Water Supply Rate Research Articles

Cluster root allocation of white lupin (Lupinus albus L.) in soil with heterogeneous phosphorus and water distribution

Cluster roots are structures formed by many plants adapted to phosphorus (P)-deficient soils. We investigated the combined influence of spatial heterogeneity in soil water and P distribution on the allocation of cluster root formation in white lupin (Lupinus albus L.). In this study, single plants were grown at a low or a high rate of water supply in containers filled with a P-poor sand to which either no P was added or which was fertilized homogeneously or heterogeneously. Furthermore, heterogeneous soil water distribution was established in half of the containers by using a finer instead of a coarser sand in a lateral third of the containers. Plant growth increased with water supply rate, but P fertilization had no influence on shoot biomass production. Although overall cluster root production decreased with increasing homogeneous P supply, localized P fertilization had no effect on cluster root allocation. However, cluster roots were preferentially allocated in the soil sections with lower water availability when overall water supply rate was low. The results suggest that overall cluster root production was a systemic response to initial plant P status, while cluster root growth was stimulated locally in drier patches when overall water supply was limiting plant growth.

The impact of irrigation water supply rate on agricultural drought disaster risk: a case about maize based on EPIC in Baicheng City, China

This study presents a methodology for risk analysis, assessment, and combination of drought disasters under the different irrigational levels in Baicheng City, which is supported by run theory, copula functions, crop growth model, and technique of natural disaster risk assessment from the viewpoints of climatology, geography, hydrology, agricultural science, disaster science, environmental science, and so on. Along with the global warming, the occurrences of water-related disasters become more frequent and more serious. It is necessary to determine the laws of the relationship between irrigational ability and the loss caused by drought. Drought events were identified by using run theory; the drought frequency was calculated by using copula function; the loss of every drought event was simulated by using EPIC model; and the relationship curves under the different irrigational supply conditions between the drought frequency and the yield reduction rate of the drought event were fitted to assess the impact of irrigational supply rate on the loss caused by drought. The results show that in the range of crop water demand, the loss caused by drought decreases as the result of the increase in irrigational supply rate; however, their variations are not proportional. The loss caused by the certain frequency drought event under the certain irrigational supply condition could be calculated by the curve of drought disaster risk assessment constructed by this study. The results obtained from this study are specifically intended to support local and national governmental agencies on agricultural disaster management.

