Reduce Water Stress Research Articles

The use of hydrogel reduces water stress and improves yield in the cultivation of purple corn

One of the problems in agriculture today is the scarcity of water available for crops. The aim of the research was to evaluate the use of a hydrogel (plantagel with a composition of 96% non-toxic potassium polyacrylate) in the water stress of the PMV-581 purple corn crop and evaluate its development and performance. The treatments were at three doses of 50, 70, 90 kg ha-1 of hydrogel (plantagel) and a control without hydrogel application, the results indicate the T0 control treatment. Treatment T1 (with 12 irrigations and 50 kg ha-1 of hydrogel) and T2 (with 10 irrigations and 70 kg ha-1 of hydrogel) require the greatest number of irrigations (with 15 irrigations and without hydrogel application) and T3 (with 8 irrigations and 90 kg ha-1 of hydrogel) T3 obtained the highest yield of 6.50 t ha-1, with a water table of 1500.84 m3, lower than the rest of the treatments, concluding that the Hydrogel influences soil moisture retention and its effect is expressed in the yield of purple corn. These results provide valuable information that the use of hydrogel (plantagel) could be effectively applied as a soil additive to alleviate drought stress in purple corn cultivation.

ІННОВАЦІЙНІ СТРАТЕГІЇ АДАПТАЦІЇ АГРАРНИХ ПІДПРИЄМСТВ ДО ВУГЛЕЦЕВОГО ЗЕМЛЕРОБСТВА В КОНТЕКСТІ ЄВРОПЕЙСЬКОГО ЗЕЛЕНОГО КУРСУ

The article examines innovative strategies for adapting agricultural enterprises to carbon farming in the context of the European Green Deal. The authors argue that the transition from traditional agriculture to carbon farming requires a profound and systematic transformation in the agricultural sector. This process involves the implementation of various technological, economic, and managerial changes to reduce greenhouse gas emissions and increase carbon sequestration. Technological changes are fundamental for carbon farming and include the use of advanced land cultivation methods, such as no-till or precision farming, which minimize soil disturbance and help retain carbon in the soil. An important element is also the implementation of crop rotations, which contribute to biodiversity preservation and the increase of organic matter content in the soil. It is substantiated that the use of drip irrigation and other water-saving technologies allows for more efficient use of water resources, reducing water stress and increasing crop resilience to climate change. Economic measures include the introduction of economic incentives and market mechanisms that encourage farmers to transition to carbon farming. It is proven that the increasing attention to products grown using sustainable technologies can stimulate demand for such products, which in turn motivates farmers to adopt more environmentally friendly production methods. This allows farmers to earn from measures that reduce greenhouse gas emissions and increase carbon sequestration, implementing advanced technologies such as precision farming or methods that minimize soil disturbance.

Management of surface flow allocation in rice cultivation by maximization of water use and economic efficiency

Abstract The multi-objective genetic algorithm was used as a decision variable to estimate the water required for irrigation in each of the growth stages. Agricultural costs and product sales prices in the agricultural year 2017–2023 in Luoyang Plain and its surrounding areas were collected for this purpose. Optimal irrigation strategies according to different water price scenarios were considered to calculate water use efficiency and net profit. In the conditions of optimal distribution, the amount of allocated water was 7,809, 2,928, 3,904, and 1,789 m3/ha for the stages of vegetative growth, flowering, crop formation, and ripening by the proposed model. On the other hand, it is necessary to reduce water stress in the periods of clustering and seed filling to increase crop yield and net income, as well as to achieve the desired irrigation schedule. Effective rainfall, especially in the ripening stage of the crop, can be considered to determine the optimal volume of water harvesting from the river. In addition, the results showed that by reducing the amount of available water, the water model allocated to leaf greening and tillering stages decreases.

