Minimize Water Use Research Articles

Interaction Between Water and Nitrogen Application on Yields and Water-use Efficiency of Tomato and Pepper in Sandy Soil

Several practices have been adopted to minimize water use and potential N leaching of vegetable production systems, including use of drip irrigation, plastic mulch, and fertigation. However, these practices may not be adequate on sandy soils with poor water and nutrient retention capacities. The objectives of this study were to evaluate the interactive effects of irrigation practices and fertilizer rates on yield, fertilizer requirements, and N-leaching of pepper and tomato production systems. Bell pepper and tomato were planted on plastic mulched to evaluate the effects of three nitrogen (N) fertilizer rates (154, 192, 288 kg·ha -1 N for pepper vs. 166, 208, and 312 kg·ha-1 N for tomato) and three irrigation scheduling methods were evaluated. Depending on sensor readings, soil moisture sensor (SMS) irrigation treatments allowed up to five watering events per day where as for the fixed duration treatment irrigation was applied once a day. For tomato, the effect of subsurface drip irrigation (SDI) was also evaluated. Compared to TIME, use of SMS control system reduced water use by 29& to 44% and 37% to 66% for tomato and pepper, respectively. Tomato yield was significantly higher on SMS and SDI treatments compared to TIME treatments. For pepper yield and biomass accumulation were not affected by irrigation treatments. The average yields were 24.6 and 27.8 Mg·ha-1 of fresh marketable fruits for pepper and tomato, respectively. Nitrogen rate did not affect yield and optimal yield N rate did not affect yield for either crop. On average, SMS treatments increased irrigation water use efficiency 2–3 times compared to TIME treatments for both tomato and pepper.

Design procedure for water/wastewater minimization: single contaminant

Development of methodologies to minimize water use in industries has become an important area in Process Integration due to an increase in environmental awareness, at the cost of fresh water, of effluent treatment and disposal. In this context, this paper presents a heuristic algorithmic procedure, water source diagram procedure (WSD), to synthesize water mass-exchange networks for the following different situations: (i) water re-use; (ii) availability of multiple external water sources in the industrial plant; (iii) water losses along the process; (iv) flowrate constraints; (v) regeneration before re-use in other operations; and (vi) regeneration followed by recycling. WSD is a new tool presented as part of the approach and allow that example networks are also created. It was applied in a single contaminant example case, and it can easily be extended to multiple contaminant processes. This new procedure has advantageous features when compared to other available methodologies. Among them the procedure uses hand calculations, a very useful feature for process engineers.

Canopy temperature variability as an indicator of crop water stress severity

Irrigation scheduling requires an operational means to quantify plant water stress. Remote sensing may offer quick measurements with regional coverage that cannot be achieved by current ground-based sampling techniques. This study explored the relation between variability in fine-resolution measurements of canopy temperature and crop water stress in cotton fields in Central Arizona, USA. By using both measurements and simulation models, this analysis compared the standard deviation of the canopy temperature \( {\left( {\sigma _{{T_{{\text{c}}} }} } \right)} \) to the more complex and data intensive crop water stress index (CWSI). For low water stress, field \( \sigma _{{T_{{\text{c}}} }} \) was used to quantify water deficit with some confidence. For moderately stressed crops, the \( \sigma _{{T_{{\text{c}}} }} \) was very sensitive to variations in plant water stress and had a linear relation with field-scale CWSI. For highly stressed crops, the estimation of water stress from \( \sigma _{{T_{{\text{c}}} }} \) is not recommended. For all applications of \( \sigma _{{T_{{\text{c}}} }} , \) one must account for variations in irrigation uniformity, field root zone water holding capacity, meteorological conditions and spatial resolution of Tc data. These sensitivities limit the operational application of \( \sigma _{{T_{{\text{c}}} }} \) for irrigation scheduling. On the other hand, \( \sigma _{{T_{{\text{c}}} }} \) was most sensitive to water stress in the range in which most irrigation decisions are made, thus, with some consideration of daily meteorological conditions, \( \sigma _{{T_{{\text{c}}} }} \) could provide a relative measure of temporal variations in root zone water availability. For large irrigation districts, this may be an economical option for minimizing water use and maximizing crop yield.

