Salinity stress is a major environmental constraint limiting crop productivity worldwide. The application of beneficial microorganisms is an effective strategy to improve plant tolerance to abiotic stresses. This study evaluated the role of Saccharomyces cerevisiae inoculation in enhancing physiological performance, oxidative stress tolerance, and yield of rice genotypes under saline-water irrigation. A lysimeter experiment was conducted during the 2024 and 2025 seasons. Five rice genotypes were exposed to saline water (6 000 ppm) with and without inoculation. Gas exchange, water status, oxidative stress markers, antioxidant enzyme activities, and yield-related traits were assessed. The results showed that inoculation significantly enhanced CO2 assimilation (12.27%), stomatal conductance (15.71%), transpiration rate (8.78%), and relative water content (16.36%) across both seasons. Furthermore, inoculation significantly reduced malondialdehyde (MDA) by 19.75% and hydrogen peroxide (H2O2) by 23.72%. While superoxide dismutase activity (SOD) increased by 35.32% and catalase activity (CAT) by 20.63%. Grain yield per plant improved by 18.91% and biological yield by 12.84%, accompanied by a reduction in grain sterility (14.47%). The assessed genotypes exhibited significant variation across all parameters studied. IRRI-165 and Giza-179 exhibited superior performance and responsiveness. Giza-182 and Sakha-104 displayed intermediate levels, while Giza-177 was the most sensitive genotype. Multivariate analyses confirmed strong positive associations between inoculation and genotypic performance. Whereas genotypic performance was negatively associated with oxidative stress markers. These results suggest that S. cerevisiae inoculation improves rice performance under salinity stress. The enhancement may contribute to the integration of physiological and biochemical mechanisms. Therefore, combining microbial inoculation with tolerant genotypes provides a sustainable strategy to improve rice productivity in salt-affected environments.
Cadmium (Cd) is a common heavy metal contaminant in agricultural soils; its high bioaccumulation potential and toxicity mean it enters the human body via the food chain, posing a health risk. Perennial ryegrass (Lolium perenne L.) is renowned for its high tolerance to heavy metal toxicity and is frequently used in phytoremediation. This study examined growth morphology, activities of ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione peroxidase (GPX), and glutathione reductase (GR), as well as non-enzymatic antioxidant contents in two perennial ryegrass cultivars: WNS (Venus, low Cd accumulation) and YY (Excellent, high Cd accumulation), under Cd treatments of 0, 3, 6, and 12 mg/kg Cd2+. Under Cd stress, WNS exhibited significantly higher plant height, leaf length, tiller number, GPX activity, and glutathione (GSH) content compared with YY. At 12 mg/kg Cd, GR activity in WNS was also significantly higher than in YY (P < 0.05). In contrast, at each Cd level, YY showed significantly higher leaf Cd accumulation, APX and DHAR activities, and ascorbic acid (AsA) content than WNS (P < 0.05), accompanied by elevated oxidised glutathione (GSSG) content. The comprehensive response index of YY under 3, 6, and 12 mg/kg Cd was 2.77, 2.91, and 2.94 times that of WNS, respectively. These findings suggest that WNS mitigates Cd toxicity and sustains growth homeostasis by maintaining higher GPX and GR activities and higher GSH content within the GSH-GSSG cycle. This study provides a theoretical basis for elucidating the differential Cd tolerance mechanisms among ryegrass cultivars with contrasting Cd accumulation capacities and offers insights to refine phytoremediation strategies in Cd-contaminated soils.
