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26 pages, 23657 KiB  
Article
A Digital Twin Approach for Soil Moisture Measurement with Physically Based Rendering Simulations and Machine Learning
by Ismail Parewai and Mario Köppen
Electronics 2025, 14(2), 395; https://doi.org/10.3390/electronics14020395 - 20 Jan 2025
Viewed by 490
Abstract
Soil is one of the most important factors of agricultural productivity, directly influencing crop growth, water management, and overall yield. However, inefficient soil moisture monitoring methods, such as manual observation and gravimetric in rural areas, often lead to overwatering or underwatering, wasting resources [...] Read more.
Soil is one of the most important factors of agricultural productivity, directly influencing crop growth, water management, and overall yield. However, inefficient soil moisture monitoring methods, such as manual observation and gravimetric in rural areas, often lead to overwatering or underwatering, wasting resources and reduced yields, and harming soil health. This study offers a digital twin approach for soil moisture measurement, integrating real-time physical data, virtual simulations, and machine learning to classify soil moisture conditions. The digital twin is proposed as a virtual representation of physical soil designed to replicate real-world behavior. We used a multispectral rotocam, and high-resolution soil images were captured under controlled conditions. Physically based rendering (PBR) materials were created from these data and implemented in a game engine to simulate soil properties accurately. Image processing techniques were applied to extract key features, followed by machine learning algorithms to classify soil moisture levels (wet, normal, dry). Our results demonstrate that the Soil Digital Twin replicates real-world behavior, with the Random Forest model achieving a high classification accuracy of 96.66% compared to actual soil. This data-driven approach conveys the potential of the Soil Digital Twin to enhance precision farming initiatives and water use efficiency for sustainable agriculture. Full article
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<p>The soil digital twin development scheme.</p>
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<p>Experimental setup for real soil: (<b>Left</b>) Indoor setup for soil moisture analysis with LED lighting and real-time data display. (<b>Right</b>) Low-light indoor setup capturing soil properties with LED lighting for digital twin modeling.</p>
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<p>Experimental setup in Unreal Engine for soil texture and lighting analysis: (<b>Left</b>) daylight scene with camera placement and spotlight direction shown by arrows; (<b>Right</b>) simulation of blue LED lighting effect on soil texture.</p>
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<p>Comparison of real soil images (top row) and digital twin images (bottom row) across different color channels: (<b>a</b>,<b>e</b>) blue; (<b>b</b>,<b>f</b>) green; (<b>c</b>,<b>g</b>) red; (<b>d</b>,<b>h</b>) yellow.</p>
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<p>Accuracy comparison across soil types.</p>
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<p>Confusion matrix results for Artificial Neural Networks (ANNs): real soil (top row) vs. digital twin (bottom row).</p>
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<p>Confusion matrix results for Random Forest (RF): real soil (top row) vs. digital twin (bottom row).</p>
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<p>Confusion matrix results for Support Vector Machine (SVM): real soil (top row) vs. digital twin (bottom row).</p>
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14 pages, 1291 KiB  
Article
Determining Validity and Reliability of an In-Field Performance Analysis System for Swimming
by Dennis-Peter Born, Marek Polach and Craig Staunton
Sensors 2024, 24(22), 7186; https://doi.org/10.3390/s24227186 - 9 Nov 2024
Viewed by 826
Abstract
To permit the collection of quantitative data on start, turn and clean swimming performances in any swimming pool, the aims of the present study were to (1) validate a mobile in-field performance analysis system (PAS) against the Kistler starting block equipped with force [...] Read more.
To permit the collection of quantitative data on start, turn and clean swimming performances in any swimming pool, the aims of the present study were to (1) validate a mobile in-field performance analysis system (PAS) against the Kistler starting block equipped with force plates and synchronized to a 2D camera system (KiSwim, Kistler, Winterthur, Switzerland), (2) assess the PAS’s interrater reliability and (3) provide percentiles as reference values for elite junior and adult swimmers. Members of the Swiss junior and adult national swimming teams including medalists at Olympic Games, World and European Championships volunteered for the present study (n = 47; age: 17 ± 4 [range: 13–29] years; World Aquatics Points: 747 ± 100 [range: 527–994]). All start and turn trials were video-recorded and analyzed using two methods: PAS and KiSwim. The PAS involves one fixed view camera recording overwater start footage and a sport action camera that is moved underwater along the side of the pool perpendicular to the swimming lane on a 1.55 m long monostand. From a total of 25 parameters determined with the PAS, 16 are also measurable with the KiSwim, of which 7 parameters showed satisfactory validity (r = 0.95–1.00, p < 0.001, %-difference < 1%). Interrater reliability was determined for all 25 parameters of the PAS and reliability was accepted for 21 of those start, turn and swimming parameters (ICC = 0.78–1.00). The percentiles for all valid and reliable parameters provide reference values for assessment of start, turn and swimming performance for junior and adult national team swimmers. The in-field PAS provides a mobile method to assess start, turn and clean swimming performance with high validity and reliability. The analysis template and manual included in the present article aid the practical application of the PAS in research and development projects as well as academic works. Full article
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<p>Set-up and camera path of a sport action camera to capture (<b>a</b>) start and (<b>b</b>) turn trials.</p>
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<p>Validity analysis for start performance using Bland–Altman plots with a 95% confidence interval for the difference between the methods (PAS—KiSwim values) and limits of agreement. Values on the x-axis show the means of the two methods.</p>
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<p>Validity analysis for turn performance using Bland–Altman plots with a 95% confidence interval for the difference between the methods (PAS–KiSwim values) and limits of agreement. Values on the x-axis show the means of the two methods.</p>
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21 pages, 5750 KiB  
Article
Remote Sensing of Residential Landscape Irrigation in Weber County, Utah: Implications for Water Conservation, Image Analysis, and Drone Applications
by Annelise M. Turman, Robert B. Sowby, Gustavious P. Williams and Neil C. Hansen
Sustainability 2024, 16(21), 9356; https://doi.org/10.3390/su16219356 - 28 Oct 2024
Viewed by 1614
Abstract
Analyzing irrigation patterns to promote efficient water use in urban areas is challenging. Analysis of irrigation by remote sensing (AIRS) combines multispectral aerial imagery, evapotranspiration data, and ground-truth measurements to overcome these challenges. We demonstrate AIRS on eight neighborhoods in Weber County, Utah, [...] Read more.