Water relations and photosynthesis as criteria for adequate irrigation management in 'Tahiti' lime trees

Irrigation scheduling based on soil moisture status is one of the most useful methods because of its practicality and low cost. The effects of available soil water depletion on evapotranspiration (ETc), transpiration (E), leaf water potential at predawn (psiP) and midday (psiM), stomatal conductance (gs) and net CO2 assimilation (A) in lime 'Tahiti' trees (Citrus latifolia) were evaluated to improve irrigation schedule and minimize water use without causing water stress. The trees were spaced 7 <FONT FACE=Symbol>´</FONT> 4 m and drip-irrigated by four drippers with the available soil water content (AWC) depleted by suspension of irrigation (40 days). Leaf water potential was measured on a pressure chamber (psiP and psiM) and leaf gas exchange was measured by infrared gas analyzer (E, gs and A). Evapotranspiration was determined with the aid of weighing lysimeter. Water soil content and potential (psiS) were monitored with TDR probes and tensiometers, respectively, installed at 0.3, 0.6 and 0.9 m depths. Meteorological variables were monitored with an automatic weather station in the experimental area. The threshold AWC level for the onset of ETc decline was 43%, and 60% for gs, A, E and Y P. Also, psiP was more sensitive to AWC than psiM, and is therefore a better tool for irrigation. When AWC was around 60%, values of psiP and psis were -0.62 MPa and -48.8 kPa, respectively.

SOIL MOISTURE CONTROLLED SUBSURFACE DRIP IRRIGATION ON SANDY SOILS

Subsurface drip irrigation (SDI) is being adopted in areas to conserve water while maintaining economicalproduction of crops. These systems have not been evaluated on sandy soils common to Florida. An SDI system was installedon a well-drained sandy soil for sweet corn production in Florida. SDI tubing was buried under each row (76-cm spacing)at either two depths of 23 or 33 cm below the ground surface to result in two experimental treatments. Additionally, twomethods of irrigation scheduling were imposed on the SDI treatments. One scheduling treatment was the initiation andtermination of irrigation based on soil moisture measured by time domain reflectometry (TDR) probes installed 5 cm abovethe drip line. The other scheduling treatment was a daily irrigation event at rates consistent with typical practice in the region.Sprinkler irrigation scheduled similar to farmer practices in the region and non-irrigated control treatments were alsoestablished. The soil moisture based irrigation scheduling regime resulted in high frequency short duration (30-min)irrigation events to meet crop water needs. The 23-cm deep soil moisture-based treatment resulted in similar yields andsimilar water use in 2002 and reduced water use 11% with similar yields compared to sprinkler irrigation in 2003. Thisindicates that 23-cm deep SDI is feasible for sweet corn production under these conditions. The combination of optimum yieldand minimum water use was achieved with soil moisture based set points of 10% to 12% by volume (on-off). The 33-cm depthSDI treatment was found to be too deep for optimal yield results on sweet corn under the type of sandy soil in the study.Time-based SDI treatments were under-irrigated but showed evidence of considerable drainage based on soil moisturemeasurements due to single daily irrigation events that promoted movement of irrigation water below the root zone.Comparison of drainage calculations beneath the SDI treatments and sprinkler treatments indicated that up to 24% lessdrainage may have occurred on SDI plots compared to sprinkler plots largely because SDI applied water to the root zone andnot the furrows.

Reuse of textile reactive azo dyebaths following biological decolorization.

The objective of this work was to evaluate the feasibility of biological decolorization and reuse of textile reactive azo dyebaths with the goal of developing an in-plant, closed-loop decolorization system leading to water conservation and wastewater minimization. Decolorization of three spent dyebaths was investigated using a suspended-growth, halophilic mixed culture under anoxic conditions. A high rate and extent of color removal ranging from 77 to 90% was achieved. The three azo dyebaths and their decolorization products did not inhibit the halophilic culture. Although single dyeings using the biologically renovated dyebaths as process water resulted in highly reproducible and consistent fabric color shades, pH adjustment of the renovated dyebaths during the dyeing cycle was necessary. The extent of color removal using a biofilm reactor ranged from 86 to 95% during five repetitive dyebath decolorization and reuse cycles without any inhibition and residual color buildup. Repetitive dyeing with the same biologically decolorized dyebath for up to five cycles using a biofilm reactor and dyebath pH adjustment during the redyeing process resulted in almost identical fabric color shades as standard dyeing using fresh water. Excellent reproducibility in fabric color shades was also obtained by using biologically decolorized dyebaths in cross dyeings with different dyeing recipes. To our knowledge, this is the first report on the feasibility of biological decolorization of spent reactive dyebaths using a halophilic mixed culture and the direct reuse of the renovated dyebath as process water in the dyeing process. The results of this study demonstrate that in-plant application of closed-loop dyeing and decolorization is feasible and has the potential to not only decrease wastewater volume and treatment cost, but also minimize water use as well as the discharge of textile pollutants such as salt and dyes.