Fall/winter cover crop roots change soil hydrology to control the drought status of subsequent season summer maize in Ultisol

Climate change has increased drought frequency, necessitating strategies to reduce water stress, increase water use efficiency, and improve agricultural productivity. The impacts of different fall/winter cover crops on alleviating maize drought in the subsequent season by changing soil water content remain unclear in Ultisol. Our aim was to investigate whether different fall/winter cover crops (taproot and fibrous root) can improve soil water content to attenuate subsequent season maize drought and its underlying mechanism. This research compared four fall/winter cover crops (2 rapeseed cultivars, lucerne and vetiver) and fallow control (no cover crop in winter) to investigate their root traits, root effect on subsequent season soil water content (SWC), soil drought degree (D), maize leaf and root water potential (Ψl, Ψr), maize crop water stress index (CWSI), and maize growth components (aboveground plant and root parameters) in 2019 (a dry year), 2021 (a normal wet year), and 2022 (a severe dry year). The fibrous-rooted vetiver displayed higher average root diameter and higher average root length density, leading to increased SWC (17%, 15%, 15%), and lower D values in all three years. Additionally, it exhibited a more substantial gradient between Ψl, and Ψr and lower CWSI than taproot (rapeseed cultivars and lucerne) and fallow treatment. Furthermore, the cover crop treatments enhanced the gradient between maize Ψl and Ψr to varying degrees in different drought years. Ultimately, the improvement in SWC resulting from cover crop treatments increased maize aboveground growth (plant height, stem diameter, and leaf area) and maize root development, ultimately improving maize yield. This study introduces a new perspective on investigating the role of cover crops in alleviating seasonal drought in subsequent crops, especially by changing soil water properties in the subtropical climate.

Microbial inoculants for drought stress tolerance

Temperature, rain, humidity, wind, and solar radiation are all climatic factors that affect agricultural activities. While some agricultural areas of the world are irrigated, the vast majority rely on natural rainfall patterns. Farmers will consume more water as a result of climate change and experience less water availability, resulting in a decrease in production capacity. As one of the most important natural phenomena affecting agricultural productivity, drought is a limiting environment for plant growth. Bacteria have been shown to reduce water stress in these plant species and promote greater growth by regulating gene expression and the integration of hormones. Phytohormones modulation, stress-induced enzymatic apparatus, and metabolites are integrated into the root-to-shoot phenotypic changes in growth rate, architecture, hydraulic conductivity, water conservation, plant cell protection, and damage restoration. By demonstrating how plant growth-promoting bacteria can mitigate plant stress and provide examples of technology conversion in agroecosystems, this review illustrates how water stress can be mitigated.

Effect of Irrigation, Phosphorous and Potassium Application on Root Traits, Soil Microbial Growth and Physiology of Green Gram

Aims: To manage the implication of irrigation water at different growth stages coupled with basal phosphorus and foliar potassium application targeting to reduce water stress.
 Study Design: Split split-plot design.
 Place and Duration of Study: Agricultural Research Station, Chatabar, Odisha. India, during 2022-2023 cropping season.
 Methodology: Three irrigation treatments in main plots (I1, I2 and I3) - I1 included three irrigations at vegetative, flowering and pod formation periods, I2 skipped one irrigation at pod formation and I3 skipped at flowering. Sub-plot consisted of phosphorus fertilizer treatments (P1, P2 and P3) providing 100, 85 and 115% recommended dose of P. In sub sub-plots- 2% foliar spray of KCl at vegetative and flower initiation periods. The parameters recorded soil moisture depletion, root traits, microbiological parameters, plant physiological parameters and grain yield.
 Results: The depletion of soil moisture increased with crop growth; I3 depleted at a maximum rate (4.5 mm d-1) followed by I2 (4.1 mm d-1). The enhanced availability of root zone soil moisture improved microbial biomass carbon (MBC) and dehydrogenase activity (DHA). The I1 improved the maximum root tips, forks and crossings; while I3 reduced an overall of 131% of the root traits than I1. The crop growth rate (CGR) and leaf area index (LAI) were also improved according to soil moisture availability; however, I2 merely decreased 8 and 13% in CGR and LAI as compared to I1. P3 improved the maximum of the soil microbiology (MBC and DHA), root improvement and plant physiology. I1P3 produced the highest grain yield of 9.06 q ha-1, although, I2P3 produced was just 7% lower than I1P1.
 Conclusion: The application of three irrigation produced maximum grain yield; while the skipping of one irrigation at pod formation stage with 15% higher P application could provide satisfactory yield where availability of irrigation water is limited.