This study examined whether exogenous proline (Pro, 10 mmol/L, foliar) uniformly alleviates drought stress in peppermint (Mentha × piperita L.) or whether its benefit intensifies with increasing stress severity. Plants were grown under four water field capacity (WFC) levels (95, 75, 50, 25%), with or without Pro, in a 4 × 2 factorial randomised design. Two-way ANOVA (Levene's test confirmed homogeneous variance) partitioned each variable into WFC and Pro main effects and their interaction, followed by Tukey's HSD (P < 0.05). Water deficit reduced growth and relative water content, increased osmolytes, disrupted ionic homeostasis (higher Na+ and Na+/K+; lower K+, Ca2+, Mg2+), activated antioxidant defences, and altered hormone levels (higher abscisic acid (ABA); lower indole-3-acetic acid (IAA), gibberellic acid (GA3)). Pro significantly improved growth, water status, most osmolytes, antioxidants, IAA, GA3, and essential oil (EO) yield, with no significant WFC × Pro interaction detected for these variables, providing no statistically detectable evidence that the magnitude of the effect differed among WFC levels. Pro's effect on Na+, the Na+/K+ ratio, and ABA instead showed a significant WFC × Pro interaction (P = 0.040, 0.046, 0.001), intensifying under severe deficit. EO yield showed a biphasic response, rising at 75% and 50% WFC and falling at 25%, with Pro further increasing yield and menthol content. Pro thus acts mainly as a consistent protectant with no detected WFC × Pro interaction, alongside a distinct, stress-dependent role in ion and ABA regulation under severe drought.
To clarify the effects of post-anthesis low light on grain yield and starch quality of waxy and non-waxy soft wheat, a field experiment was conducted from 2023 to 2025. Two wheat cultivars, Jinuo 2 (waxy soft wheat) and Quanmai 725 (non-waxy soft wheat), were employed as test materials, and four shading treatments (no shading, 10% shading, 20% shading, and 30% shading) were applied after anthesis. The regulatory effects of different shading intensities on wheat yield, grain quality, starch granule size distribution and starch viscosity properties were systematically analysed. The results showed that post-anthesis low light stress significantly reduced the grain number per spike, 1 000-grain weight and grain yield, while increasing the protein content, wet gluten content and sedimentation value of wheat grains. Under low light stress, the volume and surface area proportions of A-type starch granules increased, while those of B-type starch granules decreased. Under the same shading condition, Jinuo 2 exhibited a higher proportion of B-type starch granules and a lower proportion of A-type starch granules than Quanmai 725. With increasing shading intensity, the peak, trough and final viscosities, as well as the breakdown and setback values, of grain starch decreased continuously, and all viscosity parameters of Quanmai 725 were significantly higher than those of Jinuo 2. Furthermore, post-anthesis low light reduced the onset, peak and conclusion gelatinisation temperatures and increased gelatinisation enthalpy. Quanmai 725 had higher gelatinisation temperatures, whereas Jinuo 2 possessed higher gelatinisation enthalpy. Correlation analysis indicated that the volume distribution of B-type starch granules (≤ 10 μm) was significantly positively correlated with starch viscosity parameters, while A-type starch granules (> 10 μm) showed a significant negative correlation. In conclusion, post-anthesis low light reduces the yield and the proportion of B-type starch granules, increases the proportion of A-type starch granules, decreases starch pasting viscosity and elevates gelatinisation enthalpy in both soft wheat cultivars. Compared with Quanmai 725, Jinuo 2 is more sensitive to post-anthesis low light stress in terms of starch granule distribution characteristics.
Desert grasslands are critical carbon sinks in arid regions, where herbaceous species selection plays a vital role in ecosystem restoration. While plant life cycle (annual vs. perennial) is known to affect soil organic carbon (SOC) stocks, its influence on SOC molecular composition remains poorly understood. This study examined the accumulation and environmental drivers of plant- and microbial-derived carbon biomarkers (lignin phenols and amino sugars) across the 0-40 cm soil profile under four desert herbaceous species: perennial Karelinia caspica (Pall.) Less. and Glycyrrhiza inflata Batalin., annual Chenopodium glaucum L. and Salsola lanata (Pall.) Botsch. Plant-derived C contributed more to SOC (9-15%) than microbial-derived C (3-8%), with contributions differing significantly between plant life cycles. These differences were shaped primarily by edaphic factors: plant-derived C accumulation was mainly regulated by pH, whereas microbial-derived C was affected by labile organic carbon (LOC), elemental stoichiometry (C/N, C/P), electrical conductivity, and pH. Our results indicate that herbaceous species influence SOC sequestration through divergent plant and microbial pathways. Perennial species, especially K. caspica and G. inflata, enhance SOC storage more effectively and should be prioritised in desert grassland restoration.
