Variation In Water Uptake Research Articles

Root Distribution and Water Uptake Applied by Hydrogen and Oxygen Stable Isotopes for Lianas in Northwest China

The root distribution and water uptake of irrigated vines (Vitis vinifera L.) in arid oasis areas remain poorly understood, particularly in terms of the variations in water uptake resulting from plant type and growing period. In this study, excavation and soil coring were employed to investigate the root distribution of vines. Meanwhile, the water uptake dynamics of irrigated vines in an arid oasis area were developed using stable isotopes of hydrogen and oxygen in water bodies (δD and δ18O) and in crops and soil water, coupled with a direct inference approach and a linear mixed model (IsoSource). The soil layers were divided into nine layers via hierarchical cluster analysis. The results indicated that the vertical distributions of the total and fine roots of grapevines were mainly in the range of 40–160 cm, accounting for 93.1% (91.2%) and 92.5% (90.0%) of the total root (200 cm) distribution during May and October, respectively. In the horizontal direction, both the total root and fine root systems were mainly distributed within 0–100 cm from the trunk and contributed 81.2% and 79.8% of the total root distribution, respectively. Meanwhile, both the total root weight (length) density and fine root weight (length) density decreased gradually with increasing radial distance from the trunk in the 0–80 cm range. The main water uptake of vines was at 0–40 cm in June, 20–80 cm in July, and 40–100 cm in August. These findings suggest that the main depth of root water uptake increases during the whole growth stage for grapevines in arid oasis ecosystems. This information will help growers to improve irrigation efficiency and provide a data analysis of water conservation in an arid oasis area during water stress.

Seasonal variations in water uptake and transpiration for plants in a karst critical zone in China

Despite substantial drought conditions in the karst critical zone (KCZ), the KCZ landscapes are often covered with forest woody plants. However, it is not well understood how these plants balance water supply and demand to survive in such a water-limited environment. This study investigated the water uptake and transpiration relationships of four coexisting woody species in a subtropical karst forest ecosystem using measurements of microclimate, soil moisture, stable isotopes (δ18O, δ2H, and δ13C), intrinsic water-use efficiency (WUEi), sap flow, and rooting depth. The focus was on identifying differences within- and between-species across soil- and rock-dominated habitats (SDH and RDH) during the rainy growing season (September 2017) and dry season (February 2018). Species across both habitats tended to have higher transpiration with lower WUEi during the rainy season and lower transpiration with higher WUEi during the dry season. Compared to those in the SDH, species in the RDH showed lower transpiration with higher WUEi in both seasons. The dominant water sources were soil water and rainwater for supporting rainy-season transpiration in the SDH and RDH, respectively, and groundwater was the main water source for supporting dry-season transpiration in both habitats. A clear ecohydrological niche differentiation was also revealed among species. Across both habitats, shallower-rooted species with higher soil-water uptake, compared to deeper-rooted species with higher groundwater uptake, showed higher transpiration and lower WUEi during the rainy season and vice versa during the dry season. This study provides integrated insights into how forest woody plants in the KCZ regulate transpiration and WUEi in response to drought stress through interactions with seasonal water sources in the environment.

Effect of Fibre Surface Treatment on the Mechanical Properties of Jute Fibre Reinforced Unsaturated Polyester Composite

ABSTRACT Interface between the fiber and polymer matrix plays a key role in fiber-reinforced composites. Modification of the interface by chemicals or particles promotes the interaction between fiber and matrix. In the present study, attempt has been made to modify the surface of jute fiber with starch particles, an eco-friendly and low-cost material. Coating of starch on jute fiber has been carried out by a solution-based approach with variation in fiber to starch ratio (100:1, 100:5, 100:10). Composites have been prepared by hand lay-up technique using starch uncoated and coated fibers along with unsaturated polyester resin (UPR). Fibers have been characterized by microscopy and thermal analysis which reveals the coating of starch particles on fibers. It has been observed that with increasing starch concentration roughness increases but higher content leads to smooth surface of the fiber. The mechanical properties of composite sheets have been evaluated by tensile, flexural and impact testing. Maximum tensile strength of 20.5 MPa and Young’s modulus of 1457.7 MPa has been obtained in composites having starch-coated fibers with fiber to starch ratio of 100:5. water absorption studies show marginal variation in water uptake by the composites with starch-coated jute fibers.

