Total Water Use Research Articles

POTASSIUM APPLICATION USING THE 4R NUTRIENT STEWARDSHIP APPROACH FOR IMPROVING WHEAT GROWTH AND YIELD TRAITS

Potassium (K) plays a key role in numerous plant metabolic processes, and its adequate amount is necessary for proper plant growth and development. Imbalanced fertilizer application has rapidly depleted the soil available K and harmed crops. However, the science-based K application in crops must follow the 4R nutrient stewardship approach to enhance crop yields. Therefore, a planned pot study used the 4R nutrient management technique for wheat potassium management. The evaluation of two wheat cultivars (Punjab-2008 and Barani-2011) employed two commercial K sources (MOP and SOP) with different application methods (basal and foliar) and sowing times (15 October, 15 November, and 15 December). The wheat variety Punjab-2008 performed better in root and shoot length, fresh biomass, and grain yield between 15 October and 15 November. Meanwhile, the Barani-2011, sown on 15 November, produced higher total chlorophyll contents and water use efficiency (WUE). The use of SOP (high dose), MOP (medium to high dose), and foliar spray of SOP at 1.5% and 3% resulted in maximum shoot length and the root-to-shoot ratio for both tested cultivars. Punjab-2008 produced higher grain yield when applied with a high SOP level than a high level of MOP. Similarly, a maximum leaf area index and proline contents observed in Punjab-2008 occurred with a high level of SOP applied. In contrast, a higher net photosynthesis rate and WUE emerged in Barani-2011 under a medium SOP level and a higher level of MOP. Thus, the conclusion is that medium to high rates of SOP proved a better source of K nutrition for improving yield parameters of wheat cultivars.

Comparative effects of mineral fertilizer and digestate on growth, antioxidant system, and physiology of lettuce under salt stress

Salt stress in plants presents a major challenge to future agricultural production. Digestate has various effects on plant growth, but little information is available on its effects on the antioxidant system and physiological characteristics of lettuce under salt stress. In this study, the impacts of mineral fertilizer and digestate application on edible parts of lettuce were compared under three salinities. Experimental treatments comprised application of two types of fertilizer (mineral fertilizer and digestate) and three NaCl concentrations (0, 3, and 7.5 dS m− 1). High NaCl concentrations resulted in significantly lower photosynthesis, growth, and physiological indices compared with those under no NaCl addition. However, under the 7.5 dS m− 1 NaCl condition, digestate application (DA) increased the fresh weight (42%), dry weight (27%), photosynthetic pigment contents and photosynthesis (20%) of lettuce compared with that under mineral fertilizer application (MFA). Accumulation of reactive oxygen species was markedly lower, and the membrane stability index was therefore higher, under DA compared with under MFA within the same salinity level. Lipid peroxidation was lower under DA compared with under MFA in all salinity treatments. Salt stress up-regulated the antioxidant system and DA further increased the enzymatic and non-enzymatic antioxidant capability compared with that under MFA. In addition, the total water use was lower and water-related indices, such as water use efficiency of fresh weight, water use efficiency of dry weight and relative water content, were higher under DA compared with under MFA. The application of digestate instead of mineral fertilizer could be a promising practice to alleviate the negative impact of salt stress on the productivity and physiological characteristics of lettuce plants.

Spatial pattern and driving factors for interprovincial water use in China: Based on SNA and LMDI

China, the world's largest developing country, faces a severe water shortage. As the government has set a goal of limiting water use to 7000 × 108 m3 by 2035, how to control the increase in water use will be a thorny issue for China. Unbalanced and uncoordinated regional socio-economic development is an important feature of China. Research on the interaction between provincial water use will help to optimize the rational allocation of water resources and control of water use. In this paper, SNA (social network analysis) method is first used to explore the characteristics of social network relationship between inter-provincial water use, construct a two-stage model of SNA–LMDI, and decompose the driving factors of inter-provincial water use evolution. We found the following points. (1) From 2000 to 2018, the spatial correlation network structure of water use is tending to be stable, and the stability and risk resistance of the whole network are enhanced. (2) From different angles to quantify the centricity analysis, can be found that eastern provinces located right in the heart of water network, obviously larger impact on water resources utilization in other provinces, Shanghai and Beijing is located in the former two, and central and western provinces in the edge position. (3) The national water use spatial correlation network can be divided into four blocks, net beneficial block, bidirectional spillover block, brokers block, and net spillover block. (4) Technological progress and industrial structure adjustment were the primary and secondary factors inhibiting the increase of total water use, while income increase was the main factor promoting the increase of total water use, population scale expansion had a weak role in promoting the increase of total water use. Some policy implications are put forward related to our research conclusions.

