Search Results (4,673)

This study evaluates the agronomic and environmental performance of pelletized compost derived from olive mill waste as a sustainable alternative to mineral fertilizers for cultivating wheat (Triticum turgidum L.) under conventional tillage methods. A field experiment was conducted in semi-arid Spain, employing three fertilization strategies: inorganic (MAP + Urea), sewage sludge (SS), and organic compost pellets (OCP), each providing 150 kg N ha⁻¹. The parameters analyzed included wheat yield, grain quality, soil properties, and greenhouse gas (GHG) emissions. Inorganic fertilization yielded the highest productivity and nutrient uptake. However, the OCP treatment reduced grain yield by only 15%, while improving soil microbial activity and enzymatic responses. The SS and OCP treatments showed increased CO₂ and N₂O emissions compared to the control and inorganic plots. However, the OCP treatment also acted as a CH₄ sink. Nutrient use efficiency was greatest under mineral fertilization, though the OCP treatment outperformed the SS treatment. These results highlight the potential of OCP as a circular bio-based fertilizer that can enhance soil function and partially replace mineral inputs. Optimizing application timing is critical to aligning nutrient release with crop demand. Further long-term trials are necessary to evaluate their impact on the soil and improve environmental outcomes. Full article

We clarified the effect of wheat straw return combined with microbial agents on rice yield and soil properties. A field experiment was conducted using hybrid indica rice ‘Chuankangyou 2115’ and five treatments: no wheat straw return (T₁), wheat straw return alone (T₂), T₂+ microbial agent application (Bacillus subtilis/Trichoderma harzianum = 1:1) (T₃); T₂+ microbial agent application (Bacillus subtilis/Trichoderma harzianum = 3:1) (T₄); T₂+ microbial agent application (Bacillus subtilis/Trichoderma harzianum = 1:3) (T₅). T₂–T₅ significantly increased dry matter accumulation, soil total N, ammonium N, nitrate N, and organic matter, improving yield by 3.81–26.63%. T₃ exhibited the highest yield increases in two consecutive years. At the jointing and heading stages, Penicillium and Saitozyma dominated under T₃ and positively correlated with dry matter, yield, and nitrogen levels. Straw return combined with Bacillus subtilis and Trichoderma harzianum (20 g m⁻² each) enhanced soil nitrogen availability and dry matter accumulation and translocation. Our findings guide efficient straw utilization, soil microbial regulation, and sustainable high-yield rice production. Full article

Agriculture and animal feeding operations are responsible for 87% of ammonia emissions in the UK. Controlling NH₃ concentrations below 20 ppm is crucial to preserve workers’ and livestock’s well-being. Therefore, ammonia control systems are required for maintaining adequate air quality in livestock facilities. This study assessed the ammonia reduction efficiency of a novel air pollution abatement (APA) system used in a pig farm building. The monitoring duration was 11 weeks. The results were compared with the baseline from a previous pig cycle during the same time of year in 2023. A ventilation-controlled room was monitored during a two-phase campaign, and the actual ammonia concentrations were measured at different locations within the site and at the inlet/outlet of the APA system. A 98% ammonia reduction was achieved at the APA outlet through NH₃ absorption in tap water. Ion chromatography analyses of farm water samples revealed NH₃ concentrations of up to 530 ppm within 83 days of APA operation. Further scanning electron microscopy and energy-dispersive X-ray inspections revealed the presence of salts and organic/inorganic matter in the solid residues. This research can contribute to meeting current ammonia regulations (NECRs), also by reusing the process water as a potential nitrogen fertiliser in agriculture. Full article