Analyzing irrigation patterns to promote efficient water use in urban areas is challenging. Analysis of irrigation by remote sensing (AIRS) combines multispectral aerial imagery, evapotranspiration data, and ground-truth measurements to overcome these challenges. We demonstrate AIRS on eight neighborhoods in Weber County, Utah, using 0.6 m National Agriculture Imagery Program (NAIP) and 0.07 m drone imagery, reference evapotranspiration (ET), and water use records. We calculate the difference between the actual and hypothetical water required for each parcel and compare water use over three time periods (2018, 2021, and 2023). We find that the quantity of overwatering, as well as the number of customers overwatering, is decreasing over time. AIRS provides repeatable estimates of irrigated area and irrigation demand that allow water utilities to track water user habits and landscape changes over time and, when controlling for other variables, see if water conservation efforts are effective. In terms of image analysis, we find that (1) both NAIP and drone imagery are sufficient to measure irrigated area in urban settings, (2) the selection of a threshold value for the normalized difference vegetation index (NDVI) becomes less critical for higher-resolution imagery, and (3) irrigated area measurement can be enhanced by combining NDVI with other tools such as building footprint extraction, object classification, and deep learning. Full article
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<p>Approach for Analysis of Irrigation by Remote Sensing (AIRS) [<a href="#B16-sustainability-16-09356" class="html-bibr">16</a>].</p>
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<p>Eight study areas within West Haven, Utah, with metered parcels.</p>
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<p>Drone flight restrictions with our general study area (rectangle). The red region represents restricted zones, the blue region represents authorization zones, the orange region represents enhanced warning zones, and the yellow region represents warning zones.</p>
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<p>Adjusting NDVI threshold values. (<b>a</b>) Base image without NDVI pixels. (<b>b</b>) Base image with 0.10 NDVI threshold value. (<b>c</b>) Base image with 0.15 NDVI threshold value. (<b>d</b>) Base image with 0.19 NDVI threshold value.</p>
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<p>NDVI variations from shadows (top, base image; bottom, base image with NDVI overlay).</p>
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<p>(<b>a</b>) NDVI pixel count distributions for 2018, (<b>b</b>) NDVI pixel count distributions for 2021, (<b>c</b>) NDVI pixel count distributions for 2023.</p>
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<p>(<b>a</b>) NDVI value vs. pixel count distribution of Landsat (30 m resolution), (<b>b</b>) NDVI value vs. pixel count distribution for NAIP (0.6 m resolution), (<b>c</b>) NDVI value vs. pixel count distribution of drone images (0.067 m resolution).</p>
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<p>(<b>a</b>) Base image, (<b>b</b>) base image with NDVI pixels and a legend, demonstrating that roofs are being classified as irrigated area.</p>
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<p>ModelBuilder process used to measure irrigated area.</p>
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<p>Variation of irrigated area due to imagery type: (<b>a</b>) 2018 NAIP image and irrigated area, (<b>b</b>) 2021 NAIP image and irrigated area, (<b>c</b>) 2023 drone image and irrigated area.</p>
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<p>Distribution of percentage of overwatering for all parcels.</p>
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<p>Percentage of overwatering grouped by study area.</p>
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<p>(<b>a</b>) Changes in percentage of overwatering during 2018, (<b>b</b>) Changes in percentage of overwatering during 2021, (<b>c</b>) Changes in percentage of overwatering during 2023.</p>
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<p>(<b>a</b>) Irrigated area vs. percentage of overwatering for 2018, (<b>b</b>) Irrigated area vs. percentage of overwatering for 2021, (<b>c</b>) Irrigated area vs. percentage of overwatering for 2023.</p>
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<p>(<b>a</b>) Irrigated area vs. percentage of overwatering for 2018, (<b>b</b>) Irrigated area vs. percentage of overwatering for 2021, (<b>c</b>) Irrigated area vs. percentage of overwatering for 2023.</p>
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19 pages, 2468 KiB  
Article
Water Conservation Practices and Nitrogen Fertility for the Reduction of Greenhouse Gas Emissions from Creeping Bentgrass Putting Greens
by Kristina S. Walker and Katy E. Chapman
Grasses 2024, 3(3), 221-239; https://doi.org/10.3390/grasses3030016 - 18 Sep 2024
Viewed by 726
Abstract
Irrigation practices that conserve water use have the potential to reduce greenhouse gas (GHG) emissions but may adversely affect turfgrass appearance. The purpose of this study was to identify irrigation practices and N fertilizers that will decrease carbon dioxide (CO2), methane [...] Read more.
Irrigation practices that conserve water use have the potential to reduce greenhouse gas (GHG) emissions but may adversely affect turfgrass appearance. The purpose of this study was to identify irrigation practices and N fertilizers that will decrease carbon dioxide (CO2), methane (CH4,), and nitrous oxide (N2O) emissions while evaluating turfgrass color and quality. In both years, supplemental rainfall (SRF) soil moisture content was higher than business as usual (BAU) irrigation and syringing (SYR). Higher soil moisture led to increased fluxes in both soil CO2 and soil N2O. In 2017, the SRF fluxed lower soil CO2 as soil moisture reached levels that restricted respiration. Soil moisture was also an important predictor of soil N2O flux with BAU and SRF having higher soil N2O fluxes. SRF produced the greenest turf from May to July, whereas SRY and SRF produced the greenest turf from August to October in 2016. Both BAU and SRF had the greenest turf in 2017. BAU had the highest turfgrass quality ratings in 2016 followed by SRF and SRY, respectively, whereas in 2017 SRF and SRY had higher turfgrass quality ratings. When adopting water conservation practices to reduce GHG emissions, soil moisture content and site-specific rainfall should be closely monitored to prevent overwatering. Full article
(This article belongs to the Special Issue Advances in Sustainable Turfgrass Management)
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<p>Total rainfall (mm) and mean air temperatures (°C) during the growing season (May–October) of 2016 and 2017. Total rainfall is indicated by a bar chart (left axis) and mean air temperature is indicated by a line graph (right axis). Weather data were collected by the Grand Forks International Airport (Grand Forks, ND, USA).</p>
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<p>Canopy temperature by irrigation regime (SRF = supplemental rainfall, SYR = syringing, and BAU = business as usual) in 2016 (<b>a</b>) and 2017 (<b>b</b>). * Means are significantly different at the 0.05 level according to Fisher’s protected LSD <span class="html-italic">t</span>-test.</p>
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<p>Soil moisture content (%) by irrigation treatment in the 2016 (<b>a</b>) and 2017 (<b>b</b>) growing seasons. BAU, business as usual; SRF, supplemental rainfall; SYR, syringing.</p>
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<p>Carbon dioxide (CO<sub>2</sub>) emissions by fertilizer source in 2016 (<b>a</b>) and 2017 (<b>b</b>). Notes: a = urea &gt; unfertilized control; b = milorganite and urea &gt; unfertilized control; c = milorganite &gt; urea; d = milorganite &gt; urea and unfertilized control; e = milorganite &gt; unfertilized control. Means are significantly different at the 0.05 level according to Fisher’s protected LSD <span class="html-italic">t</span>-test.</p>
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<p>Carbon dioxide (CO<sub>2</sub>) emissions by fertilizer rate in 2016 (<b>a</b>) and 2017 (<b>b</b>). Notes: a = 147 kg N ha<sup>−1</sup> yr<sup>−1</sup> &gt; unfertilized control (0 kg N ha<sup>−1</sup> yr<sup>−1</sup>); b = 294 kg N ha<sup>−1</sup> yr<sup>−1</sup> &gt; unfertilized control (0 kg N ha<sup>−1</sup> yr<sup>−1</sup>); c = 147 and 294 kg N ha<sup>−1</sup> yr<sup>−1</sup> &gt; unfertilized control (0 kg N ha<sup>−1</sup> yr<sup>−1</sup>); d = 294 kg N ha<sup>−1</sup> yr<sup>−1</sup> &gt; 147 kg N ha<sup>−1</sup> yr<sup>−1</sup>; e = 294 kg N ha<sup>−1</sup> yr<sup>−1</sup> &gt; 147 kg N ha<sup>−1</sup> yr<sup>−1</sup> and unfertilized control (0 kg N ha<sup>−1</sup> yr<sup>−1</sup>). Means are significantly different at the 0.05 level according to Fisher’s protected LSD <span class="html-italic">t</span>-test.</p>
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<p>Carbon dioxide (CO<sub>2</sub>) emissions by irrigation regime in 2016 (<b>a</b>) and 2017 (<b>b</b>). Notes: a = SYR &gt; SRF &gt; BAU; b = SYR and SRF &gt; BAU; c = BAU &gt; SRF; d = SRF &gt; SYR &gt; BAU; e = SRF &gt; SYR &gt; BAU; f = SRF &gt; BAU; g = BAU and SRF &gt; SYR; h = SRF &gt; SYR and BAU; i = BAU &gt; SRF and SYR; j = BAU &gt; SRF; k = SRF &gt; BAU &gt; SYR; l = BAU &gt; SYR &gt; SRF; m = BAU and SYR &gt; SRF; n = SYR &gt; BAU; o = SYR &gt; SRF. Means are significantly different at the 0.05 level according to Fisher’s protected LSD <span class="html-italic">t</span>-test.</p>
