Search Results (2,889)

This systematic literature review investigates microstrip antenna applications in image acquisition, focusing on their design characteristics, reconstruction algorithms, and application areas. We applied the PRISMA methodology for article selection. From selected studies, classifications were identified based on antenna patch geometry, substrate types, and image reconstruction algorithms. According to inclusion criteria, a significant increase in publications on this topic has been observed since 2013. Considering this trend, our study focuses on a 10-year publication range, including articles up to 2023. Results indicate that medical applications, particularly breast cancer detection, dominate this field. However, emerging areas are gaining attention, including stroke detection, bone fracture monitoring, security surveillance, avalanche radars, and weather monitoring. Our study highlights the need for more efficient algorithms, system miniaturization, and improved models to achieve precise medical imaging. Visual tools such as heatmaps and box plots are used to provide a deeper analysis, identify knowledge gaps, and offer valuable insights for future research and development in this versatile technology. Full article

Remote sensing is essential in precision agriculture as this approach provides high-resolution information on the soil’s physical and chemical parameters for detailed decision making. Globally, technologies such as remote sensing and machine learning are increasingly being used to infer these parameters. This study evaluates soil fertility changes and compares them with previous fertilization inputs using high-resolution multispectral imagery and in situ measurements. A UAV-captured image was used to predict the spatial distribution of soil parameters, generating fourteen spectral indices and a digital surface model (DSM) from 103 soil plots across 49.83 hectares. Machine learning algorithms, including classification and regression trees (CART) and random forest (RF), modeled the soil parameters (N-ppm, P-ppm, K-ppm, OM%, and EC-mS/m). The RF model outperformed others, with R² values of 72% for N, 83% for P, 87% for K, 85% for OM, and 70% for EC in 2023. Significant spatiotemporal variations were observed between 2022 and 2023, including an increase in P (14.87 ppm) and a reduction in EC (−0.954 mS/m). High-resolution UAV imagery combined with machine learning proved highly effective for monitoring soil fertility. This approach, tailored to the Peruvian Andes, integrates spectral indices and field-collected data, offering innovative tools to optimize fertilization practices, address soil management challenges, and merge modern technology with traditional methods for sustainable agricultural practices. Full article

The growing population and the impacts of climate change present a major challenge to forests, which play a crucial role in regulating the carbon cycle. Pakistan, as a Kyoto Protocol signatory, has implemented afforestation initiatives such as the Khyber Pakhtunkhwa (KP) government’s Billion Tree Afforestation Project (BTAP). Quantifying the environmental impacts of such initiatives is very important; however, carbon pool data for BTAP plantation regions remain unavailable and are underexplored. This study aims to quantify aboveground biomass (AGB) and carbon sequestration potential (CSP) in the BTAP plantation regions using remote sensing and field data. Random sampling of 310 circular plots (17.84 m radius) provided measurements for tree height and diameter, from which AGB was calculated using allometric equations. Remote sensing data from Sentinel-1 and Sentinel-2, combined with polarization rasters and vegetation indices, were used to train and evaluate multiple regression models including multiple linear regression (MLR), support vector regression (SVR), and random forest regression (RFR). The RFR model outperformed the others (R² = 0.766) when using combined optical and radar data, yielding a mean AGB of 4.77 t/ha, carbon stock of 2.24 t/ha, and CO₂ equivalent of 10.36 t/ha. For BTAP plantations, the total biomass reached 1.19 million tons, with 2.06 million tons of CO₂ equivalent sequestered, corresponding to an annual sequestration of 0.47 t/ha/yr and a potential of 99.18 ± 15 t/ha. This research introduces innovative predictive models and a comprehensive carbon assessment framework for afforestation projects, providing critical insights for policymakers and climate change mitigation efforts. Full article

