1,720,962 research outputs found
Driplines Layout Designs Comparison of Moisture Distribution in Clayey Soils, Using Soil Analysis, Calibrated Time Domain Reflectometry Sensors, and Precision Agriculture Geostatistical Imaging for Environmental Irrigation Engineering
No full textThe present study implements novel innovative geostatistical imaging using precision agriculture (PA) under sugarbeet field conditions. Two driplines layout designs (d.l.d.) and soil water content (SWC)–irrigation treatments (A: d.l.d. = 1.00 m driplines spacing × 0.50 m emitters inline spacing; B: d.l.d. = 1.50 m driplines spacing × 0.50 m emitters inline spacing) were applied, with two subfactors of clay loam and clay soils (laboratory soil analysis) for modeling (evaluation of seven models) TDR multi-sensor network measurements. Different sensor calibration methods [method 1(M1) = according to factory; method 2 (M2) = according to Hook and Livingston] were applied for the geospatial two-dimensional (2D) imaging of accurate GIS maps of rootzone soil moisture profiles, soil apparent dielectric Ka profiles, and granular and hydraulic parameters profiles, in multiple soil layers (0–75 cm depth). The modeling results revealed that the best-fitted geostatistical model for soil apparent dielectric Ka was the Gaussian model, while spherical and exponential models were identified to be the most appropriate for kriging modelling, and spatial and temporal imaging was used for accurate profile SWC θvTDR (m3·m−3) M1 and M2 maps using TDR sensors. The resulting PA profile map images depict the spatio-temporal soil water and apparent dielectric Ka variability at very high resolutions on a centimeter scale. The best geostatistical validation measures for the PA profile SWC θvTDR maps obtained were MPE = −0.00248 (m3·m−3), RMSE = 0.0395 (m3·m−3), MSPE = −0.0288, RMSSE = 2.5424, ASE = 0.0433, Nash–Sutcliffe model efficiency NSE = 0.6229, and MSDR = 0.9937. Based on the results, we recommend d.l.d. A and sensor calibration method 2 for the geospatial 2D imaging of PA GIS maps because these were found to be more accurate, with the lowest statistical and geostatistical errors, and the best validation measures for accurate profile SWC imaging were obtained for clay loam over clay soils. Visualizing sensors’ soil moisture results via geostatistical maps of rootzone profiles have practical implications that assist farmers and scientists in making informed, better and timely environmental irrigation engineering decisions, to save irrigation water, increase water use efficiency and crop production, optimize energy, reduce crop costs, and manage water resources sustainably
Geostatistics Precision Agriculture Modeling on Moisture Root Zone Profiles in Clay Loam and Clay Soils, Using Time Domain Reflectometry Multisensors and Soil Analysis
No full textAccurate measurement and understanding of the spatiotemporal distribution of soil water content (SWC) are crucial in various environmental and agricultural sectors. The present study implements a novel precision agriculture (PA) approach under sugarbeet field conditions of two moisture-irrigation treatments with two subfactors, clay loam (CL) and clay (C) soils, for geostatistics modeling (seven models’ evaluation) of time domain reflectometry (TDR) multisensor network measurements. Two different sensor calibration methods (M1 and M2) were trialed, as well as the results of laboratory soil analysis for geospatial two-dimensional (2D) imaging for accurate GIS maps of root zone moisture profiles, granular, and hydraulic profiles in multiple soil layers (0–75 cm depth). Modeling results revealed that the best-fitted semi-variogram models for the granular attributes were circular, exponential, pentaspherical, and spherical, while for hydraulic attributes were found to be exponential, circular, and spherical models. The results showed that kriging modeling, spatial and temporal imaging for accurate profile SWC θvTDR (m3·m−3) maps, the exponential model was identified as the most appropriate with TDR sensors using calibration M1, and the exponential and spherical models were the most appropriate when using calibration M2. The resulting PA profile maps depict spatiotemporal soil water variability with very high resolutions at the centimeter scale. The best validation measures of PA profile SWC θvTDR maps obtained were Nash-Sutcliffe model efficiency NSE = 0.6657, MPE = 0.00013, RMSE = 0.0385, MSPE = −0.0022, RMSSE = 1.6907, ASE = 0.0418, and MSDR = 0.9695. The sensor results using calibration M2 were found to be more valuable in environmental irrigation decision-making for a more accurate and timely decision on actual crop irrigation, with the lowest statistical and geostatistical errors. The best validation measures for accurate profile SWC θvTDR (m3·m−3) maps obtained for clay loam over clay soils. Visualizing the SWC results and their temporal changes via root zone profile geostatistical maps assists farmers and scientists in making informed and timely environmental irrigation decisions, optimizing energy, saving water, increasing water-use efficiency and crop production, reducing costs, and managing water–soil resources sustainably
Soil Moisture Depletion Modelling Using a TDR Multi-Sensor System, GIS, Soil Analyzes, Precision Agriculture and Remote Sensing on Maize for Improved Irrigation-Fertilization Decisions
