scholarly journals Monitoring the Effects of Water Stress in Cotton using the Green Red Vegetation Index and Red Edge Ratio

2019 ◽  
Vol 11 (7) ◽  
pp. 873 ◽  
Author(s):  
Ballester ◽  
Brinkhoff ◽  
Quayle ◽  
Hornbuckle
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Vegetation Index ◽  
Water Status ◽  
Plant Water Status ◽  
Lint Yield ◽  
Plant Water ◽  
Fibre Quality ◽  
Matric Potential ◽  
Red Edge

The main objective of this work was to study the feasibility of using the green red vegetation index (GRVI) and the red edge ratio (RE/R) obtained from UAS imagery for monitoring the effects of soil water deficit and for predicting fibre quality in a surface-irrigated cotton crop. The performance of these indices to track the effects of water stress on cotton was compared to that of the normalised difference vegetation index (NDVI) and crop water stress index (CWSI). The study was conducted during two consecutive seasons on a commercial farm where three irrigation frequencies and two nitrogen rates were being tested. High-resolution multispectral images of the site were acquired on four dates in 2017 and six dates in 2018, encompassing a range of matric potential values. Leaf stomatal conductance was also measured at the image acquisition times. At harvest, lint yield and fibre quality (micronaire) were determined for each treatment. Results showed that within each year, the N rates tested (> 180 kg N ha-1) did not have a statistically significant effect on the spectral indices. Larger intervals between irrigations in the less frequently irrigated treatments led to an increase (p < 0.05) in the CWSI and a reduction (p < 0.05) in the GRVI, RE/R, and to a lesser extent in the NDVI. A statistically significant and good correlation was observed between the GRVI and RE/R with soil matric potential and stomatal conductance at specific dates. The GRVI and RE/R were in accordance with the soil and plant water status when plants experienced a mild level of water stress. In most of the cases, the GRVI and RE/R displayed long-term effects of the water stress on plants, thus hampering their use for determinations of the actual soil and plant water status. The NDVI was a better predictor of lint yield than the GRVI and RE/R. However, both GRVI and RE/R correlated well (p < 0.01) with micronaire in both years of study and were better predictors of micronaire than the NDVI. This research presents the GRVI and RE/R as good predictors of fibre quality with potential to be used from satellite platforms. This would provide cotton producers the possibility of designing specific harvesting plans in the case that large fibre quality variability was expected to avoid discount prices. Further research is needed to evaluate the capability of these indices obtained from satellite platforms and to study whether these results obtained for cotton can be extrapolated to other crops.

Single hyperspectral bands are highly sensitive to water stress in adult mandarin trees

2021 ◽  
Author(s):  
Pablo Berríos ◽  
Abdelmalek Temnani ◽  
Susana Zapata ◽  
Manuel Forcén ◽  
Sandra Martínez-Pedreño ◽  
...  
Keyword(s):  
Water Stress ◽  
Water Deficit ◽  
Phase Ii ◽  
Irrigation Water ◽  
Water Status ◽  
Irrigation Scheduling ◽  
Plant Water Status ◽  
Phase Iii ◽  
Plant Water ◽  
Severe Water Stress