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<p>Nitrous oxide (N<sub>2</sub>O) emissions by fertilizer source in 2016 (<b>a</b>) and 2017 (<b>b</b>). Notes: a = milorganite &gt; urea; b = milorganite and urea &gt; unfertilized control; c = milorganite &gt; unfertilized control; d = milorganite &gt; urea &gt; unfertilized control; e = urea &gt; unfertilized control; f = urea &gt; milorganite and unfertilized control. Means are significantly different at the 0.05 level according to Fisher’s protected LSD <span class="html-italic">t</span>-test.</p>
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<p>Nitrous oxide (N<sub>2</sub>O) emissions by fertilizer rate in 2016 (<b>a</b>) and 2017 (<b>b</b>). Notes: a = 294 kg N ha<sup>−1</sup> yr<sup>−1</sup> &gt; 147 kg N ha<sup>−1</sup> yr<sup>−1</sup>; b = 294 kg N ha<sup>−1</sup> yr<sup>−1</sup> and 147 kg N ha<sup>−1</sup> yr<sup>−1</sup> &gt; unfertilized control (0 kg N ha<sup>−1</sup> yr<sup>−1</sup>); c = 294 kg N ha<sup>−1</sup> yr<sup>−1</sup> &gt; 147 kg N ha<sup>−1</sup> yr<sup>−1</sup> &gt; unfertilized control (0 kg N ha<sup>−1</sup> yr<sup>−1</sup>); d = 294 kg N ha<sup>−1</sup> yr<sup>−1</sup> &gt; unfertilized control (0 kg N ha<sup>−1</sup> yr<sup>−1</sup>); e = 294 kg N ha<sup>−1</sup> yr<sup>−1</sup> &gt; 147 kg N ha<sup>−1</sup> yr<sup>−1</sup> and unfertilized control (0 kg N ha<sup>−1</sup> yr<sup>−1</sup>). Means are significantly different at the 0.05 level according to Fisher’s protected LSD <span class="html-italic">t</span>-test.</p>
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<p>Nitrous oxide (N<sub>2</sub>O) emissions by irrigation regime in 2016 (<b>a</b>) and 2017 (<b>b</b>). Notes: a = BAU &gt; SYR and SRF; b = SYR and SRF &gt; BAU; c = SYR &gt; SRF and BAU; d = SRF &gt; SYR and BAU; e = BAU &gt; SYR; f = SRF &gt; BAU &gt; SYR; g = SRF and BAU &gt; SYR; h = SRF &gt; SYR. Means are significantly different at the 0.05 level according to Fisher’s protected LSD <span class="html-italic">t</span>-test.</p>
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<p>The effects of the irrigation regime ((<b>a</b>,<b>b</b>); SRF = supplemental rainfall, SYR = syringing, BAU = business as usual) and fertilizer ((<b>c</b>,<b>d</b>); MILH = milorganite high, 294 kg N ha<sup>−1</sup> yr<sup>−1</sup>, MILL = milorganite mow, 147 kg N ha<sup>−1</sup> yr<sup>−1</sup>, UREH = urea high, 294 kg N ha<sup>−1</sup> yr<sup>−1</sup>, UREL = urea low, 147 kg N ha<sup>−1</sup> yr<sup>−1</sup>, UNTC = unfertilized control, 0 kg N ha<sup>−1</sup> yr<sup>−1</sup>) on turfgrass color (NDVI = normalized difference vegetation index, −1 to 1) in 2016 and 2017. Datapoints on the graphs represent means by date. * Means are significantly different at the 0.05 level according to Fisher’s protected LSD <span class="html-italic">t</span>-test. Plots were fertilized the first week of every month from May to October with a high N rate of 49 kg N ha<sup>−1</sup>, a low N rate 24.5 kg N ha<sup>−1</sup>, or an unfertilized control of 0 kg N ha<sup>−1</sup> per application.</p>
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<p>The effects of irrigation regime ((<b>a</b>,<b>b</b>); SRF = supplemental rainfall, SYR = syringing, BAU = business as usual) and fertilizer ((<b>c</b>,<b>d</b>); MILH = milorganite high, 294 kg N ha<sup>−1</sup> yr<sup>−1</sup>, MILL = milorganite low, 147 kg N ha<sup>−1</sup> yr<sup>−1</sup>, UREH = urea high, 294 kg N ha<sup>−1</sup> yr<sup>−1</sup>, UREL = urea low, 147 kg N ha<sup>−1</sup> yr<sup>−1</sup>, UNTC = unfertilized control, 0 kg N ha<sup>−1</sup> yr<sup>−1</sup>) on turfgrass quality (1–9 visual scale; where 1 = completely brown dead turf, 6 = minimally acceptable turf, and 9 = optimum uniformity, density, and greenness) in 2016 and 2017. Datapoints on the graphs represent means by date. * Means are significantly different at the 0.05 level according to Fisher’s protected LSD <span class="html-italic">t</span>-test. Plots were fertilized the first week of every month from May to October with a high N rate of 49 kg N ha<sup>−1</sup>, a low N rate 24.5 kg N ha<sup>−1</sup>, or an unfertilized control of 0 kg N ha<sup>−1</sup> per application.</p>
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13 pages, 1959 KiB  
Article
Dual-Frequency Soil Moisture Meter Method for Simultaneous Estimation of Soil Moisture and Conductivity
by Jerzy S. Witkowski and Andrzej F. Grobelny
Sensors 2024, 24(10), 2969; https://doi.org/10.3390/s24102969 - 7 May 2024
Viewed by 3235
Abstract
The measurement of soil water content is a very important factor in plant cultivation, both from an economic and ecological point of view. Proper estimation of moisture content not only allows for proper yields but can also contribute to ecologically appropriate use of [...] Read more.
The measurement of soil water content is a very important factor in plant cultivation, both from an economic and ecological point of view. Proper estimation of moisture content not only allows for proper yields but can also contribute to ecologically appropriate use of fresh water, of which the world’s resources are limited. It is important, for example, that the moisture content in the root area of plants is optimal for their growth, while over-watering can result in losses in the form of water, which seeps below the root layer and is lost. The novel, inexpensive electronic meter for measuring soil moisture is presented in the article. The meter, based on a capacitive method, uses an optimization algorithm to calculate soil electrical permeability and a simplified new formula between soil electrical permeability and volumetric moisture content. Moreover, by using two high-frequency signals for measurements, it is possible not only to estimate moisture content but also soil conductivity. Both readings obtained from the meter not only allow for rational management of crop optimization for economic reasons but are also important for environmental protection. In addition, the inexpensive meter, based on the principle of operation presented, can be made as an IoT module, which allows for its wide application. Full article
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<p>Soil textural triangle. Source: United State Department of Agriculture.</p>
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<p>Illustrative retention curves for basic soil types (adapted from [<a href="#B4-sensors-24-02969" class="html-bibr">4</a>]).</p>
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<p>Typical curves of water capacity (FC) and permanent wilting point (PWP) vs. soil type (adapted from [<a href="#B6-sensors-24-02969" class="html-bibr">6</a>]).</p>
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<p>Basic illustration of capacitive measurement principle.</p>
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<p>Measuring electrodes (<b>a</b>) and their equivalent circuit (<b>b</b>). (Rs—resistance in series to the probe; Cs—the capacity of the electrodes to the medium; Cp—the self-capacity part of the capacitor due to its construction; Cx—capacity being measured; Rx—the loss of the dielectric being measured).</p>
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<p>Basic illustration of capacitive measurement principle. The types of major integrated circuits used in the sensor prototype are given.</p>
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<p>Calibration curves and their measurement points for 17 MHz (solid line and □) and for 166 MHz (solid line and O); measurement result point (<span class="html-italic">ε<sub>w</sub></span> = 32, <span class="html-italic">σ</span> = 0.49 dS/m) against transmittance curves (dashed lines and “rhombus”) for <span class="html-italic">f</span><sub>1</sub> = 17 MHz (top line) and <span class="html-italic">f</span><sub>2</sub> = 166 MHz (bottom line).</p>
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<p>Prototype of the sensor and its housing.</p>
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<p>Volumetric moisture as a function of dielectric permittivity. Dashed lines are obtained from Formula (15) for <span class="html-italic">(A</span>; <span class="html-italic">ε<sub>w</sub></span>) = (0.075; 2) and (0.05; 3), respectively. Continuous lines are plotted based on the experimental data from [<a href="#B16-sensors-24-02969" class="html-bibr">16</a>,<a href="#B24-sensors-24-02969" class="html-bibr">24</a>].</p>
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<p>Overall uncertainty of irrigation control.</p>
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26 pages, 10832 KiB  
Article
Numerical Investigation of Local Scour Protection around the Foundation of an Offshore Wind Turbine
by Ning Zhang, Bingqian Yu, Shiyang Yin, Caixia Guo, Jianhua Zhang, Fanchao Kong, Weikun Zhai and Guodong Qiu
J. Mar. Sci. Eng. 2024, 12(5), 692; https://doi.org/10.3390/jmse12050692 - 23 Apr 2024
Viewed by 1182
Abstract
The pile foundations of offshore wind turbines face serious problems from scour damage. This study takes offshore wind turbine monopile foundations as the research object and proposes an innovative anti-scour device for the protection net. A numerical simulation research method based on CFD-DEM [...] Read more.