ЖАМБЫЛ ОБЛЫСЫ ЖАҒДАЙЛАРЫНДАҒЫ КӨКӨНІС ДАҚЫЛДАРЫНЫҢ СУ ПАЙДАЛАНУ ЖИЫНТЫҒЫН ЗЕРТТЕУ

The scientific article presents the results of a study of the water-use aggregate of crops during irrigation of vegetable crops by various irrigation methods on loamy gray soils of the Zhambyl region. Vegetable crops were watered systematically and drip. For irrigation, a drip irrigation system was used, which has a high water-saving capacity and does not require high funds. The daily and total water use of vegetable crops during the growing season are determined. As a result of the study, it was found that the daily set of water consumption of vegetable crops showed a low indicator in the drip irrigation variant. The total water use of vegetable crops showed high indicators in the variant of systematic irrigation and amounted to 4151m3/ha, and in the variant of drip irrigation 2333m3/ha, that is-1818m3/ha. The total water use of vegetable crops for months showed low rates in the drip irrigation option. The average daily water use of vegetable crops in the drip irrigation variant in June and July was 22-24m3/ha, and in systematic irrigation in these months was 33-43m3/ha. Low average daily water use of crops was observed in the drip irrigation variant in August and was equal to 18m3/ha. The main revenue part of the water balance of vegetable crops was irrigation work. It was found that the total water use of vegetable crops in the variant of systematic irrigation showed a high rate of 44%.

A Novel Approach for Optimum Conjunctive Use Management of Groundwater and Surface Water Resources under Uncertainty

Uncertainty in determining optimum conjunctive water use lies not only on variability of hydrological cycle and climate but also on lack of adequate data and perfect knowledge about groundwater-surface water system interactions, errors in historic data and inherent variability of system parameters both in space and time. Simulation-optimization models are used for conjunctive water use management under uncertain conditions. However, direct application of such approach whereby all realizations are considered at every-iteration of the optimization process leads to a highly computational time-consuming optimization problem as the number of realizations increases. Hence, this study proposes a novel approach—a Retrospective Optimization Approximation (ROA) approach. In this approach, a simulation model was used to determine aquifer system responses (draw-downs) which were assembled as response matrices and incorporated in the optimization model (procedure) as coefficients in the constraints. The sample optimization sub-problems generated, were solved and analyzed through ROA-Active-Set procedure implemented under MATLAB code. The ROA-Active Set procedure solves and evaluates a sequence of sample path optimization sub-problems in an increasing number of realizations. The methodology was applied to a real-world conjunctive water use management problem found in Great Letaba River basin, South Africa. In the River basin, surface water source contributes 87% of the existing un-optimized total conjunctive water use withdrawal rate (6512.04 m3/day) and the remaining 13% is contributed by groundwater source. Through ROA approach, results indicate that the optimum percentages contribution of the surface and subsurface sources to the total water demand are 58% and 42% respectively. This implies that the existing percentage contribution can be increased or reduced by ±29% that is groundwater source can be increased by 29% while the surface water source contribution can be reduced by 29%. This reveals that the existing conjunctive water use practice is unsustainable wherein surface water system is overstressed while groundwater system is under-utilized. Through k-means sampling technique ROA-Active Set procedure was able to attain a converged maximum expected total optimum conjunctive water use withdrawal rate of 4.35 × 104 m3/day within a relatively few numbers of iterations (6 to 8 iterations) in about 2.30 Hrs. In conclusion, results demonstrated that ROA approach is capable of managing real-world regional aquifers sustainable conjunctive water use practice under hydro-geological uncertainty conditions.

