Search Results (55)

Calcium cyanamide (CaCN₂), commercially known as Perlka^®, is re-emerging as a multifunctional nitrogen (N) fertilizer with significant agronomic and environmental advantages. Composed of 19.8% nitrogen and 50% calcium oxide (CaO), CaCN₂ not only supplies slow-release nitrogen but also acts as a liming agent, improving soil pH and structure. Its transformation pathway: cyanamide → urea → ammonium → nitrate—ensures a gradual nitrogen release that aligns with crop demand, enhances nitrogen use efficiency, and minimizes nitrate leaching and nitrous oxide emissions. Additionally, the presence of dicyandiamide, a known nitrification inhibitor, further stabilizes nitrogen in the soil. Field studies across diverse cropping systems, including curly endive and short-day onions, have demonstrated that CaCN₂ improves yield, crop quality, and soil health. In onions, preplant application of 80 kg ha⁻¹ N from CaCN₂ increased bulb yield by up to 18%, enhanced phytochemical content (e.g., phenolics and flavonoids), and reduced nitrate leaching by over 40% compared to urea and limestone ammonium nitrate (LAN). In curly endive, CaCN₂ significantly improved ascorbic acid, total soluble solids, and phenolic content, particularly in fall-grown crops, while reducing nitrate accumulation and improving physiological and recovery efficiency of applied nitrogen. Beyond its role as a nutrient supplier, CaCN₂ exhibits biocidal properties that suppress soil-borne pathogens such as Sclerotinia and Plasmodiophora brassicae, reduce weed pressure, and stimulate beneficial microbial activity. Its high calcium content also addresses physiological disorders linked to calcium deficiency, such as tip-burn and blossom-end rot. However, proper application timing and dosage are critical to avoid phytotoxicity, especially in sensitive crops. This review synthesizes current knowledge on CaCN₂’s chemical behavior, agronomic performance, and environmental implications, and identifies research gaps to guide its optimized use in climate-smart and resource-efficient agriculture. Full article

To scientifically assess the effects of environmentally friendly fumigants on soil microbial communities, soils from a 7-year continuous cropping tomato greenhouse were studied, with unfumigated soil used as the control (CK). Rhizosphere soil samples treated with dazomet (DZ), metam sodium (MS) and calcium cyanamide (CC) were collected at the seedling recovery and fruiting stages. The influences of different fumigants and growth stages on soil microbial communities, tomato yield and soil-borne diseases were investigated. The results indicated that soil fumigation significantly decreased microbial community richness and diversity at the seedling recovery stage, which gradually recovered at the fruiting stage. The variation trends of microbial relative abundance at the phylum and genus levels differed among the treatments at both stages. At the phylum level, Actinobacteria and Proteobacteria were the dominant bacterial phyla, and Ascomycota was the dominant fungal phylum. Genus-level clustering revealed that the bacterial communities under MS and CC were similar to those under CK at the fruiting stage, whereas the fungal communities under all the fumigation treatments were significantly distinct from those under CK. Fumigation effectively inhibited pathogenic genera, including Amesia, Fusarium, Rhizopus and Ascobolus, at the seedling recovery stage, but some pathogens recovered at the fruiting stage. The relative abundance of Fusarium in the MS treatment increased to 8.25%. DZ treatment performed optimally: it increased beneficial genera such as Bacillus and Streptomyces at the seedling recovery stage, suppressed harmful genera, including Amesia and Fusarium, and further enriched Remersonia at the fruiting stage. Fumigation significantly improved tomato yield and reduced the incidence of soil-borne diseases. The yield of CC was the highest, at 35.41% greater than that of CK, but it was not significantly different from that of DZ in terms of cost. In conclusion, the DZ treatment had the best overall effect. Full article

