Biochar, Compost, and Biochar-Compost Blend Applications Modulate Growth, Photosynthesis, Osmolytes, and Antioxidant System of Medicinal Plant Alpinia zerumbet

Alleviation of cotton growth suppression caused by salinity through biochar is strongly linked to the microbial metabolic potential in saline-alkali soil

Biochar is a typical soil organic amendment; however, there is limited understanding of its impact on the metabolic characteristics of microorganisms in saline-alkaline soil microenvironment, as well as the advantages and disadvantages of plant-microorganism interactions. To elucidate the mechanisms underlying the impact of saline-alkali stress on cotton, a 6-month pot experiment was conducted, involving the sowing of cotton seedlings in saline-alkali soil. Three different biochar application levels were established: 0 % (C0), 1 % (C1), and 2 % (C2). Results indicated that biochar addition improved the biomass of cotton plants, especially under C2 treatment; the dry weight of cotton bolls were 8.15 times that of C0. Biochar application led to a rise in the accumulation of photosynthetic pigments by 8.30-51.89 % and carbohydrates by 7.4-10.7 times, respectively. Moreover, peroxidase (POD) activity, the content of glutathione (GSH), and ascorbic acid (ASA) were elevated by 23.97 %, 118.39 %, and 48.30 % under C2 treatment, respectively. Biochar caused a reduction in Na+ uptake by 8.21-39.47 %, relative electrical conductivity (REC) of plants, and improved K+/Na+ and Ca2+/Na+ ratio indicating that biochar alleviated salinity-caused growth reduction. Additionally, the application of biochar enhanced the absorption intensity of polysaccharide fingerprints in cotton leaves and roots. Two-factor co-occurrence analysis indicated that the key differential metabolites connected to several metabolic pathways were L-phenylalanine, piperidine, L-tryptophan, and allysine. Interestingly, biochar altered the metabolic characteristics of saline-alkali soil, especially related to the biosynthesis and metabolism of amino acids and purine metabolism. In conclusion, this study demonstrates that biochar may be advantageous in saline soil microenvironment; it has a favorable impact on how plants and soil microbial metabolism interact.

A Comprehensive Quality Analysis of Different Colors of Medicinal and Edible Honeysuckle

Honeysuckle (the dried flower bud or opening flower of Lonicera japonica Thunb.), a medicinal and edible substance, has is greatly popular among consumers for its remarkable health effects, such as antioxidant, antibacterial, and anti-inflammatory effects. However, due to the influences of processing methods, storage conditions, and other factors, honeysuckles show different colors which can directly reflect the quality and the price on the market. In order to comprehensively compare the quality of different colors, 55 batches of honeysuckle samples were collected and analyzed. Their color parameters, chlorophyll content (chl), total phenol content (TPC), total flavonoid content (TFC), antioxidant activity (AA), main active compounds, and metabolites were measured. As a result, the initial green-white (GW) samples, a kind of highest-quality honeysuckle, had the smallest a* value, largest h*, chl, TPC, TFC, and AA values, and highest content of chlorogenic acid and cynaroside. There was a significant difference between GW samples and a series of discolored samples. As the color darkened or lightened, the quality gradually decreased. The yellow-brown (YB) samples were of the worst quality and were no longer available for clinical and health purposes. A series of differential metabolites, such as quercetin-7-O-glucoside and secologanoside, could be used as important references to evaluate the quality of differently colored samples. The metabolic profile of honeysuckle provided new insights into the process of color change and laid a foundation for further honeysuckle quality control. The correlation results showed that the a* and h* values significantly affect the abovementioned quality indicators and the 10 main active compounds. In other words, the color difference could directly reflect the quality and clinical efficacy. Multiple regression analysis was carried out using combined L*, a*, and b* values to predict the quality of honeysuckle. This is the first time the quality of different color honeysuckle samples on the post-harvest link has been systematically compared and a demonstration of medicinal and edible substances with different colors has been provided.

Biochar improves the growth and physiological traits of alfalfa, amaranth and maize grown under salt stress

Purpose

Salinity is a main factor in decreasing seed germination, plant growth and yield. Salinity stress is a major problem for economic crops, as it can reduce crop yields and quality. Salinity stress occurs when the soil or water in which a crop is grown has a high salt content. Biochar improve plant growth and physiological traits under salt stress. The aim of the present study, the impact of biochar on growth, root morphological traits and physiological properties of alfalfa, amaranth and maize and soil enzyme activities under saline sands.

