ROLE OF MULCHES AND PLANTING TIME IN ENHANCING PRODUCTION OF CLONALLY OR SEED PROPAGATED INDUSTRIAL HEMP IN TENNESSEE

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: ACTIVE
• Funding Source: OTHER GRANTS
• Reporting Frequency: Annual
• Accession No.: 1030306
• Grant No.: 2023-38821-40122
• Cumulative Award Amt.: $499,598.00
• Proposal No.: 2022-09558
• Project Start Date: May 1, 2023
• Project End Date: Apr 30, 2026
• Grant Year: 2023
• Program Code: [EQ]- Research Project

Recipient Organization
TENNESSEE STATE UNIVERSITY
3500 JOHN A. MERRITT BLVD
NASHVILLE,TN 37209

Performing Department
(N/A)

Non Technical Summary
Industrial hemp (Cannabis sativa L.) is one of the earliest domesticated crops and has been cultivated for centuries all over the world. However, given many years of Federal legislation outlawing the genus Cannabis L, industrial hemp is considered a new crop for the United States. The 2014 Agricultural Act provided opportunities for university institutions, like 1890 Institutions such as Tennessee State University (TSU), to be at the forefront of hemp research including production, marketing, and extension. These reforms caused resurgence in hemp production in the U.S. in general, with Tennessee being among the leading states in adopting industrial hemp as a specialty crop. More than 36 states have passed legislation in support of hemp and the number continues to grow. However, the initial enthusiasm for and adoption of the "new crop" by growers is dissipating as the legislative, production, and market realities become better understood. There is need to develop an integrated approach on hemp production to help growers realize the profitability of this new crop.Previous definition of industrial hemp distinguished it from marijuana depending on its concentration of the psychoactive molecule delta-9 tetrahydrocannabinol (THC), which is primarily formed in the inflorescence and responsible for the "high" obtained from using marijuana. According to the 2014 Farm Bill, a delta-9 THC concentration greater than 0.3% identified a Cannabis plant as marijuana, while a concentration less than 0.3% identified the plant as industrial hemp, even though both plants are visually indistinguishable from each other. Federal definition of industrial hemp has recently changed to identify industrial hemp as having a maximum of 0.3% total THC, which includes both Delta-9 THC and its precursor, tetrahydrocannabinolic acid (THCA). Many producers faced substantial challenges complying with the previous 0.3% delta-9 THC limit and are likely to face even greater hurdles meeting the new compliance limit.Apart from compliance with changing regulations governing its production, industrial hemp producers face a host of other challenges including management of diseases and pests (including weeds), choice of varieties suited to their locales, skills on how hemp best fits in rotation with other crops, information on how cultivars and timing of planting can affect growing success, post-harvest handling, and how best to identify and take advantage of prevailing markets. This project will focus on two key areas of interest: compliance with THC regulations and the production systems to reduce problems in disease, insects and weeds, which are some of the greatest problems in hemp production. The project results are expected to influence a much broader scope of hemp agronomic management. This project targets small, medium, and historically underserved farmers in the state of Tennessee, the majority of whom are significantly affected by various regulatory changes and lack of clarity on industrial hemp production and market uncertainties. The project fits well within the primary goals of Tennessee State University, a historically black land grant institution, that provides quality research, technical support, and training assistance to small, medium size farms and rural communities across the State of Tennessee for economic and environmental sustainability. Given that industrial hemp is an emerging and unique high-value economic specialty crop, this project is an excellent fit for the University and College of Agriculture's medium- and long-term goals in promoting regional, national, and international agricultural development, and will tremendously strengthen TSU's research contribution to science. Results will be disseminated through various extension outreach channels including print and electronic media, field days, workshops, and professional meetings.

Animal Health Component

80%

Research Effort Categories

Basic

10%

Applied

80%

Developmental

10%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
202	0430	3100	10%
203	0420	3100	10%
205	2499	3100	40%
216	1730	3100	20%
601	1730	3100	20%

Knowledge Area
601 - Economics of Agricultural Production and Farm Management; 203 - Plant Biological Efficiency and Abiotic Stresses Affecting Plants; 205 - Plant Management Systems; 216 - Integrated Pest Management Systems; 202 - Plant Genetic Resources;

Subject Of Investigation
0420 - Weather; 0430 - Climate; 1730 - Hemp; 2499 - Plant research, general;

Field Of Science
3100 - Management;

Keywords

industrial hemp

cannabinoids

cultural practices

mulches

organic

propagation material

Goals / Objectives
The overall goal of this project is to establish best management agronomic practices for economically profitable production of floral industrial hemp that includes higher cannabinoid yields within the delta-9 tetrahydrocannabinol (THC) compliance limits, better pest (including weeds) and disease control strategies, lower input costs, and relatively higher farm incomes among the small, medium, and historically underserved farmers in the state of Tennessee. The majority of these farmers have been significantly affected by various regulatory changes and lack of clarity on industrial hemp production and market uncertainties. The project fits well within the primary goals of Tennessee State University (TSU), a historically black land grant institution, that provides quality research, technical support, and training assistance to small, medium size farms and rural communities across the State of Tennessee for economic and environmental sustainability. Given that industrial hemp is an emerging and unique high-value economic specialty crop, this project is an excellent fit for the University and College of Agriculture's medium- and long-term goals in promoting regional, national, and international agricultural development, and will tremendously strengthen TSU's capacity to proactively contribute to science.Specific objectives of the project include the following:To assess the effects of timing of planting combined with black plastic and straw mulch on hemp started as clones or seed on southern blight and other disease prevalence, insect pests, weeds, cannabinoid production and THC complianceScreening of floral industrial hemp cultivars under organic or conventional management practices to assess the impacts of cultivar by cropping system management on diseases, insect pests, weeds, cannabinoid production and THC complianceEvaluate the potential of no-till transplanting of floral industrial hemp in cereal rye, hairy vetch, or a combination of the two cover crops terminated by a roller crimper, on pests and diseases prevalence, weeds, cannabinoid production and THC complianceEconomic analysis of the different production methods to determine the cost-benefit analysis of the different production methods.

