Large-scale Field Research Articles

Response of stomatal conductance to plant water stress in buffalograss seed production: Observation with UAV thermal infrared imagery

Stomatal conductance (gs) is an indicator that allows for direct evaluation of plant water status, but it is challenging to achieve rapid monitoring in large-scale fields due to limitations in observation methods. Here this study was conducted to identify the thresholds of gs with different target yields and develop a gs-based water stress diagnostic model for buffalograss (Buchloe dactyloides (Nutt.) Engelm.) using UAV thermal infrared imagery for buffalograss in 2022 and 2023. The results of the field experiment demonstrated that the gs rapidly response to changes in the water stress status of buffalograss. The thresholds of gs were 403 and 385 mmol m−2 s−1 for the vegetative and reproductive growth stages, respectively, with the target seed yield of 1224 kg ha−1. The gs values were classified into three levels for the vegetative growth and four levels for the in reproductive growth stage of buffalograss, respectively. The canopy temperature depression response to water stress is consistent with the gs. Based on this relationship, this study developed a gs-based diagnostic model with a random forest algorithm for buffalograss. Furthermore, a spital map of gs was created using UAV thermal infrared imagery. The modification test results indicated that the model made a good estimation of gs were good with normalized root mean square errors of 15% in the vegetative stage and 11% in the reproductive stage, respectively. Therefore, it is feasible to use thermal infrared imagery for monitoring gs and evaluating the water stress of plants in buffalograss fields.

Feasibility of Modernizing the Acceptable International Roughness Index Value

The U.S. National Highway System has set a standard for acceptable pavement roughness, measured by the international roughness index (IRI) at less than 2.68 m/km (170 in./mi). This value corresponds to a present serviceability rating (PSR) of 2.5, where half of the highway drivers perceive the pavement ride quality as unacceptable with a repair need. For over 3 decades, public transportation agencies in the U.S. have used this IRI value to determine when pavement surface rehabilitation is needed. However, with advancements in vehicle suspension systems improving ride quality, the current acceptable IRI value corresponding to 2.5 PSR has been questioned. To our knowledge, studies in the literature have yet to explore this issue. This study aims to evaluate the feasibility of modernizing the acceptable IRI value through nationwide, large-scale field testing, which is typically expensive and time-consuming. The IRI-present serviceability index (PSI) equation that is capable of converting the acceptable IRI value into the estimated 2.5 PSR (i.e., the PSI) was selected and calibrated by applying test quarter-car parameters synthesized through a literature review. Then, the calibrated IRI-PSI equation was used to find a new acceptable IRI value that was evaluated for the statistical significance and the financial benefits of the new value. The evaluation results suggest a need for a nationwide field test to modernize the current acceptable IRI value. Public transportation agencies can easily adapt the technical approach we used to calibrate the IRI-PSI equation without altering their current IRI measurement systems.

“Farming with alternative pollinators” provides benefits also in large-scale fields

Insect pollinators are declining worldwide due to many challenges and several approaches have been implemented to mitigate their loss. Farming with Alternative Pollinators (FAP) uses marketable habitat enhancement plants (MHEP) that yield substantial benefits for farmers from the first year. Studies with small-scale farmers have shown that FAP sustains high diversity and abundance of flower visitors and natural enemies, resulting in significant increases in smallholders' incomes, on average 121% higher. For the first time, we analyzed this approach in large-scale fields. Trials were conducted in 16 farms in two regions of Morocco, Sidi Slimane and Ksar El-Kebir, in 2021. We used melon (Cucumis melo) as the main crop and coriander, anise and sunflower as MHEP and selected in each farm 1 ha as trial area in larger monocultures. We compared FAP and control fields regarding abundance and richness of flower visitors, natural enemies and pests as well as net income of the whole field (1 ha). Flower visitors and natural enemies were significantly more diverse and abundant in FAP fields and there were also fewer pests. Our economic results show 17% higher net income per ha in FAP fields versus control fields in the Ksar El-Kebir region, and 12% higher net income in FAP fields compared to control fields in Sidi Slimane region. Although the mean yield difference was statistically significant, the income difference was not. We suggest more FAP trials are needed in different large-scale fields systems.

