Search Results (4,546)

Since 2019, the NextGen pilot wastewater treatment unit—also known as the NextGen Sewer Mining concept—has been operating at the Athens Plant Nursery, transforming sewage from Athens’ central network into irrigation water and compost. This unit produces resources for plant growth through membrane bioreactors (MBRs) and aerobic sludge digestion. This study experimentally evaluates the effects of NextGen reused water and compost on two common ornamental plant species in Athens, Pittosporum tobira (Angelica) and Myrtus communis (Common Myrtle), compared to the use of tap water and red soil without additional fertilization. The results indicate that NextGen reused water combined with compost significantly promotes both height and weight growth in these plants. However, by the end of the experiment, compost fertilization had a greater effect on the height and weight growth of both Angelica and Myrtus plants when applied independently and watered with tap water, compared to the use of NextGen reused water combined with red soil. Notably, none of the 96 plants withered throughout the experiment, indicating that promising and sustainable technologies like the concept of Sewer Mining can effectively replace conventional and environmentally outdated methods of plant nutrition and irrigation by producing reused water and compost. Full article

The use of treated wastewater (TWW) in agriculture is an important technological alternative for decreasing freshwater consumption and improving soil physicochemical and biological properties. The aim of this study was to investigate how the quality of soil and olive plants was affected by irrigation with TWW, surface water (SW), and blended water (BW), using tap water as the control. Several plant growth, chemical, and microbial parameters, namely plant height, trunk diameter, chlorophyll content, pH, total organic carbon (TOC), total nitrogen (TN), metals, salinity, and microbial population were selected for this purpose. The short-term irrigation of olive plants for 3 years with TWW, BW, and SW increased the electrical conductivity, TOC, TN, phosphorus, and potassium in the soil. There were notable differences in plant height and chlorophyll content observed in the third year of the experiment, with the greatest values found for the TWW-irrigated plants. These differences were attributed to the rise in the TOC and TN in the soil, which promoted rapid plant growth. The reduction in microbial contamination during the cold seasons may indicate the natural control of these harmful pathogens. Accordingly, it can be concluded that the blending of TWW with SW can reduce the negative effects of TWW resulting from the accumulation of TOC, TN, and metals. Full article

The phytoremediation potential of the halophytic plant, Tamarix smyrnensis (T. smyrnensis), was examined in toxic metal spoils assisted by biochar and irrigation by air nanobubbles. The substrate (spoil) used in the present study was derived from areas close to laterite (Ni-containing ores) mines. The efficiency of biochar addition in two rates (5 t/ha and 20 t/ha) to improve microbial properties and stabilize soil aggregates was also examined. Furthermore, the effect of irrigation with air-nanobubble-supplemented water was evaluated for the remediation of toxic metal spoils. The physiological condition of the plant species was investigated in terms of biomass, height, chlorophyll content, and antioxidant enzymes. The alkali and heavy metal accumulation and their distribution in the plant parts were assessed to explore whether toxic metals could accumulate in the root and further translocate to the aboveground tissues. The growth of T. smyrnensis was not adversely affected by its cultivation in lateritic spoil, and the highest rate of biochar exhibited a beneficial effect on plant growth in terms of weight (aerial and subterranean biomass). The highest biochar application rate led to significant increases in total chlorophyll content, showing a 97.6% increase when biochar is used alone and a 136% increase when combined with nanobubble irrigation. Remarkably, only when combining irrigation with air nanobubbles and low biochar supplementation did the translocation of the metals from soil to the aboveground tissues occur as the translocation factor was estimated to be greater than unity (TF > 1). The bioconcentration factors remained below 1.0 (BCF < 1) across all treatments, demonstrating limited mobilization from soil to plant tissues despite the application of soil amendments. Finally, the application of nanobubbles increased slightly but not substantially the total uptake of metals, which showed a significant decrease compared to the control groups when the lower dosage of biochar was utilized. Full article

