Water Use Characteristics Research Articles

Water relations of seedlings of three Quercus species: variations across and within species grown in contrasting light and water regimes

We compared seedling water relations of three Mediterranean Quercus species (the evergreen shrub Q. coccifera L., the evergreen tree Q. ilex L. subsp. ballota (Desf.) Samp. and the deciduous or marcescent tree Q. faginea L.). We also explored seedling potential for acclimation to contrasting growing conditions. In March, 1-year-old seedlings of the three species were planted in pots and grown outdoors in a factorial combination of two irrigation regimes (daily (HW) and alternate day watering (LW)) and two irradiances (43 and 100% of full sunlight). At the end of July, predawn and midday water potentials (Psi(pd), Psi(md)) were measured, and pressure-volume (P-V) curves were obtained for mature current-year shoots. Species exhibited similar Psi(pd) and Psi(md) values, but differed in leaf morphology and water relations. The evergreens possessed larger leaf mass per area (LMA) and were able to maintain positive turgor pressure at lower water potentials than the deciduous species because of their lower osmotic potential at full turgor. However, the three species had similar relative water contents at the turgor loss point because Q. faginea compensated for its higher osmotic potential with greater cell wall elasticity. Values of Psi(pd) had a mean of -1.12 MPa in LW and -0.63 MPa in HW, and Psi(md) had a mean of -1.13 MPa in full sunlight and -1.64 MPa in shade, where seedlings exhibited lower LMA. However, the P-V curve traits were unaffected by the treatments. Our results suggest that Q. faginea seedlings combine the water-use characteristics of mesic deciduous oak and the drought-tolerance of xeric evergreen oak. The ability of Q. coccifera to colonize drier sites than Q. ilex was not a result of higher drought tolerance, but rather may be associated with other dehydration postponement mechanisms including drought-induced leaf shedding. The lack of treatment effects may reflect a relatively low contrast between treatment regimes, or a low inherent responsiveness of these traits in the study species, or both.

Effect of irrigation frequency and amount on water use efficiency and yield of sesame ( Sesamum indicum L.) under field conditions

The water-use characteristics of sesame ( Sesamum indicum L.) were studied in the field under furrow irrigation. Irrigation water quantities were based on pan evaporation ( E pan) from a screened class-A pan. Treatments consisted of three irrigation intervals ( I 1: 7 days; I 2: 14 days, I 3: 21 days), and four pan coefficients ( K cp 1 : 0.60; K cp 2 : 0.80, K cp 3 : 1.00 and K cp 4 : 1.20). Average irrigation values for each treatment varied from 467 to 857 mm in 2003 and 398 to 654 mm in 2004. The highest seasonal evapotranspiration was obtained from the I 3 K cp 4 treatment in 2004 (1019 mm); the lowest value was observed in the I 1 K cp 1 treatment in the same year (598.0 mm). Data collected in 2003 and 2004 showed that the amount of irrigation water applied significantly the affected seed yield. However, the effects of irrigation interval on yield were not significant. On average, the K cp 3 treatment gave the highest seed yield (1.915 t ha −1), whereas K cp 1 treatment gave the lowest (1.538 t ha −1). Seasonal yield response factors ( k y) were 1.01 and 0.54 in 2003 and 2004, respectively. ET/ E pan ratios for each treatment varied from 0.3 to 1.3 in 2003 and from 0.1 to 1.1 in 2004. In conclusion, the K cp 3 plant-pan coefficient is recommended for sesame grown under field conditions in order to maximise yield.

Study on Residential Water Use in North China: Analysis of Nationwide Statistical Data and Case Study of Taiyuan City

Residential water use is gradually becoming the focus in China's municipal water supply planning and management in recent years. Little is known, however, about the residential water use in modem China due to the transition of economy and enhancement of management on water conservation. In order to better understand the characteristics of residential water use in North China, a model for identifying the determinants of residential water use was established and analyzed by using panel data and cross-section data methodologies. Then Taiyuan city, the capital city of Shanxi Province in Northern China was selected as a case study. Both the analyses and field investigation indicate that the relatively slow increase of residential water use in recent years may result from the implementation of strict laws and regulations on water conservation. And through the investigation, first-hand information about water consumption pattern, water reuse/conservation, people's attitude toward water quantity and quality, etc. have been obtained.