No full textThe effects of three drip irrigation (IR1: Farmer’s, IR2:Full (100%ETc), IR3:Deficit (80%ETc) irrigation), and two fertilization (Ft1, Ft2) treatments were studied on maize yield and biomass by applying new agro-technologies (TDR—sensors for soil moisture (SM) measurements, Precision Agriculture, Remote Sensing—NDVI (Sentinel-2 satellite sensor), soil-hydraulic analyses and Geostatistical models, SM-rootzone modelling-2D-GIS mapping). A daily soil moisture depletion (SMDp) model was developed. The two-way-ANOVA statistical analysis results revealed that irrigation (IR3 = best) and fertilization treatments (Ft1 = best) significantly affect yield and biomass. Deficit irrigation and proper fertilization based on new agro-technologies for improved management decisions can result in substantial improvement on yield (+116.10%) and biomass (+119.71%) with less net water use (−7.49%) and reduced drainage water losses (−41.02%)
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Hydrological 2D Modelling of Lithaios River Flows (Greece) Using GIS and Geostatistics for Environmental and Agricultural Water Resources Administration
No full textThe goal of our investigation is the hydrological 2D modelling of Lithaios River’s (Central Greece) streamflow, using GIS and geostatistics for studying water velocity and discharge, stage elevation, and hydraulic features (streamflow depth, water flow area, wettable circumference, hydraulic radius and depth, n Manning’s coefficient, Chow’s composite n, Froude number, etc.). Moreover, compilations and validations of rating curves (RC) were performed from a series of stage h(t)–discharge Q(t) couples metrics, aiming to use these as a river toolkit to aid environmental and agriculture surface water resources management and help environmental flows calculation, streamflow tracking, and irrigation programming in the regional basin range. The statistical results showed that the Froude number during the study period was Fr < 1 showing that Lithaios River’s streamflow is classified as subcritical. The models’ validation outcomes by using various statistics and geostatistical alternative methods, model simulations and statistics errors criterions, were correlated with the retrieved power models’ streamflow data matching for the RC curves and 2D GIS modelling and mapping of river velocity and discharge relationships and were highly satisfying since the stabilities of the deployed relationships were solid. The outcomes of the study results are recommended to provide a hydrological serving toolkit for environmental water resources administration and irrigation programming. This toolkit could assist water supply principalities to rapidly and precisely calculate streamflow volumes and features with a minimal cost rate and workload, and it could be engaged in water supply and agricultural watering administration, the calculation of environmental flows, flood protection, groundwater recharge, and other objectives
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Modeling Soil Erodibility by Water (Rainfall/Irrigation) on Tillage and No-Tillage Plots of a Helianthus Field Utilizing Soil Analysis, Precision Agriculture, GIS, and Kriging Geostatistics
No full textThe aim of our study is the modeling at the field level of the soil erodibility (K factor) by water (rainfall and irrigation) on traditional tillage (CoTl) and no-tillage (NoTl) plots cultivated with Helianthus annuus utilizing plot observations, soil sampling laboratory analyses, GIS, precision agriculture (PA), and Kriging geostatistical modeling. A split-plot layout consisting of four handlings × three replicates of trial blocks (with a southeast facing 7.5% slope) was used. Grid template surface soil core (0.0–5.0 cm) samples were taken to characterize the textures (sandy, silty, clayey, very fine sandy, and gravelly), organic matter concentrations, and the soil’s microstructure and water permeability categories. One GPS satellite tracker system was utilized to define the sampled positions, and 40 soil cores were air-dried and sieved with a 2 mm sieve to identify the soil’s mechanical microtexture using the Bouyoucos methodology. The organic matter was extracted by chemical oxidation with 1 mol L−1 K2Cr2O7 and titration of the remaining reagent with 0.5 mol L−1 FeSO4. The soil microstructure and permeability categories were defined following the USDA classification system. The soil erodibility by water modeling of K (Mg·ha·h·ha−1·MJ−1·mm−1) was derived according to the Wischmeier nomographic method by incorporating it into a developed GIS geospatial model using Kriging geostatistics. The statistical results of the ANOVA test (p = 0.05) among the soil erodibility datasets showed significant differences between the two tillage systems, as well as between the four management treatments. Moreover, it was found that the no-tillage (NoTl) plots and the treatment of no tillage plus vegetative coverage were the best tillage and agricultural practices for hillslope farm fields and can be considered environmentally friendly farming methods to curb soil erodibility by water, reduce runoff hazard, and maintain the soil’s environment and its beneficial nutrients
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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