内蒙古高原西部荒漠区四种锦鸡儿属植物水力结构变化的比较研究

PDF HTML阅读 XML下载 导出引用 引用提醒 内蒙古高原西部荒漠区四种锦鸡儿属植物水力结构变化的比较研究 DOI: 10.5846/stxb201306041317 作者: 作者单位: 天津师范大学,天津师范大学,天津师范大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（面上项目，重点项目，重大项目） Variation in hydraulic architecture of four Caragana species in the desert region on the Inner Mongolian Plateau Author: Affiliation: Tianjin Normal University,Tianjin Normal University,Tianjin Normal University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:本文采用改良的冲洗法，比较了内蒙古高原西部荒漠区锦鸡儿属(Caragana) 4 种优势植物—柠条锦鸡儿（C. korshinsk）、狭叶锦鸡儿（C. stenophylla）、垫状锦鸡儿（C. tibetica）和荒漠锦鸡儿（C. roborovoskyi）的水力结构日变化和季节变化，目的是了解4种锦鸡儿属植物对荒漠区环境的适应性及其差异。研究发现：4种锦鸡儿属植物的比导率、叶比导率均为早晚高、中午低的单谷日变化曲线；三个季节相比较，夏季的比导率、叶比导率最大；胡伯尔值春季>夏季>秋季。三个季节比导水率日平均值、夏季和秋季的叶比导率、三个季节的胡伯尔值都表现为：柠条锦鸡儿>荒漠锦鸡儿>狭叶锦鸡儿>垫状锦鸡儿；三个季节比导水率日变幅和春季叶比导率表现为：柠条锦鸡儿>荒漠锦鸡儿>垫状锦鸡儿>狭叶锦鸡儿。4个种比导水率日平均值的季节变幅相似。这些结果表明：（1）荒漠区锦鸡儿属植物的水力结构限制了水分运输，使其避免了中午的高蒸腾。（2）荒漠区锦鸡儿属植物通过较高的水分运输效率及较好的叶供水效率适应夏季的高温和强辐射，维持水分平衡；锦鸡儿属植物胡伯尔值的季节变化保证了其在春、夏季快速生长期有较好的水分供应。（3）较高的比导率、叶比导率和胡伯尔值导致了柠条锦鸡儿良好的水分供应和高蒸腾速率，进而导致了柠条锦鸡儿较快的生长速度，这说明柠条锦鸡儿对荒漠环境的适应性好于其它三个种；柠条锦鸡儿的输水效率高，但易发生严重的空穴和栓塞。 Abstract:Caragana species are able to survive in the stressful climatic conditions (e.g. very limited precipitation, high temperature and strong solar radiation) within the desert region on the Inner Mongolian Plateau through ecological adaptations to the environment. In the desert region, precipitation has the most important influence on plant growth and development. In order to understand how Caragana species are adapted to the arid desert environment, we investigated daily and seasonal variation in the hydraulic architecture (specific conductivity, leaf specific conductivity and Huber value) of four dominant Caragana species (Caragana korshinskii, C. stenophylla, C. tibetica and C. roborovsky), which grow in the desert region on the Inner Mongolian Plateau. We examined the hydraulic architecture of these Caragana species using the improved flushing method. The results showed that there was significant daily and seasonal variation in the hydraulic architecture of the four Caragana species. For all four Caragana species, the specific conductivity and leaf specific conductivity were high in the morning and afternoon and low at noon, showing a curve with single valley. Specific conductivity and leaf specific conductivity were highest in the summer, while Huber values were highest in spring, lower in summer, and lowest in autumn. There was also significant interspecific variation in hydraulic architecture among the four Caragana species. For daily averages of specific conductivity in the three seasons, leaf specific conductivity in summer and autumn, and Huber value in the three seasons, our results followed the pattern : C. korshinski > C. roborovoskyi > C. tibetica > C. stenophylla. For diurnal variation extent of specific conductivity in the three seasons, and leaf specific conductivity in the spring, our results followed the pattern: C. korshinski > C. roborovoskyi > C. stenophylla > C. tibetica. Seasonal variation extent of the daily average of specific conductivity was similar among the four Caragana species. Based on our results, we drew the following conclusions: (1) The hydraulic architecture of the four desert Caragana species limited water transport, which might decrease transpiration at noon. (2) Caragana species might be adapted to high temperatures and strong solar radiation through high water transport efficiency and better water supply to leaves to maintain relatively stable water status. The seasonal variation in Huber values ensured better water supplies to the four Caragana species in the spring and summer, when these species grew relatively rapidly. (3) Among the four Caragana species, C. korshinskii had the highest specific conductivity, leaf specific conductivity and Huber values, resulting in better water supply and higher transpiration rates, and thereby faster growth rates, which suggests that C. korshinskii is better adapted to the desert environment than the other three Caragana species. However, although C. korshinskii had higher water transpiration efficiency, this species was more prone to having serious cavitation and embolism. 参考文献 相似文献 引证文献

A multi-dimensional water transport model to reproduce preferential flow in the snowpack

A multi-dimensional water transport model for a snowpack was developed to reproduce preferential flow. Darcy–Buckingham's law and the van Genuchten model were used to simulate water movement. Parameters for the van Genuchten model were determined as functions of snow density and grain size, based on a previous gravity drainage column experiment. Water entry suction was newly incorporated to simulate liquid water infiltrating dry snow, based on the results of a previous capillary pressure experiment. Heterogeneity of grain size and snow density were also implemented. Heterogeneity alone was not sufficient for the development of preferential flow paths. When both water entry suction and heterogeneity were implemented, the model could simulate the formation of a preferential flow path. Validation of the simulation results by comparison with the results of a previous laboratory experiment showed that the simulated preferential flow path reproduced the experimental result fairly well. The size of the preferential flow path was negatively correlated with grain size and positively correlated with the water supply rate in both the simulation and the experiment. Comparison of the time series of suction between the simulation and the experimental result suggested that some additional measurements need to be obtained experimentally to improve the accuracy of the model. Sensitivity experiments showed that grain size and snow density heterogeneity affected both the size of the preferential flow path and the arrival time of liquid water at the snow base. These results suggest that more measurements of small-scale spatial variability in natural snow are needed to improve the model.