Evolution of the Magnetic Field in High- and Low-β Disks with Initially Toroidal Fields

Abstract We present the results from a pair of high-resolution, long-timescale (∼105 GM/c 3), global, three-dimensional magnetohydrodynamical accretion disk simulations with differing initial magnetic plasma β in order to study the effects of the initial toroidal field strength on the production of a large-scale poloidal field. We initialize our disks in approximate equilibrium with purely toroidal magnetic fields of strength β 0 = 5 and 200. We also perform a limited resolution study. We find that simulations of differing field strengths diverge early in their evolution and remain distinct over the time studied, indicating that the initial magnetic conditions leave a persistent imprint in our simulations. Neither simulation enters the magnetically arrested disk regime. Both simulations are able to produce poloidal fields from initially toroidal fields, with the β 0 = 5 simulation evolving clear signs of a large-scale poloidal field. We make a cautionary note that computational artifacts in the form of large-scale vortices may be introduced in the combination of initially weak field and disk-internal mesh refinement boundaries, as evidenced by the production of an m = 1 mode overdensity in the weak field simulation. Our results demonstrate that the initial toroidal field strength plays a vital role in the simulated disk evolution for the models studied.

Weakened Magnetic Braking in the Exoplanet Host Star 51 Peg

The consistently low activity level of the old solar analog 51 Peg not only facilitated the discovery of the first hot Jupiter, but also led to the suggestion that the star could be experiencing a magnetic grand minimum. However, the 50 yr time series showing minimal chromospheric variability could also be associated with the onset of weakened magnetic braking (WMB), where sufficiently slow rotation disrupts cycling activity and the production of large-scale magnetic fields by the stellar dynamo, thereby shrinking the Alfvén radius and inhibiting the efficient loss of angular momentum to magnetized stellar winds. In this Letter, we evaluate the magnetic evolutionary state of 51 Peg by estimating its wind braking torque. We use new spectropolarimetric measurements from the Large Binocular Telescope to reconstruct the large-scale magnetic morphology, we reanalyze archival X-ray measurements to estimate the mass-loss rate, and we detect solar-like oscillations in photometry from the Transiting Exoplanet Survey Satellite, yielding precise stellar properties from asteroseismology. Our estimate of the wind braking torque for 51 Peg clearly places it in the WMB regime, driven by changes in the mass-loss rate and the magnetic field strength and morphology that substantially exceed theoretical expectations. Although our revised stellar properties have minimal consequences for the characterization of the exoplanet, they have interesting implications for the current space weather environment of the system.

A Large-scale Magnetic Field Generation System for Pesticide-free Agriculture Based on Cascaded Inductive Coupling

A Large-scale Magnetic Field Generation System for Pesticide-free Agriculture Based on Cascaded Inductive Coupling

Laboratory modeling of YSO jets collimation by a large-scale divergent interstellar magnetic field

Context. Numerical studies as well as scaled laboratory experiments suggest that bipolar outflows arising from young stellar objects (YSOs) could be collimated into narrow and stable jets as a result of their interaction with a poloidal magnetic field. However, this magnetic collimation mechanism was demonstrated only for the simplified topology of the uniform poloidal magnetic field. Aims. We have extended the experimental studies to the case of a plasma outflow expanding in a region of strong poloidal magnetic field and then propagating through divergent magnetic field lines. In this case the magnetic field distribution is closer to the hourglass magnetic field distribution expected near YSOs. Our aim was to find out whether (and under what conditions) magnetic collimation is possible in such a strongly nonuniform B-field configuration. Methods. The experiments were carried out on the PEARL high-power laser facility. The laser produced plasma outflow was embedded in a strong (~10T) magnetic field generated by our unique magnetic system. The morphology and dynamics of the plasma were diagnosed with a Mach-Zehnder interferometer. Results. Laboratory experiments and 3D numerical modeling allow us to reveal the various stages of plasma jet formation in a divergent poloidal magnetic field. The results show (i) that there is a fundamental possibility for magnetic collimation of a plasma outflow in a divergent magnetic field; (ii) that there is good scalability of astrophysical and laboratory flows; (iii) that the conditions for the formation of a magnetic nozzle, hence collimation by poloidal magnetic field, have been met; and (iv) that the propagation of the jet proceeds unimpeded through the region of weak and strongly divergent magnetic fields, maintaining a high aspect ratio. Conclusions. Since we have verified that the laboratory plasma scales favorably to YSO jets and outflows, our laboratory modeling hints at the possibility of the YSO jet collimation in a divergent poloidal magnetic field.