Photosynthesis and water-use characteristics in Indian mangroves

Photosynthesis and water efflux were measured in different PAR and stomatal conductance in members of Avicenniaceae and Rhizophoraceae. Trend of leaf temperature with irradiance and its effect on photosynthesis were also estimated. In most of the studied species, photosynthesis and stomatal conductance followed similar trends with increase in irradiance. The rate of net photosynthesis and stomatal conductance were higher in members of Avicenniaceae than in Rhizophoraceae. In Avicenniaceae, the optimum PAR for maximum photosynthesis ranged between 1340–1685 (μmol m-2s-1, which was also higher than that of Rhizophoraceae (840-1557 μmol m-2s-1). Almost in all the studied taxa, transpiration and stomatal conductance followed similar trends and reached the maximal peaks at the same PAR value. The range of breakeven leaf temperature was almost the same in both the families (34-36°C in Avicenniaceae and 33.5-36.3°C in Rhizophoraceae), beyond which assimilation rate declined.

A comparative analysis of the characteristics of domestic water use in metropolitan Adelaide

An understanding of domestic water consumption is important for planning and development purposes. This paper presents a methodology for estimating in-house and ex-house water consumption in Adelaide in the absence of detailed water use studies. Bi-annual water meter readings enable metropolitan water usage to be separated into “domestic” and “other” use categories; while monthly metropolitan water treatment plant discharges are used to divide the domestic consumption component into in-house and ex-house uses and to establish the monthly trends of ex-house demand. Average annual water demand results for in-house and ex-house uses are compared with those obtained in water use studies conducted in Perth and Melbourne. The results compare well, giving validity to the methodology applied. The study shows that average in-house water consumption for Adelaide households is 140 kL; water use outdoors is 136 kL per annum.

Economic Instruments and Canadian Industrial Water Use

Water is an important input for many industrial sectors including manufacturing, mining and energy generation. Industrial water use differs from other sectors in its high reliance on self-supplied water, the potential for internal water recycling and the possibility of use leading to diminished water quality. Furthermore, industrial water use has a number of interrelated components including intake, internal recirculation, treatment prior to and following use and discharge. In principle, each of these activities can be expected to depend upon the economic and regulatory environment facing the firm. This paper examines the economic characteristics of Canadian industrial water use and considers the experiences of other jurisdictions in employing economic instruments to promote industrial water conservation. The paper then assesses the potential efficacy of economic instruments as a means of promoting integrated water resources management in the Canadian industrial sector. The paper concludes by identifying the opportunities and barriers for enhanced reliance on economic instruments.

Using Economic Instruments for Water Demand Management: Introduction

Water is an important input for many industrial sectors including manufacturing, mining and energy generation. Industrial water use differs from other sectors in its high reliance on self-supplied water, the potential for internal water recycling and the possibility of use leading to diminished water quality. Furthermore, industrial water use has a number of interrelated components including intake, internal recirculation, treatment prior to and following use and discharge. In principle, each of these activities can be expected to depend upon the economic and regulatory environment facing the firm. This paper examines the economic characteristics of Canadian industrial water use and considers the experiences of other jurisdictions in employing economic instruments to promote industrial water conservation. The paper then assesses the potential efficacy of economic instruments as a means of promoting integrated water resources management in the Canadian industrial sector. The paper concludes by identifying the opportunities and barriers for enhanced reliance on economic instruments.

Damla Sulama Yöntemi ile Sulanan Fasulyenin (Phaseolus vulgaris L.) Su Kullanım Özellikleri

Damla sulama yöntemi ile sulanan kuru fasulyenin su kullanım özelliklerinin belirlenmesi amacıyla yürütülen bu çalışmada, bitkiye, tükettiği su miktarının % 0, 25, 50, 75 ve 100’ ün karşılandığı beş farklı sulama programı uygulanmıştır. Araştırma sonucunda, bitki su ihtiyacının tamamının karşılandığı koşullarda, fasulye bitkisinin mevsimlik bitki su tüketimi 732 mm olarak ölçülmüştür. Elde edilen tane verimleri, uygulanan toplam sulama suyu ve mevsimlik bitki su tüketimi ile doğrusal ilişkiler göstermiştir. Çalışmada, mevsimlik su-verim ilişkisi faktörü ky 1.04 olarak saptanmıştır. Ayrıca, deneme konularına göre sulama suyu kullanım randımanı IWUE 0.34 – 0.41 kg/m, su kullanım randımanları WUE ise 0.20 – 0.37 kg/m3 arasında değişmiştir

Quantitative and spatial characteristics of river water use in Japanese watersheds A comparative study of Naka and Kinu-Kokai River basins

Quantitative and spatial characteristics of river water use in Japanese watersheds A comparative study of Naka and Kinu-Kokai River basins

Water Consumption and Drainage in the Volga Basin

Data on water withdrawal and use in different economic branches in the Volga basin in 1970–2000 are analyzed. Time variations in the removed volumes of waste, mine, and drainage waters, as well as in their chemistry, are considered. Characteristics of water use in 2010 are forecasted based on predictions of the socioeconomic development of Russia and extrapolation of the tendencies established in the dynamics of the analyzed indices.