Integrative effect of activated biochar to reduce water stress impact and enhance antioxidant capacity in crops

Biochar is a soil amendment that can change soil's physical and hydraulic properties. However, biochar application is far from being a ‘one size fits-all’ approach. The impact of the management practices is dependent on biochar type (feedstock and production conditions), application depth and method, climate and site characteristics. Hence, this study aims to enrich the available inconclusive information on how biochar could affect clay loamy soil and to assess the potential impact of the induced change on water stress mitigation of rain-fed durum wheat under the specific condition of the semi-arid environment of North West of Tunisia. A field experiment was investigated in which three biochar rates 0 (B0), 10 (equivalent to 0.5% of weight) (B1) and 20 t/ha (equivalent to 1% of weight), (B2), were tested. Other laboratory analysis allowed the evaluation of soil water retention curve (SWRC), saturated hydraulic conductivity (Ks), dry density (ρb) and biostress biomarkers such as glutathione-S-transferase (GST), catalase activities (CAT) and malondialdehyde content (MDA) as well as yield attributes. Results showed that treatment B2 significantly decreased ρb and Ks with relative change values of about −3.1% and −19%. Consequently, SWRC showed a better water retention capacity, mostly from saturation to matric potential value (h) of 33 kPa. Total (TAWC), plant (PAWC) and readily (RAWC) available water contents, significantly increased under B2 with relative changes of +6%, +44% and +44% respectively. Moreover, GST and CAT were also boosted under B2. Consequently, biological and grain yields as well as grain water use efficiency (GWUE) significantly increased. GWUE increased from 0.81 ± 0.04 in B0 to 1.09 ± 0.01 kg/m3 in B2. The correlation analysis showed a significant and positive correlation, between GWUE and soil water parameters (θs, θfc and θmre) suggesting the indirect effect of biochar on water-use efficiency for grain yield of wheat. Therefore, among the tested rates 20 t/ha could be suggested to improve plant soil water availability and reduce the harmful impact of drought stress on rain-fed durum wheat.

Silicon Improved Water Stress Tolerance in Rice Genotypes

Rice is an important cereal crop, is mostly grown as a staple food in developing nations. One of the main causes restricting rice productivity is drought, which has a detrimental effect on global food security. Silicon increases antioxidant activity and lessens plant oxidative damage. In the current study, eight rice cultivars were subjected to foliar silicon spray to evaluate its effectiveness in reducing water stress. The plants were foliar sprayed with silicon under well-watered and drought-stressed circumstances. The collected data showed that drought stress significantly reduced physiological parameters, growth, and yield. In comparison with control, silicon application (T2) has increased LAI by 50.13%, RWC by 0.24%, total dry matter by 18.86%, productive tiller number by 30%, number of panicles m-2 by 26.10%, number of grains panicle-1 by 24.60%, test weight by 29.26% and grain yield by 10.60%; water stress alone (T3) reduced LAI by 38.06%, RWC by 21.02%, total dry matter by 38.88%, productive tiller number by 30%, number of panicles m-2 by 33.45%, number of grains panicle-1 by 42.85%, test weight by 34.87% and grain yield by 40.88%; while silicon + water stress (T4) reduced LAI by 3.41%, RWC by 16.89%, total dry matter by 8.45%, productive tiller number 0.00%, number of panicles m-2 by 13.97%, number of grains panicle-1 by 18.25%, test weight by 24.50% and grain yield by 19.24% only. Overall, silicon application has ameliorated the negative impacts of drought stress on rice and improved the growth, physiological traits and yield under both well-watered and water stress conditions. To increase the quality of the yield and to generate rice cultivars that can withstand drought stress, silicon should be incorporated into breeding programmes.

Amino acids foliar spraying palliate the negative effects of low irrigation on greenhouse sweet Cayenne pepper

