Levels Of Water Stress Research Articles

Dependence of CWSI-Based Plant Water Stress Estimation with Diurnal Acquisition Times in a Nectarine Orchard

Unmanned aerial vehicle (UAV) remote sensing has become a readily usable tool for agricultural water management with high temporal and spatial resolutions. UAV-borne thermography can monitor crop water status near real-time, which enables precise irrigation scheduling based on an accurate decision-making strategy. The crop water stress index (CWSI) is a widely adopted indicator of plant water stress for irrigation management practices; however, dependence of its efficacy on data acquisition time during the daytime is yet to be investigated rigorously. In this paper, plant water stress captured by a series of UAV remote sensing campaigns at different times of the day (9h, 12h and 15h) in a nectarine orchard were analyzed to examine the diurnal behavior of plant water stress represented by the CWSI against measured plant physiological parameters. CWSI values were derived using a probability modelling, named ‘Adaptive CWSI’, proposed by our earlier research. The plant physiological parameters, such as stem water potential (ψstem) and stomatal conductance (gs), were measured on plants for validation concurrently with the flights under different irrigation regimes (0, 20, 40 and 100 % of ETc). Estimated diurnal CWSIs were compared with plant-based parameters at different data acquisition times of the day. Results showed a strong relationship between ψstem measurements and the CWSIs at midday (12 h) with a high coefficient of determination (R2 = 0.83). Diurnal CWSIs showed a significant R2 to gs over different levels of irrigation at three different times of the day with R2 = 0.92 (9h), 0.77 (12h) and 0.86 (15h), respectively. The adaptive CWSI method used showed a robust capability to estimate plant water stress levels even with the small range of changes presented in the morning. Results of this work indicate that CWSI values collected by UAV-borne thermography between mid-morning and mid-afternoon can be used to map plant water stress with a consistent efficacy. This has important implications for extending the time-window of UAV-borne thermography (and subsequent areal coverage) for accurate plant water stress mapping beyond midday.

Inter-relationships between water depletion and temperature differential in row crop canopies in a sub-humid climate

Irrigation has a great impact on global food security as it contributes to the majority of the world’s agricultural food supply. It is essential to judiciously utilize water resources through efficient irrigation management since the majority of U.S. groundwater aquifers are rapidly depleting. Thus, quantification of the relationships between water depletion and environmental factors is important for understanding crop response to varying levels of water stresses that depletion can cause. The objectives of this research were to: 1) investigate the relationship between root zone water depletion (Drw) and canopy temperature differential (ΔT) at different ranges of Drw; and 2) develop upper (water stressed) and lower (non-water stressed) baselines for quantification of crop water stress index (CWSI) in a sub-humid climate. The research was conducted over maize and soybean during 2018, 2019, and 2020 growing seasons. Sensor node stations comprising of an infrared thermometer and three soil water sensors were installed at various sites over maize and soybean fields. ΔT tends to increase with the increase in Drw when the range of Drw includes values greater than 170 mm for maize and values greater than 160 mm for soybean. The results indicate that ΔT and Drw are unrelated until a soil-water depletion threshold is attained, and these Drw threshold values could be considered as indicators to trigger irrigation for efficient agricultural water management. To the best of the authors’ knowledge, the research is the first to develop upper and lower CWSI baselines for east-central Nebraska. The baselines developed in this study could facilitate the quantification of CWSI for irrigation scheduling of maize and soybean in east-Central Nebraska. Future work should aim to investigate the potential in using Drw and/or ΔT to determine efficient water allocation and if a threshold CWSI could be used for timing of irrigation to prevent yield loss.

Estimation of Water Stress in Potato Plants Using Hyperspectral Imagery and Machine Learning Algorithms

This work presents quantitative detection of water stress and estimation of the water stress level: none, light, moderate, and severe on potato crops. We use hyperspectral imagery and state of the art machine learning algorithms: random decision forest, multilayer perceptron, convolutional neural networks, support vector machines, extreme gradient boost, and AdaBoost. The detection and estimation of water stress in potato crops is carried out on two different phenological stages of the plants: tubers differentiation and maximum tuberization. The machine learning algorithms are trained with a small subset of each hyperspectral image corresponding to the plant canopy. The results are improved using majority voting to classify all the canopy pixels in the hyperspectral images. The results indicate that both detection of water stress and estimation of the level of water stress can be obtained with good accuracy, improved further by majority voting. The importance of each band of the hyperspectral images in the classification of the images is assessed by random forest and extreme gradient boost, which are the machine learning algorithms that perform best overall on both phenological stages and detection and estimation of water stress in potato crops.

