Search Results (84)

Analyzing the soil organic carbon (SOC) stock in dryland areas of southern Shanxi, particularly under the influence of fertilization and mulching conditions, is crucial for enhancing soil fertility and crop productivity and understanding the SOC pool’s resilience to future climate change scenarios in the region. In a long-term experimental site located in Hongtong County, Shanxi Province, soil samples were collected from the 0–100 cm depth over a nine-year period. These samples were analyzed to evaluate the impact of five treatments: no fertilization and no mulching (CK), conventional farming practices (FP), nitrogen reduction and controlled fertilization (MF), nitrogen reduction and controlled fertilization with ridge-film furrow-sowing (RF), and nitrogen reduction and controlled fertilization with flat-film hole-sowing (FH). The average annual yield of wheat grain, SOC stock, water-soluble organic carbon (WSOC), particulate organic carbon (POC), light fraction organic carbon (LFOC), mineral-associated organic carbon (MOC), and heavy fraction organic carbon (HFOC) stocks were measured. The results revealed that the FH treatment not only significantly increased wheat grain yield but also significantly elevated the SOC stock by 23.71% at the 0–100 cm depth compared to CK. Furthermore, this treatment significantly enhanced the POC, LFOC, and MOC stocks by 106.43–292.98%, 36.93–158.73%, and 17.83–81.55%, respectively, within 0–80 cm. However, it also significantly decreased the WSOC stock by 34.32–42.81% within the same soil layer and the HFOC stock by 72.05–101.51% between the 20 and 100 cm depth. Notably, the SOC stock at the 0–100 cm depth was primarily influenced by the HFOC. Utilizing the DNDC (denitrification–decomposition) model, we found that future temperature increases are detrimental to SOC sequestration in dryland areas, whereas reduced rainfall is beneficial. The simulation results indicated that in a warmer climate, a 2 °C temperature increase would result in a SOC stock decrease of 0.77 to 1.01 t·ha⁻¹ compared to a 1 °C increase scenario. Conversely, under conditions of reduced precipitation, a 20% rainfall reduction would lead to a SOC stock increase of 1.53% to 3.42% compared to a 10% decrease scenario. In conclusion, the nitrogen reduction and controlled fertilization with flat-film hole-sowing (FH) treatment emerged as the most effective practice for increasing SOC sequestration in dryland areas by enhancing the HFOC stock. This treatment also fortified the SOC pool’s capacity to withstand future climate change, thereby serving as the optimal approach for concurrently enhancing production and fertility in this region. Full article

The formation of polycyclic aromatic hydrocarbons (PAHs) during catagenesis does not exclusively lead to planar structures. The inclusion of five-ring elements increases the curvature of PAHs and yields bent molecules. These bowl-like configurations may end in the formation of spherical carbon allotropes as fullerenes or nanotubes, as recently shown. The presence of fullerenes in crude oil raises the question of why the reaction is feasible under catagenic conditions although the laboratory synthesis of fullerenes commonly requires high-energy environments. This study focuses on the feasibility of the simulation of catagenesis under laboratory conditions and the question of which building blocks may lead to spherical structures. Possible educts, reaction mechanisms, and conditions such as temperature are discussed and related to experimental outcomes. For the simulation under laboratory conditions, a light gas condensate was fractionated by distillation in order to reduce the number of compounds per fraction and make them distinguishable. The characterization of the resulting fractions was performed through GC-MS and GC-FID measurements before heat application in a closed reactor. High-resolution mass spectrometry (HRMS) measurements of the products indicated PAH growth and, more importantly, the formation of fullerenes. Interestingly, the characterized fullerenes mostly comprised the range of non-IPR (isolated pentagon rule) fullerenes. Full article

Pollution of soil by heavy metals has become a critical environmental issue. This study investigated an innovative approach to heavy metals removal, focusing on the desorption of nickel and zinc from vermiculite using a combination of leaching and ultrasonic (US) irradiation at 20 or 362 kHz. When 0.1 M HCl was used as a washing solution, Zn²⁺ desorption yields around 85% were obtained in all conditions. Under 20 kHz US, fragmentation of the particles occurred, leading to the formation of new sites where released Zn²⁺ could sorb, allowing improved decontamination by cation exchange. Even higher yields were obtained with the biobased citric acid. Ni²⁺ desorption yields were lower due to its distribution in less accessible Tessier fractions. They significantly increased under US, especially at 362 kHz. It is shown that US leads to transfer of the contaminant from less accessible fractions (in particular the residual one) to more accessible ones, and that at low frequency, new sorption sites are created by fragmentation, leading to readsorption in the exchangeable fraction. This study brought to light for the first time the potential of high-frequency US in enhancing soil washing, to a higher extent compared to low-frequency (20–50 kHz) US. Full article