Corn Plant Counting Using Deep Learning and UAV Images

The adoption of new technologies, such as unmanned aerial vehicles (UAVs), image processing, and machine learning, is disrupting traditional concepts in agriculture, with a new range of possibilities opening in its fields of research. Plant density is one of the most important corn (Zea mays L.) yield factors, yet its precise measurement after the emergence of plants is impractical in large-scale production fields due to the amount of labor required. This letter aims to develop techniques that enable corn plant counting and the automation of this process through deep learning and computational vision, using images of several corn crops obtained using a low-cost unmanned aerial vehicle (UAV) platform assembled with an RGB sensor.

Impact of submerged culture different parameters on growth and naringinase activity of Bacillus amyloliquefaciens D1 isolated from citrus gardens of North-East India

The study aims at screening, isolation, and characterization of naringinase enzyme producing bacterial strains from soil samples. In this study, 45 bacterial isolates were screened for naringinase activity, and among them, 20 bacterial isolates are found to be capable of naringinase production in liquid mineral medium. Bacterial isolate D1 exhibited the highest naringinase activity in liquid mineral medium. Based on the morphological, biochemical, fatty acid profile, and molecular characterization, bacterial isolate D1 was identified as Bacillus amyloliquefaciens. Impact of different submerged culture parameters were evaluated in different experimental conditions. The study revealed that 48 hrs of incubation periods, pH 6.0 and temperature 350 C is optimal for naringinase activity when the culture medium is supplemented with starch and yeast extract as carbon and nitrogen sources. Thus, it can be concluded that due to the potential naringinase activity of the strain Bacillus amyloliquefaciens D1, further the identifying strain may be used in citrus processing and bioprocess industries upon large scale field applications.

Development of Bio-Herbicides from the Phytotoxic Metabolite of Pseudomonas Putida

A strain of Peudomonas putida capable of producing phytotoxic metabolite was investigated for its biocontrol activity against Chromolaena odorata, Tridax procumbens and Physalis angulata. The organism was mass produced separately in fermentation media and phytotoxic metabolite was precipitated from the culture. Bioherbicide formulation was produced from metabolite viz the bioherbicide formula (which is made up of ten percent of the metabolite yield dissolved in water to make a total of 100 ml). The formulation was sprayed on the three weeds and their effects on the leaves of the three weeds were expressed as percentage and shown pictorially. The volume of the phytotoxic materials obtained from organism was 20ml. The bioherbicide formular obtained from- P. putida showed complete withering of the Chromolaena weed by the 8th day while it took 9 days for Physalis and Tridax to be completely withered after application. Hence, it has therefore been shown that Phytotaxic metabolic of P. putida is efficacious and safe and therefore can be used as an alternative to chemical herbicide and can therefore be optimized for large scale field application.

Time-Series Field Phenotyping of Soybean Growth Analysis by Combining Multimodal Deep Learning and Dynamic Modeling.

