Effects Of Water Stress Research Articles

The increasing water stress projected for China could shift the agriculture and manufacturing industry geographically

The sustainable development of China has been challenged by the misalignment of water demand and supply across regions under varying climate change scenarios. Here we develop a water stress prediction index using a fuzzy decision-making approach, which analyzes spatiotemporal variations of water stress and concomitant effects on the populace within China. Our results indicate that water stress will increase from 2020 to 2099 under both low and high emission scenarios, primarily due to decreased water supplies like surface runoff and snow water content. Seasonal analysis reveals that annual fluctuations in water stress are mainly driven by changes in spring and autumn. Water stress is projected to be considerably lower in southeastern provinces compared to northwestern ones, where, on average, over 20% of the Chinese population could be severely impacted. These changes in water stress could lead to the north-to-south migration of the agriculture sector, manufacturing sector, and human population.

Simulation of Onion Response to Soil Moisture Stress at Different Growth Stages on Yield and Water Productivity Using Aquacrop

The objective of this study is to select the most effective water-saving techniques and improve the water productivity of irrigated onion. The phenological growth of onion, the crop was subjected to moisture stress during one, two, or three of the growth stages. The highest yield attained was 21.157 tons/ha and the lowest was 7.177 tons/ha. Treatments T3 & T4 were water stressed during second and last growth stages produce yields that weren’t significantly different from the yield achieved under completely irrigated (T1). Compared to the maximum yield, 22.3% to 48.4% lower yields were recorded under treatments subjected to water deficiency during two growth stages. Treatments that were stressed during one growth stage had a 2.6 to 42.7% yield reduction relative to the maximum yield. The highest yield reduction was observed under treatment irrigated during the first growth stage (T8), followed by irrigated during first and second growth stages (T7), first and late stages (T5) and then treatment not irrigated during midseason (T2). This shows that a prolonged deficiency over three growing stages has more yield reduction (T8). Plots stressed during both third and fourth growth stages were producing lower yields indicating the severe effects of water stress during flowering and early bulb filling stages on yield. Water savings achieved under different treatments with no significant differences in yield from full irrigated plots range 11.8% to 21.7% (T4 & T3) respectively.

Leaves and roots metabolomic signatures underlying rootstock-mediated water stress tolerance in grafted pepper plants

Grafting onto pepper rootstock NIBER® is an effective strategy to mitigate water stress effects on the grafted variety. In this work, we comparatively explored the metabolomic responses to water stress in the pepper variety “Maestral F1” (V) grafted onto NIBER® (V/N) and self-grafted (V/V) by untargeted metabolomics on leaves and roots. Leaf water status was also evaluated by relative water content (RWC) and gas exchange measurements. Under water stress, the V/N water use efficiency (WUE) and leaf RWC were higher than V/V, in agreement with major stomata closure and water retention in leaves. V/N showed a tolerance response, which was manifested in the untargeted metabolomic analysis. NIBER® modulated the grafted variety response to water stress as reflected in the differential metabolomic profiles in leaves and roots. The V/N-enriched metabolic pathways showed that the NIBER® response to water stress involved cutin and suberin biosynthesis, which act as protection layers, and jasmonic acid (JA) and jasmonates biosynthesis to favor signaling pathways. NIBER® did not induce flavonols and chlorophyll b synthesis, but likely promoted anthocyanins biosynthesis and maintained an undisturbed chlorophyll a:chlorophyll b ratio. Moreover, NIBER® increased vitamin B6, anthocyanins and stearic acid concentration in the variety leaves, whereas siroheme content rose in roots to improve nitrogen assimilation. Further studies are required to understand the contribution of secondary metabolites, such as phenylpropanoids, glycoalkaloids, and nitrogen-containing secondary metabolites, to NIBER® water stress tolerance.

Effects of High Salinity and Water Stress on Wetland Grasses from the Spanish Mediterranean Coast.