In this study, we investigated the effect of particle size and solids loading on the magnesite yield in the direct aqueous mineral carbonation of heat-activated lizardite. Experimentation was conducted under single-step reaction conditions (130 bar partial pressure of carbon dioxide (CO₂) and 150 °C, with 0.64 M sodium bicarbonate (NaHCO₃) and 15 wt% solids) as developed by the Albany Research Center (ARC). The objective of the study was to enhance the understanding of the direct aqueous mineral carbonation process in heat-activated lizardite. Furthermore, we aimed to shed light on how variations in particle size could affect the reaction rate, yield, and the development of protective silica layers. Our experimental data suggest that the extraction of magnesium from finer particles (sub 20 µm) is marginally more effective than from the larger size fractions. This difference likely stems from the larger surface area of fine particles (sub 20 µm) in both low and high solids loading experiments. The highest magnesite yield was 50% after 60 min, and this was achieved for both solids loadings (5 and 15 wt%), demonstrating that the solids loading had no impact on the yield. Our findings indicate rapid heat-activated lizardite reaction within 20 min, which achieved 34% and 40% conversion for 5 wt% and 15 wt% solids loading, respectively. This is followed by declining rates with increasing solids loading. Full article

Aspirin (Asp) is extensively used in human health as an anti-inflammatory, antipyretic, and anti-thrombotic drug. In this study, we investigated if the foliar application of Asp on tomato plants has comparable beneficial effects on photosynthetic function to that of salicylic acid (SA), with which it shares similar physiological characteristics. We assessed the consequences of foliar Asp-spray on the photosystem II (PSII) efficiency of tomato plants, and we estimated the reactive oxygen species (ROS) generation and the chloroplast ultrastructural changes. Asp acted as an osmoregulator by increasing tomato leaf water content and offering antioxidant protection. This protection kept the redox state of plastoquinone (PQ) pull (qp) more oxidized, increasing the fraction of open PSII reaction centers and enhancing PSII photochemistry (Φ_PSII). In addition, Asp foliar spray decreased reactive oxygen species (ROS) formation, decreasing the excess excitation energy on PSII. This resulted in a lower singlet oxygen (¹O₂) generation and a lower quantum yield for heat dissipation (Φ_NPQ), indicating the photoprotective effect provided by Asp, especially under excess light illumination. Simultaneously, we observed a decrease in stomatal opening by Asp, which reduced the transpiration. Chloroplast ultrastructural data revealed that Asp, by offering a photoprotective effect, decreased the need for the photorespiration process, which reduces photosynthetic performance. It is concluded that Asp shares similar physiological characteristics with SA, having an equivalent beneficial impact to SA by acting as a biostimulant of the photosynthetic function for an enhanced crop yield. Full article

1-Methyl cyclopropene (1-MCP) is known as an ethylene antagonist, yet its mechanisms in regulating photosynthetic electron transport and energy dissipation in chrysanthemum under heat stress are not well understood. Here, the chlorophyll a fluorescence and modulated 820 nm reflection transients were analyzed in heat-tolerant and heat-sensitive chrysanthemum plants. This study demonstrates that 1-MCP pre-treatment helps maintain the net photosynthetic rate (P_n) and the reaction center activity of photosystems I and II (PSI and PSII) during heat stress. Specifically, 1-MCP treatment significantly increases the fraction of active oxygen-evolving complex (OEC) centers and reduces relative variable fluorescence intensity at the J step (V_J) as well as the efficiency of electron transfer at the PSI acceptor side (δ_Ro). These effects mitigate damage to the photosynthetic electron transport chain. Additionally, 1-MCP-treated plants exhibit decreased quantum yield of energy dissipation (φ_Do) and reduced energy flux per reaction center (DI_o/RC). Overall, 1-MCP enhances light utilization efficiency and excitation energy dissipation in the PSII antennae, alleviating heat stress-induced damage to PSI and PSII structures and functions. This study not only advances our understanding of 1-MCP’s regulatory role in photosynthetic processes under heat stress but also provides a basis for using exogenous substances to improve chrysanthemum heat resistance. Full article