This study reports the synthesis and comprehensive spectroscopic characterization of 4-indolylcyanamide (4ICA), a novel indole-derived infrared (IR) probe designed for assessing local microenvironments in biological systems. 4ICA was synthesized via a two-step procedure with an overall yield of 43%, and its structure was confirmed using high-resolution mass spectrometry and ¹HNMR. Fourier Transform Infrared (FTIR) spectroscopy revealed that the cyanamide group stretching vibration of 4ICA exhibits exceptional solvent-dependent frequency shifts, significantly greater than those of conventional cyanoindole probes. A strong linear correlation was observed between the vibrational frequency and the combined Kamlet–Taft parameter, underscoring the dominant role of solvent polarizability and hydrogen bond acceptance in modulating its spectroscopic behavior. Quantum chemical calculations employing density functional theory (DFT) with a conductor-like polarizable continuum model (CPCM) provided further insight into the solvatochromic shifts and suppression of Fermi resonance in high-polarity solvents such as DMSO. Additionally, IR pump–probe measurements revealed short vibrational lifetimes (~1.35 ps in DMSO and ~1.13 ps in ethanol), indicative of efficient energy relaxation. With a transition dipole moment nearly twice that of traditional nitrile-based probes, 4ICA demonstrates enhanced sensitivity and signal intensity, establishing its potential as a powerful tool for site-specific environmental mapping in proteins and complex biological assemblies using nonlinear IR techniques. Full article

Preventing soil degradation caused by water erosion is essential for sustainable agriculture and long-term agroecological development. The objective of this study was to evaluate the effectiveness of an ethylene-vinyl acetate (EVA) polymer-based soil conditioner in mitigating soil erosion, a key driver of soil degradation. Laboratory experiments and simulations employing the Water Erosion Prediction Project (WEPP) model were conducted to assess soil erodibility parameters and sediment yield of two soil types from Okinawa, Japan. A key contribution of this work is the integration of these experimentally determined erodibility parameters into the WEPP model for robust validation. Interrill and rill erosion processes were analyzed under different soil conditioner application rates. Laboratory results showed that applying the soil conditioner reduced interrill erodibility by 59 to 99% and rill erodibility by 65 to 100%, while increasing critical shear stress and water infiltration rate. The effectiveness varied between the two soil types due to differences in particle-size distribution and inherent erodibility. The soil conditioner exhibited a more pronounced impact on rill erosion. WEPP simulations confirmed sediment yield reductions of 73% to 99%, primarily influenced by changes in rill erodibility and critical shear stress. While its practical application will be subject to various field conditions, our findings confirm the significant potential of this soil conditioner as a strategy for preserving topsoil resources. Full article

The UV-induced photolysis of 2-aminothiazole-4-carboxylic acid (ACA), a biologically active molecule, was studied using the infrared matrix isolation method. As the first step of photolysis, a decarboxylation reaction occurred. Subsequently, two main photolysis pathways of 2-aminothiazole were observed, during which a number of new molecules, including potential prebiotic carbodiimides or molecular complexes, were identified. The CS–CN bond cleavage path produced N-(1-sulfanylethen-2-yl)carbodiimide (fp1), N-(thiiran-2-yl)carbodiimide (fp3), N-(1-thioethan-2-yl)carbodiimide (fp2), N-(1-thioethan-1-yl)carbodiimide (fp4) and N-(1-thioethan-2-yl)cyanamide (fp33), which were identified for the first time. In this channel, additional disruption of the N–C bond produced cyanamide (fp27) and thiirene (fp28) and subsequent photoreactions generated carbodiimide (fp29) or ethynethiol (fp30). The CS–CC bond cleavage path occurred simultaneously and produced several new molecules: N’-ethynylcarbamimidothioic acid (fp14), N-ethynylcarbamimidothioic acid (fp17), N-ethenylidenecarbamimidothioic acid (fp18) and N-ethenylidenethiourea (fp15). In this channel, additional disruption of the N–C bond produced acetylene (fp23) and N-thiolcarbodiimide (fp26). Among the small molecules, N-thiolcarbodiimide and thiirene, as well as all molecular complexes, were observed for the first time. Full article