The impacts of climate change are reaching unprecedented levels, heightening the risk of species loss and ecosystem service degradation. Wetlands, highly threatened ecosystems, serve vital ecological functions by capturing carbon, filtering water, and harbouring diverse wildlife. Coastal wetlands encounter many challenges, such as increased drought periods and escalating salinity levels, severely impacting plant biodiversity. Assessing how plants respond to various environmental stress factors is imperative for devising successful conservation strategies. In the present study, we examined three representative grass species found in various habitats within the Albufera Natural Park, close to the city of Valencia on the Spanish Mediterranean coast: Imperata cylindrica, Phragmites australis, and Saccharum ravennae. High salinity and water stress conditions were induced by subjecting the plants to irrigation with solutions containing 200, 400, 600, and 800 mM NaCl or withholding irrigation altogether to mimic coastal flooding and drought scenarios. The treatments were maintained until noticeable wilting of the plants occurred, at which point a range of stress biomarkers were determined, including photosynthetic pigments, ions, osmolytes, oxidative stress markers, and antioxidant metabolites, as well as antioxidant enzyme activities. Saccharum ravennae displayed the highest sensitivity to salt stress, whereas I. cylindrica appeared to be the most tolerant. The primary salinity tolerance mechanism observed in I. cylindrica and P. australis was a blockage of ion transport from the root zone to the aerial part, together with the salt-induced accumulation of proline and soluble sugars to high concentrations in the former. No significant effects of the water deficit treatment on the growth or biochemical parameters were observed for any of the analysed species. These findings offer valuable information for the effective management and conservation of coastal wetlands facing the challenges posed by climate change.

Effect of Growth Stage-based Water Stress on Yield and Water Use Efficiency of Tomatoes (Solanum lycopersicon L.) in Semi-arid Regions of Tigray, Ethiopia

Water availability is a major concern in regions with limited water resources. Implementation of best irrigation water management methods can maximize crop yields and irrigation water use efficiency. An experiment was conducted in Laelay Koraro district, Tigray, Ethiopia for two consecutive years (2018 and 2019 off seasons) to investigate the effect of growth stage-based deficit irrigation on tomato yield, yield characteristics and water usage efficiency. The experiment used a randomized complete block design (RCBD) with three replications. The treatments were three irrigation levels (100%, 50%, and 25% of crop irrigation requirement) and four FAO-defined tomato growth stages (initial, developmental, mid, and late seasons). Data on agronomic parameters and irrigation water were collected and analyzed statistically. The results revealed that reducing irrigation amount by up to 75% during the development growth stage significantly decreased marketable yield by up to 66.5%. However, the highest water use efficiency (9.2kgm-3) was achieved by reducing irrigation amount by 75% at the end-growth stage of tomato. Treatments with the lowest water use efficiency (3.5kgm-3) were those receiving 75% less irrigation amount than the full requirement during the development growth stage. Irrigation deficit up to 75% of the full requirement during tomato development stages greatly affect marketable yield and water use efficiency. Therefore, the tomato crop is highly susceptible to water stress when receiving more than a 50% reduction in full irrigation requirement during its developmental growth stage.

Effect of Water Stress and Potassium on Growth, Flowering, and Proline Content of Zinnia hybrid

Effect of Water Stress and Potassium on Growth, Flowering, and Proline Content of Zinnia hybrid