The rate of soybean canopy establishment largely determines photoperiodic sensitivity, subsequently influencing yield potential. However, assessing the rate of soybean canopy development in large-scale field breeding trials is both laborious and time-consuming. High-throughput phenotyping methods based on unmanned aerial vehicle (UAV) systems can be used to monitor and quantitatively describe the development of soybean canopies for different genotypes. In this study, high-resolution and time-series raw data from field soybean populations were collected using UAVs. The RGB (red, green, and blue) and infrared images are used as inputs to construct the multimodal image segmentation model-the RGB & Infrared Feature Fusion Segmentation Network (RIFSeg-Net). Subsequently, the segment anything model was employed to extract complete individual leaves from the segmentation results obtained from RIFSeg-Net. These leaf aspect ratios facilitated the accurate categorization of soybean populations into 2 distinct varieties: oval leaf type variety and lanceolate leaf type variety. Finally, dynamic modeling was conducted to identify 5 phenotypic traits associated with the canopy development rate that differed substantially among the classified soybean varieties. The results showed that the developed multimodal image segmentation model RIFSeg-Net for extracting soybean canopy cover from UAV images outperformed traditional deep learning image segmentation networks (precision = 0.94, recall = 0.93, F1-score = 0.93). The proposed method has high practical value in the field of germplasm resource identification. This approach could lead to the use of a practical tool for further genotypic differentiation analysis and the selection of target genes.

Magnetic Fields of the Starless Core L 1512

We present JCMT POL-2 850 μm dust polarization observations and Mimir H-band stellar polarization observations toward the starless core L 1512. We detect the highly ordered core-scale magnetic field traced by the POL-2 data, of which the field orientation is consistent with the parsec-scale magnetic fields traced by Planck data, suggesting the large-scale fields thread from the low-density region to the dense core region in this cloud. The surrounding magnetic field traced by the Mimir data shows a wider variation in the field orientation, suggesting there could be a transition of magnetic field morphology at the envelope-scale. L 1512 was suggested to be presumably older than 1.4 Myr in a previous study via time-dependent chemical analysis, hinting that the magnetic field could be strong enough to slow the collapse of L 1512. In this study, we use the Davis–Chandrasekhar–Fermi method to derive a plane-of-sky magnetic field strength (B pos) of 18 ± 7 μG and an observed mass-to-flux ratio (λ obs) of 3.5 ± 2.4, suggesting that L 1512 is magnetically supercritical. However, the absence of significant infall motion and the presence of an oscillating envelope are inconsistent with the magnetically supercritical condition. Using a virial analysis, we suggest the presence of a hitherto hidden line-of-sight magnetic field strength of ∼27 μG with a mass-to-flux ratio (λ tot) of ∼1.6, in which case both magnetic and kinetic pressures are important in supporting the L 1512 core. On the other hand, L 1512 may have just reached supercriticality and will collapse at any time.

The unimodal latitudinal pattern of K, Ca and Mg concentration and its potential drivers in forest foliage in eastern China

Potassium (K), calcium (Ca), and magnesium (Mg) are essential elements with important physiological functions in plants. Previous studies showed that leaf K, Ca, and Mg concentrations generally increase with increasing latitudes. However, recent meta-analyses suggested the possibility of a unimodal pattern in the concentrations of these elements along latitudinal gradients. The authenticity of this unimodal latitudinal pattern, however, requires validation through large-scale field experimental data, and exploration of the underlying mechanisms if the pattern is confirmed. Here, we collected leaves of common species of woody plants from 19 montane forests in the north-south transect of eastern China, including 322 species from 160 genera, 67 families; and then determined leaf K, Ca, and Mg concentrations to explore their latitudinal patterns and driving mechanisms. Our results support unimodal latitudinal patterns for all three elements in woody plants across eastern China, with peak values at latitude 36.5 ​± ​1.0° N. The shift of plant-functional-type compositions from evergreen broadleaves to deciduous broadleaves and to conifers along this latitudinal span was the key factor contributing to these patterns. Climatic factors, mainly temperature, and to a lesser extent solar radiation and precipitation, were the main environmental drivers. These factors, by altering the composition of plant communities and regulating plant physiological activities, influence the latitudinal patterns of plant nutrient concentrations. Our findings also suggest that high leaf K, Ca, and Mg concentrations may represent an adaptive strategy for plants to withstand water stress, which might be used to predict plant nutrient responses to climate changes at large scales, and broaden the understanding of biogeochemical cycling of K, Ca, and Mg.

