Yield Enhancement Research Articles

SUSTAINABLE PRECISION AGRICULTURE: INTEGRATING ARTIFICIAL INTELLIGENCE AND IOT FOR OPTIMIZED GREEN FARMING PRACTICES

Agriculture is the backbone of Indian economy. It is evolved in due course of time. The purpose of this study is to assess how well internet of things (IoT) and artificial intelligence (AI) technologies can improve precision farming methods and encourage resource sustainability. The goal of the project is to determine the obstacles farmers have when implementing these innovations and to examine the economic and environmental effects of incorporating these technologies into farming, with an emphasis on yield enhancement and resource conservation. Method: To investigate the connection between AI, IoT, and sustainable farming results, data were collected from a sample of 225 farmers via trials and sensor readings using a quantitative descriptive research technique. Descriptive statistics, independent t-tests, and regression analysis were among the statistical techniques used to evaluate how AI and IoT affected productivity and environmentally friendly agricultural methods. Result: The results reveal a strong positive correlation, with the regression model indicating that IoT and AI play a substantial role in sustainable agriculture and higher production, accounting for around 55.2% of the variation in results. The model's effectiveness is further supported by the ANOVA findings, which show that smart farming, AI, and IoT have a major influence on green agricultural practices (p < 0.001). It is found that AI and IoT have a great deal of contribution towards sustainable agriculture by increasing sustainability and production. However, it is significant to address certain challenges for wider acceptance and scalability across many agricultural groups.

Multiplex yield enhancers and their effect on growth, yield, and pest and disease incidence of potato crop

The effect of different multiplex yield enhancers was studied on the growth and yield parameters of potatoes, it worked variably at different stages of the crop. The treatment T10 which includes a recommended dosage of fertilizer, organic manures, essential nutrients, and biostimulants has shown a positive effect in increasing the plant height (36.00 cm, 46.67 cm, and 48.33 cm), number of branches/ plant (5.89, 7.56, and 10.22), number of leaves/ plant (65.78, 82.78 and 98.44) and numbers of tubers/ plant (at 30,60 and 90DAP). The treatment T15 has reported the highest yield/ plant and hectare (0.54 kg and 17.86 t/ha respectively) because of the foliar application at the reproductive phase. Whereas the treatment included Biojodi has recorded the lowest pest and disease incidence. As potatoes are a nutrient-exhaustive crop, combining Organic and inorganic sources of nutrient management would be helpful over chemical fertilizers.

Intermittent Supplementation with Far-Red Light Accelerates Leaf and Bud Development and Increases Yield in Lettuce.

Supplementation with far-red light in controlled environment agriculture production can enhance yield by triggering the shade avoidance syndrome. However, the effectiveness of this yield enhancement can be further improved through intermittent far-red light supplementation. In this study, the effects are explored of varying far-red light photon intensities and intermittent exposure durations-specifically at 5, 15, 30, and 45 min intervals-on the growth and development of lettuce (Lactuca sativa) in plant factories, while maintaining a constant red light photon flux and daily light integral. The results showed that compared to constant far-red light, 30 min intermittent far-red light increased yield by 11.7% and the number of leaves and buds by 2.66. Furthermore, the various metrics demonstrated that intermittent far-red light supplementation enhanced the overall effectiveness of the far-red light treatment. This was validated by analyzing phytohormone content and the expression of genes related to hormone metabolism and transport at the tip of the lettuce stems. Transcriptome analysis revealed that the differences in gene expression between treatments were primarily concentrated in genes related to signaling, hormone metabolism, and transport. Weighted Gene Co-expression Network Analysis identified the co-expression modules associated with yield and quality. Additionally, dynamic expression analysis showed genes involved to far-red photoreception, response, and hormone metabolism and transport exhibited optimal rhythmic responses only under 30 min intermittent far-red light supplementation. This suggests that intermittent far-red light irradiation at 30 min intervals is the most effective for activating far-red light signaling influencing hormone metabolism and transport, thereby accelerating the growth of lettuce leaves and buds and ultimately increasing yield.

Enhancing crop yields to ensure food security by optimizing photosynthesis.