Bees were exposed for 10 days to a sucrose solution containing acetamiprid at concentrations of 48, 4.8, and 0.48 mg a.i./kg of solution, corresponding to the maximum recommended field application rate and its 1/10 and 1/100 dilutions. An increase in mortality was observed at the highest tested concentration, with a cumulative mortality of 30.4% by day 10, whereas lower concentrations showed effects comparable to the control. In addition, the expression of selected genes related to detoxification (glutathione S-transferase, thioredoxin reductase), oxidative stress (superoxide dismutase 1, superoxide dismutase 2), immunity (abaecin, hymenoptaecin, apidaecin), and neural regulation (acetylcholinesterase 1) was analysed. No significant changes were detected in most genes, except for sod2, which showed increased expression at the lowest concentration. Overall, the results suggest that acetamiprid exhibits relatively low chronic toxicity at environmentally relevant concentrations but may induce significant effects at higher or continuous exposure levels. These findings highlight the importance of considering both lethal and sublethal endpoints, including molecular responses, in assessing pesticide risks to honeybees.
In Central Europe, soybeans are typically sown in narrow rows (125 mm), whereas wide-row (500 mm) precision planters offer more accurate within-row spacing and greater flexibility for inter-row cultivation and targeted applications. We evaluated whether soybeans established with a precision planter respond to changes in seeding rate. A two-year on-farm strip trial (2023-2024) was conducted in Czechia with two determinate cultivars, Satelia and Tertia, at four target seeding rates (20, 40, 60 and 80 germinating seeds/m2). Plant morphology, seed yield, and seed composition were assessed. Branch number (3.1-1.0 pcs/plant for Satelia, 2.4-1.1 pcs/plant for Tertia), pod number (54.2-22.6 pcs/plant for Satelia, 53.4-28.0 pcs/plant for Tertia), and fertile nodes (11.6-9.3 pcs/plant for Satelia, 12.2-10.0 pcs/plant for Tertia) all decreased linearly with increasing seeding rate in both tested cultivars, indicating strong morphological compensation at low plant densities. Dry matter seed yield and seed composition were not significantly affected by seeding rate within the tested range, while year and cultivar effects were more pronounced for several seed quality components. These results suggest that soybean yield and quality are largely buffered against variation in plant population.
This study investigated the alleviating effects and physiological responses to foliar-applied potassium dihydrogen phosphate (KDP) on rice seedlings under high-temperature (HT) stress. An early indica hybrid rice, YLY17 (high-temperature-sensitive), was used as the planting material. Four treatment groups were set up: (a) NT - normal temperature; (b) NT + KDP - normal temperature with foliar application of different KDP concentrations (0.1, 0.2, 0.3, and 0.4%); (c) HT - high temperature treatment without foliar application of KDP, and (d) HT + KDP - high temperature with foliar application of different KDP concentrations. At the three-leaf stage, rice seedlings were subjected to simulated HT stress (32 similar to 38 degrees C during the day and 26 similar to 32 degrees C at night) for 10 days. Growth indicators, photosynthetic parameters, antioxidant characteristics, osmotic adjustment substances, and related metabolic enzymatic activities of young rice seedlings were quantified, and the alleviating effect of KDP was comprehensively evaluated by principal component analysis (PCA). The results showed that HT stress significantly reduced plant height, fresh weight, and dry weight, decreased chlorophyll content and SPAD value, and decreased the net photosynthetic rate (P-n), stomatal conductance (g(s)), and transpiration rate (T-r), while increasing intercellular carbon dioxide (CO2) concentration (c(i)). At the same time, it led to the accumulation of superoxide anion (O-2(-)), hydrogen peroxide (H2O2), and malondialdehyde (MDA), and induced increases in