The pile foundations of offshore wind turbines face serious problems from scour damage. This study takes offshore wind turbine monopile foundations as the research object and proposes an innovative anti-scour device for the protection net. A numerical simulation research method based on CFD-DEM was used to model the local scour of the pile foundation and protection net. The validity of the numerical model was verified by comparing the simulation results of the local scour of the pile foundation under the condition of clear water scour and the results of the flume test. The permeability rate was defined to characterize the overwatering of the protection net, and numerical simulations were performed for protection nets with permeability in the range of 0.681 to 0.802. The flow field perturbations, changes in washout pit morphology, and changes in washout depth development due to the protective netting were also analyzed. It was found that the protection net can effectively reduce the flow velocity around the pile, cut down the intensity of the submerged water in front of the pile, and provide scouring protection. Finally, the analysis and summary of the protection efficiency of the different protection nets revealed that the protection efficiency within the nets was consistently the highest. On the outside of the net, the protection efficiency is poor at a small permeability rate but increases with an increasing permeability rate. Full article
(This article belongs to the Special Issue New Era in Offshore Wind Energy)
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<p>Schematic diagram of monopile foundation with protection net.</p>
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<p>Hertz–Mindlin no-slip model.</p>
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<p>Overall schematic of the geometric model (unit: mm).</p>
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<p>Localized schematic of the protection net and seabed model.</p>
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<p>Local meshing results for pile foundation and protection net.</p>
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<p>Localized structure of the protection net.</p>
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<p>Dimensionless mean flow velocity distribution.</p>
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<p>Time course of maximum scour depth.</p>
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<p>Localized velocity cloud of the protection net.</p>
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<p>Flow velocity distribution before and after the protection net.</p>
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<p>Localized streamlines in front of the pile.</p>
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<p>Scour equilibrium patterns of scour pits in different cases.</p>
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<p>Profile of 0° scour slope in front of the pile.</p>
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<p>Profile of the 45° scour slope in front of pile.</p>
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<p>Approximate area of the maximum scour depth inside and outside the net.</p>
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<p>Time course of the maximum scour depth outside the net.</p>
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<p>Time course of maximum scour depth inside the net.</p>
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<p>Reduction rate of the maximum scour depth for different values of φ.</p>
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<p>Schematic representation of selected observation areas in the granular bed.</p>
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<p>Development of particle loss over time.</p>
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13 pages, 3046 KiB  
Article
Assessment of Post-Tensioned Grout Durability by Accelerated Robustness and Corrosion Testing
by Samanbar Permeh and Kingsley Lau
Constr. Mater. 2023, 3(4), 449-461; https://doi.org/10.3390/constrmater3040029 - 23 Nov 2023
Viewed by 1506
Abstract
The corrosion of steel in post-tensioned tendons has been associated with deficient grout materials containing high free sulfate ion concentrations. In a Florida bridge in 2011, tendon corrosion failures occurred for a prepackaged thixotropic grout that had developed material segregation. However, the available [...] Read more.
The corrosion of steel in post-tensioned tendons has been associated with deficient grout materials containing high free sulfate ion concentrations. In a Florida bridge in 2011, tendon corrosion failures occurred for a prepackaged thixotropic grout that had developed material segregation. However, the available grout and corrosion testing prescribed in material specifications, such as grout bleed water testing, was not able to identify the propensity or modality for the grout deficiencies and the associated steel corrosion that was observed in the field. It was of interest to identify corrosion testing methods that could prescribe grout resistance to segregation-related deficiencies that can form by aberrations in construction. The objectives of the work presented here included (1) characterizing the development of physical and chemical grout deficiencies due to excess mix water and water volume displacement, (2) developing small scale test methodologies that identify deficient grout, and (3) developing test methodologies to identify steel corrosion in deficient grout. The inverted-tee test (INT) and a modified incline-tube (MIT) test were assessed and both were shown to be useful to identify the robustness of grout materials to adverse mixing conditions (such as overwatering and pre-hydration) by parameters such as sulfate content, moisture content, electrical resistance, and steel corrosion behavior. It was shown that the different grout products have widely different propensities for segregation and accumulation of sulfate ions but adverse grout mixing practices promoted the development of grout deficiencies, including the accumulation of sulfate ions. Corrosion potentials of steel < −300 mVCSE developed in the deficient grout with higher sulfate concentrations. Likewise, the corrosion current density showed generally high values of >0.1 μA/cm2 in the deficient grouts. The values produced from the test program here were consistent with historical data from earlier research that indicated corrosion conditions of steel in deficient grout with >0.7 mg/g sulfate, further verifying the adverse effects of elevated sulfate ion concentrations in the segregated grout. Full article
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<p>INT–test schematic: (<b>a</b>) grout material testing and (<b>b</b>) corrosion testing.</p>
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<p>MIT–test set up. <b>Left</b>: tendon schematic. <b>Right</b>: outdoor test setup.</p>
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<p>Moisture content of grout cast in INT with 10% extra mix water. Values for grout in the tee body and at various elevations of the tee header given.</p>
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<p>Comparison of sulfate ion concentrations in grout from INT and MIT. Values for grout in the tee body and at various elevations of the tee header given.</p>
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<p>Open–circuit potential for INT testing. Values for grout at various elevations of the tee header given.</p>
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<p>Open–circuit potential of steel in MIT specimens. <b>Left</b>: Grout A. <b>Right</b>: Grout B.</p>
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<p>Measured polarization resistance grout from MIT and INT specimens. Values for grout at various elevations of the INT tee header or MIT duct location given.</p>
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<p>Solution resistance of grout from MIT and INT specimens. Values for grout at various elevations of the INT tee header or MIT duct location given.</p>
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<p>Correlation of steel corrosion potential and grout sulfate content. Circle: Grout A. Triangle: Grout B. Square: Grout C. Diamond: Grout D. Cross: Neat Grout. Filled: Expired Grout. Blue: MIT. Black: INT.</p>
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<p>Correlation of steel corrosion current density and grout sulfate content. Circle: Grout A. Triangle: Grout B. Square: Grout C. Diamond: Grout D. Cross: Neat Grout. Filled: Expired Grout. Blue: MIT. Black: INT.</p>
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20 pages, 15819 KiB  
Article
Detection of Water Leakage in Drip Irrigation Systems Using Infrared Technique in Smart Agricultural Robots
by Levent Türkler, Taner Akkan and Lütfiye Özlem Akkan
Sensors 2023, 23(22), 9244; https://doi.org/10.3390/s23229244 - 17 Nov 2023
Cited by 1 | Viewed by 3240
Abstract
In the future, the world is likely to face water and therefore food shortages due to reasons such as global warming, population growth, the melting of glaciers, the destruction of agricultural lands over time or their use for different purposes, and environmental pollution. [...] Read more.