&lt;p&gt;Mandarin is one of the most important Citrus cultivated in Spain and the sustainability of the crop is subject to a constant pressure for water resources among the productive sectors and to a high climatic demand conditions and low rainfall (about 250 mm per year). The availability of irrigation water in the Murcia Region is generally close to 3,500 m&lt;sup&gt;3&lt;/sup&gt; per ha and year, so it is only possible to satisfy 50 - 60% of the late mandarin ETc, which requires about 5,500 m&lt;sup&gt;3&lt;/sup&gt; per ha. For this reason, it is necessary to provide tools to farmers in order to control the water applied in each phenological phase without promoting levels of severe water stress to the crop that negatively affect the sustainability of farms located in semi-arid conditions. Stem water potential (SWP) is a plant water status indicator very sensitive to water deficit, although its measurement is manual, discontinuous and on a small-scale. &amp;#160;In this way, indicators measured on a larger scale are necessary to achieve integrating the water status of the crop throughout the farm. Thus, the aim of this study was to determine the sensitivity to water deficit of different hyperspectral single bands (HSB) and their relationship with the midday SWP in mandarin trees submitted to severe water stress in different phenological phases. Four different irrigation treatments were assessed: i) a control (CTL), irrigated at 100% of the ETc throughout the growing season to satisfy plant water requirements and three water stress treatments that were irrigated at 60% of ETc throughout the season &amp;#8211; corresponding to the real irrigation water availability &amp;#8211; except &amp;#160;during: ii) the end of phase I and beginning of phase II (IS IIa), iii) the first half of phase II (IS IIb) and iv) phase III of fruit growth (IS III), which irrigation was withheld until values of -1.8 MPa of SWP or a water stress integral of 60 MPa day&lt;sup&gt;-1&lt;/sup&gt;. When these threshold values were reached, the spectral reflectance values were measured between 350 and 2500 nm using a leaf level spectroradiometer to 20 mature and sunny leaves on 4 trees per treatment. Twenty-four HVI and HSB were calculated and a linear correlation was made between each of them with SWP, where the &amp;#961;940 and &amp;#961;1250 nm single bands reflectance presented r-Pearson values of -0.78** and -0.83***, respectively. Two linear regression curves fitting were made: SWP (MPa) = -11.05 &amp;#8729; &amp;#961;940 + 7.8014 (R&lt;sup&gt;2&lt;/sup&gt; =0.61) and SWP (MPa) = -13.043 &amp;#8729; &amp;#961;1250 + 8.9757 (R&lt;sup&gt;2&lt;/sup&gt; =0.69). These relationships were obtained with three different fruit diameters (35, 50 and 65 mm) and in a range between -0.7 and -1.6 MPa of SWP. Results obtained show the possibility of using these single bands in the detection of water stress in adult mandarin trees, and thus propose a sustainable and efficient irrigation scheduling by means of unmanned aerial vehicles equipped with sensors to carry out an automated control of the plant water status and with a suitable temporal and spatial scale to apply precision irrigation.&lt;/p&gt;

Stomatal conductance and growth of five Alnusglutinosa clones in response to controlled water stress

1988 ◽  
Vol 18 (4) ◽  
pp. 421-426 ◽  
Author(s):  
T. C. Hennessey ◽  
E. M. Lorenzi ◽  
R. W. McNew
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Drought Tolerance ◽  
Leaf Area ◽  
Water Status ◽  
Height Growth ◽  
Plant Water ◽  
Black Alder ◽  
Severe Water Stress ◽  
Progressive Water Stress

An experiment to quantify the response of unnodulated, fertilized European black alder (Alnusglutinosa (L.) Gaertn.) seedlings to progressive water stress showed contrasting drought tolerance among five clones, using stomatal conductance, leaf area, and height as indices of drought sensitivity. In particular, one rapidly growing clone (AG 8022-14) showed the ability to moderate changes in water stress more efficiently than the more slowly growing clones. After 30 days of moderate levels of water stress, clones that had higher stomatal conductance also had greater leaf area and height growth. Leaf area and height were both sensitive to plant water status, although no threshold of stress associated with a cessation of leaf area or height expansion was found even though stomatal conductance decreased to 0.05 cm s−1 under severe water stress.

Development of a Continuous Leaf Monitoring System to Predict Plant Water Status

2017 ◽  
Vol 60 (5) ◽  
pp. 1445-1455 ◽  
Author(s):  
Rajveer S. Dhillon ◽  
Shrini K. Upadhaya ◽  
Francisco Rojo ◽  
Jed Roach ◽  
Robert W. Coates ◽  
...  
Keyword(s):  
Water Stress ◽  
Data Collection ◽  
Water Status ◽  
Irrigation Scheduling ◽  
Leaf Temperature ◽  
Plant Water Status ◽  
Mesh Network ◽  
Plant Water ◽  
Plant Water Stress ◽  
Precision Irrigation