Preliminary Results on Experimental Modelling of an Adsorption Chiller

Adsorption refrigeration, as a renewable cooling method, has received more attention in the last few years. The interest in this technology comes especially from developing and tropical countries, where the demand for cooling increases every year due to economy and population growth. Based on this scenario, this work aims to develop a numerical model of an adsorption chiller driven with solar energy, which can be used to optimize the cooling system operation of the building where the device is situated and compare it with the current cooling methods in use. The numerical study here presented was created using Matlab/Simulink™, it is based on a lumped parameter model that relies on physical properties and represents a cooling system using a pair of silica gel-water in a two-bed chiller. In this study, the authors proposed a simplified version of the system and the numerical model, which aims to reduce the simulation time and provide faster results. Besides the temperatures in the system, which range from 52 °C to 72 °C in the hot cycle and 12 °C to 23 °C in the chilled water cycle, the results also include the variation of water uptake in the two adsorbent beds. In general, the simulated temperature, cooling and heating power and coefficient of performance (COP) are in fair agreement with the literature data, nevertheless, the final results show that improvements still have to be performed.

DROUGHT EFFECTS ON LEAF CANOPY TEMPERATURE AND LEAF SENESCENCE IN BARLEY

Drought stress is a major threat on most of the agricultural crops grown in the East Mediterranean Region in the consequence of predicted global climate change (1). Therefore, improving essential cereal crops such as barley is extremely important for this region to increase yield production due to its economic interest and adaptability to dry environments (29). This two-year experiment was carried out in Kalar technical institute, in Garmian region, Iraq during the seasons of 2016-17 and 2017-18. Canopy temperature depression (CTd) and leaf senescence traits (Onset of leaf senescence (SENonset) and End of leaf senescence (SENend)) were evaluated under irrigated and rain-fed conditions for five hybrid genotypes of barley. Canopy temperature was increased by drought by almost one degree Celsius on average for both years (P=0.002). Leaf senescence durations were also affected by water stress and advanced SENonset by around 34% (P=0.001) and SENend by around 10% (P=0.01) averaging over years. Genotypes 3//14 scored the highest canopy temperature depression and the latest onset of leaf senescence under drought for the cross year mean (P=0.05). Genotype 3//5 was also the latest to reach the end of leaf senescence averaging over years. Genotypes 3//14, 3//5 and 3//4 were generally appeared to have cooler canopy and later onset of leaf senescence than the genotypes 3//18 and 3//1 indicating the capability of these genotypes to have a better performance under water limitations comparing to other genotypes. Canopy temperature depression was positively associated with onset of leaf senescence under drought conditions averaging over years (R2=0.89; P=0.02), but not under irrigated conditions (R2=0.45; P=0.21). There was also a trend for a positive association between canopy temperature and the end of leaf senescence under drought conditions (R2=0.59; P=0.13) in 2018. These associations might be linked to genetic variations in water uptake and/or water-use efficiency.

Water consumption in small mammals (dwarf rabbits, Guinea pigs and chinchillas): New data about possible influencing factors

Information on water requirement of small mammals is sparse and the assessment of daily water consumption is an important aspect of the veterinary practice in exotic pet nutrition. Water and feed daily intake are interlaced, that way the water to feed ratio is a meaningful indication. However, various factors such as ambient temperature or the uptake of substances to be eliminated via the kidney (i.e. calcium) must be taken into account when estimation of water consumption is carried out. Moreover, behavioural abnormalities could affect water consumption, like in the case of water uptake as a substitute action. Adequate water supply for small mammals is indispensable for health reasons (prophylaxis of urolithiasis) and consequences relevant to animal welfare. For this purpose, data from different trials enrolling no. 5 Flemish Belgian (FB) and no. 5 New Zealand White (NZW) rabbits, no. 10 dwarf rabbits, no. 7 guinea pigs and no. 7 chinchilla, were obtained to assess water intake according to feed rationing. Water balance following feed rationing was seen to differ across the species of small mammals considered in these trials. The comparative approach pointed to species-dependent water intake behaviour. Due to the species-related high variation in water uptake, it is not possible to give general recommendations for water supply of small mammals. In addition, water uptake is also influenced by the water content of the food, absolute dry matter uptake and food composition. Nevertheless, an additional supply of drinking water is recommended for all species, since unsatisfactory water supply reduces dry matter intake and may lead to energy undersupply.