Drought significantly impacts sugarcane yield, making drought resistance an important trait in drought-prone regions. The effects of the timing and duration of drought on yield and yield components, including relationships among these traits, were examined using a diverse set of sugarcane genotypes in a 2-year (planted cane and first ratoon) field study. Three drought treatments (no water stress (SD0), short-term (SD1), and long-term (SD2) drought) were assigned as the main plot and replicated four times. Within each plot, six genotypes were nested in a split-plot design. Drought reduced yield and its components, with the decline greater in SD2 than in SD1. Strong relationships between yield and its components like stalk height and density and height growth rate, especially under drought, make these traits potential surrogates for yield in drought screening experiments. The genotypes F03–362 and KK3 displayed high, stable yield potential across drought treatments, but KK3 lost potential in ratoon crop under drought. Although KK09–0358 displayed high yield potential, it was very sensitive to drought stress while UT12 and KK09–0939 displayed low yield potential and sensitivity to drought. TPJ04–768 displayed low but stable yield potential across drought treatments and crops. F03–362 and TPJ04–768 have utility in studies seeking to couple physiological with agronomic parameters promoting drought resistance and as parents for developing cultivars combining high and stable yield performance under drought. Full article

Forests, being the largest and most intricate terrestrial ecosystems, play an indispensable role in sustaining ecological balance. To effectively monitor forest productivity, it is imperative to accurately extract structural parameters such as the tree height and diameter at breast height (DBH). Airborne LiDAR technology, which possesses the capability to penetrate canopies, has demonstrated remarkable efficacy in extracting these forest structural parameters. However, current research rarely models different tree species separately, particularly lacking comparative evaluations of tree height-DBH models for diverse tree species. In this study, we chose sample plots within the Bila River basin, nestled in the Greater Hinggan Mountains of the Inner Mongolia Autonomous Region, as the research area. Utilizing both airborne LiDAR and field survey data, individual tree positions and heights were extracted based on the canopy height model (CHM) and normalized point cloud (NPC). Six tree height-DBH models were selected for fitting and validation, tailored to the dominant tree species within the sample plots. The results revealed that the CHM-based method achieved a lower RMSE of 1.97 m, compared to 2.27 m with the NPC-based method. Both methods exhibited a commendable performance in plots with lower average tree heights. However, the NPC-based method showed a more pronounced deficiency in capturing individual tree information. The precision of grid interpolation and the point cloud density emerged as pivotal factors influencing the accuracy of both methods. Among the six tree height-DBH models, a multiexponential model demonstrated a superior performance for both oak and ”birch–poplar” trees, with R² values of 0.479 and 0.341, respectively. This study furnishes a scientific foundation for extracting forest structural parameters in boreal forest ecosystems. Full article

The connection between crustal anatexis and magmatism is key to understanding the mechanisms that drive the evolution of the continental crust. Isotope geology and lithochemistry are important tools for reconstructing links between these processes, as field evidence of their connection is often obliterated by deformation in high-grade terrains. Thus, this study proposes new insights into the connection between the Mesoarchean regional metamorphism, crustal anatexis, and plutonism in the northern sector of the Carajás Province (i.e., Carajás Domain), in the Amazonian Craton, around 2.89 to 2.83 Ga. The widespread crustal anatexis in the Carajás Domain involved the water-fluxed melting of banded orthogneisses of the Xingu Complex and Xicrim-Cateté Orthogranulite (crystallization age at ca. 3.06–2.93 Ga), producing metatexites and diatexites with stromatic, net, schollen, and schlieren morphologies and coeval syntectonic leucosomes with composition similar to tonalites, trondhjemites, and granites. These leucosomes yielded crystallization ages of 2853 ± 5 Ma (MSWD: 0.61), 2862 ± 13 Ma (MSWD: 0.1), and 2867 ± 7 Ma (MSWD: 1.3). Their lithochemical data are similar to those of several diachronous Mesoarchean granitoids of the Carajás Domain in terms of major, minor, and trace elements and magmatic affinity. In addition, binary log–log vector diagrams (e.g., La vs. Yb; Rb vs. Yb), Sr/Y vs. Y, and Eu/Eu* vs. Yb plots indicate that plagioclase fractionation preceded melt extraction, establishing evolving source-to-sink trends between leucosomes and granites. These results show that the interplay between high-grade metamorphism, crustal anatexis, and magmatism may have shaped the evolution of the Mesoarchean continental crust in the Carajás Province, developing a petrotectonic assemblage associated with collisional orogens. The Mesoarchean geodynamic setting played a critical role in the development of coeval ca. 2.89 Ga magmatic–hydrothermal copper deposits in the Carajás Province, as well as Neoarchean world-class iron oxide–copper–gold deposits linked to post-orogenic extensional rebound. Full article