Project Methods
Objective 1: Planting time, mulches, propagation materials, and fungicide effectsA field experiment will be established in 2023 and repeated in 2024 to examine the agronomic, climatic, and economic impacts on the southern blight severity, other common hemp diseases, insect pests, CBD production and THC compliance. The experiment will be established at the TSU Research farm in a field with known history of southern blight prevalence. Feminized seeds for Fukuoka hemp cultivar (selected due to its known susceptibility to southern blight) will be started in a greenhouse at TSU. Clones of same cultivar will be obtained from Mr. Seth Fuller, a collaborating floral hemp grower. Eight plants (4 clones or 4 seed starts) will be transplanted into each plot, covered in plastic, straw mulch, or no-mulch control. Half the plots will be treated with Defguard fungicide, the only fungicide approved for use on hemp. Each plot will be fertilized by well cured compost applied at recommended rate of 168 kg N ha-1. Seedlings will be transplanted every three weeks from May 1 to June 30 in each year of study. The experiment will be a randomized complete block factorial design and will consist of one variety by two propagation materials by two fungicide treatments [+ (treated) or - (non-treated)] by 3 mulches by three dates by 4 replicates for a total of 144 sub-plots. However, since the fungicide treatment will be a split-plot factor, actual number of plots will be 72 whole plots.In-row spacing between plants will be 1.5 meters and plot sizes will be 1.5 m x 12 m. Sampling will be done from the middle two plants of either propagation material (clones or seed) of each plot. Weeds within the plots will be managed by a combination of mechanical and manual weeding. Soil samples will be collected before research establishment and tested for primary minerals and fertility parameters.Numerous agronomic factors including disease severity, pest incidence, chlorophyl index, weed density and biomass, plant heights, and bud and flower formation will be monitored. Samples will be collected at the same time and date each year. Established protocols will be employed for weed sampling. Soil temperature and moisture will also be monitored using soil temperature and moisture sensors, on a weekly basis to detect any correlations with the different mulches, disease severity, THC and other cannabinoid profiles.Overseen by co-PI Amarasekare, insect pests will be sampled on a weekly basis to collect a wide variety of species and functional groups using multiple collection approaches. The Fruit, Vegetable, and Field Crop Entomology Laboratory at TSU will be utilized for the laboratory component of this project, field sample analysis, and technician training. We will use the insect taxonomic resources provided by the USDA-SEL in Beltsville, Maryland, and various universities for pests and other natural enemy identification and verification of identity. We will use various identification techniques to identify the collected arthropod samples to evaluate their abundance within the growing season during the experimental years.Plant disease assessment will be overseen by co-PI Mmbaga. Plots will also be visually inspected at the same time and scored for disease incidence and severity. Samples will be collected from symptomatic plants for further lab analyses to confirm their identity using morphological and DNA-Based techniques. Temperature and moisture sensors will be installed below the mulch to determine the effect of different mulch typesPhytochemical Analysis will be over-seen by co-PI Wu. The hemp CBD profile, total terpenoids and total flavonoids will be analyzed. CBD will be extracted using ethanol before subjecting for further analysis. A HPLC system will be used for analysis of 11 cannabinoids. Detailed analytical procedures are separately available.The effect of cropping management practices on dependent variables will be assessed using mixed model ANOVA. Cropping management treatments will be treated as a fixed effect and year and block (replications) as random effects for most treatments. However, year will be treated as a fixed effect in analyses to determine the variation in cannabinoid yield at different years (Schlegel et al., 2016).Objective 2: Variety screening between organic and conventional management practices.Established at the TSU research farm, the experimental design for this research will be randomized complete block with 4 floral cultivars. Four cultivars of floral hemp (Cherry, Fukuoka, Rushmore, and Virginia) will be randomly assigned to raised beds measuring 1.5 by 12 meters covered with black plastic, straw or no mulch. Half of the plots will be managed under recommended conventional management practices including use of any approved herbicides and pesticides by the start of the experiment, and mineral nitrogen applied at the typical rate of 168 kg N ha-1. Plots under organic management will be fertilized by well cured compost described in Objective 1 above. Propagation materials will be obtained from the same sources as Objective 1. Eight plants (four clones and four seed starts) will be transplanted into each plot, covered in plastic, straw, or no-mulch control. However, only the conventional plots will be treated with an approved fungicide. Agronomic, insect pests, weeds, disease pathogens, phytochemicals and statistical analyses will all be conducted as described in Objective 1.Objective 3: No-till transplanting floral industrial hemp in cover crops terminated by a roller crimperCover crops for this Objective will be started in the fall of 2023 and terminated to transplant hemp in spring of 2024 and repeated in the 2024-2025 seasonal cycle. Seedbed preparation, where applicable, will consist of primary moldboard tillage passes followed by disking and packing prior to planting. Each cover crop or cover crop combination will be planted in long rows/strips measuring 1.5 by 60 meters. There will be an allowance for three additional strips with the same dimensions for tilled treatments with three mulch treatments including plastic mulch, straw and no-mulch control. Location of each strip in the field will be random. Hairy vetch and cereal rye will be planted in late August to late September 2023, at 20.8 kg ha-1 and 188 kg ha-1 respectively. A mix of the two cover crops will be planted at half the rate of either cover crop. Cover crops will be terminated by rolling-crimping before transplanting hemp in May 2024 and 2025. Eight hemp propagation starts (4 clones and 4 seedlings) will be transplanted into raised plots replicated four times along each cover crop mulch, plastic mulch, straw mulch, or no-mulch strips. All agronomic, insect pests, weeds, disease pathogens, phytochemicals and statistical analyses will be conducted as described in Objective 1.Objective 4: Economic Analysis of different production methods.We will perform a comprehensive economic analysis to determine the potential cost-effectiveness of CBD hemp production under the various agronomic practices described above. We will compare the profitability of hemp production with other farm enterprises. Existing supply chains for hemp will be assessed to determine marketing opportunities available for existing and emerging growers in Tennessee. In-depth interviews with hemp producers will be undertaken to understand the economic opportunities and challenges involved in growing hemp. Interviews will also be conducted with current and potential processors, manufacturers and other retailers of hemp products to determine gaps in marketing prospects for hemp growers and understand the potential of current and future opportunities in the hemp marketplace. Data obtained from grower and buyer interviews will be combined and analyzed to determine the marketing gaps between the two groups.