Child mortality and water stress under the framework of Sustainable Development Goals (SDGs): Evidence from twenty developing countries

Both child mortality and water stress are included into the Sustainable Development Goals (SDGs). Existing studies have explored the relationship between child mortality and water stress with different perspectives, however, the results vary due to differences in methods and context. There is still insufficient cross-country comparative research on the association between child mortality and water stress under the framework of SDGs. This article uses data of 20 developing countries to explore the association between child mortality and water stress, based on the path analysis methodology. The results show that in term of statistics, the level of water stress is negatively but insignificantly associated with child mortality in developing countries. This unconventional result is explained by a number of possible reasons such as high reliance on food importation in some developing countries, and also the indirect link between water stress and child mortality via a country’s socioeconomic development (measured by national poverty rate). The results enrich scientific knowledge of and provide practical implications to the interactions between SDGs.

EFFECTS OF DIFFERENT WATER STRESS LEVELS ON BIOMASS YIELD AND AGRONOMIC TRAITS OF SWITCHGRASS (Panicum virgatum L.) CULTIVARS UNDER ARID AND SEMI-ARID CONDITIONS

This study was conducted to determine the effects of different water stress levels on biomass yield, plant height, number of stalks per unit area, single stalk weight, yield reduction ratios and irrigation water use efficiency (IWUE) values of switchgrass (Panicum virgatum L.) cultivars under Central Anatolia conditions. Experiments were conducted for two years (2016 – 2017) in randomized blocks – split plots experimental design with three replications under Konya ecological conditions. Six switchgrass cultivars (Shelter, Alamo, Cave in rock, Shawnee, Kanlow and Trailblazer) and five different irrigation treatments (water stress levels: S1: Full irrigation; S2: 75% of full irrigation; S3: 50% of full irrigation; S4: 25% of full irrigation and S5: Rain-fed without irrigation) were used in present experiments. Kanlow, Alamo and Trailblazer cultivars had greater biomass yields than the other cultivars in all water stress treatments. Under different water stress treatments, dry biomass yields varied between 48300 kg ha-1 (S5- Cave in rock) and 25120 kg ha-1 (S1- Kanlow); plant heights varied between 70 cm (S5) and 180 cm (S1); number of stalks per unit area (meter) varied between 221 (S5) and 356 (S1); stalk weights varied between 0.56 g (S5) and 2.25 g (S1). IWUE was calculated as 5.7 kg m-3 for the first harvest and as 2.1 kg m-3 for the second harvest. Considering the biomass yields from single harvest of rain-fed treatments (S5) and two harvests of the other irrigation treatments (S1-S4), IWUE values and water deficits of the region, it was concluded that single harvest was more suitable for switchgrass plants grown under ecological conditions

Effect of Liquid Organic Fertilizers and Soil Moisture Status on Some Biological and Physical Properties of Soil

<p>This study was conducted to evaluate the effects of liquid organic fertilizers (LOFs) and soil moisture status on some biological and physical properties of postharvest soil of maize cultivation. For this purpose, a factorial greenhouse experiment was performed based on the completely randomized design with three replications. Treatments consisted of five levels of LOFs (control, vermicompost tea, vermiwash, plant growth-promoting rhizobacteria [PGPR] enriched vermicompost tea and PGPR enriched vermiwash) and three levels of soil moisture status (field capacity [FC], 0.8 FC and 0.6 FC). The results showed LOFs caused an increase of soil biological properties (soil microbial respiration, soil microbial biomass, dehydrogenase activity and the number of aerobic heterotrophic bacteria) and the improvement of soil physical condition. LOFs increased aggregate stability, hydrophobicity and total porosity, while decreased bulk density and soil penetration resistance. Increasing water stress levels reduced soil biological activity and made soil physical properties more unfavorable. In general, LOFs improved soil conditions by enhancing soil physical and biological properties and decreased the negative effects of water stress. In addition, results showed that LOFs enriched with PGPR could be more effective than non-enriched ones.</p>

