Water Availability Conditions Research Articles

Performance evaluation of alternate wetting and drying irrigation for rice cultivation

An experiment was conducted during the 2009-2010 Boro season at the Shahjalal Science and Technology University campus, Sylhet, Bangladesh, to investigate the impact of alternate wetting and drying irrigation (AWDI) on rice production. Using a randomized complete block design (RCBD), four irrigation treatments were applied to a modern variety (MV) of rice (BRRIdhan 28). One control treatment, T0, maintained a continuous standing water depth of 1-5 cm. Water was irrigated to three AWD treatments, T1, T2, and T3 when the water level dropped 10, 20, and 30 cm below ground level, respectively. In spite of the fact that treatment T0 produced the highest grain yield (4.90 t/ha), its water use efficiency was 38.64 kg/ha/cm. Compared to treatment T1, which produced 4.68 t/ha, treatment T1 had a water use efficiency of 41.86 kg/ha/cm. Treatments T2 and T3 yielded 3.96 t/ha and 3.63 t/ha, respectively. When water levels fall below 10 cm below ground level, treatment T1 may be the best option for rice cultivation in conditions of limited water availability.

Impact of Source, Sink Manipulation on Sunflower Yield Physiology under Different Water Availability Conditions

Impact of Source, Sink Manipulation on Sunflower Yield Physiology under Different Water Availability Conditions

Projected changes in heatwaves and its impact on human discomfort over India due to global warming under the CORDEX-CORE framework

Due to climate change, rapid warming and its further intensification over different parts of the globe have been recently reported. This has a direct impact on human health, agriculture, water availability, power generation, various ecosystems, and socioeconomic conditions of the exposed population. The current study thus investigates the frequency and duration of heatwaves, human discomfort, and exposure of the human population to these extremes using the high-resolution regional climate model experiments under two Representative Concentration Pathways (RCP2.6, RCP8.5) over India. We find that more than 90% of India will be exposed to uncomfortable warm nights by the end of the 21st century with the highest rise over western India, Madhya Pradesh (MP), Uttar Pradesh (UP), Punjab, and the Haryana region. States like Odisha, Chhattisgarh, eastern parts of MP and UP, and some parts of J&K will be the worst hit by the intense and frequent heatwaves and human discomfort followed by the densely populated Indo-Gangetic plains under RCP8.5. Strict enforcement of the stringent policies on stabilization of population growth, improvement of local adaptive capacities, and economic status of the vulnerable population along with enforcing effective measures to curb greenhouse gas emissions are important to reduce human exposure to future heat stress. We demonstrate that a proper mitigation-based development (RCP2.6) instead of a business-as-usual scenario (RCP8.5) may help to reduce 50–200 heatwave days, 3–10 heatwave spells, and 10–35% warm nights over the Indian region. Consequently, this can avoid the exposure of 135–143 million population to severe discomfort due to extreme heat conditions by the end of the 21st century.

Effect of scheduling of irrigation on yield and economics of safflower genotypesunder limited water availability conditions

A field experiment was carried out to find out the effect of irrigation schedules for a suitable variety of safflower (Carthamus tinctorius L.) using 3 genotypes and seven irrigation schedules.. The seed yield of safflowerwas significantly influenced by safflower genotypes. The seed yield of safflower was significantly higher in DSH 184 (1253 kg /ha) which was followed by TSF-1 (1123 kg /ha). While NARI-6 recorded the lowest yields (972 kg /ha). The seed yield of safflower differed significantly due to the application of irrigation at critical stages of the crop. The crop received 3 irrigations each at the Stem elongation stage + Early flowering stage + Seed filling stage resulting in significantly superior yields (1489 kg/ha) which was followed by 2 irrigations each at the Stem elongation stage + Early flowering stage (1408 kg/ha) and 2 irrigations each at the Stem elongation stage + Seed filling stage (1303 kg/ha). Crop grown completely under rainfed conditions recorded the lowest yield (776 kg/ha). The seed yield increased up to 47.88% by providing 3 irrigations each at Stem elongation, Early flowering and Seed filling stages as compared to rainfed conditions.