The Effects of Water Stress on Grain Yield and Yield Components in Bread Wheat

The Effects of Water Stress on Grain Yield and Yield Components in Bread Wheat

PERFORMANCE OF MUNGBEAN WITH ELEVATED NPKS NUTRITIONS UNDER WATER STRESS

Drought is one of the most serious environmental stresses that hinders mungbean (Vigna radiata L.) production seriously. Improvement of soil nutrition is one of the effective measures to enhance drought tolerance of upland crops like mungbean. This study was conducted to evaluate the effect of higher levels of macro nutrients on growth and yield performance of mungbean. Recommended dose, and two, three and four folds of the recommended dose of major fertilizers (N-P-K-S) were applied on two popular mungbean varieties namely, Binamoog-5 and BU mug4 under water stress. The effect of the higher levels of fertilizer on stressed plants was evaluated by examining different morphological parameters of growth such as plant height, parameters of growth analyses, yield attributes and grain yield. Water stress in general had a negative effect on plant growth and development. However, the enhanced levels of nutritions lessened the water stress effect. Increased plant height, leaf area, CGR, RGR, NAR, and grain yield and yield attributes were measured in plants that received elevated nutrients. In general Binamoog-5 showed higher water stress tolerance than BU mug4 in relation to the production of grain yield and yield attrbutes. Under water stress the highest number of pods plant-1 was recorded in T4 where Binamoog-5 produced 15.33 plant-1 and BU mug4 had 13.33 plant-1. The highest 100-seed weight was recorded in Binamoog-5 (4.65 g) and BU mug4 had 4.29 g with the three-fold increased doses of N-P-K-S fertilizer (T4 ). The highest grain yield plant-1 was also recorded in T4 where Binamoog-5 produced 4.95 g plant-1 and BUmug4 produced 3.95 g plant-1. It was concluded that higher levels of NPKS enhanced productivity of mungbean, than the recommended.

Severe Preharvest Drought Elevates Respiration and Storage Rot in Postharvest Sugarbeet Roots

ABSTRACTSugarbeets are largely produced without irrigation, making drought stress inevitable when rainfall is insufficient. Whether drought stress impacts root storage, however, is currently unknown. Research was conducted to determine the effect of preharvest water stress on postharvest sugarbeet root respiration rate and susceptibility to storage rots as these traits are the primary determinants for sucrose loss and quality deterioration. Greenhouse‐grown plants were subjected to four levels of water deficit by discontinuing watering for 0, 7, 14 or 21 days prior to harvest. Plants receiving water‐restrictive treatments displayed physiological stress by leaf epinasty, reductions in net photosynthetic rate and leaf relative water content and increases in leaf temperature, whereas the water content of roots harvested from these plants progressively decreased with the severity of the preharvest water‐deficit treatment. Harvested roots from all watering treatments were stored at 10°C and 95% relative humidity for up to 12 weeks and evaluated for respiration rate and susceptibility to storage rot. Root respiration rate during storage was inversely related to root water content at harvest by second‐order equations, such that respiration was not significantly affected by minor reductions in root water content but increased exponentially for roots obtained from severely drought‐stressed plants with water contents at harvest of ≤75%. Similarly, roots with water contents ≤75% had elevated levels of electrolyte leakage, a measure of cellular membrane damage, and were more susceptible to dehydration and fungal infection during storage. In separate experiments, roots harvested from water‐stressed plants were inoculated with Botrytis cinerea or Penicillium vulpinum, two causal agents for storage rots. In these experiments, preharvest water stress quantitatively increased root rot and qualitatively altered symptoms of their infection. Overall, these results demonstrate that severe preharvest drought stress is likely to significantly increase sugarbeet root storage losses caused by root respiration and storage rots and that storage losses are likely to accelerate with time in storage. However, mild‐to‐moderate drought conditions prior to harvest are expected to have no or minimal effect on storage losses from root respiration or storage rots.

Mitigation of drought-induced stress in sunflower (Helianthus annuus L.) via foliar application of Jasmonic acid through the augmentation of growth, physiological, and biochemical attributes

Drought stress poses a significant threat to agricultural productivity, especially in areas susceptible to water scarcity. Sunflower (Helianthus annuus L.) is a widely cultivated oilseed crop with considerable potential globally. Jasmonic acid, a plant growth regulator, plays a crucial role in alleviating the adverse impacts of drought stress on the morphological, biochemical, and physiological characteristics of crops. Experimental detail includes sunflower varieties (Armani Gold, KQS-HSF-1, Parsun, and ESFH-3391), four drought stress levels (0, 25%, 50%, and 75% drought stress), and three levels (0, 40ppm, 80ppm) of jasmonic acid. The 0% drought stress and 0ppm jasmonic acid were considered as control treatments. The experimental design was a completely randomized design with three replicates. Drought stress significantly reduced the growth in all varieties. However, the exogenous application of jasmonic acid at concentrations of 40ppm and 80ppm enhanced growth parameters, shoot and root length (1.93%, 19%), shoot and root fresh weight (18.5%, 25%), chlorophyll content (36%), photosynthetic rate (22%), transpiration rate (40%), WUE (20%), MDA (6.5%), Phenolics (19%), hydrogen peroxide (7%) proline (28%) and glycine betaine (15–30%) under water-stressed conditions, which was closely linked to the increase in stomatal activity stimulated by jasmonic acid. Furthermore, JA 80 ppm was found to be the most appropriate dose to reduce the effect of water stress in all sunflower varieties. It was concluded that the foliar application of JA has the potential to enhance drought tolerance by improving the morphological, biochemical, and physiological of sunflower.

