Seasonal Water Consumption Research Articles

Estimation of rice evapotranspiration using a microlysimeter technique and comparison with FAO Penman-Monteith and Pan evaporation methods under Moroccan conditions

This paper reviews field measurements of evapotranspiration from paddy rice fields (ET) in an experimental station in the Gharb region of Morocco, during the summer seasons in 1995 and 1996. The results showed that the seasonal average water consumption of rice was 6.7 mm $\cdot$ day$^{-1}$ with a maximum value of 8.3 mm $\cdot$ day$^{-1}$ during the panicle enlargement stage (R2). The average daily ET for 1996 was compared with US Class 'A' open pan evaporation (Ep) and with reference evapotranspiration (ET$_0$) calculated using a validated FAO Penman-Monteith equation. Both methods gave good estimates of ET with a correlation coefficient of 0.78 ($P < 0.001$, slope = 1.06) with Ep and 0.79 with ET$_0$ ($P < 0.001$, slope = 1.3). The derived mean crop coefficients were 1.06 and 1.3, respectively, for the average of the two years. The cumulated ET over the growing season was nearly equal to the cumulated Ep, and greater by about 20% of cumulated ET$_0$. This superiority might be attributed to an advective energy transferred from areas surrounding the rice zone activated by wind speed.

A simulation model of water dynamics in winter wheat field and its application in a semiarid region

Abstract Many models for water flow in cropped soil contain parameters such as rooting density, root permeability, and root water potential. Usually these parameters are chosen by trial-and-error method and direct measurements are difficult and impractical in some cases. This study presents a simulation model capable of analyzing water transport dynamics in a soil–plant–atmosphere continuum (SPAC). This model is developed by combining an existing mathematical model for soil water flow, a modified transpiration model taking into account of the air pressure and diurnal changes of the extinction coefficient of crop canopies, and a new simple model for root water uptake. Using data from lysimeters in a field experiment carried out on a wheat crop, we also developed two new empirical equations for the estimation of total canopy resistance and soil evaporation. We then applied the model for 2 years (1990–1991, 1991–1992) on winter wheat in a semiarid area of northwest China. Required parameters, particularly soil hydraulic and crop parameters, were determined by field and laboratory tests. Outputs from the simulation were in good agreement with the independent field measurements of seasonal changes in soil water content, canopy transpiration, surface evaporation, and root water uptake along the soil profile. In addition, this simulation agreed well with the actual measurements of seasonal crop water consumption and soil water balance among the treatments for different irrigation amounts.

Water Conservation in Urban Landscapes

other seasonal water uses, such as evaporative coolers and swimming pools, but evidence indicates that landscape irrigation accounts for most of the seasonal increase in municipal water use. When a severe water shortage in Seattle, Wash., in Summer 1992 resulted in the banning of turfgrass irrigation, consequent municipal water use did not deviate from winter levels (Fig. 1, bottom), indicating that increased seasonal water use in Seattle indeed goes to landscapes. Water consumption for landscape use varies with rain and ET (Table 1). Applying the subtraction method described above to data from six cities around the United States, those in the summer-rainfall region east of the Mississippi River increase water use about one-third during the spring to fall growing season. Summing the increased seasonal water use showed that landscapes account for approximately 10% of total seasonal water consumption for these cities, the rest going to indoor and other, nonirrigation, uses. In the arid Mountain West, seasonal water use increases nearly 3to 4-fold during the growing season, and landscapes can account from a third to nearly half of the total municipal yearly water use (Vickers, 1991). The amount of water applied to landscapes can be divided into three levels of usage. The first level is water needed to meet baseline physiological plant water needs. The second level is water needed to compensate for system nonuniformity to ensure that the all plants receive the baseline level, particularly in turf. The third is water applied in excess of that needed by plants or for system uniformity, which is potentially conservable.

Water use in rice schemes in the Senegal river Delta and Valley

The water use of rice schemes was derived from field measurements made during the 1991 and 1992 season at 13 irrigation schemes situated in the delta and valley of the Senegal river. The seasonal water consumption, as well as the water distribution throughout the season and the operation of the pumping stations were evaluated. The water consumption was compared with standards which ranged from 16,650 to 21,100 m3 ha−1 depending on the season and the location of the scheme. Half of the analyzed schemes used more water than required. Analysis of the water distribution throughout the season revealed that in general the supply follows the demand. In small-scale schemes however, the fit between supply and demand is often lacking, resulting in crop stress and yield reduction. Furthermore, the study shows that the capacity of half of the pumping stations are under-used as a result of a long stretched saturation period and/or the irrigation of only a small fraction of the total area of the scheme.

Seasonal Energy, Water, and Food Consumption of Negev Chukars and Sand Partridges