Soybean (Glycine max) is a protein-rich legume crop that plays an important role in achieving food security. The aim of this study was to isolate soybean-nodulating rhizobia from Côte d’Ivoire soils and evaluate their potential as efficient strains in order to develop local bioinoculants. For this objective, 38 composite soil samples were collected from Côte d’Ivoire’s five major climatic zones. These soils were used as substrate to trap the nodulating rhizobia using the promiscuous soybean variety R2-231. A total of 110 bacterial strains were isolated and subsequently identified. The analysis of ITS (rDNA16S-23S), glnII and recA sequences revealed a relatively low genetic diversity of these native rhizobia. Moreover, the ITS phylogeny showed that these were scattered into two Bradyrhizobium clades dominated by the B. elkanii supergroup, with ca. 75% of all isolates. Concatenated glnII-recA sequence phylogeny confirmed that the isolates belong in the majority to ‘B. brasilense’, together with B. vignae and some putative genospecies of Bradyrhizobium that needs further elucidation. The core gene phylogeny was found to be incongruent with nodC and nifH phylogenies, probably due to lateral gene transfer influence on the symbiotic genes. The diversity and composition of the Bradyrhizobium species varied significantly among different sampling sites, and the key explanatory variables identified were carbon (C), magnesium (Mg), nitrogen (N), pH, and annual precipitation. Based on both shoot biomass and leaf relative chlorophyll content, three isolates consistently showed a higher symbiotic effectiveness than the exotic inoculant strain Bradyrhizobium IRAT-FA3, demonstrating their potential to serve as indigenous elite strains as bioinoculants. Full article

Petroleum-contaminated soil is an increasingly severe environmental issue. The integration of phytoremediation and microbial remediation can effectively mitigate their individual limitations and enhance remediation efficiency. In this study, four newly isolated bacterial strains (including Cytobacillus and Rhodococcus) that exhibited preferential degradation of distinct petroleum components were combined with the rhamnolipid-producing strain Pseudomonas aeruginosa SL-1. The immobilization of this petroleum-degrading microbial consortium was performed by biochar adsorption and sodium alginate embedding, subsequently optimized using response surface methodology (0.75 g·L⁻¹ of biochar, 40 g·L⁻¹ of sodium alginate, and 40 g·L⁻¹ of calcium chloride). The results showed that the highest petroleum degradation rate (97.1%) of immobilized bacterial consortium was achieved at 72 h at a petroleum concentration of 5.0 g·L⁻¹. When combined with Sudan grass for soil bioremediation, the degradation rate reached 72.8% after 120 d for soil containing 5.0 g·kg⁻¹ of petroleum, higher than the results for the treatments with only immobilized bacterial consortium (53.0%) or Sudan grass (49.2%). Furthermore, significant improvements were observed for soil pH; nitrogen, phosphorus, and potassium contents; and urease, dehydrogenase, and catalase activities. Composite treatment also significantly increased the diversity and richness of the soil bacterial community and regulated its structure, function, and network composition. This study offers theoretical insights and potential practical applications for the enhanced bioremediation of petroleum-contaminated soils. Full article

The growing negative environmental effects associated with chemical fertilizers have led to the promotion of organic fertilizers in agriculture. The purpose of this study was to evaluate the impacts of organic fertilization on nitrogen and phosphorus content, uptake and use efficiency in Origanum dictamnus (Dittany) cultivation. With this aim, a randomized complete blocks field experiment was carried out in Istron Kalou Xoriou (Agios Nikolaos—Crete). The study included three fertilization treatments (N0: 0 kg/ha⁻¹, N1: 1250 kg/ha⁻¹ and N2: 2500 kg/ha⁻¹). Throughout the growing period, measurements were taken for the plant’s content, uptake and efficiency indices of total nitrogen (TN) and phosphorus (P). The findings indicated that the fertilization doses affect nutrient uptake and efficiency. The highest values of TN and P were recorded 60 days after transplants. N1 treatment showed the greatest improvement in nitrogen use efficiency, while phosphorus use efficiency reached its maximum level under N2 treatment. That research can contribute to achieving an in-depth insight of organic fertilization practices for aromatic and medicinal plants such as Dittany, promoting a sustainable agricultural strategy and enhancing product quality. Full article

Variable-rate nitrogen (VR-N) application allows farmers to optimize nitrogen (N) input site-specifically within field boundaries, enhancing both economic efficiency and environmental sustainability. In this study, VR-N technology was applied to durum wheat in two small-scale commercial fields (3–4 ha each) located in distinct agro-climatic zones of Thessaly, central Greece. A real-time VR-N application algorithm was used to calculate N rates based on easily obtainable near-real-time data from unmanned aerial vehicle (UAV) imagery, tailored to the crop’s actual needs. VR-N implementation was carried out using conventional fertilizer spreaders equipped to read prescription maps. Results showed that VR-N reduced N input by up to 49.6% compared to the conventional uniform-rate N (UR-N) application, with no significant impact on wheat yield or grain quality. In one of the fields, the improved gain of VR-N when compared to UR-N was 7.2%, corresponding to an economic gain of EUR 163.8 ha⁻¹, while in the second field—where growing conditions were less favorable—no considerable VR-N economic gain was observed. Environmental benefits were also notable. The carbon footprint (CF) of the wheat crop was reduced by 6.4% to 22.0%, and residual soil nitrate (NO₃⁻) levels at harvest were 13.6% to 36.1% lower in VR-N zones compared to UR-N zones. These findings suggest a decreased risk of NO₃⁻ leaching and ground water contamination. Overall, the study supports the viability of VR-N as a practical and scalable approach to improve N use efficiency (NUE) and reduce the environmental impact of wheat cultivation which could be readily adopted by farmers. Full article