Progress 05/01/24 to 04/30/25

Outputs
Target Audience:This project targetsfarmers in the state of Tennessee who were significantly affected by various regulatory changes and lack of clarity on industrial hemp production and market uncertainties.Theproject fits well within the primary goals of Tennessee State University, that provides quality research, technical support, and training assistance to small, medium size farms and rural communities across the State of Tennessee for economic and environmental sustainability. Given that industrial hemp is an emerging and unique high-value economic specialty crop, this project is an excellent fit for the University and College of Agriculture's medium- and long-term goals in promoting regional, national, and international agricultural development, and will tremendously strengthen TSU's research contribution to science. Results will be disseminated through various extension outreach channels including print and electronic media, field days, workshops, and professional meetings. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Four graduate students and 20 undergraduate students have participated in the project through research, demonstrations, and field day activities: Anand Kumar is currently pursuing a PhD in Agricultural Sciences with a concentration in Plant Science. His dissertation focuses on the organic (non-certified) and conventional management of four floral industrial hemp varieties under different mulch treatments, including plastic, straw, and no-mulch controls. He is scheduled to graduate in August 2025. Sai Suvidh Maddela completed his MS in Agricultural Sciences with a concentration in Plant Sciences. His thesis research focused on the role of mulches, planting time, and a commercial biological fungicide in managing southern blight in floral industrial hemp in Tennessee. He graduated in May 2024. Rodgers Kabenomuhangi began his MS in Agricultural Sciences with a concentration in Plant Science in spring 2024. He is leading the continuation of Objective 3 of this research, evaluating the potential of no-till transplanting of floral hemp into cover crops terminated by a roller crimper or herbicides, with assessments on pest and disease prevalence, weed management, cannabinoid production, and THC compliance. Undergraduate involvement included: Four undergraduate students who participated in the project through a summer internship work-aid program in 2023 and 2024. An additional 16 undergraduate students from various disciplines participated in targeted practical activities as part of the AGSC 3250 Weed Science course (taught by PD Omondi) during fall 2023 and 2024. These activities included semester-long weed management plans for their selected sites, weed seedbank analysis of treatments within the hemp research plots, weed identification, and hemp cloning exercises. For fall 2025, six undergraduate students are enrolled in the same course, with four of them also participating in the summer internship work-aid program in spring and summer 2025. How have the results been disseminated to communities of interest?Farmer Workshops The Project Director, Dr. Omondi, and PhD student Anand Kumar delivered presentations at two in-person field workshops in Western Tennessee under the TSU Outreach Program and New Farmer Academy for farmers, ranchers, and returning veterans, held on May 12 and June 23, 2022, respectively. They also presented at the USDA Transitional to Organic Partnership Program (TOPP) workshop on June 12, 2024. These workshops covered essential agronomic management practices for industrial hemp production, as well as cover-crop-based reduced tillage strategies applicable to broader crop production systems. Additional workshop topics presented by multidisciplinary experts included small fruit tree production, tomato and pepper cultivation, organic agriculture, poultry and livestock management, risk management and business planning, and integrated pest management. Collectively, these workshops reached a total of 80 growers. In-Service Training Curricula and schedules for in-service training events across all three regions of Tennessee have been uploaded to Super 2 [Approved In-Service Training Curriculum and Schedule: My Facilitated Events - Super 2, titled Cover Cropping and Crop Rotation Strategies for Reducing Farm Inputs and Tillage (https://super.tennessee.edu/TrainingRegistration/Home/MyFacilitatedEvents)]. The inaugural in-service training, jointly facilitated by Dr. Philip Hinson and Dr. Krishna Bhandari for the Middle Tennessee region, was successfully conducted on March 10, 2025, and attracted 13 Extension Agents. Subsequent training sessions are scheduled for May 29 and September 26, 2025, in the Eastern Region, and June 6, 2026, in the Western Region. Small Farm Expo The 19th and 20th annual one-day Small Farm Expo events were held at the TSU Nashville AREC on September 7, 2023, and September 5, 2024, respectively. These expos drew over 600 participants combined. Showcasing research and demonstrations from several universities, Federal and State agencies, and small farm grant programs, the research plot tours featured Industrial Hemp Research and Demonstration (led by Dr. Omondi), Flowering Plants for Insect Pest Management (Dr. Kaushalya Amarasekare), New Grain Legume and Pseudocereal Crops for Tennessee (Dr. Matthew