Drought’s Impact on Growth and Strategies to Mitigate its Effects on Potato Cultivation: A review

The potato is the third most widely produced cereal in the world, behind rice and wheat. The contemporary potato is vulnerable to yield loss in prolonged droughts. Droughts are becoming more severe and common as a result of global warming. Because of its shallow root system, potatoes are easily parched. The occurrence of drought and water shortage has substantial ramifications for the production of potatoes, exerting influence on both the volume and quality of potato harvests. Potatoes are a crop that needs a substantial amount of water, since they rely on a regular and sufficient water supply during their whole growth cycle. The presence of drought conditions or limited water supplies might result in many adverse consequences for the cultivation of potatoes. Potato plants are susceptible to experiencing stunted growth and development as a direct result of the water stress that is brought on by drought conditions. The restricted supply of water adversely affects the absorption of vital nutrients by plants, resulting in imbalances and deficits in nutritional levels. These conditions may lead to inhibited development, diminished leaf surface, and a lower quantity of tubers. Water stress circumstances have a considerable negative impact on the total production potential of potato crops. Moreover, the phenomenon of water shortage has a significant impact on the physiological mechanisms of potato plants, specifically in relation to essential functions like photosynthesis and transpiration. A scarcity of water during the tuber bulking phases might lead to a reduction in potato size, hence impacting its commercial worth. The use of effective irrigation systems, such as drip irrigation or precision sprinklers, has the potential to optimize water usage and minimize losses resulting from evaporation. The use of water conservation methods and the adoption of drought-resistant potato cultivars are crucial solutions for mitigating the effects of water shortage on potato farming. Through the use of these procedures, farmers have the ability to augment the resilience of their potato crops and guarantee the attainment of sustainable production, even when faced with conditions of low water availability.

Farmers’ perspectives on water availability in the lower Volta Delta region in Ghana

Smallholder farmers in the lower Volta Delta of Ghana operate in a risky and uncertain context due to water scarcity. However, the conventional analyses of water availability have mainly focused on drought, rainfall occurrence, and other climatic or weather elements, using secondary biophysical data with relatively little emphasis on farmers’ perceptions and how socioeconomic factors contribute to the vulnerability of farming in the lower Volta Delta. This study examines farmers’ perceptions of vulnerability to water availability to determine how perception is socially constructed and differentiated in various locations. The study was conducted using qualitative research methods in the Ada East, Ada West, South Tongu, and Anloga Districts in the lower Volta Delta of Ghana. Findings reveal that climate is not the only stressor on livelihoods in the area. Farmers perceive their livelihoods as vulnerable to socioeconomic stressors, including limited freshwater and groundwater resources. The perceived severity of water availability conditions determines farmers’ response strategies, such as crop selection, planting dates, irrigation strategies, and other agronomic practices. These findings have important implications for researchers, agricultural extension agents, and policymakers to design appropriate measures and approaches to deal with water scarcity for farming in the region. The study also contributes valuable insights into the loss and damage incurred by farmers due to climate change and variability in the region.

Irrigation in Jatropha curcas L. cultivation and its effect on biomass for bioenergy generation

The use of biomass as a source of bioenergy has intensified in recent years and has gained strength in replacing fossil fuels and their derivatives. Jatropha curcas L. oil is currently used as a raw material for the production of biodiesel through the physical extraction of the fruit, generating a large amount of waste. The heterogeneity characteristics of these materials impose the need for thermal pre-treatments for their recovery, such as torrefaction. Thus, this study aimed to investigate the biomass of Jatropha curcas as affected by water availability and its response to the torrefaction process. This research analyzed the biomass physical, chemical, and energy characteristics. TGA/DTG evaluated the thermo-degradation profile, and infrared spectroscopy (FTIR) determined the aromatic chemical structure. The fresh biomass of epicarp and cake presented different behaviors regarding water availability conditions, as variations in lignin contents from 29% to 2.7% and 30.9%–5.7%, respectively, and extractive range from 45.3% to 19.8% and 44.6%–21.6%, respectively. Torrefaction contributed to the increase in physical-chemical characteristics such as lignin and fixed carbon levels, from 29% to 82.4% and 19.8%–52.7%, respectively, and net calorific value of biomass, valuing them for energy use, as well as to decrease in the content of volatile materials from 80.7% to 71.8%. Using renewable biomass of Jatropha curcas cake and epicarp for energy purposes contributes to the reduction of environmental impacts by reducing the disposal of these residues in the environment, providing a sustainable and more efficient destination.

