This study aimed to identify the effects of oxidized brown coal humic acid fertilizer on the relative growth rate of several tree species intended for reforestation. Field experiments were carried out during 2011–2014 at the Research and Experimental Center for Combating Desertification located at the Elsen Tasarkhai station in central Mongolia. The trees studied were Populus sibirica Tausch., Salix ledebouriana Trautv., and Acer tataricum L. The experiment was conducted with concentrations of 2000, 10,000, and 20,000 mg L⁻¹ of humic acid fertilization treatment. Measurement of the relative height growth rate (RHGR) was undertaken for a period of four years. The results demonstrated significant differences between the humic fertilizer concentrations, which varied depending on the species. Compared to monthly RHGR over the study period, the treatment using fertilizers yielded significantly better tree growth. P. sibirica, when treated with 2000 mg L⁻¹ and 10,000 mg L⁻¹ humic acid fertilizers, had significant height growth rates. S. ledebouriana with 20,000 mg L⁻¹ of humic acid fertilzers treatments showed the highest RHGR. In addition, when the humic acid treatments were compared to the control, results showed that oxidized brown coal humic acid fertilizers as an organic fertilizer can have a significant effect on the growth of A. tataricum. The results equally showed that the soil chemical properties EC, CO₂, NO₃, and K₂O were significant among all the treatments compared to control. The effect on P₂O₅ significantly increased in all the treatments; however, there was no significant effect on pH and Mg among all treatments. Combining the results obtained with reforestation and sustainable land-management practices can help to improve soil organics in degraded sandy soil regions.

Daknamu (Broussonetia × kazinoki), the primary fiber source for hanji (traditional Korean handmade paper), provides fibers that are highly durable and used in fine-edition publishing as well as in the conservation and restoration of cultural heritage materials and historic books. However, hanji production has declined due to decreased farm cultivation of B. × kazinoki, emphasizing the need for efficient vegetative propagation. This study evaluated the effects of three rooting media (commercial substrate, a mixture of commercial substrate and decomposed granite soil, and decomposed granite soil) and two plant growth regulators (auxins), 1-naphthaleneacetic acid (NAA) and indole-3-butyric acid (IBA), including a rooting powder containing 0.8% IBA, on rooting performance and physiological responses. Decomposed granite soil produced the highest rooting rate, and the rooting effect index peaked with the rooting powder treatment. Exogenous auxins consistently increased the rooting rate and improved root traits. Photosynthetic activity was enhanced in decomposed granite soil, indicating improved water uptake following root development. Chlorophyll fluorescence showed a low F_v/F_m ratio and a JIP pattern indicative of stress. Soil analyses confirmed greater aeration and drainage in decomposed granite soil but revealed limitations in post-rooting water and nutrient availability. Root traits were positively correlated with photosynthetic parameters and available phosphorus, whereas electrical conductivity, cation-exchange capacity, moisture, organic matter, total nitrogen, and exchangeable cations were negatively correlated. Decomposed granite soil combined with 1500 mg·L⁻¹ IBA or rooting powder provided practical conditions for nursery-scale propagation. These findings provide a scientific basis for developing efficient cutting propagation systems for B. × kazinoki in farms and nurseries.

Chamaecyparis obtusa is a valuable conifer species, prized for its high-quality timber and bioactive essential oils. However, commercial micropropagation is challenging due to its resistance to vegetative propagation. This study aimed to develop an efficient in vitro plant regeneration system using leaf explants and to profile the metabolic changes during organogenesis. Leaf explants from one-year-old in vitro-grown plantlets were cultured on media with various plant growth regulators (PGRs) to optimize callus induction, shoot multiplication, and rooting. Secondary metabolites were systematically analyzed throughout the developmental stages: explant, callus, regenerated shoot, and rooted plantlet. The most effective shoot regeneration, leading to whole plantlets, was achieved on a medium supplemented with 1.0 mg/L 2,4-dichlorophenoxyacetic acid and 2.0 mg/L thidiazuron. Metabolic profiling revealed significant stage-specific biochemical transitions. High-Performance Liquid Chromatography (HPLC) precisely quantified individual phenolics, resolving cross-reactivity issues seen in total flavonoid colorimetric assays. Gas Chromatography-Mass Spectrometry (GC-MS) also identified substantial shifts in volatile terpenoid biosynthesis during shoot morphogenesis. This integrated protocol provides a reliable platform for mass propagation of C. obtusa and offers fundamental insights into the metabolic dynamics of in vitro development, with significant potential for future horticultural and biotechnological applications.

This study investigated the effects of environmentally friendly soil amendments—processed red clay (PRC) and rice husk (RH)—on early establishment, growth characteristics, phytochemical accumulation, and soil chemical properties in wild-simulated ginseng (WSG; Panax ginseng C.A. Meyer) cultivated under forest conditions. PRC was produced through alkali-assisted thermal processing to improve material homogeneity and enhance plant-available mineral components, particularly silicon. We hypothesized that the combined application of PRC and RH would improve soil chemical conditions and thereby support WSG growth and phytochemical accumulation under low-input cultivation systems. Four treatments were evaluated in a randomized complete block design with four replicates: non-treated control (NMNF), PRC alone (NMPRC), RH alone (RHNF), and combined PRC and RH (RHPRC). Growth responses were assessed in one-year-old and seven-year-old WSG, including germination rate, seedling vigor index, growth traits, photosynthetic pigment composition, total polyphenol content, ginsenoside profiles, and soil chemical properties. The RHPRC treatment significantly increased germination rate and seedling vigor compared to the non-treated control and showed consistently greater biomass accumulation across cultivation stages. RH application was primarily associated with improved early establishment and increased total polyphenol content, particularly during the early growth stage, whereas PRC application was associated with enhanced root development and age-dependent increases in selected ginsenosides. Soil analyses indicated that PRC application increased available phosphorus and exchangeable cation contents, with the most stable improvements observed under combined PRC and RH treatment. Overall, the results indicate that integrated mineral–organic soil management using PRC and RH can improve soil chemical propertise and support long-term growth and phytochemical accumulation in WSG cultivated under forest conditions. This approach offers a practical, low-input strategy for enhancing the sustainability of WSG cultivation while reducing reliance on synthetic fertilizers.