Stomatal traits of maize grown by applying waste to soils under water stress conditions

Purpose: Drought will be one of the most important questions in the future. The easiest and natural way to drought recovery is to popularize the use of materials that will increase the water holding capacity of soils. The aim of this study is to determine the effect of hazelnut husk applying in water stress conditions on stomatal traits and the growth of maize.Materials and Methods: A greenhouse experiment was conducted in a randomized plot design using three factors:hazelnut husk doses (30-60-80 t ha-1) and three water stress levels (at 75%, 50% and 25% of field capacity); and two different soil texture (clay loam and sandy loam) with three replications.Results: Root fresh weight, total biomass and root:shoot ratio increased by 73%, 51% and 39% respectively when plants grown in clay loam soil are compared with sandy loam soil. Hazelnut husk applications affected both plant growth and stomatal traits, the most effective dose was 80 t ha-1 but the dose of 60 t ha-1 was found sufficient for the stomatal traits. Water stress caused a significant decrease in shoot growth (16-52%), leaf area (13-44%) and stomatal traits whereas irrigation at 50% of field capacity with 60 t ha-1 of the husk was found sufficient.Conclusion: It is thought that other morphological features are also not affected because hazelnut husk prevents the roots from being affected by stress. However, further studies are needed to determine the effects under field conditions.

Effects of Water Stress on the Phenolic Compounds of ‘Merlot’ Grapes in a Semi-Arid Mediterranean Climate

Of all the abiotic stress types to which plants grown in fields are exposed, the most influential is water stress. It is well accepted that adopting controlled deficit irrigation strategies during the growing season has beneficial effects on the chemical compositions of grapes and red wines. However, there is a discrepancy in the timing, intensity and duration of deficit. This study aimed to evaluate the changes in phenolic composition of ‘merlot’ cultivar grapes when subjected to different levels of water stress in a semi-arid Mediterranean climate. Four treatments with different water stress levels were applied within two phenological intervals (flowering-veraison, veraison-maturity) to 128 grapevines for two consecutive years. The water stress levels for Treatments 1, 2, 3 and 4 were: no-light, light-moderate, moderate-intense and intense for the flowering-veraison and veraison-maturity intervals, respectively. Water stress distinctly affected the phenolic compounds in skin and seeds. The concentrations of flavan-3-ols and total polyphenols were much higher in seeds than in skin, and in both fractions, tannins are the major compounds.

Sustainable and Resilient Smart Water Grids: A Solution for Developing Countries

According to a United Nations report, the world population will increase from 7 billion to 9 billion by 2050. Further, the water stress level is more than 70% in 22 countries while in another 31 countries it is between 25% and 70%. More than 2 billion people live in these 53 countries which are all underdeveloped. Water use has increased by 1% per year since the 1980s, so global demand is expected to rise by 30% by 2050. Thus, efficient water grid management is imperative to ensure there is sufficient water for the future. Information and Communication Technology (ICT) can be used to create smart water grids to optimize water distribution, reduce waste and leakage, and resolve quality and overuse issues. In this work, a low cost, real-time, reliable and sustainable IoT based solution called SmartTubewell is proposed for smart water grid management. It is composed of two components, a sensor node installed at tube wells and an application layer on Amazon Web Services (AWS) for data analysis, storage and processing. The sensor node is based on a Raspberry Pi with integrated current and voltage sensors and a local database. The sensor data is transmitted to AWS using a cellular (GPRS) network. A comparison between the proposed system and SCADA is presented which shows that SmartTubewell has a much lower cost. A field test with multiple tube wells in Peshawar, Pakistan indicates that this is a suitable solution for developing countries.

