

    Cover crops can be sown as a monoculture or as a mix of multiple species. Mixing cover crops with opposing nematode host status can have benefits in terms of nematode management. Previous cover crop experiments by the author in Kenya, involving a mixture of good RKN hosts with poor hosts similar to sunn hemp, created a more diverse nematode population, reduced nematode damage and increased yield of an RKN-susceptible crop in rotation.

    The lack of nematode-specific data combined with the multitude of RKN (more than 15) and other nematode species in Florida warrants exploring the host status of cover crops (including cultivars) to each species of root-knot nematode. This is tedious work that takes time. However, such information would help growers to select appropriate cover crops, including mixtures that are tailored according to the resident nematode population of a field. 

    Properly managed, cover crops improve soil quality and health. They may impact soil nematodes in different ways, by limiting nematode reproduction during cover crop growth in the case of poor hosts, and by directly killing them via production of nematicidal compounds following incorporation of the biomass. In addition, by increasing soil organic matter, which is especially important in the poor sandy soils typical of Florida, cover crops can improve soil health by stimulating biological control organisms that are natural enemies of nematodes.

  • Seed Selection Considerations

    Photo credit: © Ok / stock.adobe.com

    By Tiffany Bailey and Ida Vandamme

    Choosing vegetable varieties is probably the most important decision a grower can make and can be the difference between a crop failure or success. On our farm, we consider seed selection one of the most powerful and efficient tools as part of the cultural controls in an integrated pest management program. It takes no extra effort to plant a better variety, and huge results can be achieved in both yields and disease resistance.

    The planet we live on has many different climates and conditions, and yet people across the world all still want red tomatoes. This is where the wonderful genetic diversity of plants comes into play. A seed variety that produces a healthy, red cherry tomato commonly grown in the North may struggle in the South. A different variety with different genes, better suited for the South, may have an internal mechanism coded within to help the plant cope with intense heat and pest and disease pressures. An extra waxy cuticle, more vigorous growth to stay ahead of leaf loss, and quicker systemic responses are just a few of the many ways a plant can be better adapted to different conditions.

    DIVERSIFY FOR RESILIENCY

    In the beginning stages of an organic farm, a good practice to best protect against a crop failure is to plant several different crops and even varieties of crops. That way, if an unsuitable variety is planted, the loss will be small and other varieties can make up for it. Over time, the different seed varieties will show their strengths and weaknesses.

    Even after the stronger varieties are determined, it is still a good idea to trial new seed varieties because every year is different. What did well last year may have to make room for another variety to take the spotlight. Having a diverse crop plan will make your farm more resilient to changes and new stresses. Plants come with amazing genetic diversity, which should be used to the farmer’s advantage.

    CONSERVE RESOURCES

    A good variety is such an effective control because you will spend less time, energy, resources and tears on it. An unsuitable variety will cost you more money in labor, chemicals, and/or equipment to maintain it.

    On our farm, we have had experiences with weak seed varieties that needed to be sprayed more often with more expensive materials to keep the crop from succumbing to disease. On the flip side of that same coin, we have had solid varieties which seemed to be completely carefree with good management.

    KNOW YOUR SITE

    It is all about site-specific needs. There are hundreds of different conditions a farm could be planted under and, thankfully, hundreds of different varieties of crops available to choose from. Local Extension offices are a great tool to get started with. They will know which varieties perform best in your location, but farmers should do their own trials because every farm is different, and management strategies will affect which varieties perform the best.

    ORGANIC VS. NON-ORGANIC SEED

    National Organic Program rules state that non-organic seeds can be used only if organic seed cannot be found or is not commercially available in the quantities needed. A search record must be provided with three attempts to source organic seed if non-organic seed must be used.

    We have heard from both experienced farmers and university professors that crops grown from non-organic seeds perform better than crops grown from organic seeds. We have made our own observations on the matter and tend to agree with them.

    Photo credit: © eleonimages / stock.adobe.com

    However, others say it is a myth that organic seed crops do not perform as well. Organic seed undergoes the same rigorous disease testing as non-organic seed, according to our local Extension agent. She has assured us that there should be no difference. We encourage all farmers to see for themselves!

    Tiffany Bailey is owner and Ida Vandamme is farm manager at Honeyside Farms in Parrish, Florida.