ВОДОПОТРЕБЛЕНИЕ КУЛЬТУР ЗЕРНОТРАВЯНЫХ СЕВООБОРОТОВ ПРИ ЭНЕРГОНАКОПИТЕЛЬНОЙ СИСТЕМЕ СОДЕРЖАНИЯ ПОЧВЫ В ЗАПАДНОМ ПРИКАСПИИ

The study was carried out on the meadow-chestnut soils of farm “OOO Vympel-2002” located in Khasavyurt district of the Republic of Dagestan. The purpose of the research was to examine the effect of varying saturation levels of cereal-grain crop rotations by alfalfa and winter wheat + crop residue natural phytocenosis on the total consumptive water use and the water-use ratio in the Western Caspian region. The main criterion for sustainable yields of winter wheat at 3–4-year repeated sowing is the crop residue natural phytocenosis formed in the second half of summer after harvesting the crop and plowing its biomass for green manure. The study has found that in the cereal-grass crop rotations, alfalfa consumes the largest amount of water for its yield during four years of use. The crop rotation that employs 75 % alfalfa and 25 % of winter wheat+the crop residue natural phytocenosis demonstrates the maximum total consumptive water use of 5000 m3 per 1 ha of rotation area. A larger share of winter wheat + the crop residue natural phytocenosis is crucial for more economical use of water in the crop rotation. The water-use ratio for alfalfa used in monoculture systems was 2660.7; the ratio was 3.7 times lower for winter wheat + the crop residue natural phytocenosis. Crop rotations that used from 75, 50 and 25 % of alfalfa had lower ratios than the monoculture systems (by 38.3, 55.7 and 65.9 %, respectively). The data indicate that the combination of winter wheat + the crop residue natural phytocenosis used for green manure reduce the water needed to obtain yields. The study results should be applied for designing cereal-grass and other types of crop rotations in the region.

Environmental data and facts in the semiconductor manufacturing industry: An unexpected high water and energy consumption situation

With the expansion of the semiconductor industry, determining the huge associated water and energy consumption and accomplishing sustainable development can be key issues for this industry. This study surveyed the sustainability reports of 28 semiconductor corporations and summarized their environmental stewardship information. Overall, the total water withdrawal in 2021 was 7.89 ​× ​108 ​m3, total energy consumption was 1.49 ​× ​1011 ​kWh, and total greenhouse gas (GHG) emissions were 7.15 ​× ​107 tons CO2 equivalent. The total Scope 1 and Scope 2 GHG emissions were 2.74 and 4.41 ​× ​107 ​t CO2 equivalent, respectively. Surface water intake, municipal water supply, groundwater withdrawal, third party supply, and external reclaimed water intake accounted for 47.0%, 35.3%, 8.5%, 5.8%, and 3.2% of total water use, respectively. Electricity, fossil fuel, renewable energy, and others accounted for 83.7%, 12.0%, 2.7%, and 1.7% of the total energy use. In 2021, average water use, energy consumption, and GHG emissions were calculated to be 8.22 ​L/cm2, 1.15 ​kWh/cm2, and 0.84 ​kg CO2 equivalent/cm2, respectively, based on announced data. Ultrapure water consumption was predicted to be 5.51 and 0.95 ​× ​108 ​m3 worldwide and for China, respectively. Effective sustainability strategies are supposed to be implemented to meet the considerable growth in water and energy consumption and GHG emissions for the semiconductor industry worldwide and in China.

Revisiting the Concept of 'Virtual Water' in Light of the Impact of the Great Ethiopian Renaissance Dam on Egypt's Water Interests