The Impact of Biological Inoculation on Zea Mays L. growth, Protein Content, and Iron Availability Under Different Levels of Water Stress

This study aims to investigate the effect of biological inoculation with Azotobacter chrococcum and Glomus mosseae on the growth and yield of Zea mays L., the variety of Baghdad 3 under different levels of water stress. A field experiment was carried out in the fall season of 2020 in a private farm in the Diwaniyah Governorate-Afak district. According to the Randomized Complete Block Design R.C.B.D, the experiment was designed with three replications, and the treatment was distributed randomly. Three levels of irrigation were used in the experiment (I4 irrigation every four days, I7 irrigation every seven days, I10 irrigation every ten days) and the levels of inoculation (B1 inoculation with A-chrococcum and B0 not inoculating with bacteria) and ( F1 inoculating with G-mosseae and F0 non-inoculation) and ( B1F1 interaction between fungus and bacteria). The means were compared using the L.S.D. Test at a 5% significance level. The results present that the treatments inoculated with fungi or bacteria or both, and for a seven-day irrigation period, significantly increased the values ​​of the traits (plant height, dry weight of the vegetative part, length of corn cob, protein percentage, soil content of available iron during the flowering and end of season periods). They had the highest values ​​ 358, 85.71, 25.63, 12.23, 0.5423, and 0.4873 cm plant-1, respectively, compared to the treatments (control + irrigation every ten days) as they resulted in 165, 32.87, 9.07, 6.75, 0.3133, and 0.2823 cm plant-1, respectively.

Managing cassava growth on nutrient poor soils under different water stress conditions

Nitrogen (N), phosphorus (P) and potassium (K) fertiliser application, was able to counteract growth reductions, in cassava cultivated on nutrient poor soils, under one water stress condition. It however remains to be seen, whether N, P and K fertiliser application, would produce similar results, across different water stress conditions. A study was therefore conducted to determine how N, P and K fertiliser application, would influence cassava growth on nutrient poor soils, under various water stress conditions. Effects on new leaf formation and leaf size were also investigated. The study was a 2×3×4 factorial pot experiment, in a randomised complete block design. It included: two cassava varieties, three water stress levels and four fertiliser treatments. The water stress levels kept some plants watered at field capacities of 30% (severe water stress), 60% (mild water stress) and 100% (zero water stress). The fertiliser treatments consisted of a control (no fertiliser), a sole K fertiliser treatment (25 mg K/kg), a moderate N, P and K fertiliser treatment (25 mg N + 5 mg P + 25 mg K/kg) and a high N, P and K fertiliser treatment (50 mg N + 13 mg P + 50 mg K/kg). All data were analysed using the analysis of variance. Cassava growth was assessed by monitoring changes in the dry shoot mass of cassava plants. High and moderate N, P and K fertiliser application, produced cassava plants with higher and similar dry shoot masses, under mild water stress (10.5 g/plant, SE = 0.6 and 9.0 g/plant, SE = 0.6, respectively). High N, P and K fertiliser application, however gave cassava the highest dry shoot mass, under severe water stress (7.9 g/plant, SE = 0.4). Relatively high cassava growth was consistently achieved with high N, P and K fertiliser application, across all water stress conditions.

Su Stresi Altındaki Bazı Kızılçam Kaynaklarının Tohum Çimlenme Oranı ve Fidelerin Gaz Değişim Performanslarının İncelenmesi

With climate change, global warming has increased adverse effects on living things in our country. In these adverse effects, water scarcity is the most crucial problem due to the increase in temperature and decrease in precipitation. Forests are the most affected ecosystem among others by water scarcity in our country. This study tried to determine the 5-year-old seeds and 1-year-old seedlings (produced from the same seeds) of some Turkish red pine provenance’ responses to different water stress levels. First, how the water stress levels (0, -0.2, -0.4, -0.6, -0.8 MPa) affect seed germination of these provenances was determined. Secondly, gas exchange parameters [net photosynthesis (Anet), stomatal conductance (gs), transpiration (E), and intrinsic water use efficiency (iWUE)] under different water stress were determined in the seedlings obtained from these species' seeds. As a result of the germination test, Denizli-Çameli (DC) provenance had the highest rate (48%), while Maraş-Suçatı had the lowest rate (29%) under control treatment. The highest germination rate was obtained in Burdur/Bucak provenance (5%) under -0.2 MPa osmotic potential. For gas exchange parameters, Antalya/Gündoğmuş provenance had the highest Anet, gs values while DC provenance had the lowest Anet, gs, and E values when provenance is considered as a single factor. Besides, increasing in irrigation increased Anet, gs, and E while decreased the iWUE. The lowest seedling E under water stress can be explained because this species responds to the water shortage by closing its stomata. Among the Turkish red pine origins, DC provenance showed higher drought tolerance than others.