Spatio-Temporal Variation in Water Uptake in Seminal and Nodal Root Systems of Barley Plants Grown in Soil.

The spatial and temporal dynamics of root water uptake in nodal and seminal roots are poorly understood, especially in relation to root system development and aging. Here we non-destructively quantify 1) root water uptake and 2) root length of nodal and seminal roots of barley in three dimensions during 43 days of growth. We developed a concentric split root system to hydraulically and physically isolate the seminal and nodal root systems. Using magnetic resonance imaging (MRI), roots were visualized, root length was determined, and soil water depletion in both compartments was measured. From 19 days after germination and onwards, the nodal root system had greater water uptake compared to the seminal root system due to both greater root length and greater root conductivity. At 29 days after germination onwards, the average age of the seminal and nodal root systems was similar and no differences were observed in water uptake per root length between seminal and nodal root systems, indicating the importance of embryonic root systems for seedling establishment and nodal root systems in more mature plants. Since nodal roots perform the majority of water uptake at 29 days after germination and onwards, nodal root phenes merit consideration as a selection target to improve water capture in barley and possibly other crops.

Analysis and modeling of a membrane electrode assembly in a proton exchange membrane fuel cell

In this study, a membrane electrode assembly of a proton exchange membrane fuel cell is modeled. Using the analytical model, a computational analysis has been conducted along with an extensive parametric study. Variation of ohmic losses, water content, and voltage drops from anode to cathode side of the membrane electrode assembly with many design/operation parameters such as thickness, temperature, pressure, and local/total humidity and conductivity, diffusivity, and resistivity have been evaluated at various current densities. Also, effect of molar concentration of hydrogen on hydrogen diffusive flux due to pressure change between the anode and cathode at different membrane thicknesses has been presented. Furthermore, variation of water uptake and concentration with the ratio of water and hydrogen fluxes, the current density, and membrane dry density have been studied along with their interrelation. It is observed that as the membrane thickness increases, its resistivity increases as well, causing higher ohmic losses. On the other hand, the water content increases with the thickness until a maximum point and then starts to decrease. Therefore, the membrane thickness should be optimized carefully to have desirable humidity levels with minimum crossover and losses.

Swelling of natural fibre bundles under hygro- and hydrothermal conditions: Determination of hydric expansion coefficients by automated laser scanning

The effect of humidity conditions on the moisture content and dimensional variations of natural fibre bundles from several botanical origins with contrasting biochemical and structural characteristics is investigated. Results highlight wide variations in water uptake and swelling behaviour of fibre bundles according to plant species. Two main swelling mechanisms are identified: (i) a microscopic swelling due to the sorption of bound water in the cell walls and the middle lamella, and (ii) a macroscopic swelling related to the formation of free water in pores and lumens, which induces anisotropic deformation of bast fibre bundles cross section. Cross-sectional hygro- and hydroexpansion coefficients are determined and studied in relation with the structural features of plant fibre bundles. These results constitute key data for the predictive modelling of “in-service” mechanical behaviour of biocomposites.

Optimization of Germination Inhibitors Elimination from Sugar Beet (Beta vulgaris L.) Seeds of Different Maturity Classes

Endogenous inhibitors have a crucial effect on the success of sugar beet (Beta vulgaris) seed germination. The strength of this effect changes during seed maturation, and washing away these inhibitors can facilitate germination. Investigation of various washing factors such as water-to-seed ratio, stirring time, and speed of stirring on a mixed-maturity lot of sugar beet seeds revealed the significant effect of the interaction of all factors. Seeds with different maturity classes, from the same lot, were washed using procedures determined from the first experiment. Statistical analysis of the germination data of the washed seeds showed a significant difference in mean germination time depending on maturity class. Washing seeds of different maturity classes with 40 mL of water per gram of seed improved the germination performance of maturity classes 2 and 5, compared with 20 mL water per gram of seed. The UV absorbance of inhibitors washed from seeds differed between maturity classes. The change in seed moisture content during the washing process is another factor altered by the extent of seed development, and this variation in water uptake may reflect the pericarp structure of seed in different maturity classes. The findings in this manuscript highlight the importance of optimizing the pre-treatment procedures in accordance with the individual seed lot.