Dry matter distribution, yield and seed quality of soybean (Glycine max) genotypes as affected by water stress

Water stress is a major constraint for crop productivity and culturing right cultivars may produce a considerable yield under such stressful condition. An experiment was conducted inside a vinyl house to evaluate the effect of water stress on dry matter distribution, yield, and seed quality of eight soybean genotypes, viz. G00006, BD2336, AGS383, PK472, BCS-1, NCS-1, BU Soybean-1 and BARI Soybean-6. They were grown in pots and subjected to water stress (20% of field capacity, FC) and control (80% of FC). The water stress reduced plant height, leaf number, leaf, stem, and root dry matter by 23, 45, 46, 45 and 19%, respectively, across the genotypes. Under water stress, the soybean genotypes G00006, BCS-1, NCS-1 and BARI Soybean-6 beard only 6 to 30% pod and 5 to 34% seed compared to the control condition. The results further indicated that yield of BD2336 and AGS383 were less affected by the stress than those of other genotypes. Interestingly, water stress exerted positive effect on seed germination, viability, speed of germination and vigor index in BD2336 and AGS383, respectively. Nitrogen and seed protein content were found the highest in BCS-1 under control (9.82 and 58.42% respectively) followed by AGS383. Phosphorus content in seed also reduced by the stress in the tested genotypes, except BD2336 (0.29% in control and 0.96% in water stress) and BARI Soybean-6. Potassium content in seed was reduced by the stress in the tested genotypes, except G00006 and BARI Soybean-6. Based on the findings related to water stress effects on yield and seed quality, particularly seed protein of the tested eight soybean genotypes, it was concluded that genotypes AGS383 and BD2336 might be considered for field trial under water deficit condition.

Could regulated and sustained deficit irrigation be applied in temperate climates? A case study of soybean production under field conditions

A field experiment was conducted to study the effects of full (F), regulated (RDI), and sustained deficit irrigation (SDI) on yield (Y), evapotranspiration (ET), and water use efficiency (WUE) of drip irrigated soybean. The yield response factor (Ky) was calculated to express the effect of water stress on soybean yield. The water balancing approach was used to schedule irrigation. Daily water used for plants' evapotranspiration was calculated by multiplying reference evapotranspiration with crop coefficients. Irrigation started when readily available water in the soil layer of 0.4 m was completely depleted by plants. There were statistical differences in yield between F (4.60 t ha−1) and SDI (3.71 t ha−1) treatments, but not between F and RDI (4.44 t ha−1). The evapotranspiration rate varied between 439 and 535 mm under irrigation and between 193 and 306 mm under rainfed conditions. The WUE values were consistent with the yield of the treatments. The statistical difference in soybean yield between F and SDI strategies suggests that the SDI cannot be used in the region's soybean farming. As no water savings were recorded for the same level of soybean yield between F and RDI, it indicates that RDI is not beneficial under the temperate climate of the Vojvodina region. The yield response factors of 0.69 and 0.71 in 2022 and 2023, respectively, show that soybean is tolerant to water stress and could be grown in rainfed conditions in Vojvodina's temperate climate. However, to achieve high and consistent yields, irrigation is advised.