Impacts of Climate Change Interacting Abiotic Factors on Growth, aflD and aflR Gene Expression and Aflatoxin B1 Production by Aspergillus flavus Strains In Vitro and on Pistachio Nuts.

Pistachio nuts are an important economic tree nut crop which is used directly or processed for many food-related activities. They can become colonized by mycotoxigenic spoilage fungi, especially Aspergillus flavus, mainly resulting in contamination with aflatoxins (AFs), especially aflatoxin B1 (AFB1). The prevailing climate in which these crops are grown changes as temperature and atmospheric CO2 levels increase, and episodes of extreme wet/dry cycles occur due to human industrial activity. The objectives of this study were to evaluate the effect of interacting Climate Change (CC)-related abiotic factors of temperature (35 vs. 37 °C), CO2 (400 vs. 1000 ppm), and water stress (0.98–0.93 water activity, aw) on (a) growth (b) aflD and aflR biosynthetic gene expression and (c) AFB1 production by two strains A. flavus (AB3, AB10) in vitro on milled pistachio-based media and when colonizing layers of shelled raw pistachio nuts. The A. flavus strains were resilient in terms of growth on pistachio-based media and the colonisation of pistachio nuts with no significant difference when exposed to the interacting three-way climate-related abiotic factors. However, in vitro studies showed that AFB1 production was significantly stimulated (p < 0.05), especially when exposed to 1000 ppm CO2 at 0.98–0.95 aw and 35 °C, and sometimes in the 37 °C treatment group at 0.98 aw. The relative expression of the structural aflD gene involved in AFB1 biosynthesis was decreased or only slightly increased, relative to the control conditions at elevated CO, regardless of the aw level examined. For the regulatory aflR gene expression, there was a significant (p < 0.05) increase in 1000 ppm CO2 and 37 °C for both strains, especially at 0.95 aw. The in situ colonization of pistachio nuts resulted in a significant (p < 0.05) stimulation of AFB1 production at 35 °C and 1000 ppm CO2 for both strains, especially at 0.98 aw. At 37 °C, AFB1 production was either decreased, in strain AB3, or remained similar, as in strain AB10, when exposed to 1000 ppm CO2. This suggests that CC factors may have a differential effect, depending on the interacting conditions of temperature, exposure to CO2 and the level of water stress on AFB1 production.

Physiological and Biochemical Characterization of the GABA Shunt Pathway in Pea (Pisum sativum L.) Seedlings under Drought Stress

The physiological and biochemical role of the γ-aminobutyric acid (GABA) shunt pathway in green pea seedlings (Pisum sativum L.) was studied in response to soil water holding capacity levels: 80%, 60%, 40%, 20%, and 10% grown under continuous light at 25 °C for 7 days and 14 days, separately. Characterization of seeds germination pattern, seedlings growth (plant height, fresh and dry weight, and chlorophyll contents), GABA shunt metabolite (GABA, glutamate, and alanine) levels, total protein and carbohydrate levels, and oxidative damage (MDA level) were examined. Data showed a significant effect of drought stress on seed germination, plant growth, GABA shunt metabolites level, total protein and carbohydrate contents, and MDA level. A significant decline in seed germination percentage was recorded at a 20% drought level, which indicated that 20% of soil water holding capacity is the threshold value of water availability for normal germination after 14 days. Seedling fresh weight, dry weight, and plant height were significantly reduced with a positive correlation as water availability was decreased. There was a significant decrease with a positive correlation in Chl a and Chl b contents in response to 7 days and 14 days of drought. GABA shunt metabolites were significantly increased with a negative correlation as water availability decreased. Pea seedlings showed a significant increase in protein content as drought stress was increased. Total carbohydrate levels increased significantly when the amount of water availability decreased. MDA content increased slightly but significantly after 7 days and sharply after 14 days under all water stress levels. The maximum increase in MDA content was observed at 20% and 10% water levels. Overall, the significant increases in GABA, protein and carbohydrate contents were to cope with the physiological impact of drought stress on Pisum sativum L. seedlings by maintaining cellular osmotic adjustment, protecting plants from oxidative stress, balancing carbon and nitrogen (C:N) metabolism, and maintaining cell metabolic homeostasis and cell turgor. The results presented in this study indicated that severe (less than 40% water content of the holding capacity) and long-term drought stress should be avoided during the germination stage to ensure proper seedling growth and metabolism in Pisum sativum L.