Characteristics of Water Use and Flow Improvement of Kamachi Regional Creek in the Hanamune and Oota River Irrigation Networks

Characteristics of Water Use and Flow Improvement of Kamachi Regional Creek in the Hanamune and Oota River Irrigation Networks

Quercus species differ in water and nutrient characteristics in a resource-limited fall-line sandhill habitat.

We compared co-occurring mature Quercus laevis Walt. (turkey oak), Q. margaretta Ashe (sand post oak) and Q. incana Bartr. (bluejack oak) trees growing in resource-limited sandhill habitats of the southeastern United States for water and nutrient characteristics. The Quercus spp. differed in their distribution along soil water and nutrient gradients, and in their access to and use of water, even though the study year was wetter than average with no mid-season drought. Quercus laevis had the greatest access to soil water (least negative pre-dawn water potential, psi(pd)) and the most conservative water-use strategy based on its relatively low stomatal conductance (g(s)), high instantaneous water-use efficiency (WUE), least negative midday water potential (psy(md)) and high leaf specific hydraulic conductance (K(L)). Quercus margaretta had the least conservative water-use characteristics, exhibiting relatively high g(s), low instantaneous WUE, most negative psi(md), and low K(L). Quercus margaretta also had a low photosynthetic nitrogen-use efficiency (PNUE), but a high leaf phosphorus concentration. Quercus incana had the poorest access to soil water, but intermediate water-use characteristics and leaf nutrient characteristics more similar to those of Q. laevis. There were no species differences for photosynthesis (A), leaf nitrogen on an area basis, or seasonally integrated WUE (delta13C). Both A and g(s) were positively correlated for each species, but A and g(s) were generally not correlated with psi(pd), psi(md) or delta psi(pd-md). Although we found differences in resource use and resource status among these sandhill Quercus spp., the results are consistent with the interpretation that they are generally drought avoiders. Quercus laevis may have an advantage on xeric ridges because of its greater ability to access soil water and use it more conservatively compared with the other Quercus spp.

The aluminium response network in perennial ryegrass (Lolium perenne): II. Water fluxes and ion transport

Aluminium toxicity was investigated by analyzing the mineral nutrition and water-use characteristics of hydroponically-grown plants differing in tolerance to Al when subjected to Al (0, 20, 40, 80 μM: pH 4.5) for 28 days. Both lines reacted to Al by increasing their water-use. The Al-tolerant plants were, however, able to control the Al-stimulated water fluxes and progressive increases in water-use (increasing Al) were limited to the Al-sensitive material. Although Al was not generally transported into the foliage, Al treatments nevertheless elicited changes in the composition of the leaves including apparently opposite effects on the Ca, K and P levels found in Al- tolerant and Al-sensitive plants. Analysis of these differences revealed that leaf Ca concentrations were positively related to water-use while leaf K was antagonistically linked to Ca and thus inversely related to the Al- stimulated changes in the plants' water-use. Differences in K nutrition centred around P transport and fluctuations in leaf P paralleled the Al-stimulated changes in foliar K concentrations. These findings are used to develop a theory of root-to-shoot communication in Al-stressed plants which encompasses water fluxes and ion transport processes.

The photosynthetic drought physiology of a diverse group of southern hemisphere conifer species is correlated with minimum seasonal rainfall

1. The instantaneous and integrated leaf gas exchange of 13 species of southern hemisphere conifers grown under identical glasshouse conditions were examined to determine whether there was any correlation between the characteristics of water use at the leaf level and environmental water availability. 2. In the conifer species examined, the minimum ratio of internal to ambient CO2 measured in leaves during artificially imposed drought [(ci/ca)min] was strongly correlated with the minimum rainfall observed within the natural range of each species. This suggests that the distributions of these species are constrained by the drought tolerance of their photosynthetic apparatus. 3. A good correlation was found between the ratio of internal to ambient CO2 measured in leaves under optimal conditions (ci/ca)max and leaf δ13C (and hence inferred ∫[ci/ca]). Neither of these, however, correlated with the environmental parameters considered most likely to be limiting species distribution, i.e. precipitation and altitude. 4. These data suggest that decreasing water availability may have been the major factor responsible for the restriction and extinction of conifers in the southern hemisphere.