The crop yields achieved through traditional plant breeding techniques appear to be nearing a plateau. Therefore, it is essential to accelerate advancements in photosynthesis, the fundamental process by which plants convert light energy into chemical energy, to further enhance crop yields. Research focused on improving photosynthesis holds significant promise for increasing sustainable agricultural productivity and addressing challenges related to global food security. This review examines the latest advancements and strategies aimed at boosting crop yields by enhancing photosynthetic efficiency. There has been a linear increase in yield over the years in historically released germplasm selected through traditional breeding methods, and this increase is accompanied by improved photosynthesis. We explore various aspects of the light reactions designed to enhance crop yield, including light harvest efficiency through smart canopy systems, expanding the absorbed light spectrum to include far-red light, optimizing non-photochemical quenching, and accelerating electron transport flux. At the same time, we investigate carbon reactions that can enhance crop yield, such as manipulating Rubisco activity, improving the Calvin-Benson-Bassham (CBB) cycle, introducing CO2 concentrating mechanisms (CCMs) in C3 plants, and optimizing carbon allocation. These strategies could significantly impact crop yield enhancement and help bridge the yield gap.

Influence of Some Various Factors for Enhancement of Epsilon Toxin Yield from C. perfringens Type D

Influence of Some Various Factors for Enhancement of Epsilon Toxin Yield from C. perfringens Type D

Rhizobacterial Inoculation to Enhance Growth and Productivity of Fenugreek

The use of rhizobacterial inoculants represents a promising strategy to improve crop productivity and sustainability. This study investigates the impact of four different rhizobacterial strains on the growth and productivity of fenugreek (Trigonella foenum-graecum). Conducted under field conditions, the experiment followed a randomized complete block design with four replications. The treatments included inoculation with individual strains as well as a control with no inoculation. Key growth parameters, such as germination rate, plant height, biomass, nodulation, and seed yield, were systematically recorded. The results demonstrated significant enhancements in fenugreek growth and yield in response to rhizobacterial inoculation compared to the control. Strain F1 showed the highest increase in germination rate and plant height, while Strain F2 resulted in the maximum biomass accumulation. Strain F3 significantly improved nodulation and overall root development, contributing to better nutrient uptake. Strain F4 produced the highest seed yield, indicating its potential in enhancing fenugreek productivity. All inoculated treatments exhibited improved soil health indicators, such as increased microbial activity and nutrient availability, compared to the control. The combined analysis revealed that the use of these rhizobacterial strains not only promoted plant growth but also contributed to sustainable agricultural practices by enhancing soil fertility. This study underscores the potential of specific rhizobacterial strains in boosting fenugreek production and provides a foundation for the development of effective microbial inoculants. Further research on the synergistic effects of these strains and their application methods could optimize their benefits, offering a viable solution for enhancing crop yield and soil health in legume cultivation.

Superior haplotypes to enhance grain filling in rice (Oryza sativa L.) identified through GWAS

BackgroundKey traits for determining rice grain yield include the total number of spikelets per panicle (STOT), the total number of grains per panicle (GTOT), and the percentage of grain filling per panicle (GFTOT). Molecular genetic basis of grain yield is complex and regulates several interconnected genes. Identification of candidate genes and their favourable haplotypes associated with the spikelets, grains and grain filling would accelerate rice grain yield enhancement projects. The interface between genetic and environmental factors often influences the grain filling, affecting overall grain yield. Therefore, we executed a Genome-Wide Association Study (GWAS) to investigate the candidate genes associated with grain-filling traits and to explore genotype × environment (G × E) interactions influencing grain filling traits in rice—STOT, GTOT and GFTOT in the subset of Rice Diversity Panel 1 (RDP1).Methods and resultsA set of 188 RDP1 accessions were evaluated across two environments (wet seasons—2021 and 2022) following the standard package of practices to raise healthy crop. Phenotyping analysis identified promising genotypes for three traits of study—STOT and GTOT (Priano Guaira and Tainan-Iku No. 512) and GFTOT (IR8 and Biser-1). GWAS was carried out using 5.2 M SNP dataset in the Parallel Identification of QTL’s using EMMAX (PIQUE) pipeline. Five QTLs, one for STOT (qSTOT6.6), one for GTOT (qGTOT4.2) and three for GFTOT (qGFTOT3.4, qGFTOT3.5 and qGFTOT12.1), were detected. Further, superior haplotypes for eight candidate genes (LOC_Os6g38850 and LOC_OS6g39050 for STOT; LOC_OS4g11040 for GTOT; LOC_OS3g62720, LOC_OS3g62750, LOC_OS3g62820, LOC_OS12g03450 and LOC_OS12g03470 for GFTOT) were identified.ConclusionsOur results provide key genetic information for the enhancement of grain filling traits in rice. The identified candidate genes and superior haplotypes can possibly be utilized in marker-assisted selection to improve rice grain yield through gene-pyramid breeding/haplotype-assisted breeding.