AbstractSweet Cayenne pepper is a nutrient‐dense, sweet‐tasting greenhouse vegetable that often faces water stress in dry areas, and optimizing growth with minimum water consumption is crucial. In this study, we investigated the impacts of amino acids (AAs) foliar application on reducing water stress losses in sweet Cayenne pepper cv. “Lombard” under greenhouse conditions. The pepper bushes were irrigated in 3‐day and 6‐day intervals and simultaneously sprayed with an AA fertilizer (0, 150, and 300 mg/L). Vegetative growth, reproductive traits, and yield parameters were measured. Results showed significant decreases in the plant height, the roots length, SPAD, leaf greenness index, and the pepper leaves turn yellow under brief drought stress. The number of flowers was reduced by up to 50%, and the 3‐month yield decreased significantly from 7 to 5.05 kg/m2. However, with AAs foliar application, vegetative growth, fruit number, and yield increased significantly. The highest yield, 2.93 kg/plant, was observed in 300 mg/L AAs, while the minimum yield, with an average of 1.83 kg/plant recorded under water stress treatment without AAs application. The spray of AAs fertilizer remarkably improves the yield and quality of pepper fruit and reverses the destructive effects of low irrigation. The future direction could focus on the mechanism of the positive impact of AA foliar application on growth, yield, and quality of the fruit, particularly in water stress conditions, to further optimize growth and minimize water consumption.

Mycorrhizal inoculation under water stress conditions and its influence on the benefit of host microbe symbiosis of Terminalia arjuna species

BackgroundEntisol is a very poor, compact, and low-water-holding capacity soil. They are obstacles to the plant's root system's penetration and the availability of water, particularly in dry months. However, Arbuscular mycorrhizae fungi (AMF) is used for seedling growth and reduces water stress in the plant.ResultsIn this experiment, the growth parameters and the physiological activities of the plant were changed for the well watering (WW), fractionated watering (FW), and stopped/no watering conditions of the T. arjunaseedling. This experiment demonstrated higher mycorrhizal dependency (24.90%) under the FW condition than that of the WW condition (18.58%). Also the root colonization was higher (67%) under FW plants compared to WW plants (53%) associated with AMF+ in T. arjuna seedling. Photosynthesis was found 24.27% more with FW than the WW condition. Experiment' shows posivitivecorrelation between the photosynthesis and interval of no watering for AMF− plants (r2 = 0.873 for AMF− (control) and comparatively very weak for plants with AMF+ (r2 = 0.259 for AMF+ plants).ConclusionsThe findings confirms the use of AMF in entisol soil to improve plant growth and biomass by reducing edaphic stress.

Decoupling wastewater-related greenhouse gas emissions and water stress alleviation across 300 cities in China is challenging yet plausible by 2030

Urban wastewater treatment and reuse infrastructure play a vital role in achieving water sustainability; however, the pathways to realize water–climate synergies in planning such infrastructure are not clear. Here we examine the nexus of urban water stress and greenhouse gas (GHG) emissions resulting from expanding wastewater infrastructures across over 300 cities in China. We find that, despite a total increase of 176% in life-cycle GHG emissions, larger-scale wastewater treatment and reclaimed water reuse have nearly tripled the average amount of urban water stress alleviated between 2006 and 2015. However, with an extensive and integrated application of existing low-carbon technologies for wastewater treatment, sludge disposal and water reuse, it is possible to substantially further decouple water stress mitigation from GHG emissions by 2030. Under the optimized scenario, China can reduce wastewater-related emissions by 27% at the national level, while its eastern and northern cities could reduce emissions by over 40% for every unit of alleviated water stress. This study provides insights into the water–climate nexus and outlines feasible pathways to reduce water stress while mitigating wastewater-related GHG emissions. The rapid urbanization in China calls for an expansion of urban wastewater treatment systems, which in turn may exacerbate climate impacts. With an extensive and integrated application of existing low-carbon technologies for wastewater treatment, sludge disposal and water reuse, it is possible to substantially decouple urban water stress mitigation from greenhouse gas emissions.

Poultry Production Nexus-Few: a Study About the Effect of Public and Private Investments on the Efficient Use of Water

Purpose: This paper aims to analyse how investments in innovation, research and development in poultry production affect the water's efficient use. Theoretical framework: To understand water stress, the literature review addresses content related to the analysis of the balance between water and food production (Nexus-Few), as well as those that support the analysis of the effects of investments in research and development in poultry production and improving the efficient use of water. Method/design/approach: The data were collected from the FAOSTAT database, where were analysed the investments in research and development (government and private), poultry production, water stress and efficient water use (US$/m3). The period of analysis is from 2005 to 2019, and priority was given to countries with the highest production of poultry, based on available data (Brazil, India, Mexico, Myanmar and Russia). Results and conclusion: the results reveal that there is interdependence between water and poultry production. On the one hand, factors that can lead to water stress (climate, competition for water, food production) can also affect poultry production, as the more water stress, the greater the risk for poultry production that depends on these resources. On the other hand, public and private investments in research and development (R&D) can be crucial to reduce water stress, improve water use efficiency and poultry production performance. Research implications: The study shows to poultry farmers that water stress (demand greater than supply) interferes with poultry production, and that private or public investment in R&D is important for the efficient use of water. The paper revewls to governments and companies what actions are necessary to encourage the sector to seek the Nexus Few (balance between water and food production). Originality/value: expands understanding of the sustainability of the poultry production chain and the goals of sustainable development, in order to encourage the efficient use of water. The sudy reveals too the importance of public and private investments to promote the balance between water use and poultry production .