Water productivity, yield response factors, yield and quality of alfalfa cultivars in semi-arid climate conditions

This study was carried out for 2 years (2020 and 2021) to elucidate the effects of water stress on yield and quality of alfalfa cultivars, to determine the water-yield and quality relations and the susceptibility of cultivars to water stress. Three different irrigation treatments (100%, 75% and 50% of full irrigation, I100, I75 and I50) and 12 different alfalfa cultivars (SHN, Osmanağa, Şahin 42, Minerva, Elçi, Riviera Vicentina, Magna 601, Magnum V, Prosementi, Ezzelina, Sunter, Nimet) were used in present experiments conducted in randomized-blocks split-plots design with 3 replications to investigate effects of irrigation levels on water, yield and quality parameters of alfalfa. Present findings revealed that water stress decreased crop water productivity, but increased irrigation water productivity of alfalfa cultivars. Herbage yields of the cultivars varied between 48.20 and 64.98 t/ha, hay yields between 11.42 and 14.67 t/ha and protein yields between 2.22 and 3.07 t/ha. Alfalfa was found to be sensitive to water stress in terms of herbage yield, but more tolerant in terms of hay and protein yields. Morphological characteristics (plant height, number of stems per plant, number of main stem branches and root crown diameter) decreased with increasing water stress levels. In terms of quality traits, while acid detergent fiber (ADF), neutral detergent fiber (NDF), crude fiber and crude ash ratios increased, crude protein ratios decreased with increasing irrigation water levels. It was concluded based on present findings that water stress resulted in different responses of different alfalfa cultivars and although it increased quality traits in general, it decreased herbage, hay and protein yields. Again, based on present findings, Magna 601 cultivar could be recommended for semi-arid regions.

Temperature and water stresses on antioxidant activity of selected medicinal plants have implications for sustainable use and global warming

Some traditional healers believe that herbal medicines derived from wild populations have higher activity than cultivated medicinal plants. This has important implications for the conservation of medicinal plants if traditional healers do not want to use cultivated plants. We have previously shown that water and temperature stresses have little effect on antimicrobial activity acetone leaf extracts of Leonotis dysophylla Benth., Bulbine frutescens (L.) Willd. and Tulbaghia violacea Harv. Antioxidant activity of plant extracts may be important in treating several different diseases. We have therefore investigated the effect of water and temperature stresses on the quantitative and qualitative antioxidant activity of these species in plants with limited genetic variation using 6‑hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox) and l-ascorbic acid as positive controls. Activity was measured against two free radicals, 2,2′-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) and 2, 2-diphenyl-1-picryl hydrazyl (DPPH). All plant extracts had some antioxidant activity following 182 to 240 days of exposure to temperature (15 °C and 30 °C) and water (50–500 ml/pot every second day) treatments. The IC50 values across water treatments did not show any clear patterns, which suggests that water stress had little influence on the antioxidant activity. On the other hand, the IC50 values under high temperature of 30 °C were statistically significantly higher than those under the temperature of 15 °C, which indicates that high temperature led to a reduced antioxidant activity. The effect of fluctuating temperatures higher than 30 °C because of prevailing global warming is more likely to lower the antioxidant activity of many important medicinal plants in nature. The results also indicate that plants in nature do not necessarily have higher activity to address concerns of traditional healers. Using cultivated plants may affect the quality and/or safety of medicinal properties to be used to treat different illnesses. As such, the establishment of optimal growth regimes for ex situ cultivation for important and especially threatened medicinal plants is recommended. It may help yield consistent supply of quality and quantity of bioactive material for self-medication and commercialisation. Cultivation may also contribute to conservation of species biodiversity.

Effect of water stress on locomotor performance in Pleurodema nebulosum (Anura: Leptodactylidae) a native frog from the Argentina Monte desert

Locomotion is a fundamental aspect in the life cycle of any organism, and plays a crucial role in survival, feeding, escaping from predators, territoriality, and reproduction. Locomotion in amphibian anurans includes swimming, walking, jumping, climbing, and gliding. Amphibians living in arid regions face a constant compromise between hydration balance and locomotor performance. We studied the effects of water stress on the locomotion of the frog Pleurodema nebulosum, a specialist from the Monte Desert. Locomotor performance was measured through different physical variables during the jump. The locomotor performance of P. nebulosum showed a significant decrease in the magnitudes associated with a decrease in body hydration. Our study demonstrated how a desert-adapted frog (P. nebulosum) showed changes in locomotion related to the loss of body water. Additionally, we observed an abrupt drop in locomotion with 15% desiccation, followed by a plateau where the evaluated parameters remained stable. Pleuroderma nebulosum showed a clear adaptation to extreme desiccation. The frogs are rarely found in optimal hydration conditions as the environment in which they develop is extremely stressful from a water perspective. The data evaluated here are the beginning of a deeper exploration of the desert adaptations of South American desert frogs.