Wheat is a key staple crop globally, essential for food security and sustainable agricultural development. The results of this study highlight how innovative monitoring techniques, such as UAV-based multispectral imaging, can significantly improve agricultural practices by providing precise, real-time data on crop growth. This study utilized unmanned aerial vehicle (UAV)-based remote sensing technology at the wheat experimental field of the Hebei Academy of Agriculture and Forestry Sciences to capture the dynamic growth characteristics of wheat using multispectral data, aiming to explore efficient and precise monitoring and management strategies for wheat. A UAV equipped with multispectral sensors was employed to collect high-resolution imagery at five critical growth stages of wheat: tillering, jointing, booting, flowering, and ripening. The data covered four key spectral bands: green (560 nm), red (650 nm), red-edge (730 nm), and near-infrared (840 nm). Combined with ground-truth measurements, such as chlorophyll content and plant height, 21 vegetation indices were analyzed for their nonlinear relationships with wheat growth parameters. Statistical analyses, including Pearson’s correlation and stepwise regression, were used to identify the most effective indices for monitoring wheat growth. The Normalized Difference Red-Edge Index (NDRE) and the Triangular Vegetation Index (TVI) were selected based on their superior performance in predicting wheat growth parameters, as demonstrated by their high correlation coefficients and predictive accuracy. A random forest model was developed to comprehensively evaluate the application potential of multispectral data in wheat growth monitoring. The results demonstrated that the NDRE and TVI indices were the most effective indices for monitoring wheat growth. The random forest model exhibited superior predictive accuracy, with a mean squared error (MSE) significantly lower than that of traditional regression models, particularly during the flowering and ripening stages, where the prediction error for plant height was less than 1.01 cm. Furthermore, dynamic analyses of UAV imagery effectively identified abnormal field areas, such as regions experiencing water stress or disease, providing a scientific basis for precision agricultural interventions. This study highlights the potential of UAV-based remote sensing technology in monitoring wheat growth, addressing the research gap in systematic full-cycle analysis of wheat. It also offers a novel technological pathway for optimizing agricultural resource management and improving crop yields. These findings are expected to advance intelligent agricultural production and accelerate the implementation of precision agriculture. Full article

As a fast-growing tree species, Ochroma lagopus Swartz has a greater demand for nutrients, and urea and slow-release fertilizer addition can promote the growth and development of O. lagopus. This experiment explored the effects of urea and slow-release fertilizer on the growth and nutrient uptake of O. lagopus plantation forests. The results of the study can provide a theoretical basis for the cultivation and management of O. lagopus plantation forests. At the end of June 2023, a two-year-old O. lagopus was used as the study’s object at Mengwing Farm, Mengla County, Xishuangbanna Dai Autonomous Prefecture, Yunnan Province, China. Fertilizer is applied through root outer ring application. Seven treatments of no N control (CK) and urea and slow-release fertilizers 300 g/plant (N1, H1), 450 g/plant (N2, H2), and 600 g/plant (N3, H3) were set up to determine the breast height, diameter at breast height, as well as the nutrient contents of leaves, branches, roots, and soils of the trees. The DBH and tree height were higher under N addition than in the CK, and both were highest in H3 at 90 d after fertilization, with 16.92% and 14.64% higher than CK, respectively. The overall change in C content of each organ was not obvious, N content increased with the increase in fertilizer application, and the change pattern of P content was not consistent. Soil N content showed a significant increase with the increase in N application, while P and K content showed a trend of increasing and then decreasing, and soil N content of slow-release fertilizer treatments was higher than that of urea treatments under the same amount of N application. The soil N content was higher in the slow-release fertilizer treatment than in the urea treatment regardless of the amount of N applied. The soil N content was highly significantly positively correlated with the N content of leaves, branches, and roots. There was a highly significant allometric growth relationship among the C, N, and P content of each organ. The N addition had a significant effect on the growth and the nutrient content of each organ and soil. O. lagopus mainly adapted to changes in the soil N content by adjusting the N and P content of each organ, and the optimal effect was observed in H3. In the future, an appropriate amount of P fertilizer should be applied to complement N fertilizer, urea and slow-release fertilizer can also be applied. Full article