Discrimination of water stress in pepper using thermography and leaf turgor pressure probe techniques

The use of technology is spreading rapidly in modern agriculture with remote sensing and sensor technologies becoming more important. The objective of this study is to investigate the possibilities of determining the water stress level and irrigation time in peppers using leaf pressure probes based on turgor pressure and thermography techniques. An experiment consisting of four different irrigation treatments (100%, 75%, 50% and 25%) was conducted in Canakkale province, Turkey in the 2017–2018 summer growing seasons. During this seasons, leaf turgor pressure (Pp) and soil moisture levels were recorded in real time by a remote monitoring system. Thermographic measurements were taken before each irrigation. Data were analyzed using the analysis of variance and regression tree methods. Results show that both Pp and thermal data significantly differed according to water stress. Pp values decreased partially after irrigation and increased until the next irrigation. However, it was observed that it is not enough to decide the irrigation time using results obtained from graphical readings only. Models including meteorological features strengthen the decision-making models. According to the classification and regression tree analysis, it was revealed that there is a potential to separate the treatments, especially in models including thermal indices. Leaf turgor pressure data and thermal indices, which are plant-based monitoring techniques, have the potential to be used in determining irrigation time and distinguishing water stress in the pepper plant. However, there is a need for more studies especially in laboratory conditions, to understand the mechanisms in plants and how environmental conditions affect the responses of Pp probes.

Integration of Visible and Thermal Imagery with an Artificial Neural Network Approach for Robust Forecasting of Canopy Water Content in Rice

A total of 120 rice plant samples were scanned by visible and thermal proximal sensing systems under different water stress levels to evaluate the canopy water content (CWC). The oven-drying method was employed for assessing the canopy’s water state. This CWC is of great importance for irrigation management decisions. The proposed framework is to integrate visible and thermal imaging data using an artificial neural network as a valuable promising implement for accurately estimating the water content of the plant. The RGB-based features included 20 color vegetation indices (VI) and 6 gray level co-occurrence matrix-based texture features (GLCMF). The thermal imaging features were two thermal indicators (T), namely normalized relative canopy temperature (NRCT) and the crop water stress index (CWSI), that were deliberated by plant temperatures. These features were applied with a back-propagation neural network (BPNN) for training the samples with minimal loss on a cross-validation set. Model behavior was affected by filtering high-level features and optimizing hyperparameters of the model. The results indicated that feature-based modeling from both visible and thermal images achieved better performance than features from the individual visible or thermal image. The supreme prediction variables were 21 features: 14VI, 5GLCMF, and 2T. The fusion of color–texture–thermal features greatly improved the precision of water content evaluation (99.40%). Its determination coefficient (R2 = 0.983) was the most satisfied with an RMSE of 0.599. Overall, the methodology of this work can support decision makers and water managers to take effective and timely actions and achieve agricultural water sustainability.

Assessment of achieving sustainable development of clean water and sanitation (SDG6) goals for the Srepok river basin

This paper presents the results of the assessment of achieving sustainable development of clean water and sanitation (SDG6) goals for the Srepok river basin by the research team at the Water Resources Institute (WRI). The assessment results of some key indicators including “Proportion of the population using safely managed drinking water services 6.1.1”, “Proportion of the population using safe managed sanitation services 6.2.1a”, “Proportion of bodies of water with good ambient water quality 6.3.2”, and “Proportion of transboundary basin area with an operational arrangement for water cooperation 6.5.2” are achieved at rather high levels (83-100%) compared with the target set by the United Nations for those in 2030. Moreover, the “Current progress of implementing integrated water resources management” (6.5.1) in Vietnam in general and the Srepok river basin in particular, is still slow, according to results obtained from using the questionnaire survey developed by UNEP, as 55% (high average level). In addition, the “Increasing level of water stress (indicator 6.4.2)” globally poses a challenge for each country and river basin in the process of implementing the goal to improve this issue.