Weed management has been one of the major challenges in camelina [Camelina sativa (L.) Crantz] production owing to the limited options for selective herbicides. The aim of this study was to evaluate and screen camelina-safe herbicides and establish an effective weed management program combining pre- and post-emergence herbicide application in camelina. There were 22 herbicides (6 herbicides registered as pre- and 16 herbicides registered as post-emergence herbicides) with various modes of action tested in this study. Greenhouse evaluation showed that, of the 22 herbicides tested, post-application of s-metolachlor and prodiamine (registered as pre-emergence herbicide), and clethodim, fluazifop-p, clopyralid, and quinclorac (registered as post-emergence herbicide) possessed adequate safety (~×4 of recommended doses) when used on the two camelina genotypes (CamC1 and CamK3) by evaluation of plant visual efficacy, seed weight, and plant biomass yield per plant. Herbicides from the ALS (e.g., flumetsulam), HPPD (e.g., mesotrione), IPP (e.g., clomazone), PPO (e.g., oxyfluorfen), and PS II (e.g., bentazon) groups caused severe camelina growth suppression and mortality. Field evaluation with greenhouse-selected herbicides demonstrated the superior weed control efficacy of sequential application combining pre- (s-metolachlor) and post-emergence (clethodim, fluazifop-p, or clopyralid) herbicides (84–90% reduction in weed biomass in camelina plots relative to untreated control) than the single application of those herbicides (68–83%). Clethodim and fluazifop-p provided good post-emerged grass weed control (e.g., crabgrass), whereas clopyralid effectively controlled the broadleaf weeds, such as common vetch and shepherd’s purse. Camelina seed yields from s-metolachlor following clethodim, fluazifop-p, or clopyralid application were statistically comparable to the yield of the weed-free treatment (hand weeding) and were significantly greater than those of the untreated control, indicating the effective weed control efficacies provided by those herbicides. Sequential application of the above herbicides did not affect camelina seed oil content, the principal UFA concentrations (e.g., C18:1~3), UFA/SFA, and MUFA/PUFA. In summary, sequential application combining pre- (s-metolachlor) and post-emergence (clethodim, fluazifop-p, or clopyralid) herbicides shows effective weed control in camelina, thus providing a great opportunity to increase camelina production through herbicide-based weed management. Full article

Routine core permeability and porosity are crucial in assessing flow units within a reservoir because they define a reservoir’s storage and flow capacities. A limited amount of work has been conducted on the lower cretaceous (Barremian to Valanginian) sandstones in the Bredasdorp Basin, offshore South Africa, focusing on the flow zones and the possible effect of diagenetic minerals on the individual flow zones, limiting understanding of reservoir quality and fluid flow behavior across the field. Nine hundred routine core analysis datasets were used to determine the flow units within the reservoir from three wells (F-A10, F-A13, and F-O2) from independent methods, namely: the Pore Throat Radius, Flow Zone Indicator, Stratigraphic Modified Lorenz Plot, and Improved Stratigraphic Modified Lorenz Plot. The results showed six flow units: fracture, super-conductive, conductor, semi-conductor, baffle, and semi-barrier. The super-conductive flow units contributed the most flow, whereas the semi-barrier and baffle units contributed the least flow. Petrography analyses revealed that the diagenetic minerals present were smectite, illite, glauconite, siderite, micrite calcite, and chlorite. The pore-filling minerals reduced the pore spaces and affected pore connectivity, significantly affecting the flow contribution of the baffle and semi-barrier units. Micrite calcite and siderite cementation in FU5 of F-A13 and FU9 of F-O2 significantly reduced the intergranular porosity by filling up the pore spaces, resulting in tight flow units with impervious reservoir quality. It was noted that where the flow unit was classified as super-conductive, authigenic clays did not significantly affect porosity and permeability as they only occurred locally. However, calcite and silica cementation significantly affected pore connectivity, where the flow unit was classified as a very low, tight, semi-barrier, or barrier. Full article