Blair), Humic Acid for Organic Pepper Production (Dr. Dilip Nandwani), Alternative and Niche Fruits and Vegetable Research (Dr. Arvazena Clardy), Container Production of Food Crops for Urban/Peri-urban Residents (Dr. Dharma Pitchay), and Beginning Backyard Poultry and Basics to Nutrition, Disease, and Biosecurity (Dr. Pramir Maharjan). Stakeholder Involvement and Collaborators Extensive outreach efforts to various producer and commodity groups, particularly those impacted by the COVID-19 pandemic and the downturn in the CBD hemp market, are planned for 2025. The aim is to assess growers' needs and provide targeted interventions for Tennessee farmers who left agriculture during the market slump. This initiative seeks to encourage these growers to either return to farming or repurpose their land for profitable use. Stakeholder engagement has been integral to the development of the project's objectives and outcomes. Small and medium-sized farmers, beginning farmers, processors, and regulators have been and will continue to be involved in the project's research and extension activities. TSU remains committed to collaboration with agencies that share similar goals, including the Tennessee Department of Agriculture (TDA), Natural Resources Conservation Service (NRCS), Farm Service Agency (FSA), Hemp Alliance of Tennessee (HAT), Agricenter International, Veteran Coalition, Farm Bureau of Tennessee, and the University of Tennessee. TSU's network includes over 2,000 farmers and processors who have participated in past hemp events and continue to support the project's activities. These partners include, but are not limited to, small organizations such as Durhum Farms, Tennessee Grown, Eufloria, Green Door Gourmet, and Tennessee Homegrown. What do you plan to do during the next reporting period to accomplish the goals?During the next reporting period, results from Objective 1 and Objective 2 will be developed into at least three manuscripts for submission to peer-reviewed journals. Additionally, three fact sheets highlighting the different practices evaluated in this research have been drafted and will be submitted for publication through the TSU Cooperative Extension program. Objective 3 will be expanded in a comprehensive field experiment to further evaluate the potential of no-till transplanting of floral hemp into cover crop-based reduced tillage systems. This expanded trial will incorporate two propagation methods (seedlings and clones) crossed with four mulch treatments (plastic mulch, straw mulch, rolled cover crop mulch, and no-mulch control) and three cropping systems (non-chemical till, conventional till, and conventional no-till), replicated four times. This factorial design will critically assess the interaction effects of these variables on pest and disease prevalence, weed pressure, and productivity of floral hemp under both organic and conventional systems. Cereal rye cover crop for this study was established at the end of October 2024. A separate study will be initiated to investigate the combined effects of cultural practices, depth of transplanting, and biological control agents in managing southern blight and enhancing floral hemp productivity. This study will assess the interactions of two propagation materials (seedlings and clones) by four mulch treatments (white plastic, black plastic, straw mulch, and no-mulch control) by two fungicide treatments (including Defguard and a no-treatment control), and two planting depths, replicated four times. The rationale for this study includes: Root System and Disease Exposure: Preliminary data suggest that seedling-propagated hemp, with its extensive root system including taproots, may present a larger surface area for pathogen exposure than clones. However, extensive root system that includes a tap root could also provide a means for the plants to escape the worst effects of southern blight. Simultaneous greenhouse and field trials will assess the impact of transplanting depth on southern blight infection using clonally and seedling-propagated hemp in potting mix inoculated with Sclerotium rolfsii. These trials aim to determine whether minimizing soil contact with the crown or base of the stem reduces pathogen exposure and prolongs plant survival. Evaluation of White Plastic Mulch: Building on previous findings that straw mulch reduces soil temperature and mitigates southern blight while black plastic mulch increases temperature and disease prevalence, this objective will test whether white plastic mulch (white on the surface, black beneath) can provide similar benefits to straw, such as reflecting UV light and lowering soil temperatures, but without the challenges of heavy straw bales and potential introduction of weed seeds. Testing Biological Control Agents: Biological control agents derived from various plant (including hemp) endophytes will be compared to the commercial biocontrol agent Defguard (used in Objective 2) to assess their relative effectiveness in reducing southern blight and other soilborne diseases, while also evaluating their impact on floral hemp productivity and THC compliance. These planned activities aim to deepen understanding of the interplay between cultural practices, biocontrol measures, and environmental management strategies to improve the resilience and profitability of floral hemp production systems.