Maize is a critical crop for food, feed, and bioenergy worldwide. This study characterized the genetic diversity and population structure of 212 important inbred lines collected from the Southeast China breeding program using the Maize6H-60K single nucleotide polymorphism (SNP) array. To investigate the genetic architecture of plant height (PH) and ear height (EH), genome-wide association analysis (GWAS) was performed on this population in 2021 and 2022. Cluster analysis and population genetic structure analysis grouped the 212 maize inbred lines into 10 distinct categories. GWAS identified significant associations for PH, EH, and the EH/PH ratio. A total of 40 significant SNP (p < 8.55359 × 10⁻⁷) were detected, including nine associated with PH, with phenotypic variation explained (PVE) ranging from 3.42% to 25.92%. Additionally, 16 SNP were linked to EH, with PVE ranging from 2.49% to 38.49%, and 15 SNP were associated with the EH/PH ratio, showing PVE between 3.43% and 16.83%. Five stable SNP, identified across two or more environments, were further analyzed. Three of these SNP loci are reported for the first time in this study: two loci associated with the PH, AX-108020973, and AX-108022922, as well as one new locus, AX-108096437, which was significantly associated with the EH/PH ratio. Additionally, two other significant SNP (AX-247241325 and AX-108097244) were located within a 2 Mb range of previously identified QTL and/or related SNP. Within the 200 kb confidence intervals of these five stable SNP loci, 76 functionally annotated genes were identified. Further functional analysis indicated that 14 of these genes may play a role in regulating plant morphology, which is primarily involved in hormone synthesis, microtubule development, root growth, and cell division regulation. For instance, the homologous genes GRMZM2G375249 and GRMZM2G076029 in maize correspond to OsPEX1 in rice, a protein similar to extension proteins that are implicated in lignin biosynthesis, plant growth promotion, and the negative regulation of root growth through gibberellin-mediated pathways. The candidate gene corresponding to AX-108097244 is GRMZM2G464754; previous studies have reported its involvement in regulating EH in maize. These findings enhance the understanding of QTL associated with maize plant-type traits and provide a foundation for cloning PH, EH-related genes. Therefore, the results also support the development of functional markers for target genes and the breeding of improved maize varieties. Full article

The characteristics of soil ditching and backfilling are crucial for orchard ditching operations. However, experimentally investigating the dynamic ditching and backfilling process is currently not feasible. To address this issue, the 3DGZ-50A self-propelled orchard ditching machine (SPODM) was designed using a modular concept, incorporating three types of ditching cutter discs (01#, 02#, and 03#). These discs were designed, trial-manufactured, and tested in orchard ditching experiments. A corresponding simulation model was also constructed using EDEM 2022 software. This study evaluated the ditching and backfilling process, analyzing the performance of the three cutter discs through experimental and simulation methods. Results indicated that the 01# and 02# cutter discs created V-shaped furrows, whereas the 03# cutter disc formed an arc-shaped furrow. The relative errors in the final furrow depth (D_f) and width (W_f) between experimental and simulated results were 30.70% and 8.61%, respectively, while those in the maximum furrow depth (D_m) and width (W_m) were 9.44% and 3.00%. These minor relative errors confirmed the accuracy of the simulation model. Regarding maximum power consumption, the 01# cutter disc used 86.3% of the power consumed by the 02# cutter disc and 85.1% of that used by the 03# cutter disc. During the ditching process, the blades penetrated the soil to create the maximum furrow cross-section, which then gradually decreased due to backfilling. Both simulation and test results demonstrated that the 01# cutter disc performed best, achieving a maximum furrow cross-sectional area (46.70%), minimum final surface furrow cross-sectional area (6.04%), and lower power consumption (31.03 kW). This study provides equipment for ditching operations in low-height close-planting orchards in northern China. Full article