Abstract. There is increased demand for irrigation scheduling tools that support effective use of the limited supply of irrigation water. An efficient precision irrigation system requires water to be delivered based on crop needs by measuring or estimating plant water stress. Leaf temperature is a good indicator of water stress. In this study, a system was developed to monitor leaf temperature and microclimatic environmental variables to predict plant water stress. This system, called the leaf monitor, monitored plant water status by continuously measuring leaf temperature, air temperature, relative humidity, ambient light, and wind conditions in the vicinity of a shaded leaf. The system also included a leaf holder, a solar radiation diffuser dome, and a wind barrier for improved performance of the unit. Controlled wind speed and consistent light conditions were created around the leaf to reduce the effect of nuisance variables on leaf temperature. The leaf monitor was incorporated into a mesh network of wireless nodes for sensor data collection and remote valve control. The system was evaluated for remote data collection in commercial orchards. Experiments were conducted during the 2013 and 2014 growing seasons in walnut () and almond () orchards. The system was found to be reliable and capable of providing real-time visualization of the data remotely, with minimal technical problems. Leaf monitor data were used to develop modified crop water stress index (MCWSI) values for quantifying plant water stress levels. Keywords: Almonds, CWSI, Infrared sensor, Irrigation scheduling, Leaf temperature, Nut crops, Plant water stress, Precision irrigation, Stem water potential, Walnuts, Wireless mesh network.

scholarly journals Correlation of Field-Measured and Remotely Sensed Plant Water Status as a Tool to Monitor the Risk of Drought-Induced Forest Decline

Forests ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 77 ◽  
Author(s):  
Daniel Marusig ◽  
Francesco Petruzzellis ◽  
Martina Tomasella ◽  
Rossella Napolitano ◽  
Alfredo Altobelli ◽  
...  
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Forest Decline ◽  
Tree Mortality ◽  
Vegetation Index ◽  
Water Status ◽  
Remotely Sensed ◽  
Plant Water Status ◽  
Tree Level ◽  
Plant Water

Increased frequency of tree mortality and forest decline due to anomalous drought events calls for the adoption of effective monitoring of tree water status over large spatial and temporal scales. We correlated field-measured and remotely sensed plant water status parameters, to test the possibility of monitoring the risk of drought-induced dehydration and hydraulic failure using satellite images calibrated on reliable physiological indicators of tree hydraulics. The study was conducted during summer 2019 in the Karst plateau (NE Italy) in a woodland dominated by Fraxinus ornus L.; Sentinel-2 images were acquired on a seasonal scale on the same dates when absolute water content (AbWC), relative water content (RWC), and minimum water potential (Ψmin) were measured in the field. Plant water status parameters were correlated with normalized difference vegetation index (NDVI and NDVI 8A), normalized difference water index (NDWI), and soil-adjusted vegetation index (SAVI). Significant Pearson and Spearman linear correlations (α < 0.05) emerged between all tree-level measured variables and NDWI, while for NDVI, NDVI 8A, and SAVI no correlation was found. Our results suggest the possibility of using the NDWI as a proxy of tree water content and water potential.

Sensitivity and variability of soil and plant water stress indicators in response to withholding and resuming irrigation cycles in sweet cherry trees 

2021 ◽  
Author(s):  
Pedro José Blaya-Ros ◽  
Víctor Blanco ◽  
Roque Torres-Sánchez ◽  
Rafael Domingo
Keyword(s):  
Water Stress ◽  
Sweet Cherry ◽  
Water Status ◽  
Plant Water Status ◽  
Plant Water ◽  
Crop Water Stress Index ◽  
Stress Indicators ◽  
Drought Period ◽  
Stress Indicator ◽  
Cherry Trees