Effect of fiber orientation on fiber wetting processes

The current work incorporates a microscopic study of the effect of fiber orientation on the fiber wetting process and flow of liquid droplets along filter fibers when subjected to airflow and gravity forces. Glass filter fibers in various combinations were oriented at various angles within a plane defined by the airflow direction and were supplied with distilled water in aerosol form. The behavior and flow of the liquid collected by the fibers were observed and measured using a specially developed microscope cell, detailed in the paper. The experimental results were compared to a theoretical model developed to describe the behavior. The theory and experimental results showed good agreement. The developed theory allows an optimum angle to be determined for the internal filter fiber structure in the design of wet filters. A sensitivity analysis of the model was conducted to determine the most important parameters. This will aid design of wet filtration systems such that maximal self-cleaning can be accomplished with minimal water use.

Simulation‐based irrigation scheduling as a water management tool in developing countries

AbstractAn Irrigation District Decision Support System (IRDDESS) is described and applied to a large irrigation scheme in the Middle Awash Valley of Ethiopia. Crop yields are simulated over a 12‐year period in order to determine which of 12 separate irrigation schedules in use meet certain specified objectives. IRDDESS is a crop growth and irrigation district simulation model capable of predicting biomass development and yields for fields varying in soil type and irrigation management scenarios. IRDDESS also tracks water demand in the distribution system. Results show which of the 12 schedules will meet specific objectives of maximizing yields or minimizing water use and illustrate the potential of such decision support system in evaluation and management of large irrigation schemes. Copyright © 2001 John Wiley & Sons, Ltd.

REUSE OF TEXTILE REACTIVE AZO DYEBATHS FOLLOWING BIOLOGICAL DECOLORIZATION

The objective of this work was to evaluate the feasibility of biological decolorization and reuse of textile reactive azo dyebaths with the goal of developing an in-plant, closed-loop decolorization system leading to water conservation and wastewater minimization. Decolorization of three spent dyebaths was investigated using a suspended-growth, halophilic mixed culture under anoxic conditions. A high rate and extent of color removal ranging from 77 to 90% was achieved. The three azo dyebaths and their decolorization products did not inhibit the halophilic culture. Although single dyeings using the biologically renovated dyebaths as process water resulted in highly reproducible and consistent fabric color shades, pH adjustment of the renovated dyebaths during the dyeing cycle was necessary. The extent of color removal using a biofilm reactor ranged from 86 to 95% during five repetitive dyebath decolorization and reuse cycles without any inhibition and residual color buildup. Repetitive dyeing with the same biologically decolorized dyebath for up to five cycles using a biofilm reactor and dyebath pH adjustment during the redyeing process resulted in almost identical fabric color shades as standard dyeing using fresh water. Excellent reproducibility in fabric color shades was also obtained by using biologically decolorized dyebaths in cross dyeings with different dyeing recipes. To our knowledge, this is the first report on the feasibility of biological decolorization of spent reactive dyebaths using a halophilic mixed culture and the direct reuse of the renovated dyebath as process water in the dyeing process. The results of this study demonstrate that in-plant application of closed-loop dyeing and decolorization is feasible and has the potential to not only decrease wastewater volume and treatment cost, but also minimize water use as well as the discharge of textile pollutants such as salt and dyes.