Variation of water uptake in degradation agroforestry shelterbelts on the North China Plain

Agroforestry shelterbelts are important ecological barriers providing protection against wind and sand-related disasters in the North China Plain. However, large proportions of these agroforestry shelterbelts are degenerating or have died in recent years and the causes of degeneration are extremely complex. In this study, stable hydrogen and oxygen isotope techniques were used to quantify water sources for P. simonii Carr vegetation in four degrees of degradation (undegraded, U.D; slightly degraded, L.D; moderately degraded, M.D and seriously degraded, S.D), and to investigate how the vegetation can adapt to degradation. Results show that P. simonii Carr exhibited considerable plasticity in depth of water uptake; it prefers to utilize deeper water sources which have higher soil moisture. This vegetation predominantly absorbs water from depths below 160 cm and treatments with a relatively stable and high water content source, are characterized by U.D and L.D. The utilization of deep soil water has gradually decreased, while the utilization rate of surface soil water has gradually increased with an increase in the degree of degradation. Water and nutrient availability in depths of 0–40, 40–80, 80–120 and 120–160 cm were relatively low in M.D and S.D treatments. Therefore, P. simonii Carr degeneration in this region was attributed lack of available water and nutrients. The low precipitation levels and continuous decline in the groundwater level will be accelerating degradation and death of P. simonii Carr shelterbelts.

Electrospun Ionomeric Fibers with Anion Conducting Properties

AbstractAnion conductive nanofiber mats from FAA‐3 ionomers are obtained by electrospinning. Depending on the solvent used in the precursor solution, nanofibers with either nonhollow cylindrical or flat ribbon‐like cross‐sections are prepared. The anion conductivity and water uptake of the ionomeric nanofiber mats are measured as a function of the relative humidity in the 10–90% range and compared to that of a solid membrane cast from the same ionomer. In addition, the anion conductivity of an isolated single fiber of the ionomer is measured for the first time. The anion conductivity of the electrospun single fiber is found to be higher than that of the mats, which is, in turn, one order of magnitude higher than that of the solid ionomer membrane. The higher conductivity of the mats relative to the solid membrane (in both in‐plane and through‐plane directions) is found to be related to the variation in water uptake, which stems from the morphological distinctions. These results increase the understanding of the electrospinning process of ionomers, toward the development and design of new anion conductive ionomer fibers, useful for high performance electrochemical devices.

Determining root water uptake of two alpine crops in a rainfed cropland in the Qinghai Lake watershed: First assessment using stable isotopes analysis

Knowledge of crop root water uptake (RWU) is critical for understanding agricultural water management. However, the mechanisms underlying the RWU of alpine crops in rainfed cropland remain poorly understood. This study investigated seasonal variations in water uptake of oilseed rape (Brassica napus L.) and highland barley (Hordeum vulgare L.) coupled with dual stable isotope tracers at different growth stages. The method of direct inference showed that the soil depth layer from which water was predominantly taken up by roots was 0–30cm. More specifically, oilseed rape and highland barley exhibited different RWU patterns: oilseed rape had the high flexible performance and could revert to deep soil layers (30–60cm) as the main water source according to soil water availability due to short-term droughts at the peak growth stage. In contrast, water uptake by highland barley was primarily derived from both shallow and middle soil layers (<30cm) throughout all growth stages. These findings indicated that the appropriate irrigation wetting depth should be above 30cm for the different growth stages.