In the future, the world is likely to face water and therefore food shortages due to reasons such as global warming, population growth, the melting of glaciers, the destruction of agricultural lands over time or their use for different purposes, and environmental pollution. Although technological developments are important for people to live a more comfortable and safer life, it is also possible to reduce and even repair the damage to nature and protect nature itself thanks to new technologies. There is a requirement to detect abnormal water usage in agriculture to avert water scarcity, and an electronic system can help achieve this objective. In this research, an experimental study was carried out to detect water leaks in the field in order to prevent water losses that can occur in agriculture, where water consumption is the highest. Therefore, in this study, low-cost embedded electronic hardware was developed to detect over-watering by means of normal and thermal camera sensors and to collect the required data, which can be installed on a mobile agricultural robot. For image processing and the diagnosis of abnormal conditions, the collected data were transferred to a personal computer server. Then, software was developed for both the low-cost embedded system and the personal computer to provide a faster detection and decision-making process. The physical and software system developed in this study was designed to provide a water leak detection process that has a minimum response time. For this purpose, mathematical and image processing algorithms were applied to obtain efficient water detection for the conversion of the thermal sensor data into an image, the image size enhancement using interpolation, the combination of normal and thermal images, and the calculation of the image area where water leakage occurs. The field experiments for this developed system were performed manually to observe the good functioning of the system. Full article
(This article belongs to the Special Issue Internet of Things and Sensor Technologies in Smart Agriculture)
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<p>Evolution of global water withdrawals, 1900–2018 (km<sup>3</sup>/year) [<a href="#B3-sensors-23-09244" class="html-bibr">3</a>].</p>
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<p>Classification of irrigation control strategies. Reprinted/adapted with permission from Ref. [<a href="#B35-sensors-23-09244" class="html-bibr">35</a>].</p>
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<p>Monitoring methods in smart irrigation. Reprinted/adapted with permission from Ref. [<a href="#B35-sensors-23-09244" class="html-bibr">35</a>].</p>
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<p>The layout of the study.</p>
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<p>Irrigation methods.</p>
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<p>An example supervisory data acquisition and control system.</p>
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<p>Example water leakage. (<b>a</b>) Plant furrow view. (<b>b</b>) Detailed plant view.</p>
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<p>Schematic representation of the system.</p>
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<p>ESP32-CAM program algorithm.</p>
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<p>Test area (<b>red circle</b>: water leakage point, <b>green circle</b>: normal watering point).</p>
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<p>Test points. (<b>a</b>) Water leakage point. (<b>b</b>) Normal watering point.</p>
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<p>Test points thermal image (The colors represent heat level, blue: cold, red: hot). (<b>a</b>) Water leakage point. (<b>b</b>) Normal watering point.</p>
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<p>Combination of thermal image and video image (The colors represent heat level, blue: cold, red: hot). (<b>a</b>) Water leakage point. (<b>b</b>) Normal irrigation point.</p>
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<p>Control with another thermal sensor. (<b>a</b>) Water leakage point. (<b>b</b>) Normal irrigation point.</p>
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<p>Field control of test irrigation points (The colors represent heat level, blue: cold, red: hot). (<b>a</b>) Water leakage point. (<b>b</b>) Normal irrigation point.</p>
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10 pages, 3392 KiB  
Article
Proximal Soil Moisture Sensing for Real-Time Water Delivery Control: Exploratory Study over a Potato Farm
by Xiaoling Wu, Jeffrey P. Walker and Vanessa Wong
Agriculture 2023, 13(7), 1297; https://doi.org/10.3390/agriculture13071297 - 25 Jun 2023
Cited by 5 | Viewed by 2677
Abstract
New sensing technologies are at the cusp of providing state-of-the-art infrastructure to precisely monitor crop water requirements spatially so as to optimize irrigation scheduling and agricultural productivity. This project aimed to develop a new smart irrigation system that uses an L-band radiometer in [...] Read more.
New sensing technologies are at the cusp of providing state-of-the-art infrastructure to precisely monitor crop water requirements spatially so as to optimize irrigation scheduling and agricultural productivity. This project aimed to develop a new smart irrigation system that uses an L-band radiometer in conjunction with an irrigation boom, allowing for a precision water delivery system using derived high-resolution soil moisture information. A potato farm was selected due to its sensitivity to water and an existing irrigation system where the radiometer could be mounted. A field experiment was conducted to capture the soil moisture variation across the farm using the radiometer. A greenhouse trial was also conducted to mimic the actual growth of potatoes by controlling the soil moisture and exploring the impact on their growth. It was found that 0.3 cm3/cm3 was the optimal moisture level in terms of productivity. Moreover, it was demonstrated that on-farm soil moisture maps could be generated with an RMSE of 0.044 cm3/cm3. It is anticipated that through such technology, a real-time watering map will be generated, which will then be passed to the irrigation software to adjust the rate of each nozzle to meet the requirements without under- or over-watering. Full article
(This article belongs to the Special Issue Remote Sensing Technologies in Agricultural Crop and Soil Monitoring)
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<p>(<b>a</b>) Control unit and battery of the L-band radiometer ELBARA; (<b>b</b>) Horn antenna of ELBARA; (<b>c</b>) Waterproof house of ELBARA components; (<b>d</b>) Setup of ELBARA system onto a linear shift irrigator; and (<b>e</b>) Soil moisture monitoring over a potato farm by the Smart Irrigation System.</p>
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<p>Potato cultivation in the greenhouse (top row) and on the farm (bottom row) under similar conditions, including close seeding date, similar spacing between rows and between plants. Six watering levels were set for the greenhouse trial: W1 = air dry, W2 = 0.1 cm<sup>3</sup>/cm<sup>3</sup>, W3 = 0.2 cm<sup>3</sup>/cm<sup>3</sup>, W4 = 0.3 cm<sup>3</sup>/cm<sup>3</sup>, W5 = 0.4 cm<sup>3</sup>/cm<sup>3</sup> and W6 = 0.5 cm<sup>3</sup>/cm<sup>3</sup>, each with 5 replicates.</p>
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<p>Instruments used during the farm experiment, including (<b>a</b>) ELBARA radiometer mounted on a linear shift irrigator, (<b>b</b>) a roughness pin profiler, (<b>c</b>) a spectral radiometer for vegetation index, and (<b>d</b>) HDAS for soil moisture monitoring as ground truth.</p>
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<p>(<b>a</b>) Potato growing stage with different moisture conditions; (<b>b</b>) Harvesting of potatoes; (<b>c</b>) Potato growth status at floral stage with circle highlighting the impact of light variation on growth; (<b>d</b>) Pest infection; (<b>e</b>) Plots of height variation over time for each condition. The average height at each condition was calculated and displayed; shaded area indicates the floral stage.</p>
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<p>(<b>a</b>) Potato farm (200 m × 600 m; in green) and ELBARA monitoring strip (5 m × 600 m; in red); (<b>b1</b>–<b>b3</b>) Brightness temperature values from ELBARA along the strip at <span class="html-italic">h</span>- and <span class="html-italic">v</span>-pol, on 10 December 2018, 23 January 2019 and 25 February 2019 respectively; and (<b>c1</b>–<b>c3</b>) Comparison between ELBARA retrieved soil moisture and the ground sampled soil moisture using HDAS along the strip on 10 December 2018, 23 January 2019 and 25 February 2019 respectively.</p>
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21 pages, 2832 KiB  
Article
Model Application for Estimation of Agri-Environmental Indicators of Kiwi Production: A Case Study in Northern Greece
by Maria Kokkora, Panagiota Koukouli, Dimitrios Karpouzos and Pantazis Georgiou
Environments 2023, 10(4), 69; https://doi.org/10.3390/environments10040069 - 21 Apr 2023
Cited by 4 | Viewed by 2884
Abstract
Due to the sensitivity of kiwifruit to soil water and nutrient availability, kiwi production is often associated with over-watering and over-fertilization, especially with nitrogen (N), resulting in increased environmental risks. Crop models are powerful tools for simulating crop production and environmental impact of [...] Read more.