An Instrumented Flume to Characterize the Initiation Features of Flow Landslides

Abstract Rainfall-induced landslides are on the rise due to global warming but the associated initiation mechanisms remain unclear. To observe the local initiation features of flow landslides under different rates of water supply, a well-instrumented flume capable of tightly controlling the inflow from the groundwater supply pipes and upstream discharge was built. Basal porewater pressure transducers (PPT) were installed to monitor the water pressure evolution, and a simple method to retrofit pressure transducers into PPTs was introduced. Internal movement behaviors of the slope body prior to the onset of and during a full failure were monitored with low-cost and small-size MEMS (Micro-Electro-Mechanical-Systems) accelerometers. A MEMS sensing package, termed the Smart Soil Particle (SSP, first generation), was also developed in conjunction with the laboratory testing program for field implementation in the future. In a set of experiments designed to investigate the initiation mechanism of a loose soil sample under a small and slow constant groundwater inflow, the MEMS accelerometers and basal PPTs successfully captured the intricate internal movement features and porewater pressure patterns. This warrants more systematic studies of the flow landslide initiation mechanism using the newly developed flume instrumentation.

Risk Factors for E. coli O157 and Cryptosporidiosis Infection in Individuals in the Karst Valleys of East Tennessee, USA

This research examines risk factors for sporadic cryptosporidiosis and Escherichia coli (E. coli) O157 infection in East Tennessee, using a case-control approach and spatial logistic regression models. The risk factors examined are animal density, land use, geology, surface water impairment, poverty rate and availability of private water supply. Proximity to karst geology, beef cow population density and a high percentage of both developed land and pasture land are positively associated with both diseases. The availability of private water supply is negatively associated with both diseases. Risk maps generated using the model coefficients show areas of elevated risk to identify the communities where background risk is highest, so that limited public health resources can be targeted to the risk factors and communities most at risk. These results can be used as the framework upon which to develop a comprehensive epidemiological study that focuses on risk factors important at the individual level.

Implementation of Water Management System Based on MiddleBlock-Centered Monitoring

The evaluation standards of management efficiency for managing the water supply can be called the Revenue Water Ratio. The revenue water ratio is an important index that shows the standards on the cost of production as well as the ratio of quantities received through the rate income from the total amount of water supply produced from the water treatment plant. In general, the calculation of revenue water ratio is made on the basis of small blocks after the progression of blocking business, thus the management of water pipe network is also made on the basis of small block unit. However, the boundaries of adjacent blocks have many obscure points with many number of blocks, there are many difficulties of performing the work by the limited management personnel. Therefore in this paper, in order to improve the problems and limits of the previous block monitoring system based on inefficient small blocks, a block monitoring system based on real-time flow analysis centering on the middle block is proposed. In addition, by performing the dynamic pattern-based abnormal flow analysis considering the characteristics of each block and also by performing the real-time analysis on the rate of water supply between the classes, it will prove that the efficiency of management can be improved.

Joint Regulation and Storage of Surface Water and Groundwater in Rushan River Basin

Based on the regulating principles, the modes of joint regulation and storage of surface water and groundwater in Rushan River Basin are simulated using multi-objective programming method. The study suggests two modes as “two dry years and one normal year” and “four dry years and one wet year”. The results indicate the guarantee rates of water supply are improved, with increasing the exploitation quantity in dry years and the recharge in wet years. The study provides a strong guarantee for water resources regulation and promotes the sustainable development of regional water resources.