Leaf and wood functional traits explain the strategies developed by Byrsonima sericea (Malpighiaceae) to survive in Atlantic Forest ecosystems under water and light variations

The Atlantic Forest is a heterogeneous biome comprised of different phytophysiognomies with contrasting microclimatic and edaphic characteristics, such as sandbanks and forests. Sandbanks are ecosystems with low water availability and high irradiance, requiring leaf and wood specific adjustments from species to survive. On the other hand, tropical rain forests lack a pronounced dry season, providing enough resources to allow competition from light-demanding trees and sustaining a spectrum of shade tolerance for understory species. To better understand how functional traits are determined, it is necessary to evaluate variables that are site-specific, i.e. that are displayed within an organism in different environments. We aimed to assess how does variation in the functional traits of the leaf and wood of Byrsonima sericea influence the survival abilities of this species to thrive under contrasting scenarios of light and water availability. Also, which set of morpho-anatomical and physiological traits are considered to be site-specific responses that are affecting positively the capacity of the species to adapt in these contrasting scenarios of the Atlantic Forest? The high irradiance in sandbank shaped functional traits of B. sericea leaves that allowed an allocation strategy of the available resources, with investment in leaf mass rather than in trunk biomechanics and hydraulic efficiency. The higher leaf density through smaller and numerous cells along with higher stomatal density and area, facilitating CO2 diffusion, were associated with a greater photosynthetic capacity and greater intrinsic water use efficiency. As in the forest, light is a limiting factor for species to grow, the fluctuating light over a short timescale can influence whole plant performance, thus requiring an investment in trunk biomechanics. Additionally, a set of wood traits in the forest was related to water availability favoring wider vessel elements with thicker walls, increasing the theoretical hydraulic conductivity, even though it implicated a higher vulnerability to cavitation. Our study has demonstrated that variation of traits of different plant structures, such as the leaf and wood, within a species has direct implications in the survival strategies at each environmental conditions of light and water availability. It is also stated that there are different sets of functional traits which are responsible for allocation strategies, leading to specific trade-offs that allow the species to display site-specific responses in order to survive.

Taxonomic and functional characteristics of xerotolerant culturable bacterial community of Negev desert soil

Despite the significant expansion of the geography of soil microorganisms studies in various, including extreme natural environments, research on the biodiversity and metabolic activity of soil microbial communities under conditions of moisture deficiency are few. Biodiversity of culturable bacteria isolated from the surface horizon of the Negev desert soil (Aridic Calcisol) after pre-incubation of soil samples under the conditions of low water availability has been studied. An increase in the diversity of culturable bacteria after pre-incubation was revealed in comparison with the community isolated from the native soil. From the native and pre-incubated samples, 153 phenotypically unique pure cultures of bacteria from 22 genera belonging to the phyla Actinomycetota, Pseudomonadota, Bacillota, and Bacteroidota were isolated and identified. The taxonomic diversity of culturable bacteria isolated from the sample pre-incubated at a water activity (Aw) of 0.90 was two times higher than that obtained from the native soil. The strain of the genus Pedobacter has been identified, which may be a representative of a previously undescribed bacterial species. Bacteria of the genera Aerococcus, Bacillus, Brevibacterium, Staphylococcus, and Stenotrophomonas capable of growing at Aw 0.91 were found. One strain of the genus Microlunatus has been identified that is capable of growing on a nitrogen-free medium, exhibiting amylase and protease activity, and capable to growth on a medium with Aw down to 0.96. The obtained results confirm the hypothesis that arid ecosystems, in particular, desert soils and sediments, are a depository of a previously unexplored taxonomic diversity of bacteria with unique physiological properties that are promising for study and potential implementation in biotechnological processes.