Due to the sensitivity of kiwifruit to soil water and nutrient availability, kiwi production is often associated with over-watering and over-fertilization, especially with nitrogen (N), resulting in increased environmental risks. Crop models are powerful tools for simulating crop production and environmental impact of given management practices. In this study, the CropSyst model was applied to estimate soil N budget and environmental effects of kiwi production, with particular regard to N losses, in two grower-managed kiwi orchards in northern Greece, involving two seasons and different management practices. Management options included N fertilization and irrigation. Model estimates were compared with yield and soil mineral N content (0–90 cm depths) measured three times within the growing season. Agri-environmental indicators were calculated based on the N budget simulation results to assess the environmental consequences (focusing on N losses and water use efficiency) of the different management practices in kiwi production. According to model simulation results, kiwifruit yield and N uptake were similar in both orchards. N losses to the environment, however, were estimated on average to be 10.3% higher in the orchard with the higher inputs of irrigation water and N fertilizer. The orchard with the lower inputs showed better water and N use efficiency. N leaching losses were estimated to be higher than 70% of total available soil N in both study sites, indicating potential impact on groundwater quality. These findings demonstrate the necessity for improved irrigation and N fertilization management in kiwi production in the area. Full article
(This article belongs to the Special Issue Environmental Impact Assessment II)
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<p>(<b>a</b>) Map of the study area; (<b>b</b>) kiwi orchards (plots A and B).</p>
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<p>Flowchart of the methodology used to estimate the environmental performance of the different irrigation and N fertilization management practices in kiwi production in the present study, using CropSyst model and agri-environmental indicators.</p>
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<p>(<b>a</b>) Observed and simulated yield (kg ha<sup>−1</sup>) for the two plots (A and B) in 2020 and 2021; (<b>b</b>) comparison of observed and simulated soil inorganic N (sum of NH<sub>4</sub>-N and NO<sub>3</sub>-N) within the 0–90 cm depths in 2020 and 2021.</p>
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<p>Soil inorganic N (sum of NH<sub>4</sub>-N and NO<sub>3</sub>-N) within the 0–90 cm depths, for plots A and B in (<b>a</b>) 2020 and (<b>b</b>) 2021; observed and simulated values by the CropSyst model. The blue bars show precipitation (Pr), whereas the dark blue bars show irrigation (Ir) water applied.</p>
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<p>Daily fluctuation of inorganic N (sum of NH<sub>4</sub>-N and NO<sub>3</sub>-N) leaching in g N ha<sup>−1</sup> day<sup>−1</sup>, for plots A and B in (<b>a</b>) 2020 and (<b>b</b>) 2021; simulated by the CropSyst model. The blue bars show precipitation (Pr), whereas the dark blue bars show irrigation (Ir) water applied.</p>
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<p>Daily fluctuation of nitrous oxide emissions in g N<sub>2</sub>O-N ha<sup>−1</sup> day<sup>−1</sup>, for plots A and B in (<b>a</b>) 2020 and (<b>b</b>) 2021; simulated by the CropSyst model. The blue bars show precipitation (Pr), whereas the dark blue bars show irrigation (Ir) water applied.</p>
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<p>Daily fluctuation of gaseous losses in kg N ha<sup>−1</sup> day<sup>−1</sup>, for plots A and B in (<b>a</b>) 2020 and (<b>b</b>) 2021; simulated by the CropSyst model. The blue bars show precipitation (Pr), whereas the dark blue bars show irrigation (Ir) water applied.</p>
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<p>Mean values of crop N uptake, residual soil N (0–90 cm), leached N, and N lost to the atmosphere (N<sub>2</sub>O loss and N gaseous loss), as percentage of total available soil N (TAN) for the plots A and B.</p>
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15 pages, 1057 KiB  
Technical Note
Rapid Growth of Tropical Cyclone Outer Size over the Western North Pacific
by Yi Li, Youmin Tang, Shuai Wang and Xiaojing Li
Remote Sens. 2023, 15(2), 486; https://doi.org/10.3390/rs15020486 - 13 Jan 2023
Cited by 3 | Viewed by 2193
Abstract
The concept of rapid growth (RG) of tropical cyclones (TCs) in the north Atlantic basin was recently proposed. RG can represent a dangerous change in TC structure because it can rapidly ramp up the TC destructive potential. However, the nature of RG behaviour [...] Read more.
The concept of rapid growth (RG) of tropical cyclones (TCs) in the north Atlantic basin was recently proposed. RG can represent a dangerous change in TC structure because it can rapidly ramp up the TC destructive potential. However, the nature of RG behaviour remains obscure over the western north Pacific (WNP), where nearly one third of global TCs occur. In this study, TC RG in the WNP is investigated using TC best-tracks and reanalysis of data. We first define TC RG in the WNP as an increase of at least 84 km in the radius of a gale-force wind within 24 h, corresponding to the 90th percentile of all over-water changes. Monte Carlo experiments demonstrate the robustness of the threshold. Similar to that occurring in the north Atlantic, RG in the WNP is associated with the highest level of destructive potential. In addition, RG over the WNP occurs closer to the coast than for TCs in the Atlantic and more RG events in the WNP are accompanied by rapid intensification, which may significantly increase their destructive potential in a worst case scenario. Composite analysis shows that certain dynamic processes, such as radial inflow, may play an important role in the occurrence of RG. This study suggests that, apart from rapid intensification, TC RG is another important factor to consider for TC-related risk assessment in the WNP. Full article
(This article belongs to the Special Issue Prediction of Extreme Weather Events)
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<p>Distribution of (<b>A</b>) <math display="inline"><semantics> <mi mathvariant="normal">Δ</mi> </semantics></math>R<math display="inline"><semantics> <msub> <mrow/> <mn>34</mn> </msub> </semantics></math> (units: km/24 h) and (<b>B</b>) lifetime maximum size (LMS, units: km) for the western north Pacific (grey) and north Atlantic TCs (orange).</p>
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<p>The ratio of 24 h R<math display="inline"><semantics> <msub> <mrow/> <mn>34</mn> </msub> </semantics></math> changes as a function of (<b>A</b>) the initial R<math display="inline"><semantics> <msub> <mrow/> <mn>34</mn> </msub> </semantics></math> during each 24 h interval and (<b>B</b>) the lifetime maximum size (LMS) for the western north Pacific. The <span class="html-italic">y</span>-axis in each subplot relates to the 24 h R<math display="inline"><semantics> <msub> <mrow/> <mn>34</mn> </msub> </semantics></math> changes (units: km/24 h) and the <span class="html-italic">x</span>-axis shows the initial R<math display="inline"><semantics> <msub> <mrow/> <mn>34</mn> </msub> </semantics></math> and LMS (units: km). The unit for the blue shadings is %. The red line shows the 90th percentile for each pixel.</p>
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<p>Distribution of intensity change (units: kt/24 h) and <math display="inline"><semantics> <mi mathvariant="normal">Δ</mi> </semantics></math>R<math display="inline"><semantics> <msub> <mrow/> <mn>34</mn> </msub> </semantics></math> (units: km/24 h). The rapid growth (RG) and rapid shrinkage events identified by the isolation forest algorithm are denoted by green and purple dots, respectively, while the events not identified as RG or RS are denoted by grey circles. The thresholds of the 95th (5th) and 90th (10th) percentiles are denoted by dashed and solid lines, respectively.</p>
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<p>Probability distribution function (PDF) of the lifetime maximum size (LMS) for the western north Pacific TCs. The original and smoothed distribution of all TCs are denoted by the grey histograms and black lines, respectively. The smoothed PDFs for the TCs that undergo rapid growth, defined as the 90th percentile (≥84 km/24 h) and 95th (108 km/24 h) percentile, are denoted by the orange and green lines, respectively. The PDFs are smoothed using kernel density estimation with a bandwidth of 0.2.</p>
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<p>Probability distribution function (PDF) of the (<b>A</b>) lifetime maximum integrated power dissipation (LMIPD) and (<b>B</b>) lifetime maximum integrated kinetic energy (LMIKE) for the western north Pacific TCs. The original and smoothed distribution of all TCs are denoted by the grey histograms and black line, respectively. The PDFs for the TCs that undergo rapid growth, defined as the 90th percentile (≥84 km/24 h), and TCs undergoing RI (≥30 kt/24 h), are denoted by the orange and green lines, respectively. The PDFs are smoothed using kernel density estimation with a bandwidth of 0.2. IPD and IKE are computed using the revised Holland wind-profile model [<a href="#B30-remotesensing-15-00486" class="html-bibr">30</a>].</p>
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<p>Composite of the evolution of (<b>A</b>) R<math display="inline"><semantics> <msub> <mrow/> <mn>34</mn> </msub> </semantics></math> and (<b>B</b>) V<math display="inline"><semantics> <msub> <mrow/> <mrow> <mi>m</mi> <mi>a</mi> <mi>x</mi> </mrow> </msub> </semantics></math> for the RG and non-RG TCs. (<b>C</b>) and (<b>D</b>) are the same with (<b>A</b>) and (<b>B</b>), but for the RI and non-RI TCs. The solid lines represent the average values, while the shadows represent one standard deviation.</p>
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<p>Spatial distribution of rapid growth (orange) and rapid intensification (green) events.</p>
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<p>Temporal distribution of rapid growth (orange) and rapid intensification (green) events for the (<b>A</b>) western north Pacific and (<b>B</b>) north Atlantic basins.</p>