Impacts
What was accomplished under these goals? Objective 1: A replicated field study was initiated at the TSU Agricultural Experiment Centre in Nashville in 2022 to investigate the effects of various cultural practices, specifically mulches, planting times, and a commercial biological fungicide (Bacillus amyloliquefaciens), on southern blight management and floral hemp productivity. This study continued through 2024, incorporating lessons learned from prior years. Treatments applied include, black plastic mulch, straw/hay mulch, two planting times (early and late), and the fungicide (B. amyloliquefaciens). The selected research site has a known history of southern blight incidence, providing a relevant context for the trials. Initial phases (2022-2023) focused on seedling-based propagation due to sourcing challenges with clones. However, this limitation was addressed in 2024, enabling inclusion of clone-based plant material. The upcoming 2025 field trials will provide comparative data on disease management and productivity outcomes between seedlings and clones. Preliminary results revealed that straw mulch reduced soil temperature by about 6%, enhanced chlorophyll content by 30%, increased plant height and plant biomass by 20% and 25% respectively and reduced disease severity by 53% and 34% in the first and second time of planting, respectively. Results also revealed that straw mulch's reduction of weed density by (90.73%) was comparable to weed reduction by black plastic (97.26%). These results have been published in a 2024 MS thesis manuscript, by Sai Suvidh Maddela, and are being processed into an Agronomy Journal manuscript. However, the use of straw or hay mulch posed challenges due to the potential introduction of new weed species, which likely originate from the mulch material itself. Recognizing this risk, the project will expand in 2025 to evaluate the efficacy of white plastic mulch. White plastic is anticipated to reflect ultraviolet light and reduce soil temperatures, offering a dual benefit for disease and weed management without introducing external weed seeds. Additionally, with the inclusion of clones in 2024, the study is poised to generate robust data in 2025 comparing propagation methods (seedlings vs. clones) in terms of disease incidence, plant vigor, and floral yield. Objective 2:A replicated experiment conducted in 2023 and 2024 at the TSU AREC facility assessed the effects of floral hemp cultivar selection and cropping system management on disease incidence, insect pests, weed pressure, cannabinoid production, and THC compliance. Four cultivars; Rushmore, Cherry, Fukuoka, and Virginia, were evaluated under three mulch treatments (black plastic, straw, and no mulch) and two production systems: conventional (CBS) and non-certified organic (NCS). Propagation methods included both seedlings and clones. The results highlighted that mulch use significantly influenced biomass production, with black plastic mulch increasing yield by 41.7% and straw mulch by 16.7% over no-mulch control in 2023. In 2024, overall yields declined due to wetter and slightly warmer conditions, but CBS plots maintained 17% higher biomass compared to NCS. Fukuoka exhibited rapid root initiation and vigorous growth but was prone to higher disease severity, whereas Virginia consistently showed lower disease levels but produced male plants when propagated by seed. Cannabinoid profiles and THC concentrations did not significantly differ among cultivars, production systems, or mulch treatments across both years, and harvest timing did not alter compliance levels. Weed control was effectively managed by both plastic and straw mulches, though straw mulch raised concerns about introducing new weed species. Notably, the interaction between production system, mulch type, and cultivar significantly influenced disease severity in 2024, indicating complex environmental and management effects. The study underscores the importance of selecting appropriate cultivars and management strategies for optimizing yield, disease control, and regulatory compliance in floral hemp production systems. These findings, which have been published in the dissertation of Dr. Anand Kumar (expected to graduate in August 2025), provide a comprehensive evaluation of cultivar and management interactions under Tennessee conditions and inform future directions, including alternative mulching strategies and refined harvesting and propagation approaches. Objective 3:In 2024, a preliminary experiment was conducted at the TSU AREC in Nashville to investigate the potential of no-till transplanting of floral industrial hemp into cereal rye cover crops terminated by a roller crimper. The study evaluated impacts on pest and disease prevalence, weed management, cannabinoid production, and THC compliance. 'Cherry' feminized CBD seedlings and clones were transplanted into plots treated with rolled/crimped rye mulch, black plastic, straw mulch, or left as no-mulch controls, managed under both conventional and non-certified organic systems. Preliminary observations showed that straw mulch significantly reduced southern blight severity. Seedlings exhibited greater plant height and biomass but were more susceptible to disease, likely due to their extensive root systems increasing contact with soilborne pathogens. Building on this work, Rodgers Kabenomuhangi's MS thesis research (expected completion August 2025) expands the study's scope by incorporating additional treatments and refined methods. His research evaluates the combined effects of five mulch and tillage treatments, including rolled rye, plastic, straw, no-till no mulch, and tilled no mulch, under conventional and non-chemical systems, while also comparing clones and seedlings. Early findings suggest that cover crop-based reduced tillage systems, particularly those integrating rolled rye or rye-vetch mixes, can enhance soil health, suppress weeds, and mitigate pest and disease pressures in floral hemp. These results contribute to developing best practices for floral hemp production that support THC compliance, economic sustainability, and environmentally sound cultivation, particularly for small and medium-scale growers in Tennessee. Objective 4: A preliminary enterprise budget analysis of the floral hemp cultivars evaluated in this research revealed that the 'Fukuoka' variety, grown under plastic mulch, demonstrated promising economic potential. At an average market price of $29.20 per pound (USDA 2022 Hemp Report), the break-even yield for 'Fukuoka' was calculated at approximately 795 pounds per acre. However, projected yields from this study estimate about 1,755 pounds per acre, substantially exceeding the break-even threshold and suggesting potential for significant profitability, especially when plastic mulch is used to enhance plant performance. Despite these promising figures, the broader context of industrial hemp production in Tennessee and the U.S. highlights the volatility of this emerging market. Following hemp's removal from Schedule A under the 2018 Farm Bill, speculative investment surged, saturating the market and overwhelming limited processing and distribution infrastructure. Many growers suffered financial losses, leading to bankruptcies, closures, and a steep decline in licensed hemp acreage in Tennessee--from about 15,722 acres in 2020 to fewer than 200 acres currently. This research, including a detailed economic analysis to be presented in Dr. Anand Kumar's final dissertation (anticipated August 2025), aims to equip growers with realistic expectations and best practices to optimize profitability and sustainability, while avoiding costly missteps in a rapidly evolving market.