Water use strategies of Nitraria tangutorum in the lake-basin region of the Badain Jaran Desert.

Information regarding plant water-use strategies is essential for understanding the hydrological processes and plant survival adaptation mechanisms in desert lake basin regions. To examine the water use strategies of plants in desert lake basin areas, water uptake patterns, water use efficiency, and water potential of Nitraria tangutorum were investigated at different distances from the lake duringhe growing seasons in the lake basin regions of the Badain Jaran Desert. The results indicate that N. tangutorum primarily absorbed groundwater in May (63.8%) and August (53.5%), relied on deep soil water in June (75.1%), and uniformly absorbed soil water from different layers in July. These observations could be explained by periodic fluctuations in the groundwater level and the consequent decrease in soil water availability, as well as plant root adjustments. As soil water availability decreases, N. tangutorum adapts to water variation by increasing its water use efficiency (WUE) and reducing its leaf water potential (Ψ). With intensified water stress, N. tangutorum gradually shifted from adventurous anisohydric regulation to conservative isohydric regulation. Thus, N. tangutorum responds to diverse degrees of environmental changes by altering its water-use strategy. A better understanding of the adaptive water use strategies developed by desert plants under varying water availability conditions provides insight into the diversity of species' reactions to long-term drought and quantifies the hydrological cycle of desert ecosystems against the background of worldwide climate warming.

Narrow root cone angle promotes deeper rooting, cooler canopy temperatures and higher grain yield in a rice (Oryza sativa L.) recombinant inbred line population grown under different water availabilities in aerobic production systems

Rice crops are one of the world’s major consumers of irrigation water. With water becoming more limited, water-saving aerobic production (AP) systems may provide an alternative to traditional flooded culture. Genotypes with narrow root cone angle (RCA) and subsequently deeper rooting systems are hypothesised as key for AP adaptation ensuring water uptake at depth. Using a recombinant inbred line (RIL) population and differential genotypes (narrow and wide RCA groups) derived from a Sherpa/IRAT109 cross, a glasshouse experiment and four field experiments with different water inputs in well-watered (WW, in two seasons), mild water deficit (MWD), and intermittent water deficit (IWD) conditions were carried out to characterise the relationship of RCA with grain yield (GY) and key physiological traits. Significant genotypic variation and group differences were found in root traits, canopy temperature and GY. Expression of genotypes with narrow RCA were found to be consistent across experiments and water availability conditions. Genotypes in the narrow RCA group produced a greater proportion of roots below 20 cm (7.4–17.7%), longer total root length (69.7%), cooler canopies (0.3–1.0 °C) and higher GY (14–62%) compared with wide RCA group. Two promising RILs were identified which expressed high GY in WW (12.0–13.4 t/ha) conditions while maintaining GY in IWD (up to 9.4 t/ha). Higher GY was obtained in genotypes with cooler canopies (r = −0.72) and narrow RCA (r = −0.39) in IWD. Narrower RCA was associated with higher total root length (r = −0.70) and higher stomatal conductance (r = −0.71) in the glasshouse and proportion of deep roots (r = −0.65) and cooler canopies (r = 0.66) in the field. To our knowledge, this was one of the foremost studies exploring and demonstrating such relationships in rice AP systems. Root traits determined in the field were congruent with the other root-related traits driving differences between RCA groups measured in the glasshouse providing confidence with the field phenotyping methods. This work demonstrated the advantage conferred by the development of narrow RCA in aerobic conditions, presented improved physiological understanding of RCA and with genomics assisted breeding, is considered valuable for the development of AP-adapted, sustainably produced rice.

Comparative Analysis of Growth and Physiological Responses of Sugarcane Elite Genotypes to Water Stress and Sandy Loam Soils.