Wheat genotypes selected for their high early daytime stomatal conductance under elevated nocturnal temperatures maintain high yield and biomass

Abstract Global nighttime temperatures are increasing and correlate with a decline in crop yield. Various aspects of nocturnal physiology in plants are under-studied, one of which is the independent influence on daytime processes. Twelve elite wheat genotypes were field-grown in plots with artificially increased nighttime temperatures (+ 2°C). The stomatal conductance on the adaxial and abaxial leaf side was measured during the morning and the night, and stomatal morphological traits were assessed during the same period of plant growth. To determine whether an increase in early daytime stomatal conductance provides a growth and/or yield advantage under high temperature, the biomass, grain number, grain weight, and grain yield were measured. Genotypes exhibiting the highest early daytime stomatal conductance also showed higher biomass, grain number, and yield. An increase of 19 % in early daytime stomatal conductance led to a yield increase of 86 and 65 gm-2, in heated and control conditions respectively, translating to 43 and 35 % yield enhancement. Irrespective of the environment, the adaxial leaf side showed the highest diurnal and nocturnal conductance, mirroring direct stomatal aperture (SA) measurements. The high nighttime temperature treatment increased daytime stomatal conductance but reduced nocturnal conductance. SA varied with growing conditions; in the morning, plants under high nighttime temperatures showed larger SA than those from the control independently of the leaf side, conversely, the opposite trend was observed in the night. Stomata on the adaxial leaf side showed higher density (SD) and larger size (SL). Results from this study show that early daytime conductance increased productivity in hot-irrigated environments studied here. Previous studies showed that high pre-dawn conductance improves morning photosynthesis, and here we find that high nocturnal temperatures increased early morning conductance but reduced night time conductance and this may be a factor that contributed to minimize yield losses.

Chitosan-induced growth enhancement, piperine production and relative expression of piperine synthase gene in long pepper (Piper longum L.)

A study was undertaken to investigate the effects of chitosan (CS) at varying concentrations (0 g/L, 1 g/L, 2 g/L, 3 g/L and 4 g/L) on Piper longum. CS, a naturally occurring polysaccharide, has garnered attention for its potential to enhance plant growth and yield. The experiment involved foliar applications of CS at 2, 4 and 6 months after planting (MAP), followed by observations 1 month postapplication (3, 5 and 7 MAP). This allowed for a comprehensive assessment of the impact of CS on the growth, physiological, biochemical and yield parameters of P. longum. Notably, the findings highlighted that foliar spraying of CS at lower concentrations (1 g/L and 2 g/L) significantly stimulated the growth and yield attributes and expression of the piperine synthase gene in P. longum. These concentrations positively affected various parameters, including shoot length, physiological functions, biochemical processes and yield metrics. Conversely, higher concentrations of CS (3 g/L and 4 g/L) exhibited inhibitory effects, leading to compromised performance across the assessed parameters. Moreover, these concentrations produced poorer results than the control treatment, highlighting the detrimental effects of excessive CS application on P. longum. Overall, these findings emphasize the importance of optimizing CS concentrations for effective enhancement of growth and yield in P. longum cultivation, while also highlighting the potential risks associated with excessive CS application.

Saccharomyces Cerevisiae Diet Supplementation Affects Nutrient Digestibility and Milk and Mozzarella Cheese Yield in Dairy Buffalo Cows During the Transition.