Exploring the potential of agricultural system change as an integrated adaptation strategy for water and food security in the Indus basin

Water security and food security in the Indus basin are highly interlinked and subject to severe stresses. Irrigation water demands presently already exceed what the basin can sustainably provide, but per-capita food availability remains limited. Rapid population growth and climate change are projected to further intensify pressure on the interdependencies between water and food security. The agricultural system of the Indus basin must therefore change and adapt to be able to achieve the associated Sustainable Development Goals (SDGs). The development of robust policies to guide such changes requires a thorough understanding of the synergies and trade-offs that different strategies for agricultural development may have for water and food security. In this study, we defined three contrasting trajectories for agricultural system change based on a review of scientific literature on regional agricultural developments and a stakeholder consultation workshop. We assessed the consequences of these trajectories for water and food security with a spatially explicit modeling framework for two scenarios of climatic and socio-economic change over the period 1980–2080. Our results demonstrate that agricultural system changes can ensure per capita food production in the basin remains sufficient under population growth. However, such changes require additional irrigation water resources and may strongly aggravate water stress. Conversely, a shift to sustainable water management can reduce water stress but has the consequence that basin-level food self-sufficiency may not be feasible in future. This suggests that biophysical limits likely exist that prevent agricultural system changes to ensure both sufficient food production and improve water security in the Indus basin under strong population growth. Our study concludes that agricultural system changes are an important adaptation mechanism toward achieving water and food SDGs, but must be developed alongside other strategies that can mitigate its adverse trade-offs.

AGRICULTURAL IRRIGATION – INNOVATIVE SOLUTIONS

Bulgaria's good soil and weather conditions increase the potential of agriculture and provide good opportunities for quality and sustainable food production. These can be expanded and further improved through the use of innovation in all agricultural activities. Farm irrigation is essential for the food supply and economic development of many countries. Innovative solutions are needed to improve the efficiency and sustainability of agricultural practices. Innovations in agricultural irrigation are essential for sustainable farm development and reducing water stress in the world. They help farmers to improve their harvests and preserve water resources for future generations. Integrating different water sources such as groundwater, surface water, rainwater and wastewater can provide a more sustainable and reliable source of water for farms. Innovations in agricultural irrigation require training and education for farmers to understand how to use new technologies and methods. Governments and financial institutions can provide support and incentives to invest in innovative irrigation solutions. In recent years, aquaponics has become an innovative study of the aquaculture industry. Aquaponics is an innovation in modern farming, a sustainable micro ecosystem with a controlled environment, combining aquaculture with hydroponics. It is developing at a rapid pace as the need for sustainable food production grows and freshwater and phosphorus supplies decline. Another innovative method to tackle the problem of farm irrigation is aeroponics. It is defined as an aerial water culture system or the science of growing plants without soil or substrate culture. The plant grows in the air with the help of artificial support and no soil or substrate is required to sustain the plant. The roots of the plant are suspended in a closed container in the dark and exposed to the open air to receive nutrient-rich water dispersed through atomizers. The modernisation, rehabilitation and renewal of irrigation systems provides an opportunity to reduce the use of pesticides and fertilisers in line with the Green Deal. It also provides an opportunity for Bulgarian farmers to be competitive with their counterparts in other countries. The effect could be strongest for permanent crops, fruit and vegetable production and livestock farming. The goal of the report is to focus on solutions to the problem of farm irrigation in the country by implementing innovative solutions. Key words: technology, agriculture, environment, innovation, irrigating JEL: O3, Q1, Q5, Q16.

Efficacy of priming wheat (Triticum aestivum) seeds with a benzothiazine derivative to improve drought stress tolerance.

