Water Application Rates Research Articles

White Plastic and Deficit Irrigation Improve Pomegranate Production

ABSTRACT Developing improved water management strategies and on-farm cultural practices are important in reducing pomegranate (Punica granatum L. cv Wonderful) production costs. A pomegranate orchard established in 2010 was irrigated at water replacement rates of 35, 50 and 100% of crop evapotranspiration from 2013 to 2016. A durable white plastic tarp was installed in one half of each water replacement plot to evaluate the added benefits to soil moisture retention, weed control, and plant growth and yield. Edaphic orchard floor conditions such as light reflectance into the lower tree canopy, mid-day soil surface temperature, soil water content, and average daily soil temperatures were moderated or improved by the plastic cover. Phenological changes such as leaf greenness, trunk basal suckering, and trunk diameter were generally enhanced by increased water application rates and plastic use. Marketable and total fruit yields increased by an average of 20 to 29% from 2013 to 2016 with the use of plastic cover compared to bare soil. Total fruit yield increased linearly with increasing water replacement rates. Neither the white plastic nor irrigation rates improved external fruit color. Fruit raw product attributes were little changed by treatments. The research clearly demonstrated the benefit of plastic cover on improving pomegranate production.

Effect of Intermittent Water Application from Trickle Source on The Water Movement and Moisture Distributionin Layered Soil

Efficient design of trickle irrigation system depends on the shape and volume of wetted soil, which are affected by many factors. Among these factors are water application rate, soil profile type, initial soil moisture, and continuous or intermittent water application. The aim of this research is to study the effect of intermittent water application on the wetting pattern and soil moisture distribution for homogeneous and layered soils under trickle source. Thirty experiments were conducted to monitor the advance of the wetting front in the soil profiles. Measurements of soil moisture content were also made at selected locations to evaluate the moisture distribution in soil. A rectangular box with inside dimensions of 147 cm*90 cm*5 cm was used to build the soil profile. One of the faces of the box is transparent. Two different soils were used; a sandy loam and a silty clay loam. The soils were air dried, sieved, and packed inside the box in accordance with their apparent densities which have been measured in the field. Four types of soil profiles were built; the first was sandy loam soil, the second was silty clay loam soil, the third was (silty clay loam/ sandy loam) layered soil, and the fourth was (sandy loam/ silty clay loam) layered soil. Three water application rates were used for each soil profile. Three continuous or intermittent applications were used; continuous applications, equally intermittent applications (120 minutes ON with 120 minutes OFF), and different intermittent applications ([1]20 minutes ON with 240 minutes OFF). In addition, several cylindrical infiltration tests were conducted to describe some characteristics of each soil. Empirical relations to predict each of vertical (under trickle source) and horizontal (at soil surface) wetting front advance were found in this study. Empirical relations to predict the percentage of applied water volume in horizontal strips as a function of soil depth and in vertical strips as a function of horizontal distance from the trickle emitter were also found. The study showed that the wetted soil volume increases as either the water application rate increases, or the intermittent application ratio increases. Also, it showed that the ratio of horizontal advance to vertical advance of wetting front increases as either the water application rate increases, or the intermittent application ratio decreases. The study demonstrated that the accumulated ratio of water application volume at a certain soil depth from trickle source increases as the intermittent application ratio decreases. Also, it demonstrated that the accumulated ratio of water application volume at a certain horizontal distance from trickle source decreases as the intermittent application ratio decreases.

Salinity risk assessment of an irrigation development using treated coal seam gas water in the Condamine River catchment

All irrigation developments inherently carry a salinity risk, due to an unavoidable change in the water and salt balance. The time frame in which either land or water salinity will develop is driven by the ability of the landscape to absorb the change of water and salt supplied. Factors that influence this are landscape attributes, such as the size of the unsaturated zone and its properties (permeability and drainage), management considerations (land-use changes, water application rate and crop water use) and climate variability (temperature and rainfall). This study assessed the risk of secondary salinity expression occurring in an irrigation area in the Condamine-Balonne catchment in southern inland Queensland, Australia. The objectives were to (1) define the depth, size and properties of the unsaturated zone and regolith, (2) define deep drainage rates for past, present and future land uses and (3) assess this information to calculate the risk that groundwater table rise may result in surface salinity expression. Data collected during field investigations was used to conceptualise the regolith architecture, undertake hydrogeological modelling, estimate the available moisture storage capacity of the unsaturated zone and model paddock deep drainage characteristics. The work identified that irrigation-induced deep drainage had started to mobilise salt stores in the unsaturated zone. It also identified connectivity between land management and salt discharges into the Condamine River. As the water supply for the scheme is scheduled to continue until 2030, there is a clear risk of the unsaturated zone moisture storage capacity being exceeded, leading to both land and surface water salt expressions.

Salt Distribution in a Soil Irrigated by Subsurface Emitter

The best design of subsurface trickle irrigation systems requires knowledge of water and salt distribution patterns around the emitters that match the root extraction and minimize water losses. The transient distribution of water and salt in a two-dimensional homogeneous Iraqi soil domain under subsurface trickle irrigation with different settings of an emitter is investigated numerically using 2D-HYDRUS software. Three types of Iraqi soil were selected. The effect of altering different values of water application rate and initial soil water content was investigated in the developed model. The coefficient of correlation (R2) and the root-mean-square error (RMSE) was used to validate the predicted numerical result. This statistical analysis revealed that there was no much difference between the predicted numerical results, and the measured values. R2 varied from 0.75 to 0.93 and the (RMSE) from 0.079 to 0.116. The comparison confirms the accuracy of the developed model, and it shows that it can be used to simulate the front wetting patterns of water and salt distribution under subsurface trickle irrigation systems. The simulation outcome showed that as the distance from the emitter increased, soil salinity far from the emitter decreased. As expected, irrigation duration and amount affects the dimension of the solute distribution.

Effects of Travel Speed and Collector on Evaluation of the Water Application Uniformity of a Center Pivot Irrigation System

Water application uniformity is an important performance parameter when designing and operating an irrigation system. Performance tests of a center pivot irrigation system equipped with fixed and rotated spray plate sprinklers (FSPS and RSPS, respectively) were conducted at five travel speeds. The effects of travel speed, collector size, and setting height on water application uniformity were evaluated using Heermann and Hein’s coefficient of uniformity (CUH). The CUH was 12.7% higher for the RSPS than the FSPS and decreased as the travel speed increased. Collector size and setting height affected CUH, and CUH was higher when the collector had a large opening cross-section compared to the collector with a small opening cross-section. CUH was higher when the collector with a low setting height compared to when it a high setting height for the FSPS. However, collector setting height had no effect on CUH for the RSPS. The weighted average water application depth (Dw) decreased as the travel speed increased. Collector size had no significant effect on Dw, but Dw with a low collector setting height was larger than the values with a high collector setting height. The water application rate increased as distance from the pivot point increased and was higher for the FSPS than the RSPS. The results will improve the selection of travel speed and collector when