Using stable isotopes to determine seasonal variations in water uptake of summer maize under different fertilization treatments

Fertilization and water both affect root water uptake in the nutrient and water cycle of the Soil-Plant-Atmosphere-Continuum (SPAC). In this study, dual stable isotopes (D and 18O) were used to determine seasonal variations in water uptake patterns of summer maize under different fertilization treatments in Beijing, China during 2013–2014. The contributions of soil water at different depths to water uptake were quantified by the MixSIAR Bayesian mixing model. Water uptake was mainly sourced from soil water in the 0–20cm depth at the seeding (67.7%), jointing (60.5%), tasseling (47.5%), dough (41.4%), and harvest (43.9%) stages, and the 20–50cm depth at the milk stage (32.8%). Different levels of fertilization application led to considerable differences in the proportional contribution of soil water at 0–20cm (6.0–58.5%) and 20–50cm (6.1–26.3%). There was little difference of contributions in the deep layers (50–200cm) among treatments in 2013, whereas differences were observed in 50–90cm at the milk stage and 50–200cm at the dough stage during 2014. The main water uptake depth was concentrated in the upper soil layers (0–50cm) during the wet season (2013), whereas a seasonal drought in 2014 promoted the contribution of soil water in deep layers. The contribution of soil water was significantly and positively correlated with the proportions of root length (r=0.753, p<0.01). The changes of soil water distribution were consistent with the seasonal variation in water uptake patterns. The present study identified water sources for summer maize under varying fertilization treatments and provided scientific implications for fertilization and irrigation management.

Durability study of a ramie-fiber reinforced phenolic composite subjected to water immersion

In the present paper, ramie fiber reinforced polymer (RFRP) plates prepared by hot compression process were subjected to water immersion at 20 oC and 40 oC for four weeks, and the variation of water uptake and mechanical properties with immersion time were investigated. It was found that the saturated water content and the coefficient of diffusion in RFRP were much higher than those in synthetic fiber based composites, due to the strong hydrophilic characteristic of the ramie fiber. After fully drying of the immersed samples, mass loss from 1.6 % to 3.6 % was found, indicating occurrence of a serious hydrolysis of the resin and the ramie fibers. After a short term of immersion (i.e., 1 day), RFRP showed a remarkable deterioration in the flexural and short beam shear properties. Further increase of the immersion time, the degradation rate of the mechanical properties was much reduced. After fully drying, the mechanical properties of the samples can be recovered to some extent, but still much less than the original values. The variation of mechanical property as a function of the water uptake content exhibits three stages (i.e., dramatic reduction, leveling off and quick decrease again). This may be due to the sequent occurrence of the degradation of natural fibers, fiber debonding and hydrolysis of the fiber and resin during immersion.

Linking root traits and grain yield for rainfed rice in sub-Saharan Africa: Response of Oryza sativa × Oryza glaberrima introgression lines under drought

Rainfed rice ecosystems account for more than 80% of the total rice area in sub-Saharan Africa, and large parts of this region frequently experience drought stress. One potential approach to improve the drought resistance and local adaptation of high-yielding rice varieties in rainfed regions of sub-Saharan Africa is to cross them with the African rice species Oryza glaberrima. In this study, 200 introgression lines (ILs) from crosses of O. sativa (IR64) and O. glaberrima (RAM90 and RAM54) were evaluated in three field experiments under different rainfed drought scenarios in Tanzania and the Philippines. The objectives of the study were to select ILs for yield and traits associated with drought resistance, and to analyze the genetic variation in water uptake, root growth, and drought response that were observed among the ILs in a previous greenhouse lysimeter study. Several ILs showed improved yield under drought stress and well-watered conditions compared with the recurrent parent IR64. One cluster of ILs that showed the highest yield across all environments included genotypes with the lowest canopy temperature under drought. In 10 selected ILs, root length density was negatively correlated with canopy temperature and soil moisture, and positively related to shoot biomass, but not significantly correlated with grain yield under drought. Although root growth in the field correlated well with root growth in the previous lysimeter study, only some of the highest-yielding lines under drought in the field were those that showed more water uptake in lysimeters. These results confirm the complex relationship among grain yield, root growth, and additional physiological mechanisms underlying crop growth and productivity in the field. The high-yielding ILs under both drought and well-watered conditions in this study can be used as donors to improve drought resistance in target rainfed rice environments in sub-Saharan Africa.