The aim of the trial was to evaluate the influence of diet supplementation with Saccharomyces cerevisiae on nutrient digestibility and milk and mozzarella cheese yield in buffalo cows during the transition period. Twenty buffalo cows in the last month of pregnancy were equally divided into two groups (control, C, and treated, T) homogeneous for parity and milk yield at the previous lactation. The diet of group T was supplemented with 100 g/head/day of a product containing Saccharomyces cerevisiae (Sc 47- CNCM I-4407) for 4 weeks before and after calving. Dry matter intake and the body condition score were not affected by the dietary treatment. In contrast, organic matter, protein, NDF, and ADF digestibility significantly (p < 0.01) increased. Group T showed a higher milk yield (kg 10.5 vs. 9.2, p < 0.05) but lower milk fat (g/kg 76.0 vs. 80.1, p < 0.05). The buffalo standard milk (FPCM = 740 kcal) yield was higher in the treated group (kg 16.8 vs. 15.0, p < 0.05), whereas the mozzarella cheese yield was not affected by the treatment (p > 0.05). These findings indicate that supplementation of the diet of buffaloes with Saccharomyces cerevisiae during the transition period results in notable enhancements in nutrient digestibility and milk yield. These outcomes are worthy of further investigation.

Converting Biochar Into Biochar‐Based Urea Promotes Environmental and Economic Sustainability in Rice‐Wheat Rotation System

ABSTRACTBiochar amendments in rice‐wheat systems are sustainable for reducing GHGs (greenhouse gases) and improving soil health but the widespread adoption of biochar faces economic challenges. To address limitation, a novel biochar‐based urea was formulated for environmental and cost advantages. A pot experiment within a rice‐wheat rotation was conducted to evaluate comparative effects of biochar‐based urea (CKBU), biochar + urea (BCU), and biochar‐based urea + biochar (BCBU) over conventional mineral fertilizer (CKU) on soil ammonia (NH3) volatilization, GHG emissions, soil structure, and crop productivity. Furthermore, fertilizer N fate was tracked using the 15N isotope during wheat season. The results indicated that compared to CKU, CKBU, BCU, and BCBU treatments significantly mitigated NH3 volatilization by 22%–31% during the rice season, and a 19% reduction was observed under the BCBU treatment during the wheat season due to the response of N‐cycling microorganisms. Regarding GHG emissions, the CKBU, BCU, and BCBU treatments significantly decreased the global warming potential (GWP) value by 49%–55% during the rice season and by 26%–45% during the wheat season, compared to CKU. Additionally, CKBU enhanced 15N use efficiency by 29% during wheat season, without affecting the rice season. The economic performance indicated that applying BU alone offered a net economic benefit, whereas biochar amendment led to a net economic loss. However, biochar amendment improved SOC and aggregation structure, with a significant increase in macroaggregate distribution over 50% compared to CKU and CKBU. Therefore, BU with small portions of biochar can be as effective in reducing NH3 emissions and mitigating GHG emissions as the use of a large quantity of biochar. Additionally, the BCBU did not show additional synergistic benefits regarding emission reduction or yield enhancement. Therefore, shifting biochar to BU could be a cost‐effective approach to achieving sustainable productivity in rice‐wheat crop rotation systems.

The role of trehalose metabolism in plant stress tolerance.

Trehalose is a nonreducing disaccharide containing two glucose molecules linked through an α,α-1,1-glycosidic bond. This unique chemical structure causes trehalose levels to fluctuate significantly in plants under stress, where it functions as an osmoprotectant, enhancing plant resistance to stress. Previous studies have confirmed that the trehalose synthesis pathway is widely conserved across most plants. However, the protective role of trehalose is limited only to organelles or tissues where the concentration is sufficiently high. In this review, we summarize previous reports on improving plant stress tolerance (drought, cold, heat, salt, pathogen, etc.) by applying trehalose-6-phosphate (T6P) or trehalose and manipulating the expression of trehalose metabolism-related genes. The molecular mechanisms underlying T6P, trehalose, and their related genes that regulate plant stress resistance are reviewed. More progressive studies on the spatiotemporal control of trehalose metabolism will provide a novel tool that allows for the simultaneous enhancement of crop yield and stress tolerance. We introduce the history of trehalose and discuss the possibility of trehalose and its metabolity-related genes binding to T6P to participate in stress response through unknown signaling pathways. In addition, the effects of trehalose metabolism regulation on plant growth and stress resistance were reviewed, and the molecular mechanism was fully discussed. In particular, we came up with new insights that the molecular mechanism of trehalose metabolism to enhance plant stress resistance in the future and we propose the need to use biotechnology methods to cultivate crops with stress resistance and high yield potential.