Human-Machine Interactions in Pricing: Evidence from Two Large-Scale Field Experiments

Human-Machine Interactions in Pricing: Evidence from Two Large-Scale Field Experiments

Upsport Aplikasi Pemenuhan Kebutuhan Olahraga Berbasis Android (Menu Massage)

The background to this research is that sports carried out every day often result in sports injuries. Based on this, massage therapy is needed to treat injuries or to restore muscle fitness. The public needs a sports massage service center that provides services for sports enthusiasts through online applications. Among them is the availability of masseur sports massage. The general public's knowledge regarding sports massage, massage information makes someone withdraw from the intention of wanting to exercise but does not know the masseur information if an injury occurs. UpSport is an all in one sports application, which contains many sports features that society needs today, including the need for competent sports massage masseur information according to society's needs. This application makes it easy for someone to search for a sports massage therapist based on the nearest location, sport, license held and price or rates. The aim of this research is to create an Android application that makes it easier for people to find sports massage therapists. The research method used is development research (R&D). Data analysis techniques used in design and development research use qualitative and quantitative data. Qualitative data at the beginning of research design and development of qualitative data is more dominant than quantitative data. Qualitative data is obtained, for example, through observations and interviews during needs analysis. Quantitative data was obtained using a questionnaire and measured using a Likert scale. The output of this research is the UPSPORT application which has IPR and accredited journals. The results of the assessment carried out by researchers on users of the application "Upsport Application for Fulfilling Sports Needs Based on Android (menu massage)", were that out of 20 respondents, 15 people said it was "very feasible/very good" with a percentage of 75%, with 5 respondents saying “decent/good” with a percentage of 15%. The highest score on the results of large-scale field trials was 119 (93.60%) and the lowest score on the results of large-scale field trials was 96 (88.80%). So overall, based on the assessment of users of the massage menu application, it can be concluded that the application of the "Upsport Application to Fulfill Sports Needs Based on Android" is very good/fit to be used as an Android-based application in the sports sector.

Development of a decision making assessment application for recruitment of young futsal athletes in Indonesia

Futsal is a popular sport in Indonesia which is loved by many people, so important components are needed in selecting futsal athletes so that they can maximize the athletes’ future achievements. This research aims to develop an Android-based application to make it easier to recruit futsal athletes with clear and measurable selection components to help make athlete selection easier. The research method used is the Borg and Gall development design which establishes 10 research steps, but the focus that will be presented in this research includes testing the results carried out, namely through expert tests and small-scale and large-scale field testing. The results of the analysis carried out revealed that the small class user assessment data for all aspects of the product received a final score of 4.58 which indicates that the product is included in the Excellent category. The Overall Average results from large class user assessment data on all aspects of the product received a final score of 4.63 which indicates that the product is included in the Excellent category. Based on all the tests that have been carried out, the product is suitable for use and recommended for selecting young futsal athletes in Indonesia.

Active longitudes and the structure of the large-scale magnetic field at solar minimum

We have studied deep minima of 11-year solar activity cycles 13–14, 14–15, 22–23, 23–24, 24–25, using the RGO and USAF/NOAA sunspot group catalogs. All of them have a large number of spotless days. Nonetheless, active longitudes as preferred zones, where sunspots occur, appear at this solar cycle phase. Analysis of synoptic maps and WSO daily magnetograms reflecting the structure of a weak large-scale field shows a non-axisymmetric component of the solar magnetic field. At solar minimum in the structure of the large-scale magnetic field, there are regions of the magnetic field of positive and negative polarity elongated along the meridian and crossing the equator. The most pronounced of them are located in the zone of active longitudes and are often connected with the polar magnetic fields.
 We discuss the possible nature of the meridional structures of the large-scale field during solar minimum. This might be due to giant convection cells with a banana cell structure.