Methods

We studied the impact of biochar on plant growth and the physiological properties of alfalfa, amaranth and maize under salt stress conditions. After 40 days, plant growth parameters (plant height, shoot and root fresh weights), root morphological traits and physiological properties were measured. Soil nutrients such as the P, K and total N contents in soil and soil enzyme activities were analyzed.

Results

The results showed that the maize, alfalfa, and amaranth under biochar treatments significantly enhanced the plant height and root morphological traits over the control. The biochar on significantly increased the total root length, root diameter, and root volume. Compared to the control, the biochar significantly increased the chlorophyll a and b content, total chlorophyll and carotenoid content under salt stress. Furthermore, the biochar significantly increased enzyme activities of soil under salt stress in the three crops.

Conclusions

Biochar treatments promote plant growth and physiological traits of alfalfa, amaranth, and maize under the salt stress condition. Overall, biochar is an effective way to mitigate salinity stress in crops. It can help to reduce the amount of salt in the soil, improve the soil structure, and increase the availability of essential nutrients, which can all help to improve crop yields.

Exogenous Selenium and Biochar Application Modulate the Growth and Selenium Uptake of Medicinal Legume Astragalus Species

Astragalus species have a certain capacity to enrich selenium (Se) and are the strongest Se hyperaccumulator legumes known globally at present. The biochar application to medicinal plants has been reported to affect plant metabolites. In this study, we aimed to employ hyperaccumulating Astragalus species in the plant growth of selenium-lacked soil, while also investigating the impact of varying selenium doses and biochar application on legumes growth, selenium content, and secondary metabolite production. Applying biochar to soil, along with a Se concentration of 6 mg/kg, significantly enhanced the growth, Se content, total polysaccharide content, and calycosin-7-glucoside content of Astragalus species (p < 0.05). Importantly, the Se and biochar application also led to a significant improvement in Se content in ABH roots (p < 0.05). Meanwhile, the content of total flavonoids in ABH roots could be promoted by a Se concentration of 3 mg/kg and biochar application in soil. Additionally, the Se enrichment coefficients of Astragalus species under Se treatments were significantly higher than those under control treatment, with a marked difference observed across all treatments, whether roots or above-ground (p < 0.05). Remarkably, the Se transport coefficients of Astragalus species were observed to be lower than one, except for the transport coefficient of AB in the Se concentration of the control treatment (0 mg/kg). This result showed that a medium concentration treatment of Se and biochar application in soil not only promotes the growth of Astragalus species and the uptake of exogenous Se but also increases the active component content, meanwhile enhancing the Se enrichment and transport capacity. Taken as a whole, the present findings offer a more comprehensive understanding of the interplay between distinct Se levels, as well as the addition of biochar in soil, providing valuable insight for the cultivation of Se-rich Astragalus in Se-deficient soil-plant systems.

Pretreatment and composting technology of agricultural organic waste for sustainable agricultural development

With the continuous development of agriculture, Agricultural organic waste (AOW) has become the most abundant renewable energy on earth, and it is a hot spot of research in recent years to realize the recycling of AOW to achieve sustainable development of agricultural production. However, lignocellulose, which is difficult to degrade in AOW, greenhouse gas emissions, and pile pathogenic fungi and insect eggs are the biggest obstacles to its return to land use. In response to the above problems researchers promote organic waste recycling by pretreating AOW, controlling composting conditions and adding other substances to achieve green return of AOW to the field and promote the development of agricultural production. This review summarizes the ways of organic waste treatment, factors affecting composting and problems in composting by researchers in recent years, with a view to providing research ideas for future related studies.

Biochar: An emerging recipe for designing sustainable horticulture under climate change scenarios

The interest in sustainable horticulture has recently increased, given anthropogenic climate change. The increasing global population will exacerbate the climate change situation induced by human activities. This will elevate global food demands and the vulnerability of horticultural systems, with severe concerns related to natural resource availability and usage. Sustainable horticulture involves adopting eco-friendly strategies to boost yields while maintaining environmental conservation. Biochar (BC), a carbon-rich material, is widely used in farming to improve soil physical and chemical properties and as an organic substitute for peat in growing media. BC amendments to soil or growing media improve seedling growth, increase photosynthetic pigments, and enhances photosynthesis, thus improving crop productivity. Soil BC incorporation improves abiotic and biotic stress tolerance, which are significant constraints in horticulture. BC application also improves disease control to an acceptable level or enhance plant resistance to pathogens. Moreover, BC amendments in contaminated soil decrease the uptake of potentially hazardous metals, thus minimizing their harmful effects on humans. This review summarizes the most recent knowledge related to BC use in sustainable horticulture. This includes the effect of BC on enhancing horticultural crop production and inducing resistance to major abiotic and biotic stresses. It also discuss major gaps and future directions for exploiting BC technology.

Microbial diversity, culture conditions, and application effect of YSJ: A composite microbial system for degradation of Yanshan ginger branches and leaves

BACKGROUND

Yanshan ginger (Alpinia zerumbet) is a perennial herb used as a medicine and spice, and is beneficial for soil and water conservation in karst areas. Given the widespread utilization of Yanshan ginger in China and continuing expansion of the planting area, disposal of waste materials is problematic. The branches and leaves of Yanshan ginger contain a variety of potent antibacterial compounds, such as volatile oils, phenols, and diterpenoids, which hinder their rapid degradation by microorganisms. In this study, we screened and constructed a composite microbial system to provide a technical reference for production of organic fertilizer from the branches and leaves of Yanshan ginger.

METHODS

A composite microbial system, "YanShan Jun" (YSJ), was developed by screening for efficient detoxification and degradation of the branches and leaves of Yanshan ginger. High-throughput sequencing technology was used to investigate the stability and diversity of YSJ subcultures. The culture conditions for YSJ were optimized by sequential single-factor experiments and response surface analysis. Yanshan ginger leaves and branches were inoculated with YSJ to study its effects on composting efficiency.

RESULTS

The microbial composition of YSJ was stable and rich in diversity through continuous subculture. Through response surface analysis, the optimized culture conditions for YSJ were determined as follows: peptone 8.0 g/L, sodium chloride 9.0 g/L, calcium carbonate 5.2 g/L, yeast powder 1.6 g/L, cultivation temperature 56.1°C, and culture duration 6 d. Under these conditions, the degradation rate of Yanshan ginger was 58.32%, which was 14.22% higher than that before optimization. The ability of YSJ to degrade the antibacterial compounds of ginger after optimization was significantly enhanced. Inoculation of Yanshan ginger compost with YSJ increased the fermentation temperature, prolonged the high-temperature period, and reduced the water content and pH of the compost in the early stage.

CONCLUSIONS

Inoculation of plant compost with YSJ bacteria improves the nutritional environment of the compost, promotes the composting reaction, promotes the rapid formation of a strong indigenous microflora, forms a beneficial microecological environment, and increases the composting efficiency. This study provides a theoretical basis for practical application of YSJ for organic fertilizer production from Yanshan ginger.

Nitrogen and Biochar Addition Affected Plant Traits and Nitrous Oxide Emission From Cinnamomum camphora

Atmospheric nitrous oxide (N₂O) increase contributes substantially to global climate change due to its large global warming potential. Soil N₂O emissions have been widely studied, but plants have so far been ignored, even though they are known as an important source of N₂O. The specific objectives of this study are to (1) reveal the effects of nitrogen and biochar addition on plant functional traits and N₂O emission of Cinnamomum camphora seedlings; (2) find out the possible leaf traits affecting plant N₂O emissions. The effects of nitrogen and biochar on plant functional traits and N₂O emissions from plants using C. camphora seedlings were investigated. Plant N₂O emissions, growth, each organ biomass, each organ nutrient allocation, gas exchange parameters, and chlorophyll fluorescence parameters of C. camphora seedlings were measured. Further investigation of the relationships between plant N₂O emission and leaf traits was performed by simple linear regression analysis, principal component analysis (PCA), and structural equation model (SEM). It was found that nitrogen addition profoundly increased cumulative plant N₂O emissions (+109.25%), which contributed substantially to the atmosphere's N₂O budget in forest ecosystems. Plant N₂O emissions had a strong correlation to leaf traits (leaf TN, P _n , G _s , C _i , Tr, WUE _L , α, ETR _max, I _k , Fv/Fm, Y(II), and SPAD). Structural equation modelling revealed that leaf TN, leaf TP, P _n , C _i , Tr, WUE _L , α, ETR _max, and I _k were key traits regulating the effects of plants on N₂O emissions. These results provide a direction for understanding the mechanism of N₂O emission from plants and provide a theoretical basis for formulating corresponding emission reduction schemes.