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<p>The atmospheric conditions within a 21 <math display="inline"><semantics> <msup> <mrow/> <mo>∘</mo> </msup> </semantics></math>× 21 <math display="inline"><semantics> <msup> <mrow/> <mo>∘</mo> </msup> </semantics></math> box with the TC centered. (<b>A</b>) and (<b>B</b>) depict the composite 850 hPa radial inflow (units: m/s) for the RG and non-RG events, and (<b>C</b>) shows the difference between (A) and (B). (<b>D</b>–<b>F</b>) are the same with (<b>A</b>–<b>C</b>), but for the 600 hPa relative humidity (RH, units: %). (<b>G</b>–<b>I</b>) are the same as (<b>A</b>–<b>C</b>), but for the 700 hPa Eady growth rate (<math display="inline"><semantics> <mi>σ</mi> </semantics></math>, units: day<math display="inline"><semantics> <msup> <mrow/> <mrow> <mo>−</mo> <mn>1</mn> </mrow> </msup> </semantics></math>). The factors are composited using data from the ERA5 reanalysis. Stippled areas in the right panel indicate that the differences are statistically significant at the 99% confidence level based on Student’s t-test. The two circles are placed at radii of 5 and 10 degrees from the TC center.</p>
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<p>Composite maps of sea-surface temperature of (<b>A</b>) RG and (<b>B</b>) non-RG events and (<b>C</b>) the difference between (<b>A</b>) and (<b>B</b>). SST data are from the ERA5 reanalysis and are obtained for two days before TC approach. The units for <span class="html-italic">x</span>- and <span class="html-italic">y</span>-axis are degrees. Stippled areas in the right panel indicate that the differences are statistically significant at the 99% confidence level based on Student’s <span class="html-italic">t</span>-test. The two circles are placed at radii of 5 and 10 degrees from the TC center.</p>
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<p>Same as <a href="#remotesensing-15-00486-f004" class="html-fig">Figure 4</a>, but for the results in the Monte Carlo experiment.</p>
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11 pages, 3793 KiB  
Article
Design and Experimental Research of a Wellhead Overflow Monitoring System for Open-Circuit Drilling of Natural Gas Hydrate
by Chao Zhong, Jing’an Lu and Dongju Kang
Energies 2022, 15(24), 9606; https://doi.org/10.3390/en15249606 - 18 Dec 2022
Cited by 2 | Viewed by 1820
Abstract
Natural gas hydrate is easy to decompose and leak due to the changes in temperature and pressure during drilling, which causes safety accidents. Early monitoring of wellhead overflow is a practical and effective measure to prevent overflow blowouts and other accidents. Herein, a [...] Read more.
Natural gas hydrate is easy to decompose and leak due to the changes in temperature and pressure during drilling, which causes safety accidents. Early monitoring of wellhead overflow is a practical and effective measure to prevent overflow blowouts and other accidents. Herein, a wellhead methane monitoring system for the open-circuit drilling of marine natural gas was designed. The system consisted of an overwater acoustic reception part and an underwater self-contained methane monitoring part, matching the construction environment of marine natural gas hydrate exploitation. Compared with the existing gas logging technology (measurement while drilling), the monitoring and early warning of wellhead methane content were realized at all stages of drilling, casing running, cementing, completion and fracturing in the process of natural gas hydrate exploitation. System communication and data acquisition tests were completed at different water depths through sea trials, which verified the effectiveness of the system design. The research results provide important theoretical and technical implications for promoting the development of early spill monitoring technology at the wellhead of open-circuit drilling for marine gas hydrates. Full article
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<p>Subsea boundary layer methane monitoring methods: (<b>a</b>) ROV with methane sensor and (<b>b</b>) subsea submersible observing system.</p>
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<p>System architecture diagram.</p>
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<p>Schematic diagram of the system.</p>
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<p>System working diagram and technical route.</p>
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<p>Schematic diagram of suction filtration device design.</p>
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<p>Test data at a water depth of 500 m (18,264–18,187 sound communication module paired successfully).</p>
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<p>Test data at a water depth of 500 m (18,260–18,265 sound communication module paired successfully).</p>
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<p>Test data at a water depth of 1250 m (18,264–18,187 sound communication module paired successfully).</p>
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<p>Test data at a water depth of 1250 m (18,260–18,265 sound communication module paired successfully).</p>
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<p>Test data at a water depth of 1250 m (18,263–18,259 sound communication module paired successfully).</p>
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19 pages, 10260 KiB  
Article
Intelligent Control of Irrigation Systems Using Fuzzy Logic Controller
by Arunesh Kumar Singh, Tabish Tariq, Mohammad F. Ahmer, Gulshan Sharma, Pitshou N. Bokoro and Thokozani Shongwe
Energies 2022, 15(19), 7199; https://doi.org/10.3390/en15197199 - 30 Sep 2022
Cited by 13 | Viewed by 4910
Abstract
In this paper, we explain the design and implementation of an intelligent irrigation control system based on fuzzy logic for the automatic control of water pumps used in farms and greenhouses. This system enables its user to save water and electricity and prevent [...] Read more.
In this paper, we explain the design and implementation of an intelligent irrigation control system based on fuzzy logic for the automatic control of water pumps used in farms and greenhouses. This system enables its user to save water and electricity and prevent over-watering and under-watering of the crop by taking into account the climatic parameters and soil moisture. The irrigation system works without human intervention. The climate sensors are packaged using electronic circuits, and the whole is interfaced with an Arduino and a Simulink model. These sensors provide information that is used by the Simulink model to control the water pump speed; the speed of the water pump is controlled to increase or decrease the amount of water that needs to be pushed by the pump. The Simulink model contains the fuzzy control logic that manages the data read by the Arduino through sensors and sends the command to change the pump speed to the Arduino by considering all the sensor data. The need for human intervention is eliminated by using this system and a more successful crop is produced by supplying the right amount of water to the crop when it is needed. The water supply is stopped when a sufficient amount of moisture is present in the soil and it is started as soon as the soil moisture levels drops below certain levels, depending upon the environmental factors. Full article
(This article belongs to the Special Issue Challenges and Research Trends of Renewable Energy Power System)
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<p>Block diagram of a fuzzy logic control system.</p>
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<p>Fuzzy inference system.</p>
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<p>Soil moisture membership function plot.</p>
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<p>Solar irradiance membership function plot.</p>
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<p>Air temperature membership function plot.</p>
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<p>Air humidity membership function plot.</p>
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<p>Pump voltage membership function plot.</p>
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<p>Surface graph of air temperature and solar irradiance vs. pump voltage.</p>
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<p>Surface graph of soil moisture and air humidity vs. pump voltage.</p>
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<p>Simulink model for testing fuzzy controller.</p>
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<p>(<b>a</b>) Solar irradiance, air temperature, air humidity, and soil moisture input graph; (<b>b</b>) voltage output graph.</p>
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<p>(<b>a</b>) Soil moisture vs. time; (<b>b</b>) voltage vs. time at minimum water need; (<b>c</b>) voltage vs. time at maximum water need; (<b>d</b>) voltage vs. time at standard operating conditions.</p>
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<p>(<b>a</b>) Solar irradiance vs. time; (<b>b</b>) voltage vs. time at minimum water need; (<b>c</b>) voltage vs. time at maximum water need; (<b>d</b>) voltage vs. time at standard operating conditions.</p>
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<p>(<b>a</b>) Air temperature vs. time; (<b>b</b>) voltage vs. time at minimum water need; (<b>c</b>) voltage vs. time at maximum water need; (<b>d</b>) voltage vs. time at standard operating conditions.</p>
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<p>(<b>a</b>) Air humidity vs. time; (<b>b</b>) voltage vs. time at minimum water need; (<b>c</b>) voltage vs. time at maximum water need; (<b>d</b>) voltage vs. time at standard operating conditions.</p>
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<p>Block diagram of the control system.</p>
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<p>Simulink model.</p>
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<p>Subsystem to find solar irradiance value.</p>
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<p>Flow chart of the control algorithm.</p>
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<p>Working model of the system.</p>
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15 pages, 8537 KiB  
Article
Soil Nutrient Status and Morphometric Responses of Guava under Drip Irrigation and High-Tech Horticultural Techniques for Sustainable Farming
by Manpreet Singh Preet, Rajesh Kumar, Mohammad Valipour, Vijay Pratap Singh, Neha, Ashok Kumar Singh, Rashid Iqbal, Muhammad Umar Zafar, Rashmi Sharma, Shiv Vendra Singh, Arpna Kumari, Tatiana Minkina, Walid Soufan, Turki Kh. Faraj, Allah Ditta and Ayman El Sabagh
Hydrology 2022, 9(9), 151; https://doi.org/10.3390/hydrology9090151 - 23 Aug 2022
Cited by 8 | Viewed by 3985
Abstract
In the current study, efforts were made to standardize fertigation for providing the recommended doses of fertilizers (RDF) i.e., 300, 260, and 200 g/plant/year for N, P, and K, respectively, together with optimization of irrigation scheduling so that guava plants could avoid the [...] Read more.
