The current research was the first to prove the existence of fluctuations in the metabolite constituents and antioxidant properties in different organs (leaves, stems, and roots) of the mountain-cultivated ginseng (MCG) plant during a two-month maturation period. Four metabolites, including fatty acids, amino acids, ginsenosides, and phenolic phytochemicals, exhibited considerable differences in organs and maturation times with the following order: leaves > stems > roots. The predominant metabolite contents were found in leaves, with fatty acid (1057.9 mg/100 g) on 31 May, amino acid (1989.2 mg/100 g) on 13 July, ginsenosides (88.7 mg/g) on 31 May, and phenolic phytochemical (638.3 μg/g) on 31 May. Interestingly, ginsenoside content in leaves were highest, with 84.8 → 88.7 → 82.2 → 78.3 mg/g. Specifically, ginsenosides Re, Rd, and F2 showed abundant content ranging from 19.1 to 16.9 mg/g, 8.5 to 14.8 mg/g, and 9.5 to 13.1 mg/g, respectively. Phenolic phytochemicals exhibited remarkable differences in organs compared to maturation periods, with the highest total phenolic content and total flavonoid content recorded at 9.48 GAE and 1.30 RE mg/g in leaves on 31 May. The antioxidant capacities on radical, FRAP, and DNA protection differed significantly, with leaves on 31 May exhibiting the highest values: 88.4% (DPPH), 89.5% (ABTS), 0.84 OD593 nm (FRAP) at 500 μg/mL, and 100% DNA protection at 50 μg/mL. Furthermore, principal cluster analysis revealed metabolite variability as follows: ginsenoside (83.3%) > amino acid (71.8%) > phenolic phytochemical (61.1%) > fatty acid (58.8%). A clustering heatmap highlighted significant changes in metabolite components under the maturation times for each organ. Our findings suggest that MCG leaves on 31 May may be a potential source for developing nutraceuticals, offering highly beneficial components and strong antioxidants.

Alkali-enhanced biochars, as an environment-friendly material, combine the advantages of biomass nutrients and carbon fixation. In this study, rice-residue-derived biochars were evaluated for P and C solubility and their amendment upon plant P uptake. Biochars from rice straw (RS) and husk (RH), including raw biochar without alkaline pretreatment (0B), alkali-enhanced biochars with KOH (5KB, 5 g KOH per 100 g feedstock;10KB, 10 g KOH per 100 g feedstock), K₂CO₃ (5K2B, 5 g K₂CO₃ per 100 g feedstock; 10K2B, 10 g K₂CO₃ per 100 g feedstock), and CaO (5CB, 5 g CaO per 100 g feedstock; 10CB,10 g CaO per 100 g feedstock) were prepared at 350 °C~550 °C pyrolysis conditions. Alkali-enhanced biochars on soil water soluble P(WSP) and C(WSC) levels were assessed through a soil-biochar incubation experiment. The effect of alkali-enhanced biochar on rice P uptake was evaluated in a greenhouse pot study. The WSP content in KOH- and K₂CO₃-enhanced biochars produced at 550 °C was significantly increased by up to 144% compared with that produced by the corresponding biochars at 350 °C, while the WSC content in all alkali-enhanced biochars (except for RS-5CB) prepared at 550 °C significantly decreased by up to 6426% compared with that produced by the corresponding biochars at 350 °C. The application of 3% 10KB and 10K2B rice straw biochars (produced at 550 °C) significantly elevated the WSP content in soils. Rice grown in the RH-10K2B-550 treated soil significantly increased the grain P uptake by 15% and 8% compared with RH-0B-350 and RH-10K2B-350, respectively. The water soluble P of the KOH- and K₂CO₃-enhanced biochars increased with increasing the pyrolysis temperature. RS-10KB and RS-10K2B increased the soil WSP and WSC content compared with the unenhanced biochar (RS-0B), and showed a clear positive effect on increasing the rice P uptake. Overall, KOH- and K₂CO₃-enhanced biochars pyrolyzed at 550 °C as Si sources could also serve as a potential P pool with multi-functions in C sequestration and K nutrition.

The global focus continues with respect to increasing agricultural productivity, such as in paddy soils using inorganic fertilizers. Such practices could adversely affect the agricultural environment by deteriorating soils and increasing greenhouse gas emissions. The aim of this study was to assess the effect of biochar pellet blended with condensed molasses soluble (CMS) on rice productivity, soil quality, and methane (CH₄) emissions in a paddy condition for healthy agricultural ecosystem. This study used a commercial scale pyrolysis system to produce biochar at 600 °C from bamboo. The experiment consisted of three different treatments: control, inorganic fertilizer (IF, N-P-K = 90-45-57 kg ha⁻¹), and biochar pellet (BC_PT, 1000 kg ha⁻¹). Compared to other treatments, the biochar pellet decreased annual CH₄ flux by 15.8–18.8%. The rice grain yield under inorganic fertilizer as conventional rice management was slightly more than applied biochar pellets, despite lower soil chemical properties. However, for long-term paddy management, including environmental protection and rice production, biochar pellets are better suited for maintaining a healthy agricultural ecosystem than conventional practices. Indeed, the application of biochar pellets appears to potentially reduce CH₄ emissions and maintain stable rice productivity through the slow release of nutrients.

Effects of Lettuce Growth and Carbon Sequestration by Different Application Methods with Excessive Amount of Wood-based Agricultural and Forestry By-product Biochar-Biochar,Carbon sequestration,Excessive biochar application,Fertilization method,Lettuce

This experiment was conducted to evaluate the adsorption–desorption characteristics and mechanisms of heavy metals by the mealworm frass (MF). The adsorption characteristics of Cd by MF were predominantly influenced by initial pH, MF dosage, temperature, and reaction time. The maximum adsorption capacity of Cd by MF was 48.1 mg/g, which was well described by Langmuir isotherm and pseudo-second-order models. The optimal desorption solution for separating Cd from Cd-adsorbed MF was 0.02 M HCl, which showed a high desorption efficiency of over 90%. In particular, the adsorption mechanism of Cd by MF was confirmed through functional group change, cation exchange, precipitation experiment, and it was found that Cd was predominantly affected by cation exchange and precipitation on the MF surface. The amounts of Cd fractionated by F1 (exchangeable) and F2 (bonded to carbonate) solutions were 58.9 and 25.2% of the total fractionated Cd amount, which means that Cd adsorbed by MF can be easily eluted/mobilized by environmental changes. Considering the above results, it is believed that MF can be used as an effective adsorbent to remove Cd. However, since the adsorption of Cd by MF is sensitive to environmental changes and the bond itself is weak, it is considered that a special management plan is needed.