Mungbean is grown as a summer crop in subtropical climates globally. The global demand for mungbean is increasing, and opportunities exist to expand production regions to more marginal environments, such as southern Australia, as an opportunistic summer crop to help meet the growing global demand. Mungbean has the potential to be an opportunistic summer crop when an appropriate sowing window coincides with sufficient soil water. This expansion from subtropical to temperate climates will pose challenges, including low temperatures, a longer day length and a low and variable water supply. To assess mungbean suitability to temperate, southern Australian summer rainfall patterns and soil water availability, we conducted field experiments applying a range of water treatments across four locations with contrasting rainfall patterns within the state of Victoria (in southern Australia) in 2020–2021 and 2021–2022. The water treatments were applied prior to sowing (60 mm), the vegetative stage (40 mm) and the reproductive stage (40 mm) in a factorial combination at each location. Two commercial cultivars, Celera II-AU and Jade-AU, were used. Water scarcity during flowering and the pod-filling stages were important factors constraining yield. Analysis of yield components showed that increasing water availability at critical growth stages, viz. the vegetative and reproductive stages, of mungbean was associated with increases in total biomass, HI and grain number in addition to increased water use and water use efficiency (WUE). Average WUEs ranged from 1.3 to 7.6 kg·ha⁻¹·mm⁻¹. The maximum potential WUE values were 6.4 and 5.1 kg·ha⁻¹·mm⁻¹ for Celera II-AU and Jade-AU across the sites, with the estimated soil evaporation values (x-intercept) of 83 and 74 mm, respectively. Nitrogen fixation was variable, with %Ndfa values ranging from 9.6 to 76.8%, and was significantly affected by soil water availability. This study emphasises the importance of water availability during the reproductive phase for mungbean yield. The high rainfall zones within Victoria have the potential to grow mungbean as an opportunistic summer crop. Full article

There are discrepancies regarding the effectiveness of enhanced efficiency nitrogen (N) fertilizer (EENF) products on ammonia loss from unincorporated, surface applications of urea-based fertilizers. Soil properties and management practices may account for the differences in the performance of EENF. However, few studies have investigated the performance of urea- and urea ammonium nitrate (UAN)-based EENF on soils with contrasting properties. Controlled-environment incubation experiments were conducted on two soils with different properties to evaluate the efficacy of urea and UAN forms of EENF to minimize ammonia volatilization losses. The experiments were set up as a completely randomized design, with seven treatments replicated four times for 16 days. The N treatments, which were surface-applied at 134 kg N ha⁻¹, included untreated urea, untreated UAN, urea+ANVOL^TM (urease inhibitor product), UAN+ANVOL^TM, environmentally smart nitrogen (ESN^®), SUPERU^® (urease and nitrification inhibitor product), and urea+Excelis^® (urease and nitrification inhibitor product). In this study, urea was more susceptible to ammonia loss (24.12 and 26.49% of applied N) than UAN (5.24 and 16.17% of applied N), with lower ammonia volatility from soil with a pH of 5.8 when compared to 7.0. Urea-based EENF products performed better in soil with a pH of 5.8 compared to the soil with pH 7.0, except for ESN, which was not influenced by pH. In contrast, the UAN-based EENF was more effective in the high-pH soil (7.0). Across both soils, all EENFs reduced cumulative ammonia loss by 32–91% in urea and 27–70% in UAN, respectively, when compared to their untreated forms. The urea-based EENF formulations containing both nitrification and urease inhibitors were the least effective among the EENF types, performing particularly poorly in high-pH soil (pH 7.0). In conclusion, the efficacy of EENF is dependent on soil pH, N source, and the form of EENF. These findings underscore the importance of tailoring EENF applications to specific soil conditions and N sources to optimize N use efficiency (NUE), enhance economic returns for producers, and minimize environmental impacts. Full article