Publications

• Type: Conference Papers and Presentations Status: Accepted Year Published: 2025 Citation: Rodgers Kabenomuhangi and Omondi E.C. Cover crop based reduced tillage management in floral hemp cultivation. The 47th Annual Tennessee State University-Wide Research Symposium, March 24-28, 2025
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2024 Citation: Mustapha Olawuni, Omondi E.C., Maddela S.S., and Mmbaga M.T. "Management of southern blight in floral hemp and tomato by biological and cultural application." In ASA, CSSA, SSSA International Annual Meeting. ASA-CSSA-SSSA, Nov 10-13, 2024
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2024 Citation: Omondi E.C. 2024. TSU industrial hemp program. The 21st Association of 1890 Research Directors Symposium, Gaylord Opryland Hotel, Nashville, TN, April 6  9, 2024
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2024 Citation: Anand Kumar and Omondi E.C. 2024. Best Agronomic Practices for cannabinoids production in industrial hemp. The 21st Association of 1890 Research Directors Symposium, Gaylord Opryland Hotel, Nashville, TN, April 6  9, 2024
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2024 Citation: Mustapha ?l�wuni (PhD student), M. Mmbaga, E.C. Omondi, D. Demissie and R. Hall. 2024. Screening of endophytes for southern blight disease management and plant growth improvements in hemp production. The 21st Association of 1890 Research Directors Symposium, Gaylord Opryland Hotel, Nashville, TN, April 6  9, 2024
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2024 Citation: Mustapha ?l�wuni, M. Mmbaga, E.C. Omondi, D. Demissie and R. Hall. 2024. Screening of endophytes for southern blight disease management and plant growth improvements in hemp production [Abstract]. 46th Annual University-Wide Research Symposium March 25, 2024 - March 29, 2024, Tennessee State University, Nashville TN