Calibration, testing and application of the AquaCrop model for bean crop under irrigation regimes.

Crop growth simulation models relate the soil-water-plant-atmosphere components to estimate the development and yield of plants in different scenarios, enabling the identification of efficient irrigation strategies. The aim of this study was to calibrate crop coefficients for a common bean cultivar (IAPAR 57) and assess the AquaCrop model's efficacy in simulating crop growth under different irrigation regimes (T0 - non-irrigated, T1-fully irrigated, and T2-deficit irrigated) and sowing dates (S1-March 21, S2-April 24, and S3-August 23). Successful calibration was achieved for crop seasons with suitable temperatures to crop growth (S1 and S3). However, during periods with suboptimal temperatures (April 24 season), coupled with reduced irrigation supply (T0 and T2), the AquaCrop model did not appropriately account for the combined effects of thermal and water stresses. Despite adjustments to stress coefficients, this led to an overestimation of crop growth and yield. In long-term simulations, the model successfully replicated the variability of crop water availability over cropping seasons, reflecting the impact of precipitation variations. It recommended irrigation strategies for the study region (irrigate at depletion of 120 and 170% of readily available water for sowing on March 21 and August 24, respectively) to achieve high crop yield (> 2,769kgha-1) and water productivity (1,050 to 1,445kgm-3) with minimal application depths (< 150mm). While acknowledging the need for improvements in thermal stress calculations, the AquaCrop model demonstrates promising utility in studies and applications where water availability significantly influences crop production.

Improving mangoes' productivity and crop water productivity by 24-epibrassinosteroids and hydrogen peroxide under deficit irrigation

In nature, plants are frequently subjected to a wide range of abiotic stresses that drastically reduce crop productivity. Deficit in irrigation is one of the main factors of abiotic stresses that affect agricultural productivity. Nevertheless, not much research has been done on how to use water with brassinosteroids (Br) and hydrogen peroxide (H2O2)in deficit water conditions in order to reach comparatively good values of mango tree growth, productivity, and fruit quality as well as crop water productivity (WPC). A split-plot experiment in a complete randomized block system design study with 3 regulated deficit irrigation levels i.e. 100% IR (Irrigation requirement), 80% IR, and 60% IR was implemented in 2022 and 2023, each irrigation regime was combined with the foliar application of distilled water (control), 1 mg/L Br, 10 mM H2O2, 1 mg/L Br + 10 mM H2O2. Foliar treatments were applied at 3 different phenological stages: flower bud induction and differentiation, full bloom, and beginning of fruit set. The results showed that fruit shape index and acidity significantly improved as irrigation volume increased, however, the proportion of fruit mineral content and fruit chemical characteristics was inversely correlated with the volume of water. Meanwhile, moderate regular deficit irrigation (80% IR) achieved marked increases in leaf minerals and total chlorophyll content, fruit quality, yield, and water use efficiency. Drought stress (60% IR) significantly decreased fruit set, fruit retention, yield traits, and fruit physical and chemical properties, at the same time, significant improvements in the content of stress indicators (proline, total phenols, and carotenoids) were observed compared with control. All treatments with Br and H2O2 alone or in combination under drought stress had a pronounced effect in this regard. Overall, foliar spray of 1 mg/L Br+10 mM H2O2 was the most powerful treatment that emended the unpropitious effect of water stress.