Revisiting the Concept of 'Virtual Water' in Light of the Impact of the Great Ethiopian Renaissance Dam on Egypt's Water Interests Marwa Mamdouh-Salem (bio) Introduction Virtual water is one of the few concepts that serious disagreements have not been raised on its definition. Simply, it is the amount of water that is embedded in food or other products needed for its production. It also refers to the hidden flow of water if food or other commodities are traded from one place to another.1 Virtual water allows some countries to support other countries in their water needs. Instead of producing these goods themselves, the importing country can utilize this water for other purposes that else would have been necessary for its production. So, a water scarce country can import products that require a lot of water for their production rather than producing them domestically. By doing so, real water savings can be attained relieving the pressure on the water resources worldwide. Accordingly, several countries – such as Jordan, Israel, and the Gulf States – have consciously formulated policies to enable water saving by [End Page 12] reducing export of water-intensive products, notably crops. It is important to mention that the virtual water content of a product may inform about the environmental impact of consuming this product. By knowing the virtual water content of products, an awareness of the amount of water needed to produce a specific commodity is created. This informs us of the impact that some goods have on the water system. Moreover, the water volume results from the country's import of virtual water should be added to the total water use of the country, thus getting a picture of a nation's real call on the global water resources. Similarly, virtual water export should be subtracted from the volume of the country's water use. The sum of national water use and net virtual water import is known by the 'water footprint' of a country. This 'water footprint' can be a strong tool to show people their impact on the natural resources. The awareness of one's 'individual water footprint' aims to stimulate a more careful use of water. It may also be included in agricultural and industrial production plans and leads to more environment friendly trade policies.2 Ever since Tony Allan introduced an updated version of the concept 'embedded water' in the mid-1990s,3 virtual water trade has been subject to strong academic and scientific debate. This debate produced two main trends: The first trend – which is adopted by the majority – views virtual water as a fact of life exercised by the people since ancient times. The Old Testament tells us about the prophecy of Joseph on how "the seven years of plenty which were in the land of Egypt ended, and the seven years of famine began to come."4 Egyptians stored big quantities of food crops that they cultivated during the time of water abundance to compensate for the food shortage that will happen because of the seven years of drought. This is simply a 'water storing technique' based on the concept of virtual water. In this context, the logic of virtual water is: if the country does not have enough water to cultivate the needed food crops, then it can "import water." This can be done through the importing of crops and other food products from other countries that have water abundance.5 Therefore, this trend endorses the view that since virtual water is a reality, it is necessary to acknowledge [End Page 13] its existence and to start incorporating it – in a scientific way – into the state's national agricultural, economic, and trade strategies. The second trend is an attempt to think outside the virtual water's box as it tends to consider the political, economic, and social factors related to the cultivation of crops. Among the significant works that demonstrate this vision is Jessica Barnes who believes that water is not only limited to agricultural production; rather it should be seen as a more comprehensive process that involves people's lives. Rural environment is characterized by unique social and economic traditions and customs that control the peasants' lifestyle...

Relationship between Water Use and per Capita Income with Environmental Kuznets Curve of Developing Countries: A Case Study in Jiangsu Province, China

The relationship between economic growth and environmental variation is an important issue of sustainable development for human beings, especially in developing countries. However, developing countries usually use the standards of developed countries when dealing with environmental issues, which makes the relationship exhibit different characteristics than it does in developed countries. In order to realize a balance relationship between water use and income per capita in developing countries, a multivariable environmental Kuznets curve (EKC) simulation model based on the grey absolute correlation method was modified to improve the description of the balance relationship between water use and per capita income in the Jiangsu Province of China from 2005 to 2017. The results showed that the industrial and agricultural water uses first increased and then decreased, which agreed with an inverted “U” characteristic. The industrial water use was in the declining stage of the inverted “U” characteristic, while the agricultural water use was in a transition phase of the inverted “U” characteristic. However, the domestic water use showed an increasing trend, and it is difficult to estimate whether it showed an inverted “U” characteristic. Simultaneously, different watershed partitions in Jiangsu Province presented different EKC characteristics. In the three different watershed zoning regions of Jiangsu Province, the total water use of the Tai Lake Basin and the Yangtze River Basin exhibited the typical inverted “U” characteristic, while the Huai River Basin was just in the increasing stage. Moreover, the improved multivariable EKC model was suitable to describe the inverted U-shaped variation characteristics of water use, and the developed model outperformed the univariate EKC model in the study area. Based on the characteristics of the EKC, policy ideas for enhancing the coordination among water resources, the economy, and the ecological environment were proposed in order to achieve sustainable development.

Wheat Straw Burial Enhances the Root Physiology, Productivity, and Water Utilization Efficiency of Rice under Alternative Wetting and Drying Irrigation