The development of efficient and sustainable water recycling systems is essential for long-term human missions and the establishment of space habitats on the Moon, Mars, and beyond. Humidity condensate (HC) is a low-strength wastewater that is currently recycled on the International Space Station (ISS). The main contaminants in HC are primarily low-molecular-weight organics and ammonia. This has caused operational issues due to microbial growth in the Water Process Assembly (WPA) storage tank as well as failure of downstream systems. In addition, treatment of this wastewater primarily uses adsorptive and exchange media, which must be continually resupplied and represent a significant life-cycle cost. This study demonstrates the integration of a membrane-aerated biological reactor (MABR) for pretreatment and storage of HC, followed by brackish water reverse osmosis (BWRO). Two system configurations were tested: (1) periodic MABR fluid was sent to batch RO operating at 90% water recovery with the RO concentrate sent to a separate waste tank; and (2) periodic MABR fluid was sent to batch RO operating at 90% recovery with the RO concentrate returned to the MABR (accumulating salinity in the MABR). With an external recycle tank (configuration 2), the system produced 2160 L (i.e., 1080 crew-days) of near potable water (dissolved organic carbon (DOC) < 10 mg/L, total nitrogen (TN) < 12 mg/L, total dissolved solids (TDS) < 30 mg/L) with a single membrane (weight of 260 g). When the MABR was used as the RO recycle tank (configuration 1), 1100 L of permeate could be produced on a single membrane; RO permeate quality was slightly better but generally similar to the first configuration even though no brine was wasted during the run. The results suggest that this hybrid system has the potential to significantly enhance the self-sufficiency of space habitats, supporting sustainable extraterrestrial human habitation, as well as reducing current operational problems on the ISS. These systems may also apply to extreme locations such as remote/isolated terrestrial locations, especially in arid and semi-arid regions. Full article

Fully printable carbon-based multiporous layered electrode perovskite solar cells (MPLE−PSCs) are close to being commercialized due to their excellent stability, their ability to easily be scaled up, and their amenability to mass production via non-vacuum fabrication processes. To improve their efficiency, it is important that detailed studies of the morphologies of mesoporous electrodes be carried out. In this study, we prepared five types of ZrO₂ spacer layers for MPLE−PSCs, and the morphology of ZrO₂ and device performance were evaluated using a scanning electron microscope, nitrogen adsorption/desorption measurements, electrode resistance measurements, UV-visible light reflectance measurements, and current density–voltage measurements. The results reveal that the adequate specific surface area and pore size distribution of mesoporous ZrO₂ provided high insulation ability when used as spacers between electrodes and light absorbance, resulting in a 10.92% photoelectric conversion efficiency with a 23.22 mA cm⁻² short-circuit current density. This information can serve as a guideline for designing morphologies useful for producing high-efficiency devices. Full article

Nitrogen (N) is one of the most important nutrients determining crop growth performance. With the increasing demand for sustainability in global agriculture, improving nitrogen use efficiency in rice has become a critical issue. Nitrogen use efficiency (NUE) in rice is a complex trait influenced by multiple factors, among which phytohormones play a key role. NUE is primarily regulated through the influence of phytohormones on absorption, transport, assimilation, and utilization processes. In this review, we focus on these interactions and summarize the relationships between major hormones and nitrogen use efficiency in rice. Finally, we outline the current challenges and future research prospects in this field. Although studies have shown promising results for their role in improving crop NUE, the specific mechanisms remain unclear. Additionally, the interactions among phytohormones and the influence of environmental factors on their effectiveness require further investigation. This review provides theoretical support and technical guidance for understanding the role of phytohormones in rice NUE and offers insights into improving NUE in rice. Full article