antioxidant enzyme and osmotic adjustment-related enzyme activities. Foliar spraying of KDP could effectively alleviate the above damage caused by HT stress, with 0.3% KDP being the most effective treatment. Compared with HT treatment, 0.3% KDP treatment significantly increased plant height, fresh weight and dry weight by 7.6, 10.6 and 10.2%, respectively, improved chlorophyll content and photosynthetic parameters, enhanced the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX), reduced the accumulation of reactive oxygen species (ROS) and MDA, and promoted the accumulation of osmotic adjustment substances such as soluble protein (SP), proline (Pro), soluble sugar (SS) and sucrose (SUC), as well as increased the activities of nitrate reductase (NR), glutamine synthetase (GS), sucrose synthase (SUS) and sucrose phosphate synthase (SPS). The PCA results showed that the order of comprehensive physiological activity index was NT + KDP > NT > KDP + HT > HT, indicating that KDP enhances heat tolerance by coordinately regulating photosynthesis, antioxidant defence, and osmotic adjustments. This study provides a theoretical basis and technical reference for using KDP to alleviate HT stress in rice seedlings
Soil salinisation is a major factor limiting plant growth and land utilisation in arid and semiarid regions. This study focused on the native halophyte Suaeda salsa in western Inner Mongolia to explore halophyte-associated microbial resources with plant growth-promoting potential under saline conditions. A total of 30 salt-tolerant bacteria strains were isolated from its rhizosphere. Among them, Bacillus infantis strain 29 tolerated up to 10% NaCl (w/v) and exhibited multiple plant-growth-promoting traits, including highly active 1-aminocyclopropane-1-carboxylate (ACC) deaminase, indole-3-acetic acid (IAA) production, phosphorus solubilisation, potassium mobilisation and diazotrophic potential as indicated by growth on nitrogen-free medium. Under pot conditions, inoculation with strain 29, particularly in combination with arbuscular mycorrhizal fungi (AMF), promoted plant growth under saline stress. In Suaeda salsa, the combined treatment significantly increased fresh weight and root length relative to the control, and positive growth responses were also observed in Zea mays and Medicago sativa. This study proposes an effective "halophyte-PGPR-AMF" synergistic strategy and provides a potential biological approach and microbial resource reference for improving plant growth and crop performance in salt-affected soils of western Inner Mongolia and other arid and semiarid regions with similar environmental conditions.
Plant carbon (C) inputs and their subsequent microbial transformation affect the soil organic C (SOC) net sequestration. However, the characteristics of plant- and microbial-derived C and SOC sequestration under organic matter plus different nitrogen (N) levels in orchard soils remain unclear. Therefore, a pot experiment over 120 days was conducted to investigate the plant and microbial biomarkers in soils under 13C-labelled branches chip combined with N of 225 mg/kg (BRN1), 180 mg/kg (BRN2), 160 mg/kg (BRN3), 140 mg/kg (BRN4) and 0 mg/kg (BR). Branch residue and N addition increased the net SOC sequestration; the 13C recovered in SOC under branch residue plus N treatments was higher than the BR treatment. The highest newly formed C was found under BRN1, followed by BRN2 and BRN3; BRN4 had the lowest newly formed C. Branch residue and N increased lignin phenol content, which promoted syringyl-to-vanillyl and decreased acid-to-aldehyde ratios of vanillyl phenol, indicating branch-C retention in the soil. The microbial necromass C content under residue plus N treatments was higher than under the branch alone treatment, and the highest values were found under the BRN2 treatment. Additional N supply resulted in a greater contribution of microbial necromass C to SOC in soil under branch residue amendment, rather than plant C. Accordingly, BRN2 is considered optimal for net SOC sequestration by plant-derived and fungal necromass C.