This study evaluated whether the straw burial and alternative wetting and drying (AWD) irrigation could improve the root activity, yield, and water utilization efficiency (WUE) of rice. Accordingly, we conducted a field experiment with three straw burial levels, i.e., with no straw burial (NSB), low straw burial 300 kg.ha−1 (LSB), and dense straw burial 800 kg.ha−1 (DSB), and three irrigation regimes, i.e., alternate wetting/moderate drying (AWMD), alternate wetting/severe drying (AWSD), and alternate wetting/critical drying (AWCD). Results showed that straw burial improved the root activity, rice yield, and WUE under AWD regimes. The combination AWMD×DSB resulted in the greatest values of total dry mass (1764.7 g/m2) and water use (853.1 mm). Conversely, the treatment AWCD × NSB led to the lowest values of total biomass (583.3 g/m2) and water use (321.8 mm). Root dry weight density (1.11 g cm−3) and root active absorption area (31.6 m2 plant−1) were higher in the treatment AWMD × DSB than root dry weight density (0.41 g cm−3) and root active absorption area (21.2 m2 plant−1) were in the treatment AWCD×NSB. The former combined treatment increased root oxidation ability (55.5 mg g−1 FWh−1), the root surface phosphatase activity (1.67 mg g−1 FWh−1) and nitrate reductase activity of root (14.4 μg g−1 h−1) while the latter considerably reduced the values of root oxidation ability (21.4 mg g−1 FWh−1), the root surface phosphatase activity (0.87 mg g−1 FWh−1) and nitrate reductase activity of root (5.8 μg g−1 h−1). The following conclusions can be drawn with regard to water use and biomass yield. (i) The reduction in water consumption was greater than the reduction in yield in the case of AWSD. (ii) The decline in water consumption was less than the decline in biomass yield in the case of AWCD. (iii) The increase in in water consumption was greater than the increase in biomass yield in the case of AWMD. Therefore, the indicators of WUE were recorded in the following order: AWSD > AWMD > AWCD. This study recommends AWD irrigation to improve the root growth traits that contribute to the greater biomass yield of rice. It also suggests that farmers should implement AWD irrigation after leaving wheat straw residues in the field, and followed by deep tillage, to mitigate the negative effect of drought stress caused by AWD irrigation, preserving plant growth without large biomass losses, and thus, addressing the constrains of straw residues and sustaining rice production under limited freshwater resources.

Analyzing Embodied Energy and Embodied Water of Construction Materials for an Environmentally Sustainable Built Environment

Buildings consume over 40% of global energy in their construction and operations contributing to over 39% of global carbon emission each year. This huge environmental footprint presents an excellent opportunity to reduce energy use and help deliver an environmentally sustainable built environment. Most of the energy is consumed by buildings as embodied energy (EE) and operational energy (OE). EE is used directly and indirectly during buildings’ initial construction, maintenance and replacement, and demolition phases through construction products and services. OE is used in the processes of heating, cooling, water heating, lighting, and operating building equipment. Most environmental optimization research has been centered on energy and carbon emission overlooking another critical sustainability aspect, water use. Each building also consumes a significant amount of freshwater as embodied water (EW) or virtual water in its initial construction, maintenance and replacement, and demolition phases. Since each primary and secondary energy source depletes water in its extraction, refinement or production, there is also a water expense associated with EE and OE use that must also be included in total EW use. The total EW, therefore, includes both non-energy and energy related water use. Research suggests that there are tradeoffs between EE and EW that may complicate design decisions such as material selection for environmental sustainability. In other words, a material selected for its lower EE may have higher EW and selecting such a material may not help reach environmental sustainability goals since water scarcity is becoming a grave problem. In this paper, we created an input-output-based hybrid (IOH) model for calculating and comparing EE and EW of building materials frequently used in building construction. The main goal is to examine and highlight any tradeoffs that may exist when selecting one material over another. The results reveal that there is a weak correlation between EE and total EW that is the sum of energy and non-energy water use, which means that a design decision made solely based on EE may conflict with EW. The share of energy related water use in total EW of construction materials also varies significantly (2.5%-31.2%), indicating that reducing energy use alone may not be sufficient to reduce freshwater use; additional efforts may be needed to decrease the use of materials and processes that are water intensive. The results of this study are significant to achieving the goal of creating a truly sustainable built environment.

Fresh Water Use in Florida: Trends and Drivers

Water quality and quantity are critical issues as the Florida’s population grows. This paper analyzed water use regionally (central, north, and south Florida) as well as in rural and urban areas in Florida from 2005 to 2015 using three indicators (total water use, agriculture water use, and per capita water use). Eight (8) water-consuming categories, such as aquaculture, livestock, irrigation, public supply, thermoelectric power, mining, industrial self-supply, and domestic self-supply, were considered for total water use. Per capita water use used public supply category and agricultural water use used aquaculture, livestock, and irrigation categories. Linear regression analysis was used to observe the relationship between population and water use. The highest water use was recorded in south Florida, while the lowest was in north Florida. Water use per capita was higher in urban areas. Irrigation water use was higher among the eight water use categories. Many drivers influencing Florida water use were identified through literature review and causal loop diagram was developed. Some (e.g., household size, land use/land cover change, urbanization, agriculture, population, income, climate change, tourism, and industry) may cause an increase in water use, while others (e.g., pricing systems, conservation methods, education, and technology) may cause a decrease in water use. Overall, this research addresses the need of understanding water use trends and the drivers affecting those trends, which are important to determine whether a water conservation plan is needed.