The effect of foliar application of plant growth regulators on functional and qualitative characteristics of wheat (Triticum aestivum L.) under salinity and drought stress conditions

This study aimed to investigate the effect of salinity and water stress on the physiological and functional characteristics of winter wheat (Triticum aestivum L.) under the foliar application of plant growth regulators (PGRs). The experiment was carried out as a split plot based on a randomized complete block design with three replications in two environments. In each environment, water stress at two irrigation levels (after 90 and 120 mm of pan evaporation) and with two EC of 1.5 and 10 dS/m in the main plots and spraying of PGRs including salicylic acid (SA), gibberellic acid (GA3), and cytokinins (CK) (purine) content with a concentration of 100 ppm and the control treatment (spraying solution with normal water) were placed in subplots. Results indicated that all treatments caused significant increases in functional and qualitative characteristics and yield of Triticum aestivum L. The saline environment and irrigation level after 120 mm of pan evaporation caused a reduction in grain yield in all traits except for seed proline, seed nitrogen content, and seed protein content. Also, the combined foliar application of GA3 + CK + SA increased yield in most traits. The highest RWC of flag leaves was observed in the foliar application of GA3 + SA (3.36 kg/ha) and then in the foliar application of GA3 + SA + CK (57.87 kg/ha). GA3 interacts with PGR spraying to balance another development under saline and non-saline conditions.

Improving Irrigation Management of Cotton with Small Unmanned Aerial Vehicle (UAV) in Texas High Plains

The rapid decline in water availability for irrigation on the Texas High Plains (THP) is a significant problem affecting crop production and the viability of a large regional economy worth approximately USD 7 billion annually. This region is the largest continuous cotton-producing area in the United States, and the timely delivery and efficient use of irrigation water are critical to the sustainability and profitability of cotton production in this region. Current irrigation scheduling must be improved to reduce water consumption without compromising crop production. Presently, irrigation scheduling based on reference evapotranspiration (ETo) is limited due to the lack of reliable and readily available in-field weather data and updated crop coefficients. Additionally, in-field variability in crop water demand is often overlooked, leading to lower irrigation efficiency. To address these challenges, we explored the potential use of an unmanned aerial vehicle (UAV)-based crop monitoring system to support irrigation management decisions. This study was conducted in Lubbock, Texas, in 2022, where high temporal and spatial resolution images were acquired using a UAV from a cotton field experiment with four irrigation levels. Soil moisture and canopy temperature sensors were deployed to monitor crop response to irrigation and rainfall. The results indicated a significant effect of water stress on crop growth (revealed by UAV-based canopy cover (CC) measurements), yield, and fiber quality. Strong correlations between multi-temporal CC and lint yield (R2 = 0.68 to 0.88) emphasized a clear trend: rainfed treatments with lower yields exhibited reduced CC, while irrigated plots with higher CC displayed increased yields. Furthermore, irrigated plots produced more mature and uniform fibers. This study also explored various evapotranspiration calculation approaches indicating that site-specific CC measurements obtained from a UAV could significantly reduce irrigation application. A regression model linking evapotranspiration to canopy cover demonstrated promising potential for estimating water demand in crops with an R2 as high as 0.68. The findings highlight the efficacy of UAV-based canopy features in assessing drought effects and managing irrigation water in water-limited production regions like the THP.

Growth kinetics, spatialization and quality of potato tubers monitored in situ by MRI - long-term effects of water stress.

Understanding the potato tuber development and effects of drought at key stages of sensitivity on yield is crucial, particularly when considering the increasing incidence of drought due to climate change. So far, few studies addressed the time course of tuber growth in soil, mainly due to difficulties in accessing underground plant organs in a non-destructive manner. This study aims to understand the tuber growth and quality and the complex long-term effects of realistic water stress on potato tuber yield. MRI was used to monitor the growth kinetics and spatialization of individual tubers in situ and the evolution of internal defects throughout the development period. The intermittent drought applied to plants reduced tuber yield by reducing tuber growth and increasing the number of aborted tubers. The reduction in the size of tubers depended on the vertical position of the tubers in the soil, indicating water exchanges between tubers and the mother plant during leaf dehydration events. The final size of tubers was linked with the growth rate at specific developmental periods. For plants experiencing stress, this corresponded to the days following rewatering, suggesting tuber growth plasticity. All internal defects occurred in large tubers and within a short time span immediately following a period of rapid growth of perimedullary tissues, probably due to high nutrient requirements. To conclude, the non-destructive 3D imaging by MRI allowed us to quantify and better understand the kinetics and spatialization of tuber growth and the appearance of internal defects under different soil water conditions.