Intermittent Mist Control via Solar Cells

Comparisons were made between a commercially available, solar-activated mist control device (Weather Watcher®) and time clocks to determine their relative effectiveness, usefulness, and water-use characteristics on a greenhouse mist propagation bench. Coleus cuttings produced more roots per cutting and had greater average root lengths under Weather Watcher-controlled mist than those cuttings on a mist bench controlled by time. Paulownia cuttings produced the same number of roots under solar- or time-activated mist; however, the average root length was greater under Weather Watcher control. Mist benches controlled by the Weather Watcher used only one-third the water used by benches controlled by a time clock.

Microsystems Irrigation in Niger, West Africa

Small-scale irrigation plays a crucial role in agricultural production in Niger, West Africa. Despite the prevalence of traditional irrigation microsystems (average size of about 0.1 ha), not much is known about water-management practices. This paper examines, over a range of lifting heads, the water-lifting and water-use characteristics of 84 manual lift microsystems and intensively investigates two manual systems and two motorized lift systems. An adaptation of the Thornthwaite-Mather procedure to predict recharge is used to model the soil moisture budget. Because of the size of microsystems, irrigation efficiency tends to be high. While pumps offer a significant labor-saving advantage over manual lifting devices, many pumps are not well matched to lifting head. This paper concludes that both manual and motorized lift technologies should continue to be employed in Niger, but that pumps must be better matched to lifting heads and to the particular labor constraints for field water distribution.

Site-specific Parameter Values For the Nuclear Regulatory Commissionʼs Food Pathway Dose Model

Routine operations at the Savannah River Site (SRS) in Western South Carolina result in radionuclide releases to the atmosphere and to the Savannah River. The resulting radiation doses to the off-site maximum individual and the off-site population within 80 km of the SRS are estimated on a yearly basis. These estimates are currently generated using dose models prescribed for the commercial nuclear power industry by the Nuclear Regulatory Commission (NRC). The NRC provides default values for dose-model parameters for facilities without resources to develop site-specific values. A survey of land- and water-use characteristics for the Savannah River area has been conducted to determine site-specific values for water recreation, consumption, and agricultural parameters used in the NRC Regulatory Guide 1.109 (1977) dosimetric models. These site parameters include local characteristics of meat, milk, and vegetable production; recreational and commercial activities on the Savannah River; and meat, milk, vegetable, and seafood consumption rates. This paper describes how parameter data were obtained at the Savannah River Site and the impacts of such data on off-site dose. Dose estimates using site-specific parameter values are compared to estimates using the NRC default values.

Drip Irrigation Management and Scheduling for Vegetable Production

Proper management of vegetable drip-irrigation systems requires knowledge of soil hydraulic characteristics, plant-growth and water-use characteristics, and evaporative demand. The resultant schedule must integrate these properties and conform to existing irrigation system and cultural constraints. Irrigation management must be coupled with the fertilizer management program to avoid excessive water applications that leach plant nutrients. Because drip irrigation applies water to discrete locations along the plant row, limited irrigated areas can result, and this is an important consideration for irrigation system design, cultural practices and management, and irrigation system operation and management.

Yield variability and water use in wide-spaced furrow irrigation

Characteristics of crop yield and water use in wide-spaced furrow irrigation (W) were compared to every furrow irrigation (E). The study was conducted at Goodwell, Oklahoma on a clay loam soil with grain sorghum ( Sorghum bicolor (L.) Moench). E furrows were 1.42 m apart and W applied water to alternate furrows, making a 2.84 m spacing. W treatments caused no greater yield variation down the furrow than the E treatment, although about 1 2 the water was applied to the W plots as for E. In the W treatments not all furrows were irrigated at any one time and, on occasion, the dry furrows were noted to crack. Subsequent irrigation to cracked dry furrows showed significantly greater penetration of water into the profile than the E treatments. Soil water tended to be depleted to greater degree in the W treatments than the E treatment over the growing season, but seasonal evapotranspiration was lesser in the W plots.

Maintenance of Leaf Temperature and the Optimisation of Carbon Gain in Relation to Water Loss in a Tropical Mangrove Forest

Properties and display of foliage were studied in relation to gas exchange characteristics of tropical mangrove species. Rates of assimilation of CO2 were maximal at leaf temperatures of approximately 30°C. The species operated with higher water use efficiencies than do most C3 species, and water-use characteristics became increasingly conservative with increase in the salinity tolerance of the species. Changes in three properties of leaves, i.e. inclination, area, and succulence, contributed to maintenance of leaf temperatures near air temperatures with minimal evaporative cooling. Interspecific differences in water-use characteristics, and their relationship to the maintenance of favourable leaf temperatures, could affect the competitive abilities of mangroves and the structure of mangrove forests.