This study evaluated the effects of solid and water-soluble extracts derived from torrefied Pinus densiflora on lettuce (Lactuca sativa) germination and growth, as well as the cultivation efficiency of torrefied materials combined with plant nutrient solutions. Torrefied samples were prepared under various conditions (200°C, 220°C, 240°C for 20–80 minutes) and mixed with sand at ratios from 20% to 100%. Liquid extracts were formulated with macronutrients (N, P, K, Mg) and micronutrients (Mn, B, Fe, Cu) and applied to leafy and root vegetables. Germination tests showed that 60% and 80% torrefied treatments had the highest and most consistent rates, with torrefied samples promoting more rapid and stable germination than controls. A two-way ANOVA indicated a significant interaction between treatment and concentration (p = 0.043), suggesting concentration-specific effects. While shoot length showed no significant difference, root growth was marginally significant (p = 0.064), with washed torrefied material producing the longest roots. Physical analysis revealed that torrefied materials improved soil thermal retention and moisture-holding capacity. However, increasing torrefied content reduced porosity, likely due to fine particles filling soil pores. In conclusion, torrefied P. densiflora materials exhibit strong potential to enhance germination, root development, and soil condition. Optimal results were achieved with 40–60% solid mixtures for germination and 60–80% diluted extracts for rapid and consistent seedling growth. When optimally applied, they may serve as effective, sustainable amendments in cultivation systems.

Abstract
Introduction
Materials and Methods
    1. Plant materials and sample preparation
    2. Torrefaction conditions
    3. Preparation and application of solid and water-solubletorrefied materials
    4. Determination of physical properties of torrefactionwood mixed soil
    5. Statistical analyses
Results and Discussion
    1. Effects of torrefied P. densiflora explants on thegermination of lettuce seeds
    2. Effect of treatment type on shoot and root growthof lettuce
    3. Germination rate of lettuce treated with water-solubleextracts
    4. Growth response of lettuce to liquid extracts oftorrefied P. densiflora with and without nutrientsupplementation
    5. Determination of physical properties of torrefactionwood mixed soil
Acknowledgements
References

• Myung Suk Choi(Professor, Department of Environmental Forest Science & Institute of Agriculture and Life Science, Gyeongsang National University, Jinju, 52828, Korea) Corresponding author
• Seog Goo Kang(Professor, Department of Bio-based Materials, Chungnam National University, Daejeon 305-764, Korea)
• Jae Kyung Yang(Professor, Department of Environmental Material Science & Institute of Agriculture and Life Science, Gyeongsang National University, Jinju, 52828, Korea)
• Seong Hyeon Yong(Researcher, Plant Conservation Division, Korea National Arboretum of the Korea Forest Service, Pochen, 11186, Korea)
• Hak Gon Kim(Researcher, Forest Research Department, Gyeongsangnam-do Forest Environment Research Institute, Jinju, 52615, Korea)
• Ji Hyun Lee(Graduate Student, Department of Environmental Forest Science, Gyeongsang National University, Jinju, 52828, Korea)
• Seung A Cha(Graduate Student, Department of Environmental Forest Science, Gyeongsang National University, Jinju, 52828, Korea)
• Kwan Been Park(Graduate Student, Department of Environmental Forest Science, Gyeongsang National University, Jinju, 52828, Korea)
• Do Hyun Kim(Graduate Student, Department of Environmental Forest Science, Gyeongsang National University, Jinju, 52828, Korea)
• Seon A Kim(Graduate Student, Department of Environmental Forest Science, Gyeongsang National University, Jinju, 52828, Korea)