A dynamical system perspective on plant hydraulic failure

AbstractPhotosynthesis is governed by leaf water status that depends on the difference between the rates of transpiration and water supply from the soil and through the plant xylem. When transpiration increases compared to water supply, the leaf water potential reaches a more negative equilibrium, leading to water stress. Both high atmospheric vapor pressure deficit and low soil moisture increase the water demand while decreasing the supply due to lowered soil‐to‐root conductance and xylem cavitation. Therefore, dry conditions may eventually reduce the leaf water potential to the point of collapsing the plant hydraulic system. This “hydraulic failure” is shown to correspond to a fold bifurcation where the environmental parameters (vapor pressure deficit and soil moisture) trigger the loss of a physiologically sustainable equilibrium. Using a minimal plant hydraulic model, coordination among plant hydraulic traits is shown to result in increased resilience to environmental stresses, thereby impeding hydraulic failure unless hydraulic traits deteriorate due to prolonged water shortage or other damages.

Double row spacing and drip irrigation as technical options in energy sorghum management

The effect of two row spacing configurations and four water supply levels was investigated on sweet and fibre sorghum in Central Italy for two consecutive years. Results highlighted the influence of both irrigation and row spatial configuration on crop productivity. Indeed, several studies have pointed out the positive response of sorghum to irrigation in Mediterranean climate, as in this environment water stress represents one of the main limiting factors on crop productivity. On the other hand, few attempts have been made to explore the role of row spacing on energy sorghum productivity. Results outlined an average increase in sorghum dry biomass yield ranging from +23% to +79% at variable rates of water supply as compared to rainfed control. The positive effect of irrigation was also observed on leaf area index and radiation use efficiency. Moreover, we observed a crop yield increase, from 9% to 20%, under double row spacing compared to the standard planting pattern (i.e. single row spacing). Finally, it was confirmed the efficient use of water by sorghum and the great ability of sorghum to increase its biomass yield in response to increasing volumes of water supplied. Therefore, this work suggests how row spacing configuration and drip irrigation could be feasible technical options to increase sorghum biomass yields in Mediterranean environments. These techniques should be experienced by farmers towards a sustainable intensification of current cropping systems.

Electrical capacitance volume tomography for measurement soil water infiltration in vessel experiments

Electrical capacitance volume tomography (ECVT) is a recently-developed technique for real-time, non-invasive 3D monitoring of processes involving materials with strong contrasts in dielectric permittivity. This work is first application of the method to visualization of water flow in soil. We describe the principles behind the method, and then demonstrate its use with a simple laboratory infiltration experiment. 32 ECVT sensors were installed on the sides of an empty PVC column. Water was poured into the column at a constant rate, and ECVT data were collected every second. The column was then packed with dry sand and again supplied with water at a constant rate with data collected every second. Data were analyzed to give bulk average water contents, which proved consistent with the water supply rates. Data were also analyzed to give 3D images (216 voxels) allowing visualization of the water distribution during the experiments. Result of this work shows that water infiltration into the soil, wall flow, progress of the unstable wetting front and the final water distribution are clearly visible.

Improvement of Vase Life and Postharvest Factors of <i>Lilium orientalis</i> ‘Bouquet’ by Silver Nano Particles

Lily is one of the prominent cut flowers on the international markets, so that its longevity is an important post-storage attribute. Blockage of xylem vessels and insufficient water uptake contributes to the short vase life of cut flowers. Bacteria block stem xylem vessels and because of that reduce rates of water supply to flowers. Nano silver has antimicrobial effects at low concentration. Prolongation of vase life cut lilies (L. orientalis ‘Bouquet’) flowers by nano-silver particles was studied. Cut flowers were kept in vase containing 5, 15, 25, 30 ppm of nano-silver solutions and deionized water as control treatment under controlled conditions. During vase period, vase life, vase solution uptake, initial fresh and bacterial numbers were measured. According to the results, all nano-silver treatments extended the longevity of cut flowers compare to control. Among these treatments the concentration of 30 ppm of silver-nano showed the highest vase solution uptake, initial fresh weight and lowest bacteria colony during the first 2 days of vase life. It was concluded that nano silver particles had a high potential for eliminating of bacterial contaminants. These for suggest that application of solutions containing superior advantageous of nano-silver particles is recommended to improve postharvest of L. orientalis ‘Bouquet’.