Stumpy irrigation water availability is extremely important for sugarcane production in Pakistan today. This issue is rising inversely to river flow due to inadequate water distribution and an uneven rainfall pattern. Sugarcane growth faces a shortage of available water for plant uptake due to the low water-holding capacity of sandy loam soil, particularly under conventional flood irrigation methods. To address this problem, sugarcane clones were evaluated for their agronomic and physiological traits under conditions of low water availability in sandy loam soil. Ten cane genotypes, HSF-240, SPF-213, CPF-249, CP 77-400, S2008-FD-19, S2006-US-469, S2007-AUS-384, S2003-US-633, S2003-US-127, and S2006-US-658, were exposed to four levels of water deficit created through skip irrigations. These deficit levels occurred during the 9th, 11th, 13th, and 16th irrigations at alternate deficit levels between 2020 and 2022. Physiological data were collected during the tillering and grand growth stages (elongation) in response to the water deficit. The sugarcane clones S2006-US-658, S2007-AUS-384, and HSF-240 exhibited resistance to low water availability at both the tillering and grand growth stages. Following them, genotypes S2006-US-658, S2007-AUS-384, and HSF-240 performed better and were also found to be statistically significant. Clones susceptible to water deficit in terms of growth and development were identified as CP 77-400, S2008-FD-19, S2006-US-469, and S2003-US-633. These genotypes showed reduced photosynthetic rate, transpiration rate, stomatal conductance, relative water content, cane yield, and proline content under stressed conditions. Therefore, genotypes S2006-US-658, S2007-AUS-384, and HSF-240 were better performers concerning physiological traits under water deficit and sandy loam soil in both years. Moreover, a significant positive correlation was assessed between agronomic traits and photosynthetic rats. This study highlights that sugarcane can sustain its growth and development even with less irrigation frequency or moisture availability, albeit with certain specific variations.

Anatomical and isotopic traits in grapevine wood rings record environmental variability

Summary In the Mediterranean region, prolonged droughts affect the growth and reproductive cycles of grapevine. Changes in the physiological processes of grapevine, consequent to variations in environmental factors or cultivation management, are recorded in wood anatomical and isotopic traits in grapevine stems. In this study, we measured the anatomical traits and stable carbon isotope content in the annual rings of Vitis vinifera L. subsp. vinifera ‘Falanghina’ in four vineyards located in southern Italy, characterised by different water availability. The aim was to investigate how wood anatomical traits respond to interannual climatic variations according to local conditions. Wood cores were taken from the stem of the grapevines and subjected to both microscopy and carbon stable isotope analyses to quantify functional wood anatomical traits, such as vessel size and frequency, and the intrinsic water-use efficiency of the grapevine. Wood traits were correlated with data on precipitation and temperature. The results showed that the plants at the four vineyards were characterised by differences in wood structure influencing the grapevine’s physiology under different conditions of water availability. Overall, the analyses showed that the grapevines at the wetter sites developed wood traits, e.g., wide vessels, which favour the efficiency of water flow, while at the drier sites, they developed plant traits, e.g., small vessels, which favour safety against embolism. However, the robustness of such main trends is trait-specific and is influenced by interannual climatic variability.

Climate-smart forestry in the world’s drylands: A review of challenges and opportunities

Land degradation and desertification are widespread across the world’s drylands. These processes are substantially affected by climatic change, with long-term and severe droughts on the one hand, and high intensity rainstorms and devastating floods on the other hand. Simultaneously, land-use change and mismanagement practices have led to processes of accelerated soil erosion, depletion of soil organic carbon pools, and the degradation of extensive drylands. Forestry has been accepted as an effective means for restoring degraded drylands, and for attaining a range of regulating, provisioning, supporting, and cultural ecosystem services. Specifically, forestry is widely perceived as an effective means for soil erosion control, organic carbon sequestration, microclimate improvement, and climate change mitigation. However, forestry in drylands often proves to generate substantial environmental challenges, resulting in deterioration of ecosystem functions and health. The objective of this essay is to review the challenges and opportunities induced by dryland afforestation and reforestation, and highlight the need to attain climate-smart strategies for establishing and managing these land-uses. Particularly, tree species invasion and allelopathy, which are common in dryland forestry projects, jeopardize species richness and diversity of native vegetation communities. Further, the challenges linked with tree invasiveness necessitate predicting the distribution of potentially invasive species and foreseeing their impacts on the recipient ecosystems under projected climate change scenarios. The effect of allelopathy is significant under limited water availability conditions and is expected to be determined by the expanding drylands and intensifying aridity worldwide. Therefore, judicious selection of tree species should not only focus on ones with high water-use efficiency, low flammability, high pest resistance, and fast growth, but also on low invasiveness and allelopathic capacities. Insights of this essay may be used by land managers, stakeholders, and policy makers involved in environmental development of drylands.

