Agronomy

Southern blight, a disease caused by the soil-borne fungus Sclerotium rolfsii (S. rolfsii), is favored by the hot and humid conditions of the southeastern United States, posing a significant challenge to hemp production in Tennessee. Black plastic mulch (BPM), commonly used for weed control, can exacerbate the disease. There is limited information on the effects of straw mulch (SM), known to moderate soil temperatures and moisture, or planting time in disease management. Field studies were conducted in 2022 and 2023 at Tennessee State University to evaluate the effects of planting time, mulch type, and biofungicide application on disease severity, weed suppression, plant growth, and cannabinoid production in floral hemp. SM significantly reduced southern blight severity and moderated soil temperature, while BPM increased both. Early planting reduced disease severity by 28% in 2022 and by 53% and 34% in 2023 for first and second planting dates. SM lowered soil temperature by 6%, enhanced chlorophyll content by 30%, and increased plant height and biomass by 20% and 25%, respectively. Early planting increased cannabidiol (CBD) concentration by 0.4%, while late planting increased tetrahydrocannabinol (THC) by 0.25%. These findings demonstrate that integrating straw mulch with early planting can reduce disease severity, stabilize soil microclimate, and enhance hemp productivity under warm, humid conditions.

Soil-borne pathogens significantly threaten crop production and global food security, while green and efficient antipathogenic materials are scarce. In this study, green and efficient Ag/AgCl nanoparticles (Ag/AgCl-NPs) were developed using an aqueous extract of ginger-straw waste as the raw material. The synthesized Ag/AgCl-NPs exhibited a spherical morphology with an average size of approximately 40 nm, good crystal structure, and abundant surface groups. Additionally, they exhibited excellent antimicrobial activity against representative soil-borne pathogens, including Ralstonia solanacearum (MIC = 20 μg/mL; MBC = 40 μg/mL) and Fusarium oxysporum (spore MIC = 20 μg/mL; mycelial EC₅₀ = 64.596 μg/mL). The antimicrobial mechanism was attributed to cell membrane disruption and oxidative stress induction. This study provides an excellent antimicrobial agent for controlling crop soil-borne pathogens.

The aim of the experiment was to assess the effects of municipal sewage sludge, mushroom substrate, and hydrogel on the quality of energy grass species and their biomass yield. The experiment was conducted in the climatic conditions of central-eastern Poland between 2020 and 2022. Two perennial grass species were used: Miscanthus giganteus (giant miscanthus) M 19 and Panicum virgatum L. (rod millet) var. Northwind. Sewage sludge and mushroom substrate doses, each corresponding to 170 kg N·ha⁻¹, were applied in the spring of the first year. The experiment was established on microplots with four replications. Each year, biomass was harvested in January, and the yield of fresh and dry matter was determined. Then plant material was adequately prepared, and the total content of P, Ca, and Mg was measured with the ICP-OES method. The application of hydrogel resulted in a significant increase in the yield of each grass species: giant miscanthus by 11.87% and rod millet by 8.28%. Organic waste applied in combination with hydrogel increased the yield of energy plants and improved their chemical composition.