  • UGA Researching Organic Onion Fertilizers

    Organic onion production in Georgia is nothing new. But the data is lacking for farmers who are trying to expand and be more efficient in their operations.

    That is why Tim Coolong, associate professor in the UGA College of Agricultural and Environmental Sciences, is studying organic onion production.

    “Onions have been grown conventionally for decades. That system, I feel like we’ve got it down pretty well, although, we still have issues,” Coolong said.

    “Organic onions have also been grown for a little while, but the body of knowledge is so much less. Growers are constantly trying new things. As researchers, we’re trying new things. Sometimes they work, sometimes they don’t. But it’s just trying to build that body of knowledge to draw upon.”

    Fertilizer Applications

    That knowledge consists of fertilizer applications, which are essential in the development of onions throughout the growing season. Growers who utilize organic fertilizer sources, typically use poultry-litter based. But farmers must apply high levels of organic fertilizer prior to planting to ensure onions have adequate fertilizer levels when they start putting on growth in mid-winter.

    Unlike conventional soluble fertilizers, many organic sources continue a slow and steady release of nitrogen throughout the growing season, even later in the year when growers often try to reduce available nitrogen prior to harvest. 

    “We’re looking at standard poultry litter, which is used a lot less now than it used to be. Then we’re going to be looking at other organic fertilizers that, based on information from folks up here, they found that they have very different release rates,” Coolong said. “With the conventional fertilizer, if you put it out, it’s there. It’s readily available. But with some of these organics, they may take several weeks to release, they may take longer. What we’re hoping to do is evaluate some of these so that our onion growers can be able to time their fertilizer applications better.”

    Unfortunately, higher nitrogen levels near harvest may predispose some onions to bacterial diseases if the weather is warm, which is not uncommon in southeast Georgia.

    “We’ve done some preliminary work, so we’ve got a little bit of data. We’re hoping to really dial it in this year,” Coolong said.

  • Organic Produce Members Team Up in Organic Trade Association’s Produce Council

    organic certification

    WASHINGTON, D.C. (November 16, 2020) – The American organic produce sector is big and complex. It accounts for more sales than any other organic sector, and its production regions stretch across the United States reaping a dizzying array of fruits and vegetables. The issues facing organic produce growers, processors and distributors are equally wide-ranging: food safety, labor issues, labeling/packaging issues and climate change.

    Driven by the desire for the sector to collaboratively work together to address its most urgent challenges, inspired by the success of other sector councils at the Organic Trade Association, and wanting to take advantage of the association’s deep knowledge and expertise in organic, leading produce members initiated a drive earlier this year that has resulted in the trade association’s Board of Directors’ official approval to establish an Organic Produce Council. 

    “We whole-heartedly welcome the formation of this sector council and look forward to problem-solving and collaborating with our colleagues throughout the organic produce supply chain,” said Board member Ben Diesl of Grimmway Farms. “This council will give Organic Trade Association member companies that are involved in the organic industry an organized opportunity to benefit from the association’s expertise, to network with diverse stakeholders and to influence the overall agenda of the association. We invite other produce members to join.”

    “The new Produce Council, as with all of our sector councils, will be supported by the Organic Trade Association’s expert staff,” said Laura Batcha, CEO and Executive Director of the trade association. “Our staff has deep expertise in organic standards, food safety, farm policy, government advocacy and international marketing. Today’s organic produce sector is robust and thriving, but it faces many challenges. We are thrilled that our produce members are coming together and tapping into their association’s bank of knowledge to help them deal with those challenges.”

    Organic produce sales hold the top position in the U.S. marketplace. In 2019, organic fruit and vegetable sales reached $18 billion, as the category continued to be the star of the organic sector. Organic produce currently makes up almost a third of all organic food sales, and organic fruits and vegetables, including fresh, frozen, canned and dried, have now captured 15% of the total fruits and vegetable market in the U.S.

    The produce sector has been profoundly tested by COVID-19 as it has struggled to keep its workers in the fields, plants and trucks safe, and at the same time meet exploding demand. Wanting to hear how the pandemic was affecting their businesses, Organic Trade Association’s Farm Policy Director Johanna Mirenda and Diesl of Grimmway Farms earlier this year convened produce members for a COVID-19 listening session. Everything from how to keep workers safely socially distanced and maintain planting and harvesting schedules to keeping processing lines filled and store deliveries on time were discussed.