The phenomenon known as “dimming” or shading, caused by the increase in aerosols, air pollutants, and population density, is reducing global radiation, including both direct solar radiation and radiation scattered by the atmosphere. This phenomenon poses a significant challenge for agricultural production in many regions worldwide, with a global radiation decrease estimated between 1.4% and 2.7% per decade in areas between 25° N and 45° N. In particular, in Mediterranean regions, the production of durum wheat (Triticum turgidum L. subsp. Durum) is increasingly constrained by abiotic factors, such as spring/summer heat stress and drought, as well as reductions in solar radiation. Field experiments were conducted in Mosciano Sant’Angelo, Italy, over two cropping seasons (2016–2017 and 2017–2018) to evaluate the effects of photosynthetically active radiation (PAR) availability and nitrogen (N) fertilization on durum wheat. A split-plot design was used with two PAR levels (100% and 20% PAR) and three N rates (0, 100, and 250 kg ha⁻¹). Results highlighted that full sunlight (NoSh) significantly increased grain yield (+25%), thousand kernel weight (+46%), and total gluten fractions (+16%) compared to shaded conditions (Sh). Chlorophyll content and NDVI values were highest under Sh combined with 250 kg N ha⁻¹. Rainfall patterns strongly influenced productivity, with better vegetative growth in 2016–2017 and improved grain filling in 2017–2018. Nitrogen application significantly enhanced grain protein content, particularly under arid conditions. These findings emphasize the interaction between light availability and nitrogen management, suggesting that optimizing these factors can improve yield and quality in durum wheat under Mediterranean conditions. Full article

The fundamental key to increase photosynthetic efficiency of crop plants lies in optimizing the light energy use efficiency. In our study, we used tomato to evaluate the allocation of absorbed light energy in young and mature leaves, and to estimate if the extent of photoinhibition and photoprotection can be affected by the leaf age. A reduced efficiency of the oxygen-evolving complex, in young leaves compared to mature ones, resulted in a donor-side photoinhibition, as judged from the significantly lower Fv/Fm ratio, in young leaves. The detected increased ¹O₂ production in young leaves was probably due to a donor-side photoinhibition. The effective quantum yield of photosystem II (PSII) photochemistry (Φ_PSII), at low light intensity (LLI, 426 μmol photons m⁻² s⁻¹), was significantly lower in young compared to mature leaves. Moreover, the non-significant increase in non-photochemical energy loss in PSII (Φ_NPQ) could not counteract the decreased Φ_PSII, and as a result the non-regulated energy loss in PSII (Φ_NO) increased in young leaves, compared to mature ones. The significantly lower Φ_PSII in young leaves can be attributed to the increased reactive oxygen species (ROS) creation that diminished the efficiency of the open PSII reaction centers (Fv’/Fm’), but without having any impact on the fraction of the open reaction centers. The reduced excess excitation energy, in mature leaves compared to young ones, at LLI, also revealed an enhanced PSII efficiency of mature leaves. However, there was almost no difference in the light energy use efficiency between young and mature leaves at the high light intensity (HLI, 1000 μmol photons m⁻² s⁻¹). The ability of mature tomato leaves to constrain photoinhibition is possible related to an enhanced photosynthetic function and a better growth rate. We concluded that the light energy use efficiency in tomato leaves is influenced by both the leaf age and the light intensity. Furthermore, the degrees of photoinhibition and photoprotection are related to the leaf developmental stage. Full article

Aluminum alloy 7050-T74 with varying zinc-to-magnesium (Zn/Mg) mass fractions was synthesized using melt casting and hot extrusion techniques. This study investigated the influence of different Zn/Mg ratios on the microstructure, mechanical properties, and corrosion resistance of the alloy. Light microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), tensile testing, and corrosion testing were employed as analytical methods. The findings indicate that as the Zn/Mg ratio increases from 2.36 to 3.84, the proportion of low-angle boundaries (LABs) within the alloys initially rises and then decreases, achieving a balance between high strength and favorable elongation. Specifically, at a Zn/Mg ratio of 2.72, the alloy exhibits a tensile strength of 641 MPa, a yield strength of 609 MPa, and an elongation of 10.1%. Additionally, increasing the Zn/Mg ratio to 2.90 slightly reduces intergranular corrosion resistance while enhancing exfoliation corrosion resistance. Full article