Verticillium wilt and Fusarium wilt cause significant losses in cotton (Gossypium hirsutum) production and have a significant economic impact. This study determined the functional role of GhSTR1, a member of the ABCG subfamily of ATP-binding cassette (ABC) transporters, that mediates cotton defense responses against various plant pathogens. We identified GhSTR1 as a homolog of STR1 from Medicago truncatula and highlighted its evolutionary conservation and potential role in plant defense mechanisms. Expression profiling revealed that GhSTR1 displays tissue-specific and spatiotemporal dynamics under stress conditions caused by Verticillium dahliae and Fusarium oxysporum. Functional validation using virus-induced gene silencing (VIGS) showed that silencing GhSTR1 improved disease resistance, resulting in milder symptoms, less vascular browning, and reduced fungal growth. Furthermore, the AtSTR1 loss-of-function mutant in Arabidopsis thaliana exhibited similar resistance phenotypes, highlighting the conserved regulatory role of STR1 in pathogen defense. In addition to its role in disease resistance, the mutation of AtSTR1 in Arabidopsis also enhanced the vegetative and reproductive growth of the plant, including increased root length, rosette leaf number, and plant height without compromising drought tolerance. These findings suggest that GhSTR1 mediates a trade-off between defense and growth, offering a potential target for optimizing both traits for crop improvement. This study identifies GhSTR1 as a key regulator of plant–pathogen interactions and growth dynamics, providing a foundation for developing durable strategies to enhance cotton’s resistance and yield under biotic and abiotic stress conditions. Full article

The growth and nutrient balance of legumes can be disrupted in soils with increased nickel (Ni) concentrations. The inoculation of legumes with rhizobia, symbiotic nitrogen-fixing bacteria, can be used for the alleviation of trace metal stress in plants. This study evaluated the Ni tolerance of alfalfa rhizobia isolates and some plant growth-promoting traits in the presence of Ni: indole-3-acetic acid (IAA) production, Ni biosorption potential, and the effect of rhizobia on alfalfa (Medicago sativa L.) growth. The strains were characterized as Shinorhizobium meliloti, Sinorhizobium medicae, and Rhizobium tibeticum. In total, 70% of the tested strains tolerate up to 0.8 mM Ni, while 15% of the strains tolerate 1.2 mM Ni. The production of IAA was maintained in the presence of Ni until bacterial growth was stopped by raising the Ni concentration. Alfalfa seed germination is significantly reduced in the presence of 0.5 mM Ni, while a significant reduction in 10-day-old seedling length already occurs at a Ni concentration of 0.03 mM. In the plant experiment, when alfalfa was inoculated with rhizobial strains, nodulation was maintained up to 0.05 mM Ni, but a significant reduction in nodule number was detected at 0.01 mM Ni. At the concentration of 0.005 mM Ni, inoculation with 12 particular rhizobial strains significantly improved the number of nodules per plant, plant height, and root length, as well as plant shoot dry weight, compared to non-inoculated plants with Ni addition. However, higher concentrations caused a reduction in all of these plant growth parameters compared to the plants without Ni. The selected rhizobia strains showed a Ni biosorption capacity of 20% in the in vitro assay. The inoculation of alfalfa with effective rhizobial strains improves growth parameters compared to non-inoculated plants in the presence of certain concentrations of Ni. Full article

The summer-sowing short-season cotton cultivation model is an important method for simplified and mechanized cotton planting in the Yangtze River Basin. However, the effects of microbial fertilizers on cotton growth and soil under this model remain unclear. In 2023, we conducted a systematic analysis on the application of microbial fertilizers (compost) at varying levels (CK, MF1, MF2, and MF3) during different growth stages of cotton (bud, flowering, bolling, and boll opening). Results showed that appropriate microbial fertilizer application (MF2 and MF3) enhanced soil bacterial and fungal diversity, enriched beneficial microorganisms (e.g., Acidobacteriota and Candidatus Udaeobacter), improved soil nutrient availability, and increased antioxidant enzyme activity (POD, SOD), while reducing membrane lipid peroxidation (MDA). These effects led to significant improvements in yield traits, such as cotton plant height, number of fruiting branches and bolls, boll weight, and coat weight. The highest microbial fertilizer application level (MF3) resulted in a 54.35% increase in seed yield and a 75.37% increase in lint yield compared to CK. PLS-DA (Partial Least Squares Discriminant Analysis) and multivariate statistical analyses revealed that microbial fertilizer application fine-tuned soil microbial community composition, emphasizing the dynamic balance of the microbial ecosystem. This study provides scientific support for optimizing microbial fertilizer strategies to enhance the yield and quality of summer-sown short-season cotton and promote sustainable agriculture. Full article