Energy-saving effect of a residential polymer electrolyte fuel cell cogeneration system combined with a plug-in hybrid electric vehicle

The energy-saving effect of a residential polymer electrolyte fuel cell cogeneration system (PEFC-CGS) that adopts a daily start–stop operation with no reverse power flow, combined with a plug-in hybrid electric vehicle (PHEV) is analyzed by optimal operational planning model based on mixed-integer linear programming. This combined use aims to increase the electric capacity factor of the PEFC-CGS by charging the PHEV using the PEFC-CGS output late at night, and targets the application in regions where the reverse power flow from residential cogeneration systems to commercial electric power systems is not permitted, like in Japan. First, the optimal operational planning model that incorporates the daily start–stop operation of the PEFC-CGS is developed. The energy-saving effect of the combined use of the PEFC-CGS and PHEV is then analyzed on the basis of observations of the optimal operation patterns for a 0.75-kWe PEFC-CGS, a simulated energy demand with a sampling time of 5min, and various daily running distances of the PHEV. The results show that the combined use of the PEFC-CGS and PHEV increases the electric capacity factor and hot water supply rate of the PEFC-CGS and saves more energy in comparison with their separate use in which the PEFC-CGS is used but the PHEV is charged only using purchased electric power. Consequently, this feasibility study reveals that the combined use of the PEFC-CGS and PHEV provides the synergistic effect on energy savings in the residential and transport sectors.

Experimental Study on Solar Energy and Adsorption Radiation Air Conditioning System

This paper discusses the principles of solar adsorption refrigeration and the characteristics of air conditioning radiation, designs solar adsorbent bed with activated carbon - methanol as working pair and its accompanying condenser, evaporator, radiant cooling tubes and other equipment. Through experiments, it changes water supply by change flow rate of chilled water, in order to get chilled water supply and return water temperature and room temperature curve. To analysis COP value of system under different flow rate of chilled water, and get the optimal flow rate of chilled water supply.

Lithium in the Public Water Supply and Suicide Mortality in Greece

The purpose of the present study was to evaluate the association between lithium levels in the public water supply and prefecture-based suicide rates in Greece. Analyses were conducted with respect to lithium levels in 149 samples from 34 prefectures of Greece. The average lithium level was 11.10 μg/l (range 0.1 to 121 μg/l). The results indicate that there is a tendency for lower suicide rates in the prefectures with high levels of lithium in drinking water. Ecological studies explained by researchers Schrauzer and Shrestha have revealed the existence of statistically significant inverse associations between the lithium levels in drinking water and the incidence of suicides, homicides, rapes, possession of narcotic drugs, and in juveniles, the rates of runaway from home. Such a result of inverse relationship was not proven by Kabacs et al., most likely because the differences of the lithium levels in the selection of their case-control samples were not large enough. In addition, probably the selection of random regions in Japan and East England might have been biased. Thus, the addition of small amounts of lithium to the drinking water could provide an effective means to lower the incidence of these conditions in the general population. Furthermore, the nutritional importance of lithium in the form of the carbonate named lithium carbonate (Li2CO3) is currently still viewed primarily as a pharmacological agent. The study by Al-Chalabi et al. state that the therapeutic activity of lithium in amyotrophic lateral sclerosis (ALS) is worth investigating. Any drug that can be shown to slow the course of ALS in a clinically significant way and to be safe and well tolerated will be an important advance for patients with this disease.

Evaluation of residential rainfall harvesting systems in Jordan

A field study was conducted to evaluate the potential of rooftop rainfall harvesting (RRH), determine the smallest tank volume and the potential contribution of RRH to the national water budget. The potential water volume from rooftops nationwide is 14.7 million cubic metres per year (MCM/year), which comprises 6% of the domestic national water budget. Public water supply rates decreased for areas practicing RRH. The number of underground tank (cisterns) increased in high rainfall areas indicating adaptation behaviours for securing water. Smallest cistern volume charts were constructed for each governorate in relation to consumption rate and rooftop area. An immediate and nationwide awareness and legislative programmes are needed to spread RRH among the whole population of Jordan.