Progress 05/01/23 to 04/30/24

Outputs
Target Audience:This project targets small, medium, and historically underserved farmers in the state of Tennessee, the majority of whom are significantly affected by various regulatory changes and lack of clarity on industrial hemp production and market uncertainties. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Four graduate students and 20 undergraduate students participated in the project through research, demonstration, and field days: Anand Kumar is currently enrolled in PhD in Agricultural Sciences with a concentration in Plant Science. His dissertation research focus is on organic (non-certified) and conventional management of four floral industrial hemp varieties under different mulches including plastic, straw and no-mulch control. He is scheduled to graduate in May 2025 Sai Suvidh Maddela was a MS in Agricultural Sciences with a concentration in Plant Sciences. His thesis research work focused on the role of mulches, planting time, and a commercial biological fungicide in managing southern blight in floral industrial hemp in Tennessee. He graduated in December 2023. Mustapha Olawuni, PhD in Agricultural Sciences with a concentration in Plant Science started his studies in spring 2024. His dissertation research is focusing on the role of biocontrol agents cultured from endophytes in the lab, combined with propagation material (clone or seedling) and white plastic compared to black plastic, straw mulch, and no-mulch control in managing southern blight and enhancing productivity of industrial hemp. Rodgers Kabenomuhangi, MS in Agricultural Sciences with a concentration in Plant Science also started his studies in spring 2024 and will be responsible for continuation of Objective 3 of this research, evaluating the potential of no-till transplanting of floral hemp in cover crops terminated by a roller crimper, or terminated by herbicides on pests and diseases prevalence, weeds, cannabinoid production and THC compliance. Four undergraduate students participated in the project as part of their summer internship work-aid program in 2023 and 2024. A total of 16 undergraduate students from different disciplines taking the AGSC 3250 Weed Science course (taught by PD Omondi) participated in various targeted practical activities designed for them within the project in fall 2023 and 2024, including elaborate semester-long weed management plans for their sites of choice, weed seedbank analysis of various treatments within the hemp research, weed identification and hemp cloning practical activities. How have the results been disseminated to communities of interest?Farmer Workshops The Project Director, Dr. Omondi, and PhD Student Anand Kumar made presentations to two in-person field workshops in Western Tennessee under the TSU Outreach Program and New Farmer Academy for farmers, ranchers and returning veterans, on May 12, and June 23, 2022, respectively and to the USDA Transitional to Organic Partnership Program (TOPP) on June 12, 2024. The workshops covered the basic agronomic management practices for industrial hemp production and cover-crop based reduced tillage strategies in crop production in general. Other topics presented during the workshops by other multidisciplinary experts included small fruit tree production, tomato and pepper production, organic agriculture, poultry production, goat and cow management, risk management and business planning, and integrated pest management. A total of 80 growers participated in the three workshops. Small Farm Expo The 19th and 20th annual one-day Small Farm Expo event was conducted at the TSU Nashville AREC on September 7 and 5, 2023 and 2024 respectively. The EXPO attracted a total of more than 600 participants in the two years combined. Featuring several universities, Federal and State agencies, and small farm grants programs, the research plots tours included Industrial Hemp Research and Demonstration (led by PD Omondi), Flowering Plants for Insect Pest Management by Dr. Kaushalya Amarasekare, New Grain Legume and Pseudocereal Crops for Tennessee by Dr. Matthew Blair, Humic Acid for Organic Pepper Production by Dr. Dilip Nandwani, Alternative and Niche Fruits and Vegetable Research by Dr. Arvazena Clardy, Container Production of Food Crops for Urban/Peri-urban Residents by Dr. Dharma Pitchay, and Beginning Backyard Poultry and Basics to Nutrition, and Disease and Biosecurity by Dr. Pramir Maharjan. Extensive and intensive outreach to various producer and commodity groups, especially those adversely affected by the COVID 19 pandemic and the slump in CBD hemp market are planned for 2025. The objective of this outreach is to determine specific producer/grower needs and prescribe intervention strategies. This outreach is informed by the recognition that a significant proportion of historically underserved Tennessee growers abandoned their farms to seek other means of livelihoods in urban settings. The goal of this outreach project is to encourage as many of them as possible to either return to their farms or put them to some profitable use. Stakeholder Involvement and Collaborators Stakeholders' engagement has guided the development of the proposed objectives and outcomes. Small, and medium-sized farmers, beginning farmers, processors, and regulators will be involved in the research and extension activities throughout the duration of the proposed project. An advisory board is being created to help in the coordination and dissemination of scientific information to stakeholders and their professional network. TSU will continue to closely work with other agencies that have similar goals, including Tennessee Department of Agriculture (TDA), Natural Resources Conservation Services (NRCS), Farm Service Agency (FSA), Hemp Alliance of Tennessee (HAT), Agricenter International, Veteran Coalition, Farm Bureau of Tennessee, University of Tennessee, and Minority Hemp Association. TSU has more than 2000 farmers and processors in networks that participated in past events on hemp and that support our work. These include but are not limited small organizations like Durhum Farms, Tennessee Grown, Eufloria, Green Door Gourment, and Tennessee Homegrown. What do you plan to do during the next reporting period to accomplish the goals?Results from Objective 1 and 2 above will be developed into at least three manuscripts and submitted for peer reviewed publication. Three fact sheets on the different practices involved in this research have been developed and will be submitted for publication under the TSU Cooperative Extension program. Objective 3 above will be repeated in an expanded experiment that will include two propagation materials (clones or seedlings) by 4 mulch treatments (plastic, straw, rolled cover crop, and control) by 3 cropping systems (organic till, conventional till and conventional no-till) replicated four times to critically evaluate different cover-crop based reduced tillage strategies for growing floral hemp under organic and conventional systems, and quantify their interaction effects on pests, diseases, weeds, and productivity of industrial hemp. This expanded research will begin with cover crop establishment by the end of October 2024. A separate study will also be established to explore the role of biocontrol agents compared to other cultural practices in managing southern blight and enhancing productivity of industrial hemp. The research will assess the combined effects of 2 propagation material (clone or seedling) by 4 mulch treatments (white plastic, black plastic, straw mulch, and no-mulch control) by 4 fungicide treatments (Defguard, 2 biocontrol agents/endophytes and no treatment control) replicated 4 times. This study will be based on the following rationale: Research results reported above suggesting that extensive rooting system of seedlings that include tap roots may increase the surface area of exposure to soil borne pathogens compared to the less extensive roots of clones. Separate greenhouse trials will also be conducted simultaneously to elucidate the impact of different depths of transplanting clonally or seedling propagated industrial in potting mix inoculated with sclerotia cultured in the lab, in resisting southern blight infestation. Southern blight typically kills infected plants by girdling the crown of the stem cutting off food supply to roots, resulting in physiological draught to the plant (resulting in rapid wilting and death). The greenhouse trials will examine if minimizing exposure of the crown/base of the stem to the soil might reduce exposure of the stem to pathogens and prolong the life of the plant long enough to withstand the infection. Greenhouse results will complement field trials comparing clonal and seedling propagation of hemp. Use of white plastic in comparison with black plastic and straw mulch is informed by our preliminary results revealing that straw mulch reduces soil temperature and mitigates southern blight, and black plastic does the opposite. This objective will examine if white plastic (white on the surface but black beneath) might work just as well as straw (by reflecting UV light and reducing soil temperature), but without the challenges associated with straw or hay bales used in previous trials, including heavy and cumbersome hay bales that must be rolled on plots manually and weed seeds in many of them that can defeat their purpose for weed conntrol. Six biological control agents cultured from various plant (including hemp) endophytes in the lab will be compared with a commercial biocontrol agent (Defguard) used in our preliminary studies (under Objective 2) in quantifying their effectiveness in reducing southern blight and other soil borne diseases and enhancing floral hemp productivity and THC compliance.

