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

<b>Project Methods</b><br> 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.