Ecophysiological and Molecular Analysis of Contrasting Genotypes for Leaf Senescence in Sunflower (Helianthus annuus L.) Under Differential Doses of N in Soil.

Leaf senescence in plants is the last stage of leaf development and is characterized by a decline in photosynthetic activity, an active degeneration of cellular structures, and the recycling of accumulated nutrients to areas of active growth, such as buds, young leaves, flowers, fruits, and seeds. This process holds economic significance as it can impact yield, influencing the plant's ability to maintain an active photosynthetic system during prolonged periods, especially during the grain filling stage, which affects plant weight and oil content. It can be associated with different stresses or environmental conditions, manifesting itself widely in the context of climate change and limiting yield, especially in crops of agronomic relevance. In this work, we study the stability of two widely described sunflower (Helianthus annuus L.) genotypes belonging to the INTA Breeding Program against differential N conditions, to verify their yield stability in control conditions and under N supply. Two inbred lines were utilized, namely R453 (early senescence) and B481-6 (late senescence), with contrasting nitrogen availability in the soil but sharing the same ontogeny cycle length. It was observed that, starting from R5.5, the B481-6 genotype not only delayed senescence but also exhibited a positive response to increased nitrogen availability in the soil. This response included an increase in intercepted radiation, resulting in a statistically significant enhancement in grain yield. Conversely, the R453 genotype did not show significant differences under varying nitrogen availability and exhibited a tendency to decrease grain yield when nitrogen availability was increased. The response to nitrogen can vary depending on the specific genotype.

CRISPR/Cas9 Driven Targeted Editing of Grain Number 1a gene: sgRNA Constructs Design for Yield Enhancement in Rice (Oryza sativa L.)

Yield is the ultimate trait determined by various quantitative trait loci (QTLs). One such QTL, GRAIN NUMBER 1a (GN1a), encodes for an enzyme Cytokinin oxidase/ dehydrogenase (CKX), which negatively influences the yield by degrading the phytohormone Cytokinin. CRISPR/Cas9, a precise means for targeted editing of a gene for the improvement of a particular trait in plants. Therefore, targeted genome editing of GN1a gene was performed to down-regulate the expression using CRISPR/Cas9 for the increase in grain number and yield with improved Cytokinin content in the panicle meristem. For the site-targeted mutagenesis, the single guide RNAs (sgRNAs) were designed using plant specific CRISPR-P v2.0 software. Two efficient sgRNAs were chosen critically entrenched on their GC content, on-target values, location on the gene, off-target sites and their location, secondary structures, adjacent to the Protospacer Adjacent Motif (PAM) NGG. The binary vector pRGEB32, with Cas9 influenced by rice ubiquitin promoter and BsaI restriction site driven by rice U3 promoter was employed for cloning of sgRNAs. The sgRNAs were tempered, phosphorylated and astringed with the binary vector pRGEB32, transformed into E. coli DH5α initially, then mobilized into A. tumefaciens EHA105. The present study helps in the development of elite lines which will lead to enhancement of grain number and overall yield for the growing population and farmer’s welfare.

An interplay of salt and Ni stress on contrasting tomato (Solanum lycopersicum L.) genotypes: a physiological and biochemical insight