Mycorrhizal mixtures affect the growth, nutrition, and physiological responses of soybean to water deficit

Drought stress has a negative impact on crop growth and productivity worldwide. Plant symbionts such as arbuscular mycorrhizal fungi (AMF) can enhance plant growth and improve plant resistance to drought stress. AMF mixture inocula and plant responses to drought still require further study. The objective of this study was to investigate the effects of non-inoculation (NM) or inoculation with three commercial AMF inocula containing a single or mixtures comprising different numbers of AMF species: M1 (Rhizophagus intraradices), M2 (Rhizophagus clarus, R. intraradices, Septoglomus deserticola, Funneliformis mosseae), and M3 (Rhizophagus intraradices, R. aggregatum, Funneliformis mosseae, Olaroideoglomus etunicatum) on growth, nutritional, and physiological responses of soybean (Glycine max L. cv. Hutcheson) grown in a greenhouse under different water stress levels [WW = well watered (90% FC), MS = medium (60% FC) and SS = severe stressed (30% FC)]. The AMF-inoculated plants had significantly higher plant biomass, chlorophyll content, stomatal conductance, leaf water relations, and mineral contents in comparison to NM plants. Applied mycorrhizal inocula differed in their response to water-deficit conditions. M2 inoculant generally supported greater plant biomass, stomatal conductance, leaf water content, and leaf N, P, K, S, Mn, and Cu contents than M1 and M3 inocula, especially under MS and SS treatments. These results indicated that all mycorrhizal inocula supported plant growth both generally and with soil water deficit; however, M2-inoculated plants performed better than M1 and M3 under drought stress. Therefore, mycorrhizal inocula are effective for supporting soybean growth and offsetting the effects of drought and AMF technology that can support sustainable crop cultivation under soil water-deficit conditions. Different types of inocula have different effects, however, and thus require testing for individual crops.

Urban environment and sustainable water supply: a comprehensive analysis of Darjeeling city, India

This article is an attempt to analyse the link between the condition of city environment and availability of water in Darjeeling city. Darjeeling, located in the Eastern Himalayan Region of India, is such a city which faces acute water scarcity in most part of the year, except during monsoon. The city cannot use ground water directly, and there is no river as source of water as well. It only uses spring water and rain water. The climatic condition and local environmental conditions have higher control over the availability of daily water. This article analyses the city’s 100-year climatic conditions as well as the condition of vegetation cover and built-up areas using NDVI and BUI methods, respectively. The present study explores that the deterioration of natural environmental conditions and increasing demand from both the permanent population and transitory population accelerate the intensity of water scarcity. Measuring the fluctuation of discharge (during pre-monsoon and post-monsoon period), the paper discusses how except in monsoon, most of the spring’s discharge gets reduced and increases the level of water stress in the city. Using quantitative methods, this empirical study explores that the loss of vegetation and haphazard constructions have enormous impact on the fragile hill ecosystem and reduce the rate of infiltration of water in the sub-surface zones, thus reducing the discharge ultimately. Therefore, the study recommends immediate actions to protect the city environment and to revive those springs for the city’s water security.

Nutrient Concentration of African Horned Cucumber (Cucumis metuliferus L) Fruit under Different Soil Types, Environments, and Varying Irrigation Water Levels

The nutrient concentration of most crops depends on factors such as amount of water, growing environment, sunlight, and soil types. However, the factors influencing nutrient concentration of African horned cucumber fruit are not yet known. The objective of the study was to determine the effect of different water stress levels, soil types, and growing environments on the nutrient concentration of African horned cucumber fruit. Freeze-dried fruit samples were used in the quantification of β-carotene and total soluble sugars. The results demonstrated that plants grown under the shade net, combined with severe water stress level and loamy soil, had increased total soluble sugars (from 8 to 16 °Brix). Under the shade-net environment, the combination of moderate water stress level and loamy soil resulted in increased crude protein content (from 6.22 to 6.34% °Brix). In addition, the severe water stress treatment combined with loamy soil, under greenhouse conditions, resulted in increased β-carotene content (from 1.5 to 1.7 mg 100 g−1 DW). The results showed that African horned cucumber fruits are nutrient-dense when grown under moderate water stress treatment on the loamy or sandy loam substrate in the shade-net and open-field environments.