Within the current scenario of cropland use and forest surface loss, there is a need for the implementation of viable urban farming systems, e.g., indoor vertical farming (VF). Light management is fundamental in VF, although responses to light spectra are often species-specific. As the interest of consumers and farmers towards baby-leaf vegetables has recently increased, this study aimed at assessing the most effective red:blue (RB) ratio for enhanced baby-leaf production of kale (Brassica oleracea). Within an ebb-and-flow system, increasing RB ratios (RB₃, RB₅, RB₇ and RB₉) were tested, sharing a photoperiod of 16 h day⁻¹ and a light intensity of 215 μmol m⁻² s⁻¹. A larger yield was obtained for plants under RB_5, featuring an intermediate B fraction compared to other treatments, with plants displaying more expanded and thinner leaves. Also, for lighting energy and cultivated surface use efficiency, RB₅ was the most effective treatment, performing up to 57 g FW kWh⁻¹ and 54 kg FW m⁻² y⁻¹, respectively. From multispectral data, a tendency of reduced F_v/F_m and F_q′/F_m′ was observed as the RB ratio increased, while the chlorophyll index was enhanced under RB ≥ 7. This study highlighted the light recipe with an RB ratio of 5 as the most effective lighting mixture for optimal baby-leaf kale production in terms of balanced growth, resource use efficiency and yield. Full article

In recent years, inorganic nanoparticles, including calcium hydroxide nanoparticles [Ca Ca(OH)₂ NPs], have attracted significant interest for their ability to impact plant photosynthesis and boost agricultural productivity. In this study, the effects of 15 and 30 mg L⁻¹ oleylamine-coated calcium hydroxide nanoparticles [Ca(OH)₂@OAm NPs] on photosystem II (PSII) photochemistry were investigated on tomato plants at their growth irradiance (GI) (580 μmol photons m⁻² s⁻¹) and at high irradiance (HI) (1000 μmol photons m⁻² s⁻¹). Ca(OH)₂@OAm NPs synthesized via a microwave-assisted method revealed a crystallite size of 25 nm with 34% w/w of oleylamine coater, a hydrodynamic size of 145 nm, and a ζ-potential of 4 mV. Compared with the control plants (sprayed with distilled water), PSII efficiency in tomato plants sprayed with Ca(OH)₂@OAm NPs declined as soon as 90 min after the spray, accompanied by a higher excess excitation energy at PSII. Nevertheless, after 72 h, the effective quantum yield of PSII electron transport (Φ_PSII) in tomato plants sprayed with Ca(OH)₂@OAm NPs enhanced due to both an increase in the fraction of open PSII reaction centers (qp) and to the enhancement in the excitation capture efficiency (Fv’/Fm’) of these centers. However, the decrease at the same time in non-photochemical quenching (NPQ) resulted in an increased generation of reactive oxygen species (ROS). It can be concluded that Ca(OH)₂@OAm NPs, by effectively regulating the non-photochemical quenching (NPQ) mechanism, enhanced the electron transport rate (ETR) and decreased the excess excitation energy in tomato leaves. The delay in the enhancement of PSII photochemistry by the calcium hydroxide NPs was less at the GI than at the HI. The enhancement of PSII function by calcium hydroxide NPs is suggested to be triggered by the NPQ mechanism that intensifies ROS generation, which is considered to be beneficial. Calcium hydroxide nanoparticles, in less than 72 h, activated a ROS regulatory network of light energy partitioning signaling that enhanced PSII function. Therefore, synthesized Ca(OH)₂@OAm NPs could potentially be used as photosynthetic biostimulants to enhance crop yields, pending further testing on other plant species. Full article

To increase Europe’s self-sufficiency for protein sources, boosting plant protein production is a prerequisite. Yield variability is one of the main problems regarding the cultivation of protein crops. In this light, cereal–legume intercropping can offer a solution, as well-balanced intercropping systems are less prone to yield variations. Therefore, in this study the effects of (i) species/genotype combination, (ii) intercropping sowing densities and (iii) fertilizer regime were evaluated under Belgian (Northwestern European) conditions over three years (i.e., the 2020–2021, 2021–2022 and 2022–2023 seasons). Regarding the species combinations, winter barley x winter pea, winter wheat x winter faba bean and winter triticale x winter faba bean, it was observed that the best-performing combination varied from year to year depending on the prevailing weather conditions. A reduced sowing density (i.e., 130 seeds/m² for the cereal partner and 20 seeds/m² in the case of faba bean or 40 seeds/m² in the case of pea) was sufficient to achieve competitive yields under the prevailing conditions. Inoculation with commercial Rhizobium strains did not result in an increased yield. Fertilization with one or two nitrogen fractions significantly increased the total yield thanks to a yield increase in the cereal partner; however, as a consequence, the proportion of legumes in the mixture decreased. In conclusion, it can be stated that with the investigated cereal–legume combinations, a competitive yield and qualitative protein yield can be achieved with a reduced fertilizer input. Full article