Adenosine nucleotides and polyphosphates play a significant role in biochemistry, from participating in the formation of genetic material to serving as metabolic energy currency. In this study, we examine the stability and decomposition rates of adenosine phosphates—5′-AMP, 5′-ADP, and 5′-ATP (mentioned simply as AMP, ADP and ATP hereafter)—at temperatures of 22–25 °C, 50–55 °C, 70–75 °C, and 85–90 °C, at a pH of 4, over periods of 2 and 4 days, in both saltwater and ultrapure water, under unsealed and completely dried down conditions. We found that adenosine phosphates degrade rapidly under heat and dehydration, particularly at temperatures above 25 °C. Among the three compounds, AMP is the most stable, maintaining its integrity between 22 and 55 °C, whereas ATP begins to degrade at 22–25 °C and ADP is completely decomposed at temperatures above this range. Decomposition rates were analyzed using quantitative ³¹P-NMR, based on the detection of various phosphorus-containing species. AMP primarily hydrolyzed into phosphate, pyrophosphate and even formed 2′,3′-cAMP. In contrast, the condensed adenosine phosphates (ADP and ATP) hydrolyzed to AMP, phosphate, pyrophosphate, triphosphate, 5′-AMP and, in some cases, 2′,3′-cyclic adenosine monophosphate (2′,3′-cAMP). We also investigated the formation of these compounds in the presence of N-containing additives such as thiourea, urea, imidazole, and cyanamide at temperatures between 65 and 70 °C. Among these, cyanamide and urea were particularly effective in promoting the synthesis of adenosine monophosphates (AMPs) from phosphate and adenosine. The major products observed were 2′,3′,5′-AMPs and cyclic 2′,3′-AMPs. In some experiments, adenosine diphosphate (ADP) and dimeric nucleotide species were also detected. These findings suggest that moderately heated evaporating pools could facilitate the abiotic formation of AMPs. However, such environments would likely have been unsuitable for the long-term accumulation of these compounds due to continued degradation, though there would exist some level of these nucleotides at steady state. Full article

Climate change has contributed to a decline in winter chilling accumulation, a critical requirement for budbreak in temperate fruit crops. Its consequence has been a reduction in fruit production. To compensate for insufficient chilling, hydrogen cyanamide (HC) is widely applied, though its effectiveness remains limited. This study investigated the effect of HC application on budbreak in low-chill kiwifruit under warm conditions by correlating phenological responses with changes in carbohydrate and nitrogen concentrations in bark tissues across bud positions. Phenological observations revealed the highest budbreak percentage and total flower buds at the apical position. HC significantly increased budbreak by 58.82% at the apical position and by 375% at the middle position, with corresponding increases in total flower buds by 148.78% and 1066.67%, respectively. Additionally, shoot lengths were uniform among bud positions in HC-treated canes, whereas non-treated canes showed shoot length heterogeneity. Moreover, HC treatment triggered an earlier and more pronounced reduction in soluble sugars (sucrose and hexoses) concentrations along the gradient from apical to basal bud positions, where the response was strongest at the apical position, which was strongly associated with enhanced budbreak percentages and total flower bud formation. While total nitrogen content was highest in the apical position, it was unaffected by HC application. These findings indicate that HC may promote budbreak by enhancing the mobilization and consumption of soluble sugars for bud growth, thereby improving budbreak performance, flower bud production, and uniform shoot development in low-chill kiwifruit under warm conditions. Full article