Drought stress severely impairs seed germination. Selenium (Se) is a potential mitigator of abiotic stress, but its physiological mechanisms in alleviating osmotic stress during seed germination remain poorly understood. This study investigated how Se alleviates the inhibition of rice seed germination induced by polyethylene glycol (PEG)-simulated drought. The results indicated that co-application of Se and PEG effectively alleviated the PEG-induced suppression of germination. Se significantly increased the activities of superoxide dismutase by 31.0%, peroxidase by 39.0%, catalase by 42.9%, and ascorbate peroxidase by 41.8%, along with elevating the concentrations of glutathione by 19.0% and ascorbate by 38.3%. Consequently, Se attenuated the PEG-induced burst of reactive oxygen species, reducing H2O2 by 21.0% and O2 londialdehyde concentration. Furthermore, Se partially restored osmotic homeostasis by increasing the accumulation of soluble sugars by 15.9%, soluble proteins by 11.4%, free amino acids by 18.4%, and free proline by 26.3%. It also counteracted PEG-imposed inhibition of hydrolytic enzymes, enhancing alpha-amylase and protease activities by 26.6% and 11.2%, respectively. Notably, Se accumulation in seeds was reduced under PEG stress, suggesting impaired the penetration of exogenous Se under PEG-simulated drought. Collectively, these results demonstrate that Se alleviates PEG-induced osmotic stress in germinating rice seeds by enhancing antioxidant capacity, maintaining osmotic balance, and sustaining reserve mobilisation. - by 19.1%, and alleviated lipid peroxidation, as reflected by a 20.0% decrease in ma-
Soil available and total zinc are important indicators of soil zinc status, yet the global effects of different fertilisation practices on soil available and total zinc and the drivers of their variation remain insufficiently quantified. We conducted a global meta-analysis based on data extracted from published field studies. A total of 1 240 paired observations of soil available zinc from 94 studies and 364 paired observations of soil total zinc from 44 studies published between 1993 and 2024 were compiled. The effects of eight fertiliser types (mineral fertilisers without zinc [CF], compost, manure, zinc fertiliser, CF combined with either compost [CFC] or manure [CFM] or zinc fertiliser [CFZn], and compost combined with zinc fertiliser [CZn]) on the soil available and total zinc content were assessed by meta-analysis. The results indicated that compared to the control group, soil available zinc content increased significantly under treatments CZn, CFZn, zinc fertiliser, CFM, manure, CFC, and compost by 158, 134, 133, 84, 78, 43, and 35%, respectively. Additionally, manure, CFM, zinc fertiliser, CFZn, and CZn treatments significantly enhanced soil total zinc content, with increases ranging from 25% to 32%. Applying zinc fertiliser at > 20 kg Zn/ha significantly increased soil-available zinc. In the medium-rate CZn class (10-20 kg Zn/ha), soil available zinc increased from 0.78 mg/kg in the control soils to 3.46 mg/kg in the treated soils. Among crop systems, wheat showed a stronger response in soil-available zinc, whereas rice-growing systems showed relatively larger increases in soil-total zinc under manure and CFM treatments. Fertilisation intensity, crop types, soil organic carbon, and soil pH emerged as key drivers of variation in soil available zinc, whereas the main drivers of soil total zinc varied among fertiliser types and were more often associated with fertiliser rate and crop types. When soil organic carbon was <= 12 g/kg or soil pH was > 7.5, applying CZn at 10-20 kg Zn/ha showed greater potential to increase soil available zinc. These findings suggest that soil zinc management should be optimised based on fertilisation intensity, crop type, soil organic carbon, and soil pH to improve zinc availability while avoiding excessive accumulation.
Selenium (Se) biofortification of soybean sprouts presents a promising approach for enhancing dietary Se intake. However, the physiological mechanisms of Se promoting growth remain poorly understood. Here, we investigated the effects of selenite (Na2SeO3) at concentrations of 0, 2.5, 5.0, 7.5, and 10 & micro;mol/L on soybean sprout development over 72 h. The results indicated that 5.0 and 7.5 & micro;mol/L Na2SeO3 significantly promoted hypocotyl elongation and biomass accumulation. Se predominantly accumulated in the radicle, followed by the hypocotyl and cotyledon. Moderate selenite levels enhanced the activities of superoxide dismutase, peroxidase, and ascorbate peroxidase; increased the concentrations of reduced glutathione, ascorbic acid, and free proline; and effectively suppressed the accumulation of superoxide anion and hydrogen peroxide, thereby reducing malondialdehyde (MDA) concentration and alleviating oxidative stress. Concurrently, amylase and protease activities in cotyledons were stimulated, accelerating the hydrolysis of storage reserves. The resulting increases in soluble sugars, proteins, and free amino acids in the hypocotyl supported its elongation and biomass increase. In contrast, 10 & micro;mol/L Na2SeO3 suppressed antioxidant enzyme activities, elevated reactive oxygen species and MDA levels, and inhibited growth. Collectively, these findings demonstrate that moderate Se enhances soybean sprout growth primarily by increasing antioxidant capacity, reducing oxidative stress, and facilitating the mobilisation of storage reserves toward the elongating hypocotyl, thereby revealing key physiological mechanisms for cultivating high-quality, Se-enriched sprouts.