In the current study, efforts were made to standardize fertigation for providing the recommended doses of fertilizers (RDF) i.e., 300, 260, and 200 g/plant/year for N, P, and K, respectively, together with optimization of irrigation scheduling so that guava plants could avoid the frequent episodes of nutritional stress, water scarcity, or overwatering. The experiment’s execution was confined to a three-factor randomized block design, with a total of 19 treatments that were replicated four times. Briefly, these treatments included drip irrigation and nutrient (NPK) application through fertigation dosages (RDF; 100, 80, and 60%) with and without silver-black plastic mulching. Different applied fertilizer dosages, together with different levels of irrigation and soil mulching, had a significant impact on the guava plant’s vegetative, reproductive, and nutritional aspects. Under silver-black plastic mulch, drip irrigation at cumulative pan evaporation (CPE) 80 and 100% of the prescribed dosage of fertilizers, better macronutrient availability in the soil, and improved plant development were recorded (M1DI2F1). Overall, using drip fertigation to provide NPK fertilizers close to the root zone increased the availability of nutrients to the plants as compared to the traditional fertigation and irrigation methods. Thus, this sustainable high-tech horticultural approach could be analyzed for its efficacy or applied to other crops to obtain adequate economic outcomes. Full article
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<p>Interactive effect of mulching in combination with drip irrigation and nutrient management on (<b>a</b>) increase in plant spread and canopy volume and (<b>b</b>) leaf area and number of flower/shoot of guava cv. VNR Bihi. M (mulch), M0 (no mulch); DI (drip irrigation level: 100% CPE, 80% CPE, 60% CPE); F (fertigation level: 100% RDF, 80% RDF, 60% RDF).</p>
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<p>Nutrient availability (NPK, kg/ha) influenced by mulching and fertigation system (pooled data of two-year experiment). M (mulch), M0 (no mulch); DI (drip irrigation level: 100% CPE, 80% CPE, 60% CPE); F (fertigation level 100% RDF, 80% RDF, 60% RDF).</p>
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<p>Pearson’s correlation of plant growth response, fruit yield, and soil properties, as augmented by management practices (<span class="html-italic">p</span> &lt; 0.05, <span class="html-italic">n</span> = 76). DHD (dehydrogenase); Avl N (available nitrogen); Avl P (available phosphorus); Avl K (available potassium); SOC (soil organic carbon); LA (leaf area); CS (canopy spread). <span class="html-fig-inline" id="hydrology-09-00151-i001"> <img alt="Hydrology 09 00151 i001" src="/hydrology/hydrology-09-00151/article_deploy/html/images/hydrology-09-00151-i001.png"/></span> strong positive correlation; <span class="html-fig-inline" id="hydrology-09-00151-i002"> <img alt="Hydrology 09 00151 i002" src="/hydrology/hydrology-09-00151/article_deploy/html/images/hydrology-09-00151-i002.png"/></span> negative or no correlation; <span class="html-fig-inline" id="hydrology-09-00151-i003"> <img alt="Hydrology 09 00151 i003" src="/hydrology/hydrology-09-00151/article_deploy/html/images/hydrology-09-00151-i003.png"/></span> weak positive correlation.</p>
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<p>Correlation of soil properties as augmented by management practices with fruit yield (<span class="html-italic">p</span> &lt; 0.05, <span class="html-italic">n</span> = 76).</p>
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17 pages, 2215 KiB  
Article
Simple ETo-Based Rules for Irrigation Scheduling by Smallholder Vegetable Farmers in Laos and Cambodia
by John McPhee, Jochen Eberhard, Alice Melland, Jasim Uddin, Lucinda Dunn, Sarith Hin, Vanndy Lim, Veasna Touch, Phimmasone Sisouvanh, Inthong Somphou, Tounglien Vilayphone, Phaythoune Mounsena and Stephen Ives
Water 2022, 14(13), 2010; https://doi.org/10.3390/w14132010 - 23 Jun 2022
Cited by 2 | Viewed by 2506
Abstract
Hand-held hoses and watering cans are widely used by smallholder farmers to irrigate vegetables in Cambodia and Laos. Overwatering is common. Technology change (e.g., low-pressure drip irrigation) has been used to improve irrigation efficiency but can be unaffordable for many smallholder farmers. The [...] Read more.
Hand-held hoses and watering cans are widely used by smallholder farmers to irrigate vegetables in Cambodia and Laos. Overwatering is common. Technology change (e.g., low-pressure drip irrigation) has been used to improve irrigation efficiency but can be unaffordable for many smallholder farmers. The purpose of this study was to identify an appropriate method of predicting crop water demand, develop and field-test improved irrigation schedules for smallholder leafy vegetable farming based on that method, and then develop extension tools to communicate the schedules to smallholder farmers. Improved irrigation schedules for leafy vegetables were developed based on a crop water use prediction technique that is well established (the Penman–Monteith method) but beyond the capacity of smallholder farmers to implement without access to simple aids. Compared to conventional practice, the method approximately halved water and labour use and improved irrigation water productivity 2–3 fold in field research and demonstration trials. Simplified extension tools to assist smallholder farmers with practice change were developed. This work showed that significant efficiencies could be gained through improved irrigation scheduling without changing application technology. Full article
(This article belongs to the Section Water, Agriculture and Aquaculture)
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<p>Relationship between ET<sub>o</sub> calculated from weather data measured at CARDI and estimated from corresponding NASA POWER weather data.</p>
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<p>Daily application measured on four farms in Chhouk, Kampot Province, Cambodia, showing differences in the depth of water applied to similar crops in similar growing conditions, and compared to predicted ET<sub>c</sub>.</p>
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<p>Daily application measured during demonstration trials on three farms in Chhouk, Kampot Province, Cambodia, showing differences in the amount of water applied to similar crops in similar growing conditions, and compared to predicted ET<sub>c</sub>, and a simplified form of ET<sub>c</sub> used for demonstration of an alternative irrigation schedule.</p>
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<p>An example of daily application tables published for use by agricultural advisors and smallholder farmers (for Paksong district, Champasak Province, Laos) showing recommended daily application rates for leafy vegetables of three different growth durations.</p>
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<p>Five-day moving average ET<sub>o</sub>, and approximate ET<sub>o</sub> based on absolute cumulative 10% change in ET<sub>o</sub> for Paksong district, Champasak Province, Laos.</p>
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<p>Nomograph developed for use by advisors and smallholder farmers in the study regions of Laos and Cambodia to calculate the number of watering cans, or duration of hose watering, required to apply the recommended daily irrigation application to leafy vegetables.</p>
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