The success of double cropping in Vitis vinifera L. cultivated in temperate climates relies on bud forcing efficiency, which requires the prompt unlocking of apical dormant buds with sufficient fruitfulness. Chemical dormancy-breaking strategies need to be tested to enhance dormant bud forcing in summer pruning, as hydrogen cyanamide, the most used agent, could damage green organs. This study tested whether foliar applications of cytokinins and auxins could modulate dormancy release, potentially affecting bud forcing dynamics and shoot fruitfulness. The forcing treatments involved trimming primary shoots at the eighth node, removing lateral shoots, and retaining the main leaves and inflorescences. Five treatments were investigated: unforced control, control + 6-Benzyladenine application, forcing (FR), forcing + 6-Benzyladenine application (FBA), and forcing + Naphthaleneacetic acid application (FNAA). Phenological evolution, vegetative and productive parameters, and physiological characteristics have been assessed. Results showed that among the forcing treatments, FBA showed the highest forced/primary shoots ratio (106%), followed by FR (94%) and FNAA (21%). Primary yields were similar across treatments (2.74 kg), but total yield was highest in FBA (4.78 kg, including 2.02 kg from forced grapes), followed by FR (3.62 kg, with 1.09 kg forced). FNAA yielded no forced crop. During forced grapes maturation, photosynthesis rates were higher in forced leaves (11.1 μmol m⁻² s⁻¹, as FR and FBA average) than primary leaves (−32%). Forced grapes ripened 47 days later and achieved higher sugar content (21.7 °Brix) and titratable acidity (10.6 g/L) than primary grapes. The findings suggest cytokinins application enhances bud forcing, supporting the feasibility of double cropping, while auxins limited it. Full article

Exploring the microscopic reaction mechanism of dicyandiamide (DCD) synthesis using calcium cyanamide (CaCN₂) is highly desirable because of the low conversion of reactants and selectivity of DCD products. DCD synthesis consists of a two-step sequential hydrolysis of CaCN₂, followed by dimerization of cyanamide to DCD in an alkaline environment. Density functional theory (DFT) results revealed that the rate-limiting step (RLS) was the formation of a C-N bond between the cyanamide and cyanamide anion in the dimerization of the DCD reaction. Secondary reactions of cyanamide with water, hydrogen sulfide, and DCD were also analyzed. The effects of solvation on the principal and secondary reactions were systematically explored. A single explicit water molecule can significantly lower the free energy barrier of the RLS. Water molecules facilitate the C-N bonding of the reactants in DCD reactions, resulting in a reduction in the free energy barrier of the RLS. The facilitation of double explicit water for the reaction is weaker than that of single explicit water and even yields negative catalysis. The effect of the [OH(H₂O)₃]⁻ cluster lowering the reaction barrier with the hydrogen-bonding network is the most remarkable, which can alter the reaction path by the direct and indirect involvement of OH⁻ ions. Furthermore, the reaction rate constants were computed by canonical variational theory with the Eckart tunneling correction (CVT/Eckart) and fitted to the Arrhenius expression. The reaction mechanism and kinetics revealed at the microscopic level provide efficient and clean production of DCD with certain theoretical guidance. Full article

Soil salinization and alkalinization are pervasive environmental issues that severely restrict plant growth and crop yield. Utilizing plant growth-promoting rhizobacteria (PGPR) is an effective strategy to enhance plant tolerance to saline–alkaline stress, though the regulatory mechanisms remain unclear. This study employed biochemical and RNA-Seq methods to uncover the critical growth-promoting effects of Trichoderma spp. on Salix linearistipularis under saline–alkaline stress. The results showed that, during saline–alkaline stress, inoculation with Trichoderma sp. M4 and M5 significantly increased the proline and soluble sugar contents in Salix linearistipularis, enhanced the activities of SOD, POD, CAT, and APX, and reduced lipid peroxidation levels, with M4 exhibiting more pronounced effects than M5. RNA-Seq analysis of revealed that 11,051 genes were upregulated after Trichoderma sp. M4 inoculation under stress conditions, with 3532 genes primarily involved in carbon metabolism, amino acid biosynthesis, and oxidative phosphorylation—processes that alleviate saline–alkaline stress. Additionally, 7519 genes were uniquely upregulated by M4 under stress, mainly enriched in secondary metabolite biosynthesis, amino acid metabolism, cyanamide metabolism, and phenylpropanoid biosynthesis. M4 mitigates saline–alkaline stress-induced damage in Salix linearistipularis seedlings by reducing oxidative damage, enhancing organic acid and amino acid metabolism, and activating phenylpropanoid biosynthesis pathways to eliminate harmful ROS. This enhances the seedlings’ tolerance to saline–alkaline stress, providing a basis for studying fungi–plant interactions under such conditions. Full article