Excessive slurry applications in regions with intensive livestock production are overloading soils with phosphates, which can lead to water pollution. Pyrolysis of pig slurry solids creates a fertiliser that is potentially efficient to store and transport, hence creating the opportunity to export it from affected regions. This study aims to quantify the plant availability of phosphorus (P) from the pyrolysed pig slurry in different soils and in combination with the nitrogen application in the form of nitrate (NO3-) and ammonium (NH4+), respectively. A pot experiment with maize seedlings (Zea mays L., cv. Amadeo) was conducted under glasshouse conditions to assess changes in plant-available phosphate from pyrolysed and freeze-dried solids in three contrasting topsoils with pH values of 5.2, 6.7 and 7.4 (in 0.01 mol/L CaCl2). In two separate positive control treatments, P was applied in the form of rock phosphate and Ca(H2PO4)2, respectively, instead of processed pig slurry. To eliminate nitrification in the treatment fertilised with NH4+, the synthetic nitrification inhibitor 3,4-dimethylpyrazol phosphate (DMPP) was utilised. The plant P availability of the pyrolysed and freeze-dried product exceeded the plant P availability of rock phosphate on all tested soils, but pyrolysis lowered it compared to the freeze-dried treatment. Furthermore, the NH4+ nutrition improved plant P availability compared to the NO3- nutrition. This indicates that pyrolysis potentially leads to the formation of tri- or octa-calcium phosphates rather than crystalline apatite and that the acidification of the rhizosphere by NH4+ nutrition led to the solubilisation of P. Pyrolysis is a promising treatment for making a plant available P fertiliser, however freeze-drying led to an even better result. For the future, both procedures need to be compared economically to achieve optimal utilisation of the scarce resource P.
This study evaluated the effects of hybrid, vegetation period duration, weather conditions, and harvest timing on sugar beet (Beta vulgaris L.) yield and technological quality under short-rotation cropping systems in the Western Forest-Steppe of Ukraine. Field experiments were conducted in 2022-2024 on commercial fields using six industrial hybrids and five harvest intervals from late September to mid-November. Root yield, sugar content, sugar yield, a-amino nitrogen, K+ and Na+, invert sugars, and the technological quality index (Iq) were assessed using ANOVA, correlation analysis, and principal component analysis (PCA). Extending vegetation from 185 to 200 days increased root yield by 11-12% and sugar yield by 0.8-1.2 t/ha. The optimal harvest window (10-25 October) provided the highest performance, with root yields of 68-73 t/ha, sugar content of 16.2-16.6%, and sugar yields of 14.6-16.3 t/ha. Early harvest resulted in reduced sugar content and Iq, whereas harvesting after 10 November did not increase yield and caused deterioration of technological quality due to elevated a-amino nitrogen and molasses-forming ions. PCA showed that over 85% of the total variation was explained by technological quality and moisture-related factors. Strube hybrids demonstrated greater stability under extended vegetation compared with KWS hybrids. These results define an optimal harvest window for maximising sugar beet productivity and quality under temperate meteorological conditions.
This study evaluated a novel slow-release copper fertiliser (soileos Cu) as a sustainable alternative to conventional copper sources for improving wheat yield and nutrient use efficiency. Traditional Cu fertilisers are often limited by rapid leaching and low efficiency, especially on sandy soils with low organic matter, contributing to environmental pollution. They also exhibit low plant-use efficiency due to strong adsorption and immobilisation in soils rich in organic matter and clay minerals, thereby reducing copper availability in the soil solution and contributing to environmental pollution. A multi-scale approach was employed, including laboratory incubation, greenhouse experiments, and multi-site field trials. Copper release was quantified in water over 30 days. Greenhouse experiments compared soileos Cu with copper sulfate (CuSO4) across multiple application rates, assessing grain yield, biomass, spike count, chlorophyll index (SPAD), and tissue and grain nutrient concentrations. Field trials were conducted at four sites in Canada and the United States with contrasting soil Cu availability. Soileos Cu exhibited controlled, non-linear Cu release with substantially reduced leaching compared to CuSO4. In greenhouse conditions, soileos Cu achieved maximum grain yield, biomass, and spike number at 25-26% lower Cu application rates than CuSO4, indicating higher nutrient use efficiency. Field trials confirmed that yield responses were strongly dependent on baseline soil Cu levels, with the greatest yield increase (up to 13.3%) observed at a Cu-deficient site. Overall, soileos Cu provides an effective and environmentally responsible strategy for improving Cu nutrition and wheat productivity, particularly under Cu-limiting conditions.