Heavy oils are characterized by a high content of resins and asphaltenes, which complicates refining and leads to an increase in the cost of refinery products. These components can be strongly adsorbed on the acid sites of a supported catalyst, leading to its deactivation. Currently, various salts of group 8 metals are being considered for such processes to act as catalysts during oil cracking. At the same time, the nature of the precursor often has a significant impact on the process of refining heavy oil. In this work, catalytic cracking of heavy oil from the Ashalchinskoye field using different precursors (nanodispersed catalysts formed in situ based on NiO) has been studied. The cracking was carried out at 450 °C with a catalyst content from 0.1 to 0.5 wt.%. The catalytic cracking products were analyzed via SARA, GC, XRD and SEM. Nickel acetate and nitrate promote similar yields of by-products, while formate promotes higher yields of gaseous products. Formate and nickel acetate were shown to produce 1.8 and 2.8 wt.% more light fractions than nickel nitrate. When heavy oil is cracked in the presence of Ni(NO₃)₂∙6H₂O, the maximum decrease in sulfur content (2.12 wt.%) is observed compared to other precursors. It has been found that the composition and morphology of the resulting nickel sulfides and compaction products are influenced by the nature of the catalyst precursor. XRD and SEM analyses of coke-containing catalysts indicate the formation of Ni₉S₈ and Ni_0.96S phases during cracking when nickel nitrate is used and the formation of NiS and Ni₉S₈ when nickel acetate and formate are used. Full article

In China’s subtropical rice–wheat cropping system, the changes in the soil organic carbon (SOC) pool due to long-term straw return and its connection with crop yield remain unclear. This study aims to provide insights into establishing a sensible straw return system by evaluating the differences in the distribution and variation rates of SOC, light fraction organic carbon (LFOC), heavy fraction organic carbon (HFOC), particulate organic carbon (POC), and mineral-associated organic carbon (MOC) in the 0–20 cm soil layer under different durations of straw return. Additionally, the study analyzes the relationship between the changes in SOC and its fractions and wheat yield. The experiment was conducted in 2019 in a rice–wheat rotation field with ten years of straw return treatments: no straw return (NR) or 1, 2, 3, 4, 5, 6, 7, 8, 9 year(s) of straw return (SR1–9), and an additional treatment in 2020 (10 years of straw return, SR10). The results revealed that with an increase in the duration of straw return, the contents of SOC, LFOC, HFOC, and POC gradually increased, showing the highest increments of 45.88%, 187.22%, 41.55%, 97.89%, and 28.21%, respectively, compared to the NR treatment. However, after eight years of straw return, the compound annual increase in soil organic carbon and its components was lower than in years 1–8, indicating a trend of diminishing increments. The SOC content and its variation were significantly correlated with the content and variation of LFOC, HFOC, POC, and MOC, with the highest sensitivity observed for the variation in LFOC, indicating the strong influence of the duration of straw return. The SOC and its fraction contents showed significant positive correlations with wheat yield, with the highest contribution to wheat yield increase attributed to an increase in LFOC content. In summary, straw return enhances the 0–20 cm deep soil carbon pool, with LFOC being the most sensitive indicator, reflecting the influence of the duration of straw return on soil carbon pools. Full article

The study aimed to compare the effect of urea fatty fraction (UFF) and Pulrea^® (urea fertilizer) on plant yield and selected plant and soil parameters determined after the plants were harvested. UFF is a by-product of essential unsaturated fatty acids (UFAs) extraction from fish oil using urea, and Pulrea^® is a commercial urea fertilizer. Both products were applied to the soil and the leaves (foliar application). The effect of Pulrea^® on plant yield was generally stronger than that of UFF but depended on soil properties and plant species. Both fertilizers, but especially UFF, increased the total N content in the plant and effected nitrate accumulation. The plants used 45–90% of fertilizer nitrogen, with the plants generally using more N from Pulrea^® than from UFF. Higher nitrogen production efficiency was achieved using Pulrea^® than UFF and when plants were cultivated on medium soil than on light soil. Fertilizers increased the acidity and electrolytic conductivity of both soils but did not induce soil salinization. They increased the content of mineral nitrogen forms in soils, which was generally the case more in soil with Pulrea^® application than with UFF application. As a rule, the soil dehydrogenases activity did not change significantly or even decrease after fertilizer application. It was visibly higher in medium soil and after foliar Pulrea^® application than after foliar UFF application. This may be due to the content of accompanying substances in UFF that affect nitrogen absorption from this fertilizer. Based on the results, it cannot be clearly stated that one of the tested fertilizers had a better effect on the studied parameters. Generally, the less favorable effects of UFF compared to Pulrea^® may indicate the necessity of removing from UFF the accompanying substances that may adversely affect plants and soil microorganisms. This aspect needs to be investigated under controlled conditions in field experiments. Full article