Ionospheric longitudinal variability in the Northern Hemisphere during magnetic storms in March 2012 from ionosonde and GPS/GLONASS data

A comprehensive study of spatio-temporal variations of geomagnetic, ionospheric, and atmospheric parameters in the middle and high latitudes of the Northern Hemisphere during a series of magnetic storms in March 2012 has been expanded by including vertical total electronic content (TEC) data from measurements at the chains of dual-frequency phase receivers GPS/GLONASS in the analysis. The features of longitudinal variations in ionosphere ionization over mid-latitude Eurasia, found earlier from vertical sounding data, are confirmed by vertical TEC data. We emphasize the complex physics of the long magnetically disturbed period in March 2012 with switching between positive and negative effects of an ionospheric storm during the same magnetic storm phases for spaced mid-latitude regions of the Eastern Hemisphere. Such changes in the ionospheric storm effects might have been caused by the superposition of competing processes in the mid-latitude region of the Eastern Hemisphere due to variations in the thermospheric composition, thermospheric winds, and large-scale electric fields affecting ionospheric ionization. We have observed significant differences in the nature of the ionospheric ionization reaction between the Eastern and Western hemispheres to the prolonged geomagnetic disturbance in March 2012. According to TEC data, there was an effect of reduced ionization of the ionosphere at longitudes of the Western Hemisphere, unlike the Eastern one. The effect of a negative ionospheric storm was caused by the formation of vast areas of atmospheric gas with a reduced density ratio [O]/[N2] over the mid-latitude region of the Western Hemisphere in the zone of maximum penetration of geomagnetic disturbances from high latitudes to middle latitudes. According to the INTERMAGNET magnetometer chain data for the analyzed period of magnetic storms on March 7–20, 2012, at midlatitudes of the Northern Hemisphere the maximum geomagnetic field variations were observed in the Western Hemisphere.

Geogrid-Enhanced Modulus and Stress Distribution in Clay Soil

A series of laboratory and large-scale field model footing tests were conducted to assess the modulus and stress distribution behavior of a clayey soil foundation, both with/without geogrid reinforcement, deviating from the conventional approach of evaluating the strength performance, such as bearing capacity. The modulus was evaluated at three settlement ratios of s/B = 1, 3, and 5%, while the stress distribution angle α was estimated at three applied surface pressures of 234 kPa, 468 kPa, and 936 kPa. The results indicated a stiffer load-settlement response when geogrid reinforcement was included. The modulus of reinforced clayey soil remained nearly constant for test sections with the same reinforced ratio, with the modulus improvement increasing as the reinforced ratio (Rr) increased. The modulus improvement also increased with the settlement ratio (s/B). These results demonstrated that the stress distribution improvement decreased as the surface pressure increased. Generally, both the modulus and stress distribution improvement exhibited an increase with an increase in the tensile modulus of the geogrid. While laboratory model tests consistently provided a higher improvement in the modulus than large-scale field model tests in this study due to a higher reinforced ratio, the stress distribution improvement was similar for both.

Dilute axion stars converting to photons in the Milky Way’s magnetic field

In this paper we examine the possibility of dilute axion stars converting to photons in the weak, large-scale magnetic field of the Milky Way and show that they can resonate with the surrounding plasma and produce a sizable signal. We consider two possibilities for the plasma: free electrons and HII regions. In the former case, we argue that the frequency of the photons will be too small to be observed even by space-based radio telescopes. In the latter case, their frequency is larger, safely above the solar wind cut-off. We provide an estimate of the flux as a function of the decay constant and show that for fa< 2 × 1011 GeV, the signal will be above the radio emission of the solar system’s planets and it could potentially be detected by the NCLE instrument which is on board the Chang’e-4 spacecraft. Finally, we calculate the time scale of decay of the axion star and demonstrate that back-reaction can be neglected for all physically interesting values of the decay constant, while the minimum time scale of decay is in the order of a few hours.