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Organic fertilizers may contribute substantially to improving yield, soil quality, and reducing the environmental impacts of conventional farming. This study investigates the effects of organic fertilizers, like green manure composed of hairy vetch (HV), livestock compost (LC), or a combination of the two (LC + HV), has on red pepper growth, yield, fruit quality, and soil microbial populations as compared to more commonly used chemical fertilizers. This study investigates the effects of different fertilizer treatments on red pepper growth, yield, quality, and soil microbial populations. The experimental plot treatments were no fertilizer (CON), chemical fertilizer, HV, LC and LC + HV. In these treatments, 70-day-old red pepper plants were grown for an additional 140 days under treatment conditions. Plant dry weight, macro- and micro-nutrient contents were analyzed. Post-harvest soil properties and cultivable soil microbial population were determined. HV and LC + HV treatments had significantly high leaf and stem dry weight. All the treatments increased T–N, P and Mg contents in plants and the highest uptake was recorded for plants fertilized with HV. After harvest, soil fertilized with LC + HV had higher soil organic matter and available P, K and Ca as compared to chemical fertilizers. In addition, soil fertilized with organic fertilizers had significantly more cultivable microbial populations than chemical fertilizers. Overall, these results suggest that organic fertilizers could be used to reduce the application of synthetic fertilizers and aiding sustainable agriculture.

Arbuscular mycorrhizal fungi (AMF) are well-known for their ability to improve plant growth and help plants withstand abiotic stress conditions. Unlike other fungi and bacteria, AMF cannot be stored, as they are obligate biotrophs. Long-term preservation of AMF spores is challenging and may lead to the loss of viability and efficiency. This study aimed to understand the effect of prolonged subculture of AMF species on the growth and glomalin-related soil protein (GRSP) from red pepper (Capsicum annuum L.). AMF spores were mass-produced using different techniques and subcultured in pots with sorghum sudangrass as the host plant for 3 years. Experimental soil samples were collected from natural grassland. Five different AMF inocula were used in triplicate as treatments. After 70 days of growth, red pepper plants were harvested and plant dry weight, plant nutrient content, mycorrhizal colonization, AMF spore count, and soil glomalin content were determined. AMF-treated plants displayed higher dry weight than controls, with only fruit dry weight being significantly different. Similarly, significant differences in phosphorous and potassium contents of the above-ground plant parts were observed between mycorrhizal and control treatments. In addition, soil GRSP content was significantly higher in plants inoculated with Rhizophagus sp. and Gigaspora margarita. The increased plant growth and GRSP content suggest that AMF can be maintained for 3 years without losing their efficiency if subcultured regularly with different symbiotic host plants.

The fruits of Citrus unshiu are one of the most popular and most enjoyed fruits in Korea. As we continue to seek for bioactive metabolites from Korean natural resources, our study on the chemical constituents of the fruits of C. unshiu resulted in the isolation of a new flavonoid glycoside, limocitrunshin 1, along with seven other flavonoids 2-8 and a limonoid 9. All structures were identified by spectroscopic methods, namely 1D and 2D NMR, including HSQC, HMBC, and (1)H-(1)H COSY experiments, HRMS, and other chemical methods. Compounds 3, 5, and 9 are reported to be isolated from this fruit for the first time. The isolated compounds were applied to activity tests to verify their inhibitory effects on inflammation and nephrotoxicity. Compounds 6 and 9 showed the most potent inhibitory activity on renal cell damage and nitric oxide production, respectively. Thus, the fruits of C. unshiu could serve as a valuable natural source of bioactive components with health benefits for potential application in functional foods.