Biometric and morphological adjustments of Eugenia. dysenterica DC. seedlings in response to increased soil water deficit

Water stress can affect all aspects of plant growth and development, compromising its productive potential. The cultivation of fruit species native to the Cerrado and the study of their behavior under conditions of low water availability are necessary activities, in view of their socioeconomic and environmental potential. This study was conducted to evaluate the effect of water deficit on growth and biomass production of the cagaita tree (Eugenia dysenterica DC.), a species endemic to the Cerrado (Brazilian Savannah). The experiment was performed in a greenhouse for 120 days in a randomized block design (RBD), with a double factorial arrangement (2x5), corresponding to two cagaita mother plants and five water conditions. We evaluated the growth and leaf, stem and root functional characteristics. The most severe water deficit conditions reduced shoot growth, number of leaves, production of biomass and dry matter and increased the specific and per plant mass root length of cagaita plants. Deficit extension had negative effects on its growth and development. There was a statistical difference between mother plants, with mother plant 2 being more resistant to drought. The application of a severe or longer water deficit affected shoot growth and reduced the appearance of new leaves. The stress caused by water deficiency allowed an increase in root functional characteristics, supporting the hypothesis that plants under adverse conditions focus on higher biomass production and convert a higher amount of dry matter into the roots. Leaf area did not show to be a functional characteristic, explaining the stress effects in E. dysenterica DC plants.

Water, sanitation, and hygiene practices among rural households and related health impacts: a case study from some North Indian villages

Abstract The present study was carried out to assess the water availability, hygiene practices, and sanitary conditions in the households of open defecation-free (ODF) villages after achieving ODF status. Monitoring was conducted from 360 households of 9 ODF villages from 3 blocks of the Kurukshetra district of north India, using a questionnaire. The results interpreted that 78.33% of the surveyed population were using water supplied from government borewells and 65.55% of respondents agreed that their water is safe for drinking as they did not have any water-related diseases. Many respondents (57.2%) replied that someone in their family had suffered from waterborne disease in the preceding year. About 42.8% of households were treating their drinking water at the house level through methods like boiling, chlorination, and reverse osmosis systems. 90.8% of respondents said that they have access to a functional latrine facility. However, 5% population responded that they still prefer fields for open defecation (OD). Logistic regression results showed that the presence of garbage or litter and stagnant water near the household were associated with an increased risk of disease occurrence among the households. The findings suggested that people should maintain good sanitation and hygiene in their household surroundings to avoid health problems.

Vanilla insignisAmes. (Orchidaceae): morphological variation of the labellum in Quintana Roo, Mexico

AbstractThe shape of the flower can vary based on the type of pollinator or the environment in which the plant develops. InVanilla insignis, there are no studies that analyse the shape of the labellum of the flower as has been done inV. planifolia. Therefore, the study aimed to determine the variation in the shape of the labellum ofV. insignisthrough a morphometric analysis in different environmental conditions in the state of Quintana Roo, Mexico. The results showed that there were significant differences in the variables analysed. Principal component analysis and dendrogram analysis reveal that fourV. insignismorphotypes were possibly associated with soil water availability conditions because there were significant differences between the variables that define the apical region. In addition, the distribution of the morphotypes corresponded with the presence of humidity regardless of geographical distances such as in the populations of Tenampulco, Puebla and Caobas, Quintana Roo. The presence of these morphotypes allows the development of conservation programmes and genetic improvement of the species ofV. insignisand related commercial species.