The concurrently occurring multiple abiotic stresses like salinity and heavy metals (Nickel) pose a serious threat to plant survival and food security worldwide, especially in the face of climate change. Therefore, it is imperative to continuously test and study the plant’s physiological changes under combinations of abiotic stresses to ensure sustainability and food security. An experiment was conducted to study the interactive effects of salinity (0, 7.5, and 15 dS m−1) and Ni toxicity (0, 10, 20, and 40 mg kg−1) on a tolerant (Naqeeb) and a sensitive (Nadir) Solanum lycopersicum L. physiology and fruit quality in the soil. At maturity (50% fruit ripening), the plant growth and physiological characteristics were measured, revealing that the tolerant genotype exhibited the higher values for plant height, dry weight, potassium, membrane stability index (MSI), and antioxidant enzymes (superoxide dismutase; SOD, catalase; CAT, ascorbate peroxidase; APX, and glutathione reductase; GR). Additionally, it showed enhancement in fruit yield, size, and quality. Conversely, the tolerant genotypes showed a lower reduction in terms of plant height (25.4%) and plant dry weight (41.9%) compared to sensitive genotype (30.1 and 51.4%, respectively). Additionally, the tolerant genotype demonstrated lower values of Ni and Na+ concentration and MDA accumulation under the combined stress of salt and Ni, compared to the sensitive genotype. Furthermore, the study indicated that Ni at a concentration of 10 mg kg−1 significantly influenced tomato plant growth by enhancing its nutritional efficiency and competing with Na+. However, Ni at concentrations of 20 and 40 mg kg−1 had toxic effects on the plants, leading to a decrease in plant growth and physiological processes. Moreover, a negative relationship was observed between Ni uptake and Na+ uptake, while a positive relationship was observed between Ni and K+ uptake. Overall, this study provides valuable insights into the interaction between salinity, heavy metal toxicity, and tomato plant physiology, contributing to the development of sustainable agricultural practices.

Effects of the Application of Pseudomonas cedrina DY1-3 on the Growth of Maize Plants and the Structure of Soil Bacterial Community.

Against the background of increasing salinisation of land, the use of environmentally friendly plant growth-promoting bacteria (PGPB) resources for soil improvement is particularly important. The aim of this study was to investigate the effects of Pseudomonas cedrina DY1-3 on maize seedling growth, soil physico-chemical properties, and bacterial community structure. The study also evaluates the effects of this microbial agent on plant growth and saline soil improvement, providing theoretical references for microbial agents in promoting plant growth and improving saline soils. We found that there were significant differences between arable and saline soils in terms of soil physico-chemical properties and bacterial community structural composition, and that total salt was the main environmental factor influencing microbial communities. In both arable and saline soils, the application of DY1-3 bacterial suspension had a significant positive effect on the growth of maize plants and bacterial community richness. In arable soil, it could promote the growth of maize seedlings and significantly increase the Shannon and Simpson index, and AK was a key factor influencing the bacterial community. In saline soil, it could alleviate the mitigation stress and promote the growth of maize seedlings and cause a significant increase in Shannon's and Chao1 index, and the application of DY1-3 and potting could cause a significant decrease in total salt. In addition, DY1-3 and maize plants acting together in the soil can better improve the saline soil. The above results indicate that DY1-3 has potential for saline soil improvement and crop yield enhancement.

Cluster Frontline Demonstration: An Effective Technology Dissemination Approach for Enhancing Productivity and Profitability of Summer Mung (Vigna radiata L.)

Background: Summer mung (Vigna radiata L.) is a viable option for strengthening of soil health, highly remunerative to the farmers, short duration works as a good catch crop and better fits in paddy-wheat cropping pattern in the irrigated agro-ecosystems of Northern India. Methods: A total number of 175 cluster front line demonstrations (CFLD) were conducted on summer mung covering 70 ha land using improved variety MH-421 during summer 2022 and 2023 by Krishi Vigyan Kendra (KVK), Fatehabad in its adopted villages at farmer’s field. In present study production, productivity and economic returns of summer mung in demonstrations and farmers’ practice were compared and different yield gaps were analysed. Result: Adoption of improved technology resulted in increased average yield of demonstration plots by 30.13 and 15.37 percent in summer 2022 and 2023, respectively. The extension gap was 1.57 and 0.83 q/ha while technology gap was 5.22 and 5.77 q/ha in 2022 and 2023, respectively. The technology index varied from 43.50 48.53% during summer 2022 and 2023, respectively. The additional economic returns for farmers ranged from Rs. 9722 to Rs. 5453/ha as a results of these CFLD. Hence, adoption of latest and improved summer mung cultivation practices reflects the enhancement of yield and higher economic returns.

