The effectiveness of biochar as a mulch for weed control and soil moisture retention in strawberry cultivation

Purpose: Weed control and soil moisture retention are critical challenges in plant cultivation requiring effective solutions. This study aims to assess the impact of biochar produced from pine nut shells as a mulch for weed composition, biomass, and soil moisture retention compared to widely used spunbond covering material in strawberry cultivation. Method: The experiment with six weed species was conducted using a growth chamber over two months with sixteen replicates for each of the three treatments: control (no mulch), soil with a 2 cm layer of biochar mulch, and soil with spunbond. Results: In the control treatment, six weed species germinated, whereas only five and three species were observed in the biochar and spunbond treatments, respectively. Both mulching treatments significantly (p < 0.05) reduced the height of grass weeds, stinging nettles, and shepherds’ purse, as well as the mass of dry above-ground and root biomass of shepherds’ purse, rapeseed, and stinging nettle by 52–100%. Spunbond mulch demonstrated superior soil moisture retention overall. However, during the initial three days of a simulated dry period, biochar retained 7% more water compared to spunbond (2%). The application of spunbond mulch completely suppressed the emergence of rapeseed and burdock, while both biochar and spunbond effectively controlled fennel. Both mulching treatments significantly reduced the height of grasses, stinging nettles, and shepherds’ purse by different mechanisms. Conclusion: Biochar can be useful for reducing the weed count and increasing the water retention in the soil.