    Working Together to Address Challenges

    “Our members taking part in this discussion found it very valuable to connect with other of our produce members” said Mirenda, who is staff liaison for the new council. “Since then, individual members have come forward with other organic produce issues — such as food safety — that could serve as work plan projects for the new council to take on.”

    The interest from members was significant enough that the trade association hosted an exploratory meeting in early September to highlight the opportunity for a new sector council among all Organic Trade Association produce members. Nearly two dozen members attended. 

    Produce stakeholders said that besides food safety, they are interested in working together, with the support of the trade association’s regulatory and legislative staff, to advance outcomes relating to other key issues in organic produce, such as: implementing the U.S. Department of Agriculture’s new rule on strengthening organic enforcement, guaranteeing workforce safety and availability, supporting development of organic seeds and planting stock, and identifying tools for measuring and promoting biodiversity. Establishing organic labeling and packaging best practices, adapting to and mitigating climate change and developing resources on market data and research information were also identified as key needs.

    Members also indicated the following priorities for their engagement:

    • Amplifying the needs of the produce community within the trade association
    • Developing and sharing information resources among those in the organic produce industry
    • Learning about emerging regulatory issues that impact organic produce
    • Networking with other organic produce businesses across the value chain
    • Creating opportunities for leadership development opportunities

    Sector Councils within the trade association build community among groups of like members to provide ongoing opportunities for networking, leadership development, education, information development, and sharing. They are not policy-setting groups. The trade association previously has established such entities as its Farmers Advisory Council, Dairy Council, Dietary Supplements Council, Fiber Council, Grains Council, and Retailer Council.

    Initial companies signing up for this council include Ag. Valles del Sur SpA, Awe Sum Organics, Bolthouse Farms, Bridges Organic Produce, Cal-Organic/Grimmway Farms, Charlie’s Produce, Columbia Marketing International/CMI Orchards, Duncan Family Farm, Earl’s Organic Produce, Heath & Lejeune, Homegrown Organic Farms, Jacobs Farm/Del Cabo, Munger Farms, Naturesweet, Naturipe, Organically Grown Company, Organic Produce Network, Page’s Organics, Taylor Farms, Thermiculture Management, Vitalis Organic Seeds and Wholesum Family Farms.

    The first meeting of the council is scheduled for Dec. 8.

    Other members of the trade association in this sector are encouraged to join. The council’s membership will be diverse. The technical scope of membership for the council will be very inclusive – vegetables, fruit, mushroom, herbs, tree nuts, floriculture and other horticultural crops.

    For more information on the council, contact Johanna Mirenda. The Organic Trade Association (OTA) is the membership-based business association for organic agriculture and products in North America. OTA is the leading voice for the organic trade in the United States, representing over 9,500 organic businesses across 50 states. Its members include growers, shippers, processors, certifiers, farmers’ associations, distributors, importers, exporters, consultants, retailers and others. OTA’s Board of Directors is democratically elected by its members. OTA’s mission is to promote and protect ORGANIC with a unifying voice that serves and engages its diverse members from farm to marketplace. The Organic Trade Association does not discriminate on the basis of age, disability, national origin or ancestry, race, gender, religion, sexual orientation, marital status, political affiliation or military status. Persons with disabilities who require alternate means for communication of program information can contact us at info@ota.com.

  • Mulch Improves Water Conservation in Vegetable Production

    Sweet onions are shown growing in Tifton, Georgia, with two types of mulch: organic (wheat straw mulch) on the left and inorganic (plastic mulch film) on the right.

    By Juan Carlos Díaz-Pérez

    For centuries, horticulturists have modified the crop microenvironment to extend the production season and enhance crop growth, yield and quality. Some of the techniques to achieve environmental modification include the use of mulches, high tunnels, greenhouses, etc.

    Mulches are widely used in both conventional and organic vegetable production. According to Wikipedia, “a mulch is a layer of material applied to the surface of soil with the goal of conserving soil moisture, improving fertility and health of the soil, and reducing weed growth.”

    Mulch may be organic (straw, leaves, cover crop residue, newspaper, wood chips, etc.) or inorganic, such as plastic film. Mulch effects on crops may vary depending on different factors.

    Factors affecting organic mulches include source of organic material (plant or animal), size of the particle, thickness of the mulch (amount applied) and age of the material. Factors affecting plastic mulch films include color, thickness, composition and permeability.