The combined effects of slope gradient, rainfall intensity, and nitrogen fertilizer source on infiltration, runoff, soil loss, and nitrogen (N) leaching in agricultural areas are not thoroughly understood, despite their critical importance in sustainable agriculture. Previous studies have focused on these factors individually, leaving a significant gap in knowledge regarding their synergistic impact. Investigating the interplay between slope gradients, rainfall intensities, and N fertilizer sources is vital to developing effective soil and water conservation strategies and implementing sustainable agricultural practices. This study is comprised of two experiments. Experiment 1 was designed as a 3 × 2 × 3 factorial arrangement, incorporating three levels of rainfall intensity (RI) (45, 70, and 100 mm/h), two slope gradients (5 and 8°), and three soil types (sandy loam, silt loam, and clay loam), aimed at assessing runoff, infiltration, and soil loss. Experiment 2, laid out as 3 × 2 × 3 × 3 factorial, expanded on this, adding N fertilizer source (urea, CaCN₂, and limestone ammonium nitrate (LAN) at 130 kg/ha N) and assessing N leaching alongside the previous metrics. Both experiments used a rotating disc rainfall simulator and were replicated four times. Results revealed that steeper slopes (8°) led to increased runoff and soil loss, impeding infiltration, while gentler slopes (5°) facilitated greater infiltration and minimized soil loss. Rainfall intensity played a significant role, with 70 mm/h/5° combinations promoting higher infiltration rates (48.14 mm/h) and 100 mm/h/8° resulting in lower rates (37.07 mm/h for sandy loam and silt loam, 26.09 mm/h for clay loam). Nitrogen leaching varied based on N source; urea at 130 kg/ha N led to higher losses (7.2% in sandy loam, 6.9% in silt loam, 6.5% in clay loam), followed by LAN (6.9% in sandy loam, 6.7% in silt loam, 6.3% in clay loam) while CaCN₂ at the same rate resulted in lower N losses (6.4% in sandy soil, 4.4% in silt loam, 4.2% in clay soil). This research highlights the critical need to consider both slope gradient and rainfall intensity in conjunction with appropriate nitrogen fertilizer sources when developing strategies to mitigate soil erosion and nutrient loss in agricultural settings. Full article

The rest-breaking agent, hydrogen cyanamide (HC), can substitute insufficient chill unit accumulation in Vitis vinifera and induce uniform bud-break; however, due to its toxicity it is being banned. In South Africa, red seedless grapes, including V. vinifera Crimson Seedless (CS), are the largest table grape export group; therefore, replacing HC in V. vinifera CS is crucial. This study aimed to confirm the molecular triggers induced by HC and assess the bud-break-enhancing abilities of commercial plant biostimulants. Forced bud-break assay experiments using V. vinifera CS single-node cuttings and a small-scale field trial were performed. Results demonstrated that increased chill unit accumulation (CUA) reduced HC efficacy. Bud-break started between 10 and 20 days after treatment, irrespective of final CUA. The small-scale field trial found that HC 3% and biostimulants were similar to the negative control. The treatment of dormant grapevine compound buds with nitric oxide (NO), hydrogen peroxide (H₂O₂), and hypoxia trigger dormancy release to a certain extent, supporting the molecular models proposed for HC action. NO, H₂O₂, and hypoxia, in combination with PBs, may potentially replace HC; however, this needs to be confirmed in future experiments. Full article