Use of langbeinite to reclaim sodic and saline sodic soils

Langbeinite is a soluble potassium‐magnesium sulfate mineral (K2SO42MgSO4) found as an evaporite in many regions of the world. Langbeinite was used as a reclaiming material in a fine textured (clay loam) saline sodic soil (Grabe Series). This amendment can be dissolved and directly into the irrigation water, displacing sodium (Na) quickly with minimal water use. This amendment was superior over gypsum as a reclaiming material for a saline sodic soil in batch, column, and greenhouse studies. Langbeinite required 50% less irrigation water than gypsum to displace and leach exchangeable Na from soils. Langbeinite improved the infiltration rates of saline sodic soils, but not as effectively as gypsum. Significant increases in germination percent dry matter production mass of lima bean (Phaseolus lunatus L.) plants were observed when using langbeinite over the gypsum soil amendment.

Tree sap flow and stand transpiration of two Acacia mangium plantations in Sabah, Borneo

Water use of Acacia mangium trees grown in plantations was measured by a heat balance method in two stands that largely differed in tree density. Tree sap flow was closely coupled to climatic drivers and responded with minimal time delay. Using no time shift, sap flow rate could be tightly fitted to a simple equation that combined a parabolic response to radiation and an inverse linear response to air humidity. On the contrary, the analysis of canopy conductance showed no meaningful response to either individual or combined microclimatic variables. No indication of water deficit was observed, though the measurement period was during the dry period of the year. The measurements indicate a minimal diurnal use of water stored in plant tissues. The difference in tree water use from the two studied stands was effectively scaled by tree sapwood area. Canopy transpiration of the densest stand reached in average 3.9 mm d −1 compared with 2.7 mm d −1 for the stand representing the average conditions in the catchment.

Minimizing Water Use in Diafiltration of Whey Protein Concentrates

A multistage countercurrent diafiltration process for whey protein concentrates (WPC) production is presented. Experimental tests of whey diafiltration have validated a mathematical model for the concentration of components in the permeate for the case of washing with a dilute solution containing whey components. This model has been used together with material balances in order to simulate the multistage process. Water saving with respect to a single-stage conventional diafiltration was demonstrated. In the case of a WPC production of 95.5% from the whey of a local dairy farm which contained 7.7 g/L proteins, 43 g/L lactose, 1.1 g/L nonproteic nitrogen, and 5.4 g/L ashes, the necessary volumes of water, V D (volume of water per volume of treated solution), needed decreased from 5.4 for a single stage to 2.9 for a two-stage process down to 1.5 for a six-stage process. The adopted procedure can be easily applied to any diafiltration process.

Minimization of water use and wastewater contaminant load

This communication describes a project concerning the minimization of water use and wastewater contaminant load in an industrial setting. The location was a plant manufacturing cast aluminum parts for the automotive industry. The water used for industrial purposes was some 16 000 m 3/yr with COD values sometimes higher than 5000 mg O 2/l. After a preliminary assessment, a global reduction in industrial water consumption of 33%, by means of re-circulation of the aqueous solution used for de-molding was achieved, implying a 95% reduction in de-molding solution. To minimize water use even further, recommendations to the company included a revision of the refrigeration closed-circuit and a better control of water used for general services.

Water as a Weapon: The History of Water Supply Development in Nkayi District, Zimbabwe

Abstract This paper argues that much historical and political analysis of Zimbabwe neglects a crucial resource: water. Using data from Nkayi district, evidence is presented to show how access to water rather than land has been the critical factor in its settlement and development. Water supplies were provided by the state during the first half of the century to support economic and fiscal policies and to render forced resettlement possible. During the years of struggle preceding and including the Liberation War, control over water was used as a weapon, and this remained a significant issue in the post-Independence period. Examples are offered of people's resistance to such control through non-cooperation in water development activities and the evolution of a culture of minimal water use strongly associated with concepts of solidarity and survival. Finally the implications of this historic legacy for current development initiatives are discussed.

Monitoring Irrigation at Container Nurseries

Efficient usage of current water supplies is of great concern to container-nursery producers. Improving water management first requires knowledge of current commercial container production practices. In this study, irrigation distribution from overhead sprinklers was monitored at container nurseries to determine the distribution and the amount of irrigation applied during a typical irrigation cycle. Several nurseries surveyed had poorly designed irrigation systems; subsequently, irrigation distribution varied widely at sampling dates and within the growing-container block. Uniform distribution was achieved at some nurseries, but required careful monitoring of the irrigation system. Future water restrictions may force nurseries to improve water usage by changing irrigation delivery methods to minimize water use, resulting in reduced surface runoff and effluent from container nurseries.