The winter wheat and summer maize double cropping system is the primary cropping pattern for wheat and maize in dryland areas of China. The management of tillage in this system is typically conducted before wheat sowing. However, few studies have validated and quantified the impact of tillage methods before wheat sowing and irrigation practices during the wheat season on the yield formation and water use efficiency of summer maize. Therefore, this study hypothesized that subsoiling before wheat sowing improves maize yield and WUE by enhancing soil moisture retention and plant development. A three-year field experiment with a two-factor split-plot design was conducted at the junction of the Loess Plateau and the Huang-Huai-Hai Plain in China for validation, from 2019 to 2022. Three tillage methods before wheat sowing (RT: rotary tillage; PT: plowing, SS: subsoiling) were assigned to the main plots, and two irrigation practices during wheat growing season (W0: zero-irrigation; W1: one-off irrigation) were assigned to subplots. We measured the soil moisture, grain yield, dry matter accumulation, nitrogen (N), phosphorus (P), and potassium (K) accumulation, and water use efficiency of summer maize. The results indicated that subsoiling before wheat sowing increased soil water storage at the sowing of summer maize, thereby promoting dry matter and nutrient accumulation. Compared to rotary tillage and plowing, subsoiling before wheat sowing increased grain yield and water use efficiency of maize by an average of 19.5% and 21.8%, respectively. One-off irrigation during the wheat season had negative effects on pre-sowing soil water storage and maize productivity in terms of yield and dry matter accumulation. However, subsoiling before wheat sowing can mitigate these negative effects of one-off irrigation. Correlation analysis and path model results indicated that tillage methods before wheat sowing had a greater impact on soil water storage and maize productivity than irrigation practices during wheat growing season. The most direct factor affecting maize yield was dry matter accumulation, whereas the most direct factor affecting water use efficiency was nutrient accumulation. The technique for order preference by similarity to an ideal solution (TOPSIS) comprehensive evaluation indicated that subsoiling before wheat sowing was superior for achieving high maize yield and water use efficiency under the practice of one-off irrigation during the wheat season. These findings offer practical guidance for optimizing soil water use and maize productivity in drylands. Full article

Maize (Zea mays L.) is an important crop grown for food, feed, and energy. In general, maize yield is decreased due to drought stress during the reproductive stages, and, hence, it is critical to improve the grain yield under drought. A field experiment was conducted with a split-plot design. The main factor was the irrigation regime viz. well-irrigated conditions and withholding irrigation from tasseling to grain filling for 21 days. The subplots include six treatments, namely, (i) the control (water spray), (ii) zinc oxide @ 100 ppm, (iii) manganese oxide @ 20 ppm, (iv) nZnO @ 100 ppm + nMnO @ 20 ppm, (v) Tamil Nadu Agricultural University (TNAU) Nano Revive @ 1.0%, and (vi) zinc sulfate 0.25% + manganese sulfate 0.25%. During drought stress, the anthesis–silking interval (ASI), chlorophyll a and b content, proline, starch, and carbohydrate fractions were recorded. At harvest, the grain-filling rate and duration, per cent green leaf area, and yield traits were recorded. Drought stress increased the proline (38.1%) and anthesis–silking interval (0.45 d) over the irrigated condition. However, the foliar application of ZnO (100 ppm) and nMnO (20 ppm) lowered the ASI and increased the green leaf area, leaf chlorophyll index, and proline content over water spray. The seed-filling rate (17%), seed-filling duration (11%), and seed yield (19%) decreased under drought. Nevertheless, the seed-filling rate (90%), seed-filling duration (13%), and seed yield (52%) were increased by the foliar spraying of nZnO (100 ppm) and nMnO (20 ppm) over water spray. These findings suggest that nZnO and nMnO significantly improve the grain yield of maize under drought stress conditions. Full article

During the deposition of the Middle–Upper Triassic Yanchang Formation, the southern margin of the Ordos Basin (OB) serves as a critical area for investigating the tectonic interactions between the North China Block (NCB) and Qinling Orogenic Belt (QOB). The provenance record of this sedimentary succession can be utilized to trace basin–mountain interactions using petrological, geochemical, and zircon age geochronological studies. We analyzed lithic fragments, geochemistry, and detrital zircon U–Pb ages of samples from the Xunyi Sanshuihe field profile, Weibei Uplift. Discrimination diagrams of major and trace elements revealed provenances and tectonic-sedimentary settings. Middle–Upper Triassic sandstones comprise quartz, feldspar, and lithic fragments. Their compositions are plotted within recycled orogenic and magmatic arc provenance fields. Multiple element diagrams reveal a felsic igneous rock provenance. Detrital zircon age spectra display four prominent age groups, which are ca. 240–270, 410–450, 1800–2200, and 2400–2600 Ma, and one minor age group, that is, 870–1197 Ma in the Late Triassic sample. We conclude that the provenance of the Yanchang Formation changed significantly during the Middle–Late Triassic. The Late Triassic sediments were mainly QOB-derived, and the basement was from the NCB. The pre-Triassic strata and Longmen pluton in the southwest of OB were the provenance of Middle Triassic sediments. The QOB suffered rapid uplift and denudation, resulting in rapid deposition and deep-water deposition in the southern OB, which provides excellent conditions for the high-quality oil shale of Ch 7. Full article