Impacts
What was accomplished under these goals? Objective 1: A replicated study was conducted at the TSU Agricultural Experiment Centre in Nashville in 2022 and repeated in 2023 to determine the effect of mulches and planting time on managing southern blight and enhancing industrial floral hemp production. Treatments included black plastic mulch, straw mulch, planting time, and a commercial biological fungicide. The research site used for the study is reputed to have southern blight disease prevalence. It was difficult to obtain clones as propagules for the study, hence data analysis was based on seedlings. Our results revealed that straw mulch reduced soil temperature by about 6%, enhanced chlorophyll content by 30%, increased plant height and plant biomass by 20% and 25% respectively and reduced disease severity by 53% and 34% in the first and second time of planting,respectively. Results also revealed that straw mulch's reduction of weed density by (90.73%) was comparable to weed reduction by black plastic (97.26%) in 2022. Similar results were observed in 2023. While results revealed that mulching did not have a significant effect on cannabinoid concentration, planting early increased cannabinoid concentration although planting later reduced THC concentration demonstrating the delicate balance between CBD production and THC compliance. Objective 2: A replicated experiment was established in 2023 and repeated in 2024 at the TSU AREC to assess the impacts of cultivar by cropping system on diseases, insect pests, weeds, cannabinoid production and THC compliance. Four floral hemp cultivars (Rushmore, Cherry, Fukuoka, Virginia) were randomly assigned to plots covered with black plastic, straw mulch or no-mulch control. Half of the plots were managed under recommended conventional practices with the other half managed under non-certified organic practices. Seedlings and clones started in a greenhouse on site were transplanted into plots at the same time. Data collected were similar to those described under Objective 1. Preliminary results revealed that there were no significant differences between organic and conventional treatments for most of the response variables analyzed in 2023. However, conventionally managed hemp tended to have higher CBD while organically managed hemp tended to have lower THC concentration in 2003 in at least two varieties. THC concentration in all plots was lower than the 0.3% compliance limit. Results from 2024 are still being analyzed and it would be interesting to see if the same trends are observed. Most floral hemp producers prefer clones over seedlings as a propagating material to maintain desired genetics in terms of total cannabinoid productivity. While in general there were no significant interactions between the independent variables in our preliminary results, seedling propagated hemp had significantly (p = 0.033) greater plant biomass and percent CBD content than clonally propagated hemp in 2023, which would appear to suggest that perhaps seedlings might be a better choice than producer preference. This trend was also observed in preliminary data analysis from 2024. However, while preliminary results from the current objective revealed that straw mulch significantly reduced southern blight disease severity in conformity with results reported in Objective 1 above, clonally propagated hemp tended to be less affected by southern blight than seedling propagated hemp, suggesting that the extensive rooting system of seedlings that include tap roots may increase their surface area of exposure to soil borne pathogens compared to the less extensive roots of clones. We do not know if this may be part of the reason that experienced growers typically prefer clones over seedlings. To our knowledge, however, there is not yet any published data that has established the role of clones in mitigating soil borne diseases. These results demonstrate the delicate balance and tradeoffs that growers may need to consider in cultivation of floral hemp under different conditions, and will, therefore, be extensively explored further in additional research in 2025. Objective 3: We conducted a preliminary experiment in 2024 at the TSU AREC in Nashville to assess the impacts of no-till transplanting floral industrial hemp in cereal rye terminated by a roller crimper, on pests and diseases, weeds, cannabinoid production and THC compliance. Cereal rye was planted in October 2023 and terminated by rolling/crimping in May 2024. 'Cherry' feminized CBD seedlings and clones were raised in a nearby greenhouse as described above and transplanted into the plots measuring 1.5 by 10 meters covered with rolled/crimped rye mulch, black plastic, straw mulch or no mulch control. Half of the plots were managed under recommended conventional practices and the other half by non-certified organic practices as described in Objective 3 above. Data collected were similar to those described in the previous objectives. Preliminary results revealed that straw mulch significantly reduced southern blight disease severity in conformity with previous observations. While seedlings increased plant heights and plant biomass, clones tended to reduce disease severity compared to the seedlings. As mentioned above, we hypothesize that the more robust rooting system of seedling propagated hemp might also increase the surface area of contact with disease pathogens compared to the less well-endowed rooting system of clones. This needs to be investigated further. Our preliminary results also revealed that organic systems significantly reduced weeds compared to conventionally managed system. In both systems cereal rye was roll crimped before transplanting hemp in the resulting mulch. However, subsequent weed emergence in the conventional system were sprayed with glyphosate using an herbicide wick to avoid herbicide drift to hemp plants. We hypothesize that use of glyphosate, a contact herbicide, without including a pre-emergent herbicide, may have killed the initial weed flush and exposed the soil to more weed emergence. These observations underscore the critical and complex balance between the limited weed management options under the strict federal restrictions on herbicides use in industrial hemp and the potential soil health benefits of reduced tillage. An expanded study planned for 2025 will further examine different reduced tillage and weed management strategies under organic and conventional practices. Objective 4 Economic analysis: A preliminary enterprise budget analysis of the different hemp varieties used in this research revealed that "Fukuoka" grown under plastic mulch was potentially more profitable than the other varieties under different treatments, at the average price of $29.20 per pound (USDA 2022 Hemp Report) with a break even yield of 795 pounds per acre. Expected yield of "Fukuoka" from our model was estimated to be 1,755 pounds per acre, which would be substantially greater than the projected break-even yield. However, while our enterprise budget analysis reveals promising profitability of floral hemp production, there was excessive speculative production of industrial hemp soon after removal from the Schedule A list of controlled substance in the 2018 Farm Bill in anticipation of lucrative profits from the crop. This, unfortunately, led to a slump in the barely developed market, with many growers suffering heavy losses, including bankruptcies and ruined businesses. Thisresulted in a drastic reduction of interest in growing industrial hemp, leading to significant reduction in acreage under hemp from about 15,722 acres licensed for hemp cultivation in 2020 down to less than 200 acres currently under outdoor hemp production in Tennessee. The goal of this research is to provide information that will not only add to the basket of scientific knowledge in general, but also inform future growers and help them to avoid costly mistakes.

Publications

• Type: Theses/Dissertations Status: Published Year Published: 2024 Citation: Maddela, S. S. (2024). Effect of Mulches and Planting Time on Southern Blight and Production of Industrial Hemp Tennessee State University].
• Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Omondi, E., & Maddela, S. S. (2023). Potential Role of Mulches and Planting Time in Managing Southern Blight and Enhancing Cannabinoid Production in Floral Hemp in Tennessee. ASA, CSSA, SSSA International Annual Meeting
• Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Omondi, E., & Maddela, S. S. (2023). Potential Role of Mulches and Planting Time in Managing Southern Blight and Enhancing Cannabinoid Production in Floral Hemp in Tennessee. Cannabis Research Conference, Denver Colorado August 2, 2023