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