A field experiment aimed to evaluate grain yield and grain quality of winter wheat cultivated in a 35-year cereal monoculture and three soil tillage systems (TSs). Winter wheat grown in the plot after common pea (PS) served as the control. In the monoculture (MON) and on PS plots, winter wheat was sown in the conventional (CT), reduced (RT), and no-tillage (NT) systems. In the CT system, shallow plowing was applied after the previous crop harvest, followed by pre-sow plowing. In the RT system, a cultivator was used, and the pre-sow plowing was replaced with a pre-sowing set. In turn, in the NT system, the soil was treated with glyphosate and cultivated using a pre-sowing cultivation set. Winter wheat produced over 2-fold higher grain yield on the PS plot than in the MON as well as in the CT than in the RT and NT systems. In turn, the plant number after emergence was differentiated only by the cropping system (CS). On the PS plots, the number of plants after emergence was 15.6% higher, and the spike number was 50.5% higher than on the MON plots. Also, more spikes per m² were found on the CT than on the RT and NT plots. Similarly, the grain weight per spike and the 1000 grain weight were higher on the PS plots compared to the MON plots as well as in the CT than in the RT and NT systems. The evaluation of the variance analysis components shows that the grain yield, plant number after emergence, spike number, grain number per spike, and 1000 grain weight were more strongly influenced by CS than by TS. Grain quality, expressed by the contents of total protein, wet gluten, and starch, as well as by Zeleny’s sedimentation index and grain uniformity index, were affected to a greater extent by CS than TS and reached higher values in the grain harvested from the PS plot compared to MON. Full article

This study aimed to clarify the scientific quantification of fertilizer nitrogen (N) uptake and utilization, its destination, and its residual distribution in the soil at a depth of 0–30 cm after biochar application using ¹⁵N tracer technology. The purpose was to provide a theoretical basis for developing a scientific application strategy for N fertilizer and biochar in irrigated farmland areas. Two levels of N fertilizer application were set up using the ¹⁵N labeling method in microareas of large fields: the regular amount of N fertilizer (N1: 300 kg·ha⁻¹) and a reduction of N fertilizer by 15% (N2: 255 kg·ha⁻¹). Further, three levels of biochar application were set up: no biochar (B0: 0 kg·ha⁻¹), a low amount of biochar (B1: 10 × 10³ kg·ha⁻¹), and a medium amount of biochar (B2: 20 × 10³ kg·ha⁻¹). The tested biochar was derived from corn stover (maize straw). The natural abundance of ¹⁵N-labeled fertilizer N, the total N content of each aboveground organ, and the total N content of soil at a depth of 0–30 cm in a spring wheat field at maturity were determined, and the yield was measured in the corresponding plots. The proportion of ¹⁵N-labeled fertilizer N uptake by each organ of spring wheat and the soil N uptake was 20.60–35.32% and more than 64.68%, respectively. Moreover, the proportion of soil N uptake showed a decreasing trend with an increase in biochar application. The spring wheat N uptake and utilization rate, the residue rate in the soil at a depth of 0–30 cm, the total utilization rate, and the rate of loss of ¹⁵N-labeled fertilizer N ranged from 15.21% to 29.61%, 23.33% to 28.93%, 38.54% to 58.54%, and 41.46% to 61.46%, respectively. The spring wheat N fertilizer utilization rate, fertilizer N residue rate in soil, and total fertilizer N utilization rate all increased gradually with an increase in biochar application, except for the N loss rate, which decreased gradually. When N fertilizer reduction was combined with medium biochar (B2N2), the yield of spring wheat significantly improved, mainly due to an increase in the number of grains in spikes. Under this treatment, the number of grains in spikes of spring wheat was 41.9, and the yield reached 7075.54 kg·ha⁻¹, which was an increase of 9.69–28.25% and 10.91–25.35%, respectively, compared with other treatments. Yield increased by up to 25.35%, and nitrogen loss decreased by 48.24% under the B2N2 treatment. Biochar application could promote the amount and proportion of fertilizer N uptake in various organs of spring wheat as well as in the soil at a depth of 0–30 cm. In this study, a 15% reduction in N fertilizer (255 kg·ha⁻¹) combined with 20 × 10³ kg·ha⁻¹ biochar application initially helped achieve the goal of increasing spring wheat yield and N fertilizer uptake, as well as improving fertilizer N utilization, providing an optimal scientific application strategy for N fertilizer and biochar in the farmland of the irrigation area. These results substantiate the hypothesis that biochar application enhances spring wheat (Triticum aestivum L.) assimilation of fertilizer-derived nitrogen (¹⁵N) while concomitantly improving fertilizer nitrogen retention in the soil matrix, which could provide a sustainable framework for nitrogen management in irrigated farmlands. Full article