Comparative Study of the Cutting Efficiency and Working Life of Carbide Burs

The aim of this study was to establish the wear and cutting efficiency of tungsten carbide burs from different manufacturers by performing cutting tests with machinable glass ceramic. Cutting tests were performed with 70 tungsten carbide burs from seven manufacturers: (A) Coltene/Whaledent, (B) CEI, (C) Meisinger, (D) Axis, (E) Komet, (F) Kerr, (G) Edenta. All groups were examined under scanning electron microscope (SEM) before and after the cutting efficiency test for similarities and differences. A specially designed cutting device was used. An electric handpiece was operated at 200,000 rpm with a 120 ml/min coolant water supply rate. The burs were tested under a 165 g constant load using 3 mm wide Macor ceramic as substrate. For each bur the cutting procedure involved a total of five cuts of 3 minutes on every cut, with a total cutting time for each bur of 15 minutes. Data were analyzed using one-way ANOVA at 95.0% confidence level. Significant differences (p < 0.05) were found in the mean cutting rates of the different groups. Groups A and B showed the highest cutting rates. Higher cutting rates were associated with a longer bur lifespan. SEM photomicrographs of the burs and substrates revealed significant changes on the surfaces after the cutting process. The morphology characteristics of tungsten carbide burs are related to their effectiveness. The group that presented the worst working life also showed substantial wear on its surface according to the results of SEM.

Lithium in the public water supply and suicide mortality in Texas

There is increasing evidence from ecological studies that lithium levels in drinking water are inversely associated with suicide mortality. Previous studies of this association were criticized for using inadequate statistical methods and neglecting socioeconomic confounders. This study evaluated the association between lithium levels in the public water supply and county-based suicide rates in Texas. A state-wide sample of 3123 lithium measurements in the public water supply was examined relative to suicide rates in 226 Texas counties. Linear and Poisson regression models were adjusted for socioeconomic factors in estimating the association. Lithium levels in the public water supply were negatively associated with suicide rates in most statistical analyses. The findings provide confirmatory evidence that higher lithium levels in the public drinking water are associated with lower suicide rates. This association needs clarification through examination of possible neurobiological effects of low natural lithium doses.

The effect of fluctuation in flow rate on the performance of conventional and membrane water treatment for a smart water grid

A smart water grid can save water and energy by delivering the water to consumers according to the time-dependent demands. One of the key water treatment technologies for a smart water grid is to control the water supply rate as per the consumers' demand. However, a conventional water treatment plant is designed for a constant production rate operation, which is not appropriate for a smart water grid. The present study focuses on the effect of fluctuation on the production rate of three water treatment technologies: i.e. (1) sedimentation followed by ozonation and coagulation/flocculation, (2) sand filtration followed by coagulation/flocculation and sedimentation, and (3) membrane process (microfiltration [MF]). For sedimentation and sand filtration processes, the pilot- and real-scale plant data were analyzed to investigate the fluctuation patterns of the flow rate and water quality. For the membrane process, an MF operation was simulated to investigate the effect of fluctuation flux on the membrane fouling rate. Two key findings emerged from the pilot and field data analyses and simulation results in the present study. First, there exists a time delay between the input and output flow fluctuations for sedimentation and sand filtration processes, and the water quality is changed during and after the time delay for the flow rate fluctuation. Second, in the MF process, the flow rate fluctuation does not have any significant effect either on the permeate water quality or on the fouling behavior.

On a vegetation pattern formation model governed by a nonlinear parabolic system

A fundamental subject in ecology is to understand how an ecosystem responds to its environmental changes. The purpose of this paper is to study the desertification and vegetation pattern formation phenomena and understand the dependence of the biomass density B of vegetation on the level of available environmental water resources, controlled by a water supply rate parameter R, which is governed by a coupled system of nonlinear parabolic equations in a mathematical model proposed recently by Shnerb, Sarah, Lavee, and Solomon. It is shown that, when R is below the death rate μ of the vegetation in the absence of water, the solution evolving from any initial state approaches exponentially fast the desert state characterized by B=0; when R is above μ, the solution evolves into a green vegetation state characterized by B⁄→0 as time t→∞. In the flower-pot limit where the system becomes a system of ordinary differential equations, it is shown that nontrivial periodic vegetation states exist provided that the water supply rate R is a periodic function and maintains a suitable average level. Furthermore, some conservation laws relating the asymptotic values of the vegetation biomass B and available water density W are also obtained.