EFFECTS OF EVAPORATIVE COOLING ON COLD HARDINESS OF CHARDONNAY AND CABERNET SAUVIGNON BUDS DURING DEACCLIMATION

Freeze losses to grapes in March, after mild deacclimatizing winters, is the major production risk on the Texas High Plains. Earlier studies indicated the effectiveness of evaporative cooling in reducing grape bud heat summation with a correlated delay in budbreak. Parameters relating to water-use-efficiency were identified. In the current study, these parameters were incorporated to minimize water use. Water was applied through microjets for 25 seconds every 4 minutes any time air temperature exceeded 10°C, 15°C, and Control. Bud temperatures were monitored continuously by thermocouples and data logger, and correlated with budbreak and plant development. Random bud samples were taken weekly prior to budbreak and subjected to differential thermal analysis. A freeze on March 23 (-3.5°C) resulted in differential primary bud losses to Chardonnay during budbreak, and to Cabernet Sauvignon 15 days prior to budbreak. Evaporative cooling significantly increased yields in both cultivars. Differential thermal analysis verified differences in cold stress tolerance in Chardonay prior to budbreak.

Growth of Chrysanthemum Using an Irrigation System Controlled by Soil Moisture Tension

Abstract Chrysanthemum × morifolium Ramat. cv. Polaris plants were grown in containers using an irrigation system based either on time (5 min/day) or on soil moisture tensions of −1.5, −3.5, −7.5, and −15 kPa. Soil moisture tensions of −7.5 or −15 kPa caused significant reductions over the time-based treatment in fresh and dry weights of leaves, stems, and inflorescences and total leaf area, but had no influence on inflorescence diameter or cropping time. Stem length was reduced in those plants exposed to the two higher tensions; however, the resulting cut flowers were still long enough to satisfy commercial demands. The amount of water applied in tension-based treatments was 8% to 24% that applied in the time-based treatment. The −1.5- and −3.5-kPa treatments were best suited for minimizing water use while maintaining high crop productivity.

Protein Losses in Traditional Agidi Paste Production

ABSTRACTProtein losses from normal corn traditionally processed into agidi paste were evaluated. Results showed that overall protein losses were as high as 52% in a 12‐hr soaking and 44% in an 18‐hr soaking schedule. Soluble protein losses were higher with prolonged soaking in corn. Amino acid composition of the waste‐liquor (WL) from 12‐hr soaking was significantly (p < 0.05) different from other processing fractions. The results indicated that minimal use of water in wet‐sieving and utilization of waste‐liquor in agidi preparation improved the nutritive value of agidi.

Design and Operating Criteria for Rural Water Systems

URAL homesites in the United States require the availability of high quality water. Oue means of meeting this need is with the rural water district, a sys· tern composed of tank storage and a pipe network serv­ ing a number of homes. The tanks are filled by pumping during periods of minimal water use and serve as the immediate water source for homes. Optimum design requires consideration of not only immediate needs and economic factors but also the possibility of expansion at some future date. Accurate prediction of monthly usage rates is sometimes neces­ sary to set contractural needs. Daily water use per per­ son must be known to appropriately choose the size of the storage tank. Peak use rates are important for proper selection of pipe sizes. The temporal distribu­ tion of demand is important in determining available pump operating periods for filling of storage with a minimum of interference and has a bearing on pump and pipe selection. This paper presents the results of a study (Goodwin, 1975) describing design criteria for projects serving dairies and domiciles. Homes are divided into two dif­ ferent economic groups and design recommendations are made for each group.

Water and Waste Management Educational Program for Dairy Processing

A program is presented to assist management in controlling water and waste in a dairy processing plant. Four phases of an educational program are presented emphasizing the need for and use of an in-plant water and waste supervisor. The educational program designed for a minimum of 10h stresses the need for minimizing water use and waste discharge to achieve economic and environmental goals. The correlation between water use, waste load, and product losses is explained.