We evaluated the effects of different concentrations (0.05 and 0.15mM) of a benzothiazine (BTh) derivative on wheat (Triticum aestivum L.) in normal (100% field water capacity, FWC) and drought (60% FWC) conditions. Various morphological and physiological characteristics, and the uptake of osmo-protectants and nutrients were measured under the two FWC conditions. Results show that the drought conditions significantly reduced plant growth, affected plant composition, reduced the concentrations of photosynthetic pigments and affected gaseous exchange attributes, stomatal behaviour, and uptake fluxes of essential nutrients, while increasing the contents of different osmo-protectants and enzymatic and non-enzymatic antioxidants to decrease the production of reactive oxygen species (ROS) within the cells/tissues. However, seed priming with BTh reduced water stress conditions by increasing plant growth and biomass, photosynthetic pigments, stomatal behaviour, different gaseous exchange attributes, and uptake fluxes of essential nutrients compared with unprimed plants. In addition, the plant has a strong antioxidant defense system, which further increased its activities under BTh derivative treatments, to scavenge ROS production and maintain cell turgor under water stress conditions. In conclusion, drought stress-induced oxidative stress and altered the growth of T. aestivum, whereas seed priming increased plant growth and antioxidant production by improving the plant tolerance to drought. We suggest that seed priming with a BTh derivative as an effective priming technique in T. aestivum for reducing drought stress tends to benefit a grower in terms of better growth to fulfil the market demand for food cereals.

Ácido salicílico e prolina modulam tolerância ao estresse hídrico em variedade tradicional de feijão-caupi

ABSTRACT Exogenous applications of chemical compounds stimulate changes in plant metabolism and promote tolerance to different environmental stresses, including water deficit. This study aimed to evaluate the ability of salicylic acid (SA) and proline (PRO) to reduce water stress in a traditional variety of cowpea in a typical Brazilian semiarid climate. A completely randomized design was used in a 2 × 4 factorial scheme, with five replicates. Two irrigation regimes were evaluated corresponding to 100% (W100) and 50% of daily evapotranspiration (W50), respectively, with the addition of the following four attenuators: control (distilled water), SA (550 mg L-1), PRO (690 mg L-1), and 690 mg L-1 PRO + 550 mg L-1 SA. The treatments promoted changes in osmotic and antioxidant metabolism, which may contribute to the tolerance mechanisms of cowpea plants to water stress. The application of SA increased osmoregulator synthesis and protein concentrations, and modulated antioxidant enzyme activity in the cowpea plants under water stress. PRO concentrations increased synergistically in plants treated with PRO and SA, particularly in 50% of water replacement.

Life Cycle Assessment Tool for Food Supply Chain Environmental Evaluation

Food is at the centre of efforts to combat climate change, reduce water stress, pollution, and conserve the world’s wildlife. Assessing the environmental performance of food companies is essential to provide a comprehensive view of the production processes and gain insight into improvement options, but such a tool is currently non-existent in the literature. This study proposed a tool based on the life cycle assessment methodology focused on six stages of the food chain, raw materials acquisition, supplier, manufacturing, distribution, retail and wastes. The user can also evaluate the implementation of Internet of Things (IoT) technologies to reduce food waste applied in the real-world problems. The tool was validated through a case study of a food manufacturing company that prepares frozen meals via vending machines. The LCA results provided by the tool showed that food raw materials production is the main hotspot of nine impact categories. The IoT technologies’ contribution increased the company’s impact by around 0.4%. However, it is expected that employing these monitoring technologies would prevent food waste generation and the associated environmental impacts. Therefore, the results of this paper provide evidence that the proposed tool is suitable for determining environmental impacts and savings of food supply chain companies.