In pursuit of a low-cost, pollution-free, and scalable technology for remediating heavy metal pollution in mining areas, this study examines a gold mining area with heavy metal pollution (Cd, Pb, and Hg) and employs soil replacement, biochar passivation, and a combination of hyperaccumulators for the remediation. Results show that both soil replacement and the application of biochar significantly reduce the effective content of these three heavy metals, with pig manure biochar demonstrating superior passivation effects on Pb and Hg compared to fruitwood biochar. Combining biochar with hyperaccumulators leads to better results than using either method alone. The combined approach achieved maximum reductions of 69.8, 70.1, and 56.0% for Cd, Pb, and Hg, respectively. The application of biochar improves the originally coarse soil structure, with maximum increases in organic carbon, available potassium, available phosphorus, and total nitrogen under different treatments being 6.26 times, 4.66 times, 4.04 times, and 3.21 times, respectively. Biochar anchors heavy metals around roots, while hyperaccumulators utilise their excellent stress-resistant physiological characteristics to thrive in nutrient-deficient soil enriched with biochar, thereby absorbing the heavy metals anchored by biochar. The synergy of biochar and hyperaccumulators enhances their individual effectiveness, showing promise for remediating polluted mining areas.
Combining phosphorus management with phosphorus-efficient cultivars is an effective strategy for improving rice quality. To investigate their effects on root characteristics and photosynthetic traits, a pot experiment was conducted with two rice cultivars differing in phosphorus efficient: Liangeng 7 (weakly efficient) and Yongyou 2640 (highly efficient). Four phosphorus rates (0, 0.44, 0.88, and 1.32 g/pot, designated as P0, P1, P2, and P3, respectively) were applied. A significant cultivar-phosphorus interaction was observed. Most root traits (the length, dry weight, volume, total absorption area, active absorption area, oxidation activity, and acid phosphatase activity) and photosynthetic traits (photosynthetic rate, transpiration rate, and stomatal conductance) initially increased and then decreased with increasing phosphorus rates, while the leaf intercellular CO2 concentration showed the opposite trend. Liangeng 7 performed optimally under P2, whereas Yongyou 2640 reached its peak under P1. Compared with Liangeng 7, Yongyou 2640 exhibited better appearance quality, root traits, and photosynthetic parameters. Correlation analysis showed that root length, root physiological activity and leaf photosynthetic parameters (except intercellular CO2 concentration) were significantly negatively correlated with chalkiness degree. These findings demonstrate that matching phosphorus supply to cultivar-specific efficiency optimises root-photosynthesis synergy, leading to superior grain appearance quality with less phosphorus input.
Alluvial soils have high importance for both agriculture and biodiversity; however, these soils can also contribute to greenhouse gas (GHG) emissions including carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4). In this study, we examined GHG fluxes of three grassland and two cropland sites with alluvial soils in Abava river floodplain, Latvia (Europe). Soil CO2 fluxes representing heterotrophic respiration (Rhet) were determined using a portable CO2 gas analyser, while ecosystem respiration (Reco), soil CH4 and N2O fluxes were quantified using a manual closed chamber method combined with gas chromatography. Most alluvial soils acted as source of GHG emissions with the exception of two grassland site where annual CH4 exchange reflected a slight CH4 removal from the atmosphere. Mean total GHG emissions (sum of net CO2, CH4 and N2O) were 7.0 +/- 3.3 t CO2 eq./ha/year in grassland sites and 14.5 +/- 4.8 t CO2 eq./ha/year in cropland sites. Net CO2 contributed the most to total annual GHG emissions with mean values of 6.2 +/- 3.3 t CO2/ha/year in grassland and 13.6 +/- 4.8 t CO2/ha/year in cropland sites. Although the number of study sites is limited, the results support that, in the context of climate change mitigation, grassland represents a more climate-friendly type of floodplain land use than cropland in the hemiboreal region.