A spatial-temporal optimal allocation method of irrigation water resources considering groundwater level

The healthy and sustainable development of irrigation area not only serves as the guarantee of national food production security, but also shoulders the important task of regional ecological security, in which maintaining groundwater level plays an important role. Due to the close relationship between groundwater level and irrigation recharge groundwater, realizing rational use of water resources under strictly implementing the total limit of water use and holding reasonable groundwater level is of great significance to the healthy development of irrigated areas. Therefore, this study established a spatial-temporal optimal allocation regulation method of irrigation water resources by coupling groundwater numerical technology and the characteristics of hydrological cycle with comprehensively considering the dual constraints between total water consumption and reasonable groundwater depth. Besides, taking Helan County, a typical area of Qingtongxia Irrigation district in Ningxia as an example, a case study on optimal allocation of irrigation water resources was carried out. The results show that compared with the actual current water use situation, the total irrigation water shortage rate of Helan County Irrigation District (HCID) decreases from 21.61% to 21%. Under the combined control of total available water and groundwater depths, it is realized the fairness and balance of water use in different regions and periods by the allocation of water resources in spatial and temporal. Meanwhile, the area located in the reasonable groundwater depth range increased by 1.65% after optimization. Overall, the balanced and optimal allocation method of irrigation water resources with both total water use and groundwater depth control is not only improving the efficient and rational utilization of limited water resources, but also can regulate groundwater depth to guarantee regional ecological health and sustainable development.

Effects of Compound Biochar Substrate Coupled with Water and Nitrogen on the Growth of Cucumber Plug Seedlings

Since plug seedlings play a key role in automatic transplanting, this work aimed to explore the interaction between the biochar rate, water content, and N–fertilization in the substrate on the cultivation of cucumber seedlings before and after transplanting. The research showed that most of the factors obtained significant individual and interaction effects by measuring and analyzing the growth parameters of seedlings before transplanting. Most growth parameters significantly decreased with the increase in biochar rate except Water Use Efficiency which obtained the highest value of 2.06 g/L when the biochar rate was 10%. Furthermore, some growth parameters increased significantly with the increase in water content, while the Total Dry Matter and Water Use Efficiency reached their highest values, 0.778 g and 1.94 g/L, respectively, when the water content was 65%. All growth parameters reached their highest values when the N–fertilization was 50%; too high or too low of N–fertilization was not conducive to the growth of seedlings. The growth parameters and photosynthesis indices of seedlings cultivated after transplanting indicated that the seedlings with superior growth before transplanting performed better than other treatments in regard to growth and photosynthesis after transplanting. The interactions were in general optimal when the biochar rate was 5%, water content was 80%, and N–fertilization was 50% in the substrate, and seedlings cultivated under this treatment could not only meet the requirements of automatic transplanting, but also ensure rapid growth after transplanting. This study thus provides some guidance for the effective cultivation of vegetable plug seedlings.

Urban Water Management Using Water Self-sufficiency

Water demand is increasing because of population increases and industry developments as well as demands for improved living standards. Existing water treatment and supply systems cover large areas and have a centralized system; consequently, development of new water resources requires a construction of pipe infrastructure over long distances. The variability of water quantity, as climate changes, is hampering efforts to secure water resources and decide facility capacity. Therefore, a new urban water management system to address these problems is required. This study suggests such a system as well as a new index, i.e., the water self-sufficiency ratio (WSSR) for evaluating the system. WSSR is calculated by dividing the total self-provided water quantity with the total water use in a city. The current WSSR for Suwon City is 11 %, but there are plans to achieve 50 %. This would be accomplished by using rainwater (26.8 million ton/year), encouraging water conservation (31.3 million ton/year), building tunnel-type rainwater-retention facilities (2.5 million ton/year) and reusing treated sewage (1.72 million ton/year). In addition, financial incentives are expected through such as reduction of floor area proportion, tax reduction and governmental subsidies. The WSSR is expected to be useful in evaluating urban water self-reliance as well as in quantitativly establishing a sustainable water management system.