    In a vegetable crop field, soil water may be: 1) evaporated from the soil, 2) evaporated from the surface of the leaves of the crop, in a process called transpiration, 3) lost from surface runoff or 4) lost by percolation. In this article, we will focus on ways to improve soil water conservation.

    SOIL WATER EVAPORATION

    Both organic mulches and plastic mulch films act as barriers to water evaporation from the soil. These two types of mulches differ, however, in how they diminish soil water evaporation.

    In bare soil, water tends to evaporate from the soil. Soil water evaporation is proportional to the evaporative demand. Evaporation increases with increasing air and soil temperatures and decreasing relative humidity.  The rate of soil water evaporation also decreases as the soil water content decreases.

    According to the Food and Agriculture Organization of the United Nations, organic mulches may reduce soil water evaporation from 40 to 90 percent relative to bare soil. A thickness of 2 to 4 inches is effective in reducing evaporation. Soil evaporation tends to decrease with decreasing particle size of organic residues.


    Plastic mulch films are, in general, more effective in reducing soil water evaporation compared to organic mulches. Plastic mulch films differ in permeability to gases due to differences in film composition. For example, virtually impermeable film and totally impermeable film provide greater fumigant retention compared to low-density and high-density polyethylene film. With respect to soil evaporation, however, all plastic mulch films seem to be effective in conserving soil moisture.

    Physical damage or deterioration decrease the effectiveness of a plastic film to reduce soil water evaporation. Biodegradable mulches may be more prone to rapid deterioration compared to plastic mulch films.

    RAINFALL PENETRATION INTO SOIL

    Water-use efficiency increases when the crop uses rainfall water. Although organic mulches reduce soil evaporation, they allow for water penetration to the soil after a rainfall event. In fact, by reducing water flow through the soil surface and improving soil structure, organic mulches improve the water penetration to the soil and reduce soil runoff compared to bare soil.

    In contrast to organic mulches, plastic mulch films are impermeable to liquid water. Thus, they do not allow rainfall water penetration into the soil covered by the film. Rainwater that reaches the plastic film flows to the soil area between the beds and may result in soil runoff and soil erosion.

    In conclusion, both organic mulches and plastic mulch films are useful tools that help growers conserve soil moisture and increase irrigation efficiency.

  • UGA Researcher Part of Grant Studying Efficacy of Essential Oils in Organic Fruit Production

    File photo shows blueberries.

    Organic agricultural production is increasing in Georgia. Jonathan Oliver, University of Georgia (UGA) assistant professor and small fruits pathologist, wants to help producers be more efficient by researching ways to protect organic blueberries from diseases.

    According to UGA Extension, the U.S. Department of Agriculture National Institute of Food and Agriculture awarded a $2 million grant to the team of 15 scientists from 5 universities and the USDA Agricultural Research Study, including Oliver at UGA. While the group of researchers will focus on various fruits, including peaches, mangos and avocados, Oliver’s focus will be centered on blueberry production, the highest value fruit crop in Georgia. All will be seeing if essential oils can help suppress certain pathogens and pests.

    Oliver Comments

    Oliver

    “The essential oils organic grant is actually looking at a lot of different crops in the southeast and whether essential oils could have a role in a disease management program. There is data showing that essential oils can have antifungal properties and things like that if used in the laboratory or the greenhouse. But field studies are lacking,” Oliver said. “Since Georgia is one of the top producers of blueberries in the country and definitely in the Southeast, my role on this grant as the blueberry pathologist at UGA is to look at whether these products can be effective in the field and help our organic growers here that are growing blueberries.”

    Oliver will apply the essential oils in the field in a similar manner that producers apply other products. He’ll also be looking at diseases that affect blueberries after harvest. Will this treatment have a post-harvest impact if applied prior to harvest?

    “Cultural practices are really important in both conventional and organic, but in organic, they’re especially important. As far as chemical management in organic systems, you’re really limited on the types of products you can apply. No synthetic pesticides can be used. Typically, the synthetic pesticides are the ones that are going to be most effective. Usually, organic pesticides need to be applied more frequently to obtain control, if you can obtain control,” Oliver said. “We really need a lot more tools for our organic growers to help them manage diseases.”

    Grant Background

    The four-year project will support researchers who specialize in fruit crop management and physiology, plant pathology, entomology, post-harvest biology and organic production.