Plant growth-promoting rhizobacteria (PGPR) are beneficial rhizosphere microorganisms for plants. They can promote plant absorption of nutrients, inhibit pathogenic microorganisms, enhance plant tolerance to abiotic and biotic stresses, and improve plant growth. Isolating new beneficial microbes and elucidating their promoting mechanisms can facilitate the development of microbial fertilizers. This study combined transcriptome sequencing and related experiments to analyze the mechanism by which the endophytic fungus ‘BF-F’ promotes the growth of Sesuvium portulacastrum. We inoculated the ‘BF-F’ fungus beside S. portulacastrum seedlings as the experimental group. Meanwhile, S. portulacastrum seedlings not inoculated with ‘BF-F’ were set as the control group. After inoculation for 0 d, 7 d, 14 d, 21 d, and 28 d, the plant height and the number of roots were measured. Furthermore, transcriptome sequencing on the roots and leaves of the S. portulacastrum was conducted. Differentially expressed genes were screened, and KEGG enrichment analysis was performed. Nitrogen metabolism-related genes were selected, and qRT-PCR was conducted on these genes. Furthermore, we analyzed the metabolomics of ‘BF-F’ and its hormone products. The results showed that inoculation of ‘BF-F’ significantly promoted the growth of S. portulacastrum. After ‘BF-F’ inoculation, a large number of genes in S. portulacastrum were differentially expressed. The KEGG pathway enrichment results indicated that the ‘BF-F’ treatment affected multiple metabolic pathways in S. portulacastrum, including hormone signal transduction and nitrogen metabolism. The auxin signaling pathway was enhanced because of a decrease in AUX expression and an increase in ARF expression. Contrary to the auxin signal transduction pathway, the zeatin (ZT) signaling pathway was suppressed after the ‘BF-F’ treatment. ‘BF-F’ increased the expression of genes related to nitrogen metabolism (NRT, AMT, NR, and GAGOT), thereby promoting the nitrogen content in S. portulacastrum. The metabolites of ‘BF-F’ were analyzed, and we found that ‘BF-F’ can synthesize IAA and ZT, which are important for plant growth. Overall, ‘BF-F’ can produce IAA and enhance the nitrogen use efficiency of plants, which could have the potential to be used for developing a microbial fertilizer. Full article

Nitrogen-metabolizing microbes are the keystone drivers of reducing nitrogen pollutants in wastewater and natural waters, but the one-way experiment with fixed screening factors fails to discover the optimal scope of nitrogen-metabolizing microbes performing nitrogen reduction. This study novelly combines the one-way experiment and response surface methodology (RSM) modeling to synthesize an effective nitrogen reduction microbial community, with the RSM model showing high goodness-of-fit (R² = 0.83, p = 0.01) for optimizing the strain combination. Eight bacterial strains were isolated from contaminated sediment and activated sludge. Three efficient strains, arranged to Ignatzschieria indica, Staphylococcus epidermidis, and Acinetobacter baumannii by 16S rDNA sequencing, were screened using the above combination method to synthesize a nitrogen reduction microbial community. Within the synthetic microbial community, Ignatzschieria indica and Staphylococcus epidermidis possessed denitrification abilities, and Acinetobacter baumannii contributed to nitrification with 99% of ammonium oxidation. This synthesis microbial community displayed synchronous nitrification and denitrification under interval aeration and possessed wide pH tolerance from 6 to 10, with a steady >80% total inorganic nitrogen reduction. This research managed to synthesize a tolerant nitrogen reduction microbial community and provides novel insight for constructing synthetic microbial consortia. Full article

Selective catalytic reduction filter (SDPF) technology constitutes a critical methodology for controlling nitrogen oxide (NOx) and particulate matter emissions from light-duty diesel vehicles. A series of SDPFs with different sulfur poisoning times and concentrations were prepared using the worldwide harmonized light vehicles test cycle (WLTC). Bench testing revealed that sulfur poisoning diminished the catalyst’s NH₃ storage capacity, impaired the transient NOx reduction efficiency, and induced premature ammonia leakage. After multiple sulfur poisoning incidents, the NOx reduction performance stabilized. Higher SO₂ concentrations accelerated catalyst deactivation and hastened the attainment of this equilibrium state. The characterization results for the catalyst indicate that the catalyst accumulated the same sulfur content after tail gas poisoning with different sulfur concentrations and that sulfur existed in the form of SO₄²⁻. The sulfur species in low-sulfur-poisoning-concentration catalysts mainly included sulfur ammonia and sulfur copper species, while high-sulfur-poisoning-concentration catalysts contained a higher proportion of sulfur copper species. Neither species type significantly altered the zeolite coating’s crystalline structure. Sulfur ammonia species could easily lead to a significant decrease in the specific surface area of the catalyst, which could be decomposed at 500 °C to achieve NOx reduction performance regeneration. In contrast, sulfur copper species required higher decomposition temperatures (600 °C), achieving only partial regeneration. Full article