Influence of Rice Establishment Methods on Water Productivity, Methane Emissions and Rice Grain Heavy Metals Content from Irrigated Rice Paddies in Bangladesh

Reducing methane (CH4) emissions and water use in irrigated rice systems while maintaining production to feed the ever-increasing population is vital in Bangladesh. Different rice establishment methods viz. alternate wetting & drying (AWD), system rice intensification (SRI) and direct wet seeded rice (DWSR), have a promising mitigation potential to reduce CH4emission compared to continuous flooded (CF) rice fields. A field experiment was conducted at Bangladesh Agricultural University, Mymensingh, during the Boro season in 2018 to examine whether rice establishment methods could maintain grain yield with reduced water use and CH4emissions. A split-plot design was employed with water management in the main plots and fertilizer management in the subplots. The yield difference was not significant (p>0.05) in CF, AWD, and SRI systems other than DWSR. Planting methods in combination with organic fertilizer amendment had little effect on the grain Fe, Zn, and Cd concentration but significantly affected the as concentration. AWD, SRI, and DWSR significantly reduced the total water use by 17-33% and increased water productivity by 22-35% compared to CF. SRI system performed superior (p>0.05) by increasing the water productivity coupled with reducing water consumption compared to CF. The impact of water management on changing climate in rice fields was compared using seasonal CH4emission and yield-scaled global warming potential (GWP). Total seasonal CH4emissions were significantly distinct (p<0.05) from different rice establishment methods. Seasonal CH4 emissions from CF, AWD, SRI, and DWSR systems were 147.85, 128.11, 110.35, and 91.52kg CH4 ha-1, respectively. Emissions were reduced by about 13-38% in contrast with continuous flooded soil. The emissions of greenhouse gases per unit grain yield (yield-scaled GWP) followed the order; CF>AWD>DWSR>SRI, while reducing yield-scaled emissions from AWD, SRI and DWSR decreased around 15-25% over that of the CF system. In conclusion, it is recommended that both SRI and AWD can mitigate CH4 emission, powered reduce water consumption as well as grain content from irrigated rice fields without yield penalty.

Growth performance and immune responses of pengba ( Osteobrama belangeri ) during high‐density fingerling rearing in biofloc system

High-density fingerling rearing of pengba was conducted for 90 days in biofloc system (BFS) to study the effect of stocking density on growth, feed utilization, water quality, water use efficiency and health of animals. The study was conducted in 12 continuously aerated tanks (50 m3), grouped into four treatments T-1, T-2, T-3 and T-4, which were stocked with pengba fry (1.25 ± 0.05 g, 4.74 ± 0.70 cm) at 50, 60, 70 and 80 m−3, respectively. Supplementary feed (1 mm floating pellet) was fed twice daily, each time for 30 min duration. Molasses and urea were supplemented to maintain suitable C:N ratio at 15:1. No water exchange was given, except monthly compensation of evaporation loss. While water quality and most of the growth attributes in T-1 and T-2 remained similar, T-3 at 70 m−3 density showed better water quality, higher survival and growth than T-4. Body composition remained consistent across treatments despite impaired feed digestion and utilization associated with higher densities. The non-specific immune responses in fingerlings increased from T-1 to T-3, but further density rise showed compromised immune in T-4. Such results suggested 70 m−3 to be an ideal density for production of healthier fingerlings. But T-4 produced 13.5% more fingerlings than T-3, and fingerlings (7.56 ± 0.50 cm; 5.43 ± 0.09 g) were within acceptable size range for grow-out stocking. T-4 also showed the lowest total water use and the highest water implicating 80 fry m−3 to have more applicability. Thus, the study recommends 70–80 m−3 as ideal range for fingerling rearing of pengba in BFS.

How advances in animal efficiency and management have affected beef cattle's water intensity in the United States: 1991 compared to 2019.