The increasing severity of salinity stress, exacerbated by climate change, poses significant challenges to sustainable agriculture, particularly in salt-affected regions. Soil salinity, impacting approximately 20% of irrigated lands, severely reduces crop productivity by disrupting plants’ physiological and biochemical processes. This study evaluates the effectiveness of zinc (Zn) and silicon (Si) nanofertilizers in improving maize (Zea mays L.) growth, nutrient uptake, and yield under both saline and non-saline field conditions. ZnO nanoparticles (NPs) were synthesized via the co-precipitation method due to its ability to produce highly pure and uniform particles, while the sol–gel method was chosen for SiO₂ NPs to ensure precise control over the particle size and enhanced surface activity. The NPs were characterized using UV-Vis spectroscopy, XRD, SEM, and TEM-EDX, confirming their crystalline nature, morphology, and nanoscale size (ZnO~12 nm, SiO₂~15 nm). A split-plot field experiment was conducted to assess the effects of the nano and conventional Zn and Si fertilizers. Zn was applied at 10 ppm (22.5 kg/ha) and Si at 90 ppm (201 kg/ha). Various agronomic, chemical, and physiological parameters were then evaluated. The results demonstrated that nano Zn/Si significantly enhanced the cob length and grain yield. Nano Si led to the highest biomass increase (110%) and improved the nutrient use efficiency by 105% under saline and 110% under non-saline conditions compared to the control. Under saline stress, nano Zn/Si improved the nutrient uptake efficiency, reduced sodium accumulation, and increased the grain yield by 66% and 106%, respectively, compared to the control. A Principal Component Analysis (PCA) highlighted a strong correlation between nano Zn/Si applications with the harvest index and Si contents in shoots, along with other physiological and yield attributes. These findings highlight that nanotechnology-based fertilizers can mitigate salinity stress and enhance crop productivity, providing a promising strategy for sustainable agriculture in salt-affected soils. Full article

Accurate spectral and radiometric calibration is critical for precise Solar Spectral Irradiance (SSI) and Aerosol Optical Depth (AOD) retrievals in ground-based observations. This study introduces a pixel-based real-time noise deduction method and evaluates its performance using laser sources, Fraunhofer dark lines, and an improved Langley plot calibration. The proposed approach addresses challenges in long-term field SSI monitoring, including spectral noise variation and frequent calibration requirements for wavelength and responsivity corrections. The pixel-based noise deduction method effectively suppresses spectral dark noise to 0 ± 0.890, outperforming temperature-based corrections by 0.6%. Wavelength accuracy tests with laser sources and Fraunhofer dark lines demonstrate high consistency, with δλ < 0.3 nm, while spectral calibration uncertainty is assessed at 0.195 nm to 0.299 nm. The improved Langley plot achieves spectral responsivity differing by only 0.80% from the standard Langley plot and enhances AOD correlation with CE318 by 0.9–2.7% (RMSE: 0.002–0.003), significantly improving AOD observation accuracy. This work advances the development of field SSI hyperspectral observation and calibration, improving the accuracy of SSI and AOD measurements and contributing to the study of environmental changes and climate dynamics. Full article