&lt;p&gt;Reduced water availability is the main limiting factor for crop production in semi-arid and arid regions. For this reason, irrigation water management needs to be based on reliable information and data that are rapidly and easily acquired. The aim of the present study was to assess the sensitivity and variability of several soil and plant water status indicators in response to two cycles of withholding and resuming irrigation in sweet cherry trees. The experiment was carried out during the summers of 2018 and 2019 in an experimental orchard of sweet cherry trees [&lt;em&gt;Prunus avium&lt;/em&gt; (L.) &amp;#8216;Lapins&amp;#8217;] in SE Spain. Three irrigation treatments were studied: control, CTL, irrigated to ensure non-limiting soil water conditions (115% ETc) and two water stress treatments, medium water stress, MS, and severe water stress, SS. The threshold values of midday stem water potential (&amp;#936;&lt;sub&gt;stem&lt;/sub&gt;) proposed to the first and second drought period for MS trees were -1.3 and -1.7 MPa and for SS trees were -1.6 and -2.5 MPa. After every irrigation withholding period, MS and SS trees were fully irrigated until reaching Y&lt;sub&gt;stem&lt;/sub&gt; values of CTL trees. The experimental design was a completely randomized block design with three blocks per treatment. Soil and plant water status were assessed by measuring the soil volumetric water content (&amp;#952;v), the &amp;#936;&lt;sub&gt;stem&lt;/sub&gt;, the daily trunk growth rate (TGR), the maximum daily trunk shrinkage (MDS), the temperature of the canopy (Tc), the difference between Tc and air temperature (&amp;#916;T) and the crop water stress index (CWSI). The signal intensity (SI), the coefficient of variation (CV) and the sensitivity (S = SI/CV) of &amp;#952;v, &amp;#936;&lt;sub&gt;stem&lt;/sub&gt;, MDS and Tc were determined.&lt;/p&gt;&lt;p&gt;&amp;#952;v at 25 cm dropped significantly during the drought periods. &amp;#936;&lt;sub&gt;stem&lt;/sub&gt; of MS and SS trees reached minimum values close to those thresholds proposed both years of study. MDS and TGR had a rapid response to the irrigation regimen applied. Tc, &amp;#916;T and CWSI increased as an effect of the stomatal closure. &amp;#936;&lt;sub&gt;stem&lt;/sub&gt; and Tc were the water stress indicators with the highest sensitivity. MDS showed SI values greater than that of &amp;#936;&lt;sub&gt;stem&lt;/sub&gt; and Tc, although it also had greater variability (CV&lt;sub&gt;MDS&lt;/sub&gt; &amp;#8776; 29%). &amp;#936;&lt;sub&gt;stem&lt;/sub&gt; showed high SI values and low CV both study years. When the linear relationships between &amp;#936;&lt;sub&gt;stem&lt;/sub&gt; and the other plant water status indicators were calculated, it was observed that the Pearson correlation coefficients exceeded 0.75 in all cases, except for TGR. The relationship obtained between MDS and &amp;#936;&lt;sub&gt;stem&lt;/sub&gt; was linear from &amp;#8722;0.5 MPa to a threshold value of around &amp;#8722;1.3 MPa, from that value onwards, &amp;#936;&lt;sub&gt;stem&lt;/sub&gt; decreases were not related to MDS values. In contrast, &amp;#916;T and CWSI were always linearly related to &amp;#936;&lt;sub&gt;stem&lt;/sub&gt;. These results suggest that: i) MDS could be used as a water stress indicator up to moderate water deficit; ii) &amp;#936;&lt;sub&gt;stem&lt;/sub&gt; is a sensitive water stress indicator with low variability; and iii) the thermal indicators (Tc, &amp;#916;T and CWSI) can rapidly and easily assess sweet cherry tree water status.&lt;/p&gt;&lt;p&gt;This study was funded by the Spanish Economy and Competitiveness Ministry (AGL2013-49047-C2-1-R; AGL2016-77282-C33-R).&lt;/p&gt;

scholarly journals Feasibility of Low-Cost Thermal Imaging for Monitoring Water Stress in Young and Mature Sweet Cherry Trees

2020 ◽  
Vol 10 (16) ◽  
pp. 5461 ◽  
Author(s):  
Pedro José Blaya-Ros ◽  
Víctor Blanco ◽  
Rafael Domingo ◽  
Fulgencio Soto-Valles ◽  
Roque Torres-Sánchez
Keyword(s):  
Water Stress ◽  
Thermal Imaging ◽  
Sweet Cherry ◽  
Water Status ◽  
Low Cost ◽  
Plant Water Status ◽  
Control Treatment ◽  
Plant Water ◽  
Crop Water Stress Index ◽  
Cherry Trees

Infrared thermography has been introduced as an affordable tool for plant water status monitoring, especially in regions where water availability is the main limiting factor in agricultural production. This paper outlines the potential applications of low-cost thermal imaging devices to evaluate the water status of young and mature sweet cherry trees (Prunus avium L.) submitted to water stress. Two treatments per plot were assayed: (i) a control treatment irrigated to ensure non-limiting soil water conditions; and (ii) a water-stress treatment. The seasonal evolution of the temperature of the canopy (Tc) and the difference between Tc and air temperature (ΔT) were compared and three thermal indices were calculated: crop water stress index (CWSI), degrees above control treatment (DAC) and degrees above non-water-stressed baseline (DANS). Midday stem water potential (Ψstem) was used as the reference indicator of water stress and linear relationships of Tc, ΔT, CWSI, DAC and DANS with Ψstem were discussed in order to assess their sensitivity to quantify water stress. CWSI and DANS exhibited strong relationships with Ψstem and two regression lines to young and mature trees were found. The promising results obtained highlight that using low-cost infrared thermal devices can be used to determine the plant water status in sweet cherry trees.

scholarly journals Sequential Antioxidants Foliar Application Can Alleviate Negative Consequences of Salinity Stress in Vicia faba L.