Chukars (Alectoris chukar) and Sand Partridges (Ammoperdix heyi), two ground—dwelling phasianids, are permanent residents of the Negev desert and are sympatric over much of their ranges. Sand Partridges (body mass = 150—250 g), however, inhabit only arid and very arid areas, whereas Chukars (mb = 350—600 g) are widely distributed and inhabit deserts only at the margins of their ranges. We compared some of the desert adaptations of these phasianids by measuring the seasonal field metabolic rates (FMR) and water influxes (using doubly labelled water), diet selection, and food requirements of free—living Chukars and Sand Partridges at a site where both species occurred. Both species showed adaptation in the form of low energy metabolism, which ranged from 43 to 81% of that expected for birds of similar body mass. During summer, Sand Partridges had lower energy expenditures (5.47 kJ°g—0.61°d—1) and water influxes 72.3 mL°kg—0.75°d—1) than did Chukars (6.42 kJ°g—0.61°d—1 and 93.5 mL°kg—0.75°d—1, respectively), indicating more pronounced adjustments to arid conditions in the desert specialist. However, both species obtained more than half of their water influx in summer by drinking. Their summer diet was relatively dry, consisting mainly of seeds (80%) along with some green vegetation (18%) and, in Chukars, occasional arthropods. This situation changed abruptly after winter rains, which induced germination and reduced the availability of seeds. Chukars were unable to maintain energy balance in the face of low ambient temperatures and a diet (90% green vegetation) that contained much water but comparatively little energy, and they mobilized fat reserves to meet energy requirements. Most Sand Partridges left the study area after winter rains, apparently migrating to the lower elevation, warmer, and drier Arava (part of the Rift Valley). The winter rainy season appears to be the most stressful time of the year for both species. The adaptations to hot, dry conditions possessed by Sand Partridges may be accompanied by constraints on their abilities to cope with cool, wet conditions, and this may restrict them to arid and very arid habitats.

Potential Expansion and Water Demand of Riparian-Based Irrigation

ABSTRACT SEVERAL critical irrigation water use areas in Virginia have been identified. A method for determining the feasibility of large-scale irrigation was used to estimate potential irrigation expansion and water demand in one of these areas, the Pamunkey River Basin. The approach utilized a grid-based geographic information system for spatial evaluation of irrigation development potential. Proposed irrigation systems were then evaluated with respect to economic feasibility, after agronomic and engineering constraints were considered. The results of 20 scenarios are presented involving variations in crop price, investment interest rate, and benefit-cost ratio. For each scenario evaluated, the total number of feasible systems and resultant irrigated area, as well as cumulative pumping demand and seasonal water consumption, are quantified for the Pamunkey River area. Results indicate that future water use conflicts are likely in the region.

Water Relations of High-Elevation Phreatophytes in Wyoming

High-elevation phreatophytes were studied to identify environmental parameters influencing daily and seasonal water consumption. The water relations of Salix planifolia, S. wolfii and Betula occidentalis at 2865 m were similar throughout the day. Transpiration was reduced before 1000 hr as a result of dew on the leaves, but high stomatal conductances to water vapor (>15 mm s-1) and transpiration rates (>100 mg m-2 s-') occurred from 1000 to 1600 hr, resulting in daily water losses per unit leaf area of 4.5, 5.2 and 4.0 kg m2, respectively. Maximum stomatal conductances declined after 1 September in conjunction with minimum air temperatures consistently below 0 C and increased leaf senescence. The period of significant water consumption was from 10 July through 20 September. Diurnal variations in stomatal conductance of Salix exigua and S. amygdaloides at 2255 m were similar to those at the high-elevation site, but maximum stomatal conductances were only 51 % as great. However, transpiration occurred from sunrise to sunset at the lower elevation, resulting in daily water losses of 3.7 and 3.4 kg m2 of leaf area, respectively. Midday depressions in leaf conductance at the lower site may have been in response to xylem pressure potentials below 1.7 MPa. Seasonally, conductances were constant until a decrease occurred after 15 September, probably due to low temperatures and leaf senescence. The growth season at the low-elevation site was estimated to be from 15 June-30 September. Although there were differences between the two sites in maximum transpiration rates, microclimate and length of growth season, the data suggest that for both sites and all species examined, stomatal conductance and seasonal water use were most influenced by solar irradiance, dew on leaves, minimum air temperatures and phenology. INTRODUCTION At high elevations throughout the western United States, species of Salix often form dense thickets along streams. Although temperatures are relatively cool in these riparian communities, many high-elevation Salix species are very tolerant to low air (Sakai, 1970, 1974) and soil temperatures (Anderson and McNaughton, 1973), indicating a possibly prolonged growth season and continued water consumption when compared to other sympatric shrub species. Indeed, significant water consumption has been inferred for Salix-dominated communities based on estimates of evapotranspiration from environmental data (VanKlaveren et al., 1975). However, little information exists concerning the effects of environmental factors on the water relations of high-elevation phreatophytes, especially Salix. Bliss (1960) compared arctic and alpine Salix species with potometers, and found significantly greater transpiration rates in the alpine plants. Although he related transpiration to wind speed, air temperature and water vapor deficit of the atmosphere, measurements were not conducted throughout the growth season. Stoner and Miller (1975) and Miller et al. (1978) provided more in-depth evaluations of the water relations of Salix species on a seasonal basis, but their research was restricted to species of the wet coastal tundra of Alaska. The objective of the present study was to examine daily and seasonal patterns in the water relations of high-elevation phreatophytes. We present 'Present address and address for correspondence: Department of Biology, Virginia Commonwealth University, Richmond 23284.

Analysis of Seasonal Water Consumption in Danville, Ill.

Journal AWWAVolume 48, Issue 5 p. 479-484 Article Analysis of Seasonal Water Consumption in Danville, Ill. Keith A. Yarborough, Keith A. YarboroughSearch for more papers by this author Keith A. Yarborough, Keith A. YarboroughSearch for more papers by this author First published: 01 May 1956 https://doi.org/10.1002/j.1551-8833.1956.tb15470.xCitations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume48, Issue5May 1956Pages 479-484 RelatedInformation