Clubroot, caused by Plasmodiophora brassicae, is a destructive soil-borne disease significantly harming global Brassica crop production. This study employed the Williams and European Clubroot Differential (ECD) and Williams systems to identify the pathotypes of P. brassicae collected from Hangzhou City, Yuhang District and Quzhou City, Kaihua County in Zhejiang Province. Greenhouse and field trials were conducted to evaluate the effects of plastic film covering and four chemical agents on the growth parameters and clubroot severity of the Chinese cabbage cultivar ‘Granaat’. Potential treatment mechanisms on clubroot were explored through a qPCR analysis of the resting spore density and pH measurement of the soil. Furthermore, treatment with 1-napthaleneacetic acid (NAA), a synthetic auxin, was also evaluated for its potential role in suppressing clubroot. The results indicate that the pathotypes of P. brassicae in the two districts were P1, ECD20/31/12, and P3, ECD20/15/4. While an individual application of plastic film covering could not effectively control clubroot, calcium cyanamid, dazomet and ammonium bicarbonate demonstrated significant efficacy in its management. These three agents significantly reduced the resting spore density in the soil, with calcium cyanamid and ammonium bicarbonate also increasing soil alkalinity. Additionally, ammonium bicarbonate promotes lateral root development in ‘Granaat,’ helping infected plants access adequate water and nutrients. However, NAA exhibited no efficacy in clubroot control. Therefore, sustained lateral root development is crucial for effectively resisting P. brassicae invasion. Considering application costs and environmental friendliness, we propose the field application of ammonium bicarbonate as the optimal method for clubroot disease management in Zhejiang Province. Full article

At present, returning vegetable straw in situ is an effective measure to solve environmental pollution and improve soil properties. However, the direct return of straw to the field can reduce the release rate of soil organic matter and cause serious soilborne diseases. The combined application of calcium cyanamide (CaCN₂) and straw can solve this problem. The objective of this study was to determine the effect of CaCN₂ combined with pepper straw return on cucumber yield, soil physicochemical properties, and soil microbial communities during 2020 to 2021 in Shandong Province, China. The treatments were designed as follows: (1) calcium cyanamide soil disinfection, CC; (2) fresh pepper straw return, LJ; (3) fresh pepper straw return combined with calcium cyanamide disinfection, LJ+CC; and (4) natural soil without straw return treatment, CK. Compared with CK, the LJ+CC treatment significantly improved cucumber production by 20%. The cultivable microbial community in the soil was temporarily inhibited during soil fumigation treatment, and the cultivable bacterial and actinomycete communities in the soil return to their initial levels after the film was removed (harvest period). The numbers of culturable bacteria and actinomycetes in the soil in the LJ+CC treatment were 4.68 × 10⁷ CFU/g and 5.17 × 10⁷ CFU/g, respectively, higher than those in the soil in the CC treatment. The contents of TN and OM in the LJ+CC treatment increased by 13.1% and 13.5%, respectively, compared with that in LJ. Therefore, the LJ+CC treatment enhanced soil fertility and cucumber yields. CaCN₂ can promote straw decomposition and straw can promote soil microbial recovery, and their combined application is considered a feasible and sustainable technique for utilizing vegetable residues in the greenhouse. The combination of returning pepper straw to the field and calcium cyanamide technology achieves a win-win situation of resource circulation and economic circulation by converting agricultural waste into fertilizer before being put into production. Based on this, it is recommended that the straw returning technology receives strong policy support, stimulates researchers to explore the feasibility of different vegetable straw returning to the field, promotes the implementation of this technology achievement, and leverages the environmental benefits of the application of straw returning technology. Full article

The synthesis of 2-aminoquinazoline derivatives is achieved by using hydrochloric acid as a mediator in the [4+2] annulation reaction between N-benzyl cyanamides and 2-amino aryl ketones. In addition, 2-amino-4-iminoquinazolines are synthesized by the reaction of 2-aminobenzonitriles, instead of 2-amino aryl ketones, with N-benzyl cyanamides. A wide range of substrates can be used and high yields are obtained, demonstrating the practicality of this method for the synthesis of 2-aminoquinazoline derivatives. Full article