    In the research, scientists will:

    • Begin to test plant disease efficacy claims of essential oil products marketed for organic producers.
    • Evaluate organically certified plant essential oils on targeted pathogens such algal stem blotch, brown rot, scabs, gray mold and powdery mildew.
    • Determine the efficiency of essential oils on fruit shelf life through postharvest testing.
    • While arthropod pests are not the primary focus of this research, researchers also will test the efficacy of essential oils against insects including scales, thrips and mites.

    Organic food sales topped $50 billion in the United States in 2018. According to the Organic Trade Association, fruits, vegetables and specialty crops comprised of 36.3% of the total organic sales, which is up 5.6% from the previous year.

  • ADAI Offers Reimbursement Program for Organic Certified Growers

    Alabama producers who get certified organic between Oct. 1 and Dec. 15 are eligible for reimbursement from the Alabama Department of Agriculture and Industries.

    Farmers would be eligible to receive 50% of certification costs, up to $500. Those growers interested in recouping some of those expenses need to apply by Dec. 31.

    “That’s what makes it a little different than other cost-sharing programs is instead of them giving you the money beforehand, the farmer goes through basically the whole process; they have to go get certified and have people come look at their area and get certified organic, pay that fee. Then they reimburse you up to $500 on that fee,” said Jessie Boswell, Alabama Regional Extension agent, who specializes in commercial horticulture and farm and agribusiness management.

    Alabama Department of Agriculture and Industries

    According to the Alabama Department of Agriculture and Industries, application forms and additional details can be obtained by calling Johnny Blackmon with the ADAI at 334/240-7257 or by email at Johnny.Blackmon@agi.alabama.gov. Applicants may also apply at local USDA Farm Service Agency offices. To locate the office nearest you search https://offices.usda.gov/.

    “I do think (organic production has) become more popular. I know a lot of farmers that grow organic, they’re just not certified organic. It does cost so much to get certified organic. I think this program is just to make it easier to become certified. It’s kind of taken away that little bit of a barrier for the producer,” Boswell said.

    “They want people to become certified because that’s better branding for everyone and helps keep track of it. People have a little bit more faith, I believe, in certified organic, something that’s done through an organization that’s officially federally checked.”

  • Temporary and Permanent Pest Exclusion Systems for Vegetable Production

    Alabama Extension photo shows a pest exclusion system at work.

    According to Alabama Extension, the demand for organic crop production has experienced an upward trajectory in recent years. This increasing demand means there is a need for more farmers to produce organic vegetables at a reasonable cost, while also being environmentally sustainable.

    For these producers, insect pest management is one of the aspects where they must watch their costs and consider the environmental impact of the management strategies they implement. Luckily, there are several integrated pest management (IPM) practices that can help producers do both.

    Pest Exclusion Systems

    Vegetable production in the Southeast already comes with risks, as insect pests threaten crops from seedling to harvest. According to surveys of specialty crop producers, potential crop losses from pest feeding average 55%. Crop contamination from insect excrement and other factors can also affect farm profits. These are referred to as the yield-limiting and yield-reducing factors, which all depend on how the crop is managed. 

    IPM practices, such as pest exclusion, can help with these factors.

    Pest exclusion is based on the practice of physically blocking insects from reaching their host plants and is often overlooked by producers. Moths and large pests, such as stink bugs or leaffooted bugs, can be good targets of a well-designed pest exclusion system, especially on small acres with intensive vegetable production. There are two types of pest exclusion systems; temporary and permanent.

    • Temporary, or time-limited, systems are suitable for early season pest management to protect seedlings.
    • Permanent pest exclusion systems are a more intense use of pest exclusion fabric that provides season-long crop protection in high tunnels. This is called the high tunnel pest exclusion (HTPE) system, which is being intensively evaluated at 14 farm locations across Alabama.

    There are numerous benefits that a pest exclusion system can offer in an organic vegetable production.

    • Short-term or season-long pest reduction.
    • Variable cost depending on material and design of the system.
    • Minimal training for implementation.
    • Growth and season extension from use of insect barrier fabric.
    • Overall reduction in the use of biorational insecticides with increase in natural enemy activity.

    It’s important to note that not all crops and varieties may lend themselves to pest exclusion systems. Contact the Alabama Extension commercial horticulture regional agent in your area before making a major purchase decision. It is recommended that pest exclusion systems be integrated with the use of insect monitoring systems or traps and natural enemies for practicing true IPM.