How can virtual water trade reshape water stress pattern? A global evaluation based on the metacoupling perspective

With water scarcity increasingly becoming a growing global risk, it is prevalent to explore water supply-demand interaction within and beyond national borders driven by global virtual water trade and its effects on water sustainability. However, there is little study on system integration of differential environmental impacts of various types of trade. Based on metacoupling framework highlighting human-nature interactions across space- within a place (intracoupling), between adjacent places (pericoupling), and between distant places (telecoupling), this study quantified the linkages and intensities of three kinds of coupling processes during global virtual water trade for the first time. Correspondingly, water stress changes under a set of trade scenarios were evaluated based on the indicator of UN SDG 6.4.2 to distinguish the influence of trade taking place on different spatial scales. Results show that during 2005–2015, local water resources supported 80% of global water consumption. Distant virtual water import was about 5 times in volume as large as adjacent virtual water import, alleviating 99.8% of global average water stress. Virtual water trade reduced water stress in 86% of developed countries and increased that in 71% of developing countries in 2005. Owing to trade, water stress in many countries with poor water resources endowment declined while that of many with relatively good endowment went up from 2005 to 2015. Our findings can help to systematically understand the influence of virtual water trade on water stress change and provide scientific guidance for sustainable water management and regional regulations.

Fracking wastewater treatment: Catalytic performance and life cycle environmental impacts of cerium-based mixed oxide catalysts for catalytic wet oxidation of organic compounds

Water scarcity and the consequent increase of freshwater prices are a cause for concern in regions where shale gas is being extracted via hydraulic fracturing. Wastewater treatment methods aimed at reuse/recycle of fracking wastewater can help reduce water stress of the fracking process. Accordingly, this study assessed the catalytic performance and life cycle environmental impacts of cerium-based mixed oxide catalysts for catalytic wet oxidation (CWO) of organic contaminants, in order to investigate their potential as catalysts for fracking wastewater treatment. For these purposes, MnCeOx and CuCeOx were tested for phenol removal in the presence of concentrated NaCl (200 g L−1), which represented a synthetic fracking wastewater. Removal of phenol in pure (“phenolic”) water without NaCl was also considered for comparison. Complete (100 %) phenol and a 94 % total organic carbon (TOC) removal were achieved in both the phenolic and fracking wastewaters by utilising MnCeOx (5 g L−1) and insignificant metal leaching was observed. However, a much lower activity was observed when the same amount of CuCeOx was utilised: 23.3 % and 20.5 % for phenol and TOC removals, respectively, in the phenolic, and 69.1 % and 63 % in the fracking wastewater. Furthermore, severe copper leaching from CuCeOx was observed during stability tests conducted in the fracking wastewater. A life cycle assessment (LCA) study carried out as part of this work showed that the production of MnCeOx had 12–98 % lower impacts than CuCeOx due to the higher impacts of copper than manganese precursors. Furthermore, the environmental impacts of CWO were found to be 94–99 % lower than those of ozonation due to lower energy and material requirements. Overall, the results of this study suggest that the adoption of catalytic treatment would improve both the efficiency and the environmental sustainability of both the fracking wastewater treatment and the fracking process as a whole.

Prescribed fire after thinning increased resistance of sub-Mediterranean pine forests to drought events and wildfires

Vegetation structure affects the vulnerability of a forest to drought events and wildfires. Management decisions, such as thinning intensity and type of understory treatment, influence competition for water resources and amount of fuel available. While heavy thinning effectively reduces tree water stress and intensity of a crown fire, the duration of these benefits may be limited by a fast growth response of the understory. Our aim was to study the effect of forest structure on pine forests vulnerability to extreme drought events and on the potential wildfire behaviour after management, with a special focus on the role of the understory. In three sub-Mediterranean sites of NE Spain dominated by Pinus nigra, two intensities of thinning (light: aiming at 70–75% canopy cover; and heavy: aiming at 50–60% canopy cover) followed by two understory treatments (mechanical only and mechanical plus prescribed burning) were applied, resulting in four differently managed stands plus an untreated control per site. Four to five years after management, we measured forest structure (overstory in one 314 m2 circular plot and understory in 20 quadrats of 1 m2 per treatment unit) and fuel load (in two 10 m transects per treatment unit) and simulated water balance and fire behaviour under extreme weather conditions. Understory contribution was assessed comparing the real structure with a virtual forest stand where understory vegetation equalled the one of the untreated control. Our results suggest that the resulting mid-term structure following treatments effectively reduced water stress and fire behaviour compared with untreated control, and that the most effective treatments were the ones where prescribed burning was applied after light or heavy thinning. While understory clearing contributes to increase the resistance to both disturbances, an additive effect of burning the debris reduced the vulnerability to drought and wildfires after treatments. Our study highlights the importance of managing the understory to further increase forest resistance to both disturbances.