Near-surface ozone is a secondary pollutant, and its high concentrations pose significant risks to human and plant health. Based on an Extra Tree (ET) model, this study estimated near-surface ozone concentrations with the high spatiotemporal resolution based on Himawari-8 aerosol optical depth (AOD) data and meteorological variables from 1 January 2016 to 31 December 2020. The SHapley Additive exPlanation (SHAP) method was employed to evaluate the contribution of AOD and meteorological factors on ozone concentration. The results indicate that (1) the ET model achieves a sample-based cross-validation R² of 0.75–0.87 and an RMSE (μg/m³) of 17.96–20.30. The coefficient of determination (R²) values of the model in spring, summer, autumn, and winter are 0.81, 0.80, 0.87, and 0.75, respectively. (2) Higher temperature and boundary layer heights were found to positively contribute to ozone concentration, whereas higher relative humidity exerted a negative influence. (3) From 11:00 to 15:00 (Beijing time, UTC+08:00), ozone concentration increases gradually, with the highest occurring in the summer, followed by spring. This study has obtained high spatial and temporal resolution ozone concentration data, offering valuable insights for the development of fine-scale ozone pollution prevention and control strategies. Full article

The aim of this study was to optimize water-saving and high-efficiency irrigation and nitrogen application scheduling for greenhouse tomato cultivation in North China. Using experimental data on water and nitrogen inputs, the DSSAT-GLUE parameter adjustment tool was employed to calibrate the genetic parameters of the DSSAT–CROPGRO–Tomato model. Simulations were conducted to assess greenhouse tomato growth, water use, and yield under varying water and nitrogen conditions. After calibration, the model showed average relative errors of 3.19% for the phenological stages, 3.33% for plant height, and 4.52% for yield dry weight, meeting accuracy standards. The results from the calibrated model indicated that increasing irrigation or nitrogen levels initially enhanced yield but led to diminishing returns beyond optimal ranges. The maximum tomato yield and water–nitrogen use efficiency were achieved with irrigation quotas between 320 and 340 mm and nitrogen applications between 360 and 400 kg·ha⁻¹. These findings provide a guideline for efficient water and nitrogen management for greenhouse tomatoes under drip irrigation conditions. Full article

Wheat, a staple crop cultivated for over 8000 years, sustains more than 2.5 billion people globally, as a major source of carbohydrate, protein, fiber, and essential nutrients. Colored wheat, enriched with dietary fiber and antioxidants, offers valuable genetic resources for developing functional wheat varieties. Herein, a mutant pool of 1069 colored wheat lines was developed through gamma-ray irradiation to enhance genetic diversity. Mutant lines were classified into 10 groups based on seed color parameters (L*, a*, and b*), which were measured using the Hunter Lab system. K-means clustering categorized the mutant lines, and four representative lines from each group were analyzed for agronomic traits (plant height, spike length, thousand-seed weight, and kernels per spike) and antioxidant properties (radical-scavenging activity, ferric reducing antioxidant power, and total antioxidant capacity). Principal-component analysis revealed distinct clustering patterns, indicating associations between seed color, agronomic traits, and antioxidant activity. Darker seed color groups exhibited 3–16% higher levels of bioactive compounds and 10–18% higher antioxidant activities, whereas lighter groups showed 8–42% lower functional potential compared to the control wheat. These findings highlight the potential of mutation breeding in generating phenotypic diversity and developing wheat varieties with improved functional traits and bioactive compound content. Full article