The influence of starch pasting properties and grain protein content on water uptake in barley

Steeping is the first operation of malting and its purpose is to increase the water content of the grain up to 43–46%; however, such a simple step encompasses several metabolic processes that affect germination and the final malt quality. The aim of this study was to evaluate the effect of initial grain protein (GP) content and starch pasting properties, measured using the Rapid Visco Analyser (RVA) on water uptake in different barley varieties. The partial least squares (PLS2) regression algorithm was used to compare the two data matrices, the independent block of variables X (RVA data and GP) and the dependent block Y (water uptake at different steeping times). The first two PLS2 loadings explained 65 and 23% of the total variation in water uptake in the barley samples. Water uptake at 1 and 2 h was poorly explained by the PLS2 models, while after 5 h the models explained more than 40% of the variability. The results from this study showed that, although a relationship between GP and water uptake exists, it is not universal for all the varieties, indicating that the relationship between GP and water uptake is varietal dependent. Copyright © 2014 The Institute of Brewing & Distilling

Quantifying relationships between rooting traits and water uptake under drought in Mediterranean barley and durum wheat

In Mediterranean regions drought is the major factor limiting spring barley and durum wheat grain yields. This study aimed to compare spring barley and durum wheat root and shoot responses to drought and quantify relationships between root traits and water uptake under terminal drought. One spring barley (Hordeum vulgare L. cv. Rum) and two durum wheat Mediterranean cultivars (Triticum turgidum L. var durum cvs Hourani and Karim) were examined in soil-column experiments under well watered and drought conditions. Root system architecture traits, water uptake, and plant growth were measured. Barley aerial biomass and grain yields were higher than for durum wheat cultivars in well watered conditions. Drought decreased grain yield more for barley (47%) than durum wheat (30%, Hourani). Root-to-shoot dry matter ratio increased for durum wheat under drought but not for barley, and root weight increased for wheat in response to drought but decreased for barley. The critical root length density (RLD) and root volume density (RVD) for 90% available water capture for wheat were similar to (cv. Hourani) or lower than (cv. Karim) for barley depending on wheat cultivar. For both species, RVD accounted for a slightly higher proportion of phenotypic variation in water uptake under drought than RLD.

Generalized Coupled Source–Sink Model for Evaluating Transient Water Uptake in Trickle Irrigation: I. Model Formulation for Soils with Vertical Heterogeneity

We recently derived analytical solutions of the linearized infiltration equation for steady flows from point sources into a cylindrically confined homogeneous soil domain. The same basic concepts were used in this study to obtain the solution for unsteady flows from a surface point source toward a subsurface point sink in a cylindrically confined soil with saturated hydraulic conductivity that varies exponentially with depth. As in the previous study, the infinite and finite Hankel transformations, now coupled with the Laplace transform, were used to obtain general solutions for point sources in a cylindrical domain. The solutions were incorporated into a coupled source–sink model to illustrate the influence of soil vertical heterogeneity on steady, maximum water uptake rates and on the rate of attainment of apparently steady conditions in the root zone. Illustrative simulations include: (i) steady flow patterns that develop in coupled source–sink systems in various soil textures with vertical heterogeneity; and (ii) effects of soil vertical heterogeneity on temporal variations in water uptake. Applications of a steady coupled source–sink model that assumes only a time‐dependent sink resistance, and of an unsteady model that also takes account of a time‐dependent water source, for studying the effects of the frequency and the duration of cyclic water applications on water uptake are considered in detail in the companion article.

Variability of water uptake studies of biomedical polymers

AbstractWater uptake influences many properties of polymers and has been widely studied. In the context of polymeric biomaterials, several publications reported an unusual high variability of analytical results, without further investigating the cause for this phenomenon. Using selected polymers from the library of L‐tyrosine‐derived polyarylates and poly(D,L lactic acid), we showed that nonaged and nonannealed compression molded film samples exhibit the typical large variation in water uptake observed in previous reports. The introduction of an annealing step allows accurate and reproducible water uptake measurements for these polymers. We evaluated the use of 3H‐radiolabeled water for the determination of water uptake, finding that the use of radiolabeled water yields statistically indistinguishable measurements, compared to gravimetric methods, while providing significant advantages in throughput and sensitivity. Using the recommended methods of annealing and 3H‐radiolabled water, the water uptake profiles of 24 polymers of the library of L‐tyrosine‐derived polyarylates are reported. This article addresses experimental concerns related to water uptake studies and may assist other researchers in improving the accuracy of their water uptake results. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011