Updating the static model by Beckett and Oltjen (1993), we determined that from 1991 to 2019, U.S. beef cattle blue water consumption per kg of beef decreased by 37.6%. Total water use for the U.S. cattle herd decreased by 29%. As with the 1993 model, blue water use included direct water intake by animals, water applied for irrigation of crops that were consumed by beef cattle, water applied to irrigated pasture, and water used to process animals at marketing. Numbers of cattle, crop production, and irrigation data were used from USDA census and survey data. On 1 January 2019, a total of 31.7-million beef cows and 5.8-million replacement heifers were in U.S. breeding herds, and 26-million animals were fed annually. In total, the U.S. beef cattle herd (feedlot and cull cows) produced 7.7-billion kg of boneless beef, an increase of 10% since 1991. Beef cattle directly consumed 599-billion L of water per year. Feedlot cattle were fed various grain and roughage sources corresponding to the regions in which they were fed. Feeds produced in a state were preferentially used by cattle in that state with that state's efficiency; any additional feedstuffs required used water at the national efficiency. Irrigation of crop feedstuffs for feedlot cattle required 5,920-billion L of water. Irrigated pasture for beef cattle production required an additional 4,121-billion L of water. Carcass processing required 91-billion L of water. The model estimated that in the U.S. 2,275 L of blue water was needed to produce 1 kg of boneless meat. As with the previous model, the current model was most sensitive to changes in the dressing percentage and the percentage of boneless yield in carcasses of feedlot cattle (62.8 and 65, respectively). In conclusion, with more beef, fewer cows, and lower rates of irrigation, beef cattle's water intensity has decreased at an annual rate of 1.34% over a 28-yr period.

Evaluasi dan Redesain Instalasi Pengolahan Air Limbah (Studi Kasus: Hotel X Kota Jambi)

Hotels produce wastewater as much as 80% of the total use of clean water, the wastewater is categorized as domestic wastewater. Hotel X is a 4-star hotel with a need for clean water of 64,396 m3/day and the waste water produced is 49.33 m3/day. Based on observations and evaluations, it was concluded that Hotel X's wastewater was treated at the WWTP with performance that was still not optimal. So that the method used in this research is descriptively analyzing primary and secondary data, then proceed with evaluation and redesign of certain WWTP units based on existing conditions in the field. Laboratory test results show that the parameters that do not meet the quality standards are TSS 136 mg/L, BOD5 56 mg/L, and COD 174 mg/L, so the units that need to be evaluated based on existing conditions consists of grit chamber units, equalizing tanks, anaerobic tank, aerobic tanks, sludge tanks and sedimentation tanks. Based on the results of the evaluation on the existing WWTP unit at Hotel X, there are WWTP units that need to be optimized, namely equalizing tanks and aerobic tanks, where the detention time exceeds the design criteria. Redesign of dimensional changes to the equalizing tank and aerobic tank units. Based on the calculation results, the detention time in the equalizing tank was 8.5 hours and in the aerobic tank 14.38 hours. The equalizing tank unit has been modified to a depth of 2 m to reduce detention time in the initial processing to 6.8 hours, while for the aerobic tank 2 unit, it is modified to a width of 2.5 m and a length of 2.5 m, the length and width of the aerobic tank unit 2 is equated with the size of tube 1 to reduce detention time in processing to 7.6 hours.

Spatio-temporal disparity of water use efficiency and its influencing factors in energy production in China

Water resources are considered as the biggest obstacle to regional high-quality development in China. Increasing water use efficiency (WUE) is an effective way to alleviate the growing water scarcity. The study concentrates on the energy production in China, uses the input-output analysis (IOA), data envelopment analysis (DEA), and geographically and temporally weighted regression (GTWR), to determine the total water use, to measure WUE, and to identify the main influencing factors. The results indicated that water consumption exhibit an overall increasing trend, decreasing from the southeastern regions to the southwestern, the northeastern, and the northwestern regions, with an increasing proportion of intermediate input. Although WUE improves significantly from 2002 to 2015, there is still a large space for improvement. Globally, WUE is highly clustered in most regions, and the degree of clustering shows a continuously increasing trend. Locally, the coastal regions in north of the Yangtze River have higher efficiency, while regions in the northwestern and southwestern have lower efficiency. The positive influences of population size, economic level, and industrial structure are significant, and the negative influence of resource endowment is also significant. The influences of resource endowment, population size, economic level, and industrial structure are significantly non-stationary in both space and time, and the former is stronger than the latter. Overall, economic level and population size are the predominant factors, and their quantitative structures are extremely stable.