Previous studies have shown that selenium (Se) can influence rice growth and yield. However, the Se effect on rice lodging remains unknown. This study aimed to investigate the impact of different Se treatments on seedling growth and stem sheath hardness in fragrant rice. A hydroponic experiment was conducted using two fragrant rice varieties, Yuxiangyouzhan and Xiangyaxiangzhan, as experimental materials. Two forms of selenium fertilizers (amino acid-chelated selenium and sodium selenite) were used. There were five foliar spraying selenium fertilizer treatments (CK: no selenium fertilizer; T1: 4 μmol·L⁻¹ amino acid-chelated selenium; T2: 8 μmol·L⁻¹ amino acid-chelated selenium; T3: 4 μmol·L⁻¹ sodium selenite; and T4: 8 μmol·L⁻¹ sodium selenite), and the effects of the different selenium fertilizer treatments on seedling growth and stem sheath hardness in fragrant rice were studied. Significant Se treatment effects on root fresh weight, seedling dry weight, plant height, stem sheath length, number of leaves, chlorophyll content, stem sheath hardness, peroxidase activity in leaf and stem sheaths, and lignin content in the roots were detected. A significant Se treatment and variety interaction effect on the stem sheath hardness was observed. The different forms/levels of selenium fertilizer affected the seedling growth and the stem sheath hardness differed. The Se treatments improved seedling growth and significantly affected the dry weight, chlorophyll content, stem sheath hardness, and peroxidase activity in leaf and stem sheaths. Compared with the CK treatment, the Se treatments increased the total dry weight of seedlings in Xiangyaxiangzhan and Yuxiangyouzhan by the ranges of 25.43–52.77% and 18.97–30.09%, respectively. The T2–T4 treatments increased the stem sheath hardness values in Xiangyaxiangzhan and Yuxiangyouzhan by the ranges of 21.6–54.7% and 38.3–146.6%, respectively, as compared to the CK treatment. The Se treatments had a promoting effect on physiological indexes such as stem sheath length, lignin content in the stem sheath, and dry matter accumulation in different plant tissues, thereby increasing the total dry weight. The Se treatment had an inhibitory effect on chlorophyll b content and total chlorophyll content, whilst it increased the chlorophyll a content and chlorophyll a/b ratio, which in turn affected the photosynthesis of rice. Therefore, appropriate Se treatments (the application of 8 μmol·L⁻¹ amino acid-chelated selenium, 4 μmol·L⁻¹ sodium selenite, and 8 μmol·L⁻¹ sodium selenite) could improve seedling growth and stem sheath hardness, which was related to the parameter changes, such as the dry weight, photosynthesis pigments, and peroxidase activity. These findings suggest that different Se fertilizers can positively regulate rice resistance to lodging and growth. This study can provide theoretical support for the application of selenium fertilizer. Full article

Protected crops are intensive production systems characterized by high vegetation density, high temperatures, and high moisture, making them favorable environments for the development of pests and diseases. Consequently, these systems often require several interventions with agrochemicals to maintain profitable yields and high produce quality. However, the application of plant protection products (PPPs) in such systems is not efficient and poses environmental concerns. This study aims at analysing spray behaviour, particularly in terms of foliar deposition and losses to the ground according to spraying equipment and foliage height, focusing on a specifically designed and developed system for agrochemical application in protected crops, and comparing it with a commonly used spraying system, namely, the cannon sprayer. Such a system consists in a fixed net of tubing and anti-drip nozzles positioned at the top of the greenhouse’s apex, connected to a pneumatic sprayer ‘Special Serre 2000’ outside the greenhouse. Findings revealed a significant effect of the spraying system (Kruskal–Wallis χ² = 12.239, df = 1, and p-value = 0.0004681) on normalized foliar deposition, with higher values obtained using the fixed spraying system. In addition, a simulation of the spatial distribution based on the principle of inverse distance weighting (IDW) was performed for qualitative spray assessment, confirming the heterogeneity of foliar deposition over the greenhouse with both of the used equipment. In addition, losses to the ground were affected by both spraying equipment and captor position. Full article