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 914
Author(s):  
Wael M. Semida ◽  
Taia A. Abd El-Mageed ◽  
Reham M. Abdalla ◽  
Khaulood A. Hemida ◽  
Saad. M. Howladar ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Vicia Faba ◽  
Foliar Application ◽  
Water Status ◽  
Plant Water Status ◽  
Soil Conditions ◽  
Enzymatic Antioxidants ◽  
Plant Water ◽  
Vicia Faba L ◽  
Photosynthesis Efficiency

Salinity is one of the most limiting abiotic stresses in agricultural productivity. Exogenously applied antioxidants successfully enabled salt-stressed plants to cope with stress. Two-season field experiments were conducted consecutively in 2016/17 and 2017/18 to study the effects of foliar applications of singular (ascorbate, AsA; proline, Pro; and glutathione, GSH) or sequential (AsA-Pro-GSH and GSH-Pro-AsA) antioxidants on growth, yield, physio-biochemical attributes, and enzymatic and non-enzymatic antioxidative defense system of Vicia faba L. (CV. Sakha-1) plants grown under saline soil conditions (EC = 4.53 dS m−1). Under soil salinity conditions, AsA, Pro, or GSH-Pro-ASA improved growth and productivity, photosynthesis efficiency, stomatal conductance (gs), plant water status, as well as enzymatic and non-enzymatic antioxidants. However, sequential AsA-Pro-GSH foliar application followed by singular GSH significantly exceeded all other treatments (i.e., AsA, Pro, and GSH-Pro-AsA), improving growth characteristics (shoot length, shoot fresh and dry weights, and leaves area), photosynthesis efficiency, stomatal conductance, plant water status, and yield and its components (green pods weight/plant−1, green pods yield/hectare−1, and seed yield/hectare−1), as well as enzymatic (ascorbate peroxidase, catalase, superoxide dismutase, and glutathione reductase) and non-enzymatic (AsA, GSH, Pro, phenolic aglycone, phenolic glycosides) antioxidants compared to control. Overall, our results clearly demonstrate that sequential AsA-Pro-GSH foliar application has a positive effect on salt-stressed Vicia faba plants.

scholarly journals Effects of atmospheric and soil water status on photosynthesis and growth in tomato

2018 ◽  
Vol 64 (No. 1) ◽  
pp. 13-19 ◽  
Author(s):  
Du Qingjie ◽  
Zhang Dalong ◽  
Jiao Xiaocong ◽  
Song Xiaoming ◽  
Li Jianming
Keyword(s):  
Water Stress ◽  
Water Status ◽  
Vapour Pressure Deficit ◽  
Plant Water Status ◽  
Plant Water ◽  
Stomatal Development ◽  
Stomatal Limitation ◽  
Tomato Seedlings ◽  
Inhibition Of Growth ◽  
Whole Plant

The responses of tomato seedlings to different vapour pressure deficit (VPD) under low soil moisture were studied. Plants were grown in greenhouses with low and high VPD, under both well-watered and water stress conditions. Low VPD was effectively maintained below 1.5 kPa with a micro-fog system. Under well-watered conditions, low VPD resulted in reduced transpiration, but this did not affect plant water status or growth. Water stress induced leaf dehydration and inhibition of growth, but the adverse effects were significantly alleviated by a decrease in VPD. Under water stress, no difference in transpiration was observed between plants with or without the VPD regulation, but the whole-plant hydraulic conductance was higher under low VPD. Low VPD increased stomatal conductance in drought-stressed plants because it promoted stomatal development and increased stomatal aperture. Thus, stomatal limitation to photosynthesis was reduced by low VPD under water stress. The reduction in plant growth induced by water stress was moderated by low VPD, partially due to higher photosynthetic rate. These results suggest that decreasing VPD improves plant water status, which ultimately enhances photosynthesis and growth under water stress.

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