Impacts of climate change on streamflow in the McKenzie Creek watershed in the Great Lakes region

Introduction: This study explored streamflow dynamics of the McKenzie Creek watershed in Southern Ontario, Canada under a changing climate. The Creek is located in the southern portion of the Grand River watershed in the Great Lakes region and is an important water and ecosystem service provider for the Six Nations of the Grand River reserve, the largest (by population) Indigenous community in Canada and the fourth largest in North America.Methods: The Coupled Groundwater and Surface-Water Flow Model (GSFLOW) was used to simulate streamflow from 1951 to 2020 using observed gridded meteorological data from Natural Resources Canada (NRCANmet) and in situ data from Environment and Climate Change Canada (ECCC). Downscaled data from the Coupled Model Intercomparison Project Phase 5 (CMIP5) for two Intergovernmental Panel on Climate Change (IPCC) Representative Concentration Pathways (RCP) climate warming scenarios, RCP 4.5 and RCP 8.5 were used to run GSFLOW for the historic (1951–2020) and projected (2021–2099) period.Results: Results suggested that streamflow in the McKenzie Creek will be significantly impacted by climate change in winter months when streamflow is projected to increase due to higher temperatures causing early melting of snowpack and increasing winter precipitation. Consequently, spring streamflow is expected to decrease and little or no change in streamflow in the summer and autumn. These changes in streamflow dynamics may lead to more flooding incidents in the winter, while at the same time, the region may face reduced water availability or dry conditions in late spring and summer due to warm temperatures.Discussion: This study provides important information about streamflow and hydrologic dynamics of this watershed that will help managers and planners to better manage water resources and be prepared to deal with climate change and its impacts on water availability and security not only for the Six Nations area but also for Southern Ontario which houses one-third of Canada’s population.

Hydric Behavior: Insights into Primary Metabolites in Leaves and Roots of Cabernet Sauvignon and Grenache Grapevine Varieties under Drought Stress

The classification of grapevine cultivars into isohydric and anisohydric categories depends on their ability to close stomata under conditions of low soil water availability or high atmospheric demand. This study aimed to compare the responses of Grenache, classified as isohydric, and Cabernet Sauvignon, classified as anisohydric, both grafted onto Richter 110 rootstock, and subjected to severe drought stress. Three cycles of drought stress were applied, followed by watering, while a well-watered treatment served as the control. Stomatal conductance and stem water potential were measured at predawn and midday during the drought cycles, and primary metabolites were analyzed in leaves and roots using gas chromatography. We found that Grenache had significantly higher stomatal conductance than Cabernet Sauvignon under both well-watered and water-stressed conditions. There were no significant differences in stem water potential between the two varieties, but the control treatment maintained a higher stem water potential at predawn and midday for both varieties. Primary metabolite analysis showed that both varieties accumulated sugars and polyols in their leaves and roots under drought stress, while organic acids were more abundant in leaves than in roots. Overall, the results suggest that the hydric behavior of grapevines depends on the intensity and duration of drought stress. In this study, both varieties exhibited near-isohydric behavior by regulating stomatal closure under drought stress. The metabolites identified in this study may serve as potential biomarkers of water drought stress in Grenache and Cabernet Sauvignon grapevines under the conditions of this experiment.

Water Availability and Status of Wastewater Treatment and Agriculture Reuse in China: A Review

Due to climate change, 2/3 of the world’s population will face water shortage problems by 2025, while a 50% increase in food production is required in 2050 to feed nine billion people. In addition, the intensified anthropogenic activities have significantly increased water resource pollution. In this condition, wastewater reuse for crop irrigation to reduce water scarcity is currently becoming global, while it often causes soil pollution and heavy metal accumulation in agricultural areas. This situation has increased public concern over its environmental impact. Thus, an integrated framework was conducted to discuss the status of water availability in China, wastewater treatment and reuse in irrigation systems, and the potential health risks. Avenues for new research toward sustainable agriculture were discussed. We emphasize that wastewater reuse reduces the freshwater deficit and increases food productivity. However, adequate treatment should be applied before use to reduce its adverse impacts on human health risks and environmental pollution. Facilities and policies should support more accessible access to reclaimed water used in industries and urban facilities from secondary municipal wastewater treatment plants. This could be a long-term solution to eradicate water scarcity and inefficient water resources in agricultural systems.