Effects of Different Fertilization Treatments on Bacterial Community and Citrus Quality in Yellow Soils of the Yunnan-Guizhou Plateau

To investigate the intrinsic driving mechanism of citrus yield and quality enhancement under different fertilizer applications, a field experiment was conducted to study the effects of biochar （SW）, organic fertilizer （YJ）, farmyard manure （NJ）, chemical fertilizer （HF）, and no fertilizer as the control （CK） on soil physical and chemical properties, bacterial community characteristics, and citrus quality of citrus orchards in the yellow soil area of the Yunnan-Guizhou Plateau. The results showed that compared with those in the CK treatment, the yield, single fruit weight, edible rate, juice rate, vitamin C content, and soluble solids of citrus increased under the different fertilization treatments. In contrast, the titratable acid content of citrus decreased, resulting in an increase in the solid-acid ratio of citrus. Among the different fertilization treatments, the most significant effective treatment was SW. The SW and YJ treatments significantly increased the soil pH value, while the HF treatment decreased soil pH. Different fertilization treatments could increase the contents of soil organic matter, hydrolyzable nitrogen, available phosphorus, and available potassium. The SW treatment exhibited the most obvious effect on the contents of soil hydrolyzable nitrogen, available phosphorus, and available potassium. The YJ treatment exhibited the most obvious effect on the soil organic matter content. The different fertilization treatments significantly affected soil bacterial community diversity and community structure, among which the SW treatment significantly increased the soil Chao1 index, observed species index, and Shannon index； optimized soil bacterial community structure； and made the bacterial symbiotic network simple and stable. By contrast, the HF treatment significantly decreased the soil Chao1 index, observed species index, and Simpson index and had less effect on bacterial community structure. Redundancy analysis showed that soil available potassium （96.47%）, Chao1 index （73.80%）, and Chujaibacter （55.92%） were the key factors in improving citrus yield and quality. Variance decomposition analysis indicated that the soil bacterial community structure was the largest contributor （17.00%） to the improvement in citrus yield and quality. In conclusion, fertilization can effectively improve soil physical and chemical properties, increase soil nutrient supply level, optimize bacterial community structure, and improve citrus yield and quality. Of these, biochar can be used as a priority for the fertilization and improvement of the soil in citrus orchards in the yellow soil area of the Yunnan-Guizhou Plateau.

Chiroptical Amplification of [7]-Helicene Nanographene by Additional Helical Chirality.

Nanographenes have captivated scientific interest since the pioneering discovery of graphene. Recently, attention has shifted towards exploring chiral and nonplanar nanographenes, for their distinct optical, chiroptical, and electronic properties. Despite the growing acceptance of helicenes, the research on inducing helical chirality on π-extended derivatives to boost chiroptical properties remains unattended. In our study, we introduce a new π-extended [7]-helicene resulting from the condensation of diamines with 3,6-dibromophenanthrene-9,10-dione, complemented by two hexabenzocoronene arms in the periphery. Notably, the nanographene containing binaphtho-[1,4]diazocine, compared to the corresponding phenazine, exhibits a remarkable average 2.5, 5, and 10-fold enhancements in quantum yield, dissymmetry factor, and brightness, respectively, when measured in five different solvents. These improvements underscore the significance of the induced helical chirality by the antiaromatic binaphtho-[1,4]diazocine in influencing the chiroptical properties of the helical nanographene. Our research represents a significant stride toward unlocking the potential of π-extended helicenes and lays the groundwork for further exploration in designing and synthesizing new chiral nanomaterials.

Xenon photoionization in the vicinity of 4d giant resonance and Cooper minimum using an XUV-NIR pump-probe experiment

The relaxation processes in atomic xenon following core ionization of the 4d and 4p subshells by extreme ultraviolet (XUV) pulses from a free-electron laser (FLASH) are investigated using ion time-of-flight spectroscopy. We compare the dynamics following ionization and Auger-Meitner decays at 90-eV photon energy, i.e., near the giant resonance, with those at 160 eV, near the Cooper minimum, where cross sections for photoionization of the 4d and 4p subshells are similar. Final states with charges higher than 4 show signatures of sequential absorption of two XUV photons, followed by subsequent Auger-Meitner decay. The averaged lifetimes of some important excited states are measured in a two-color XUV-pump–near-infrared-probe experiment. A transient enhancement in the ion yield of Xe5+ with an average lifetime of (49±3) fs is obtained, attributed to transient intermediate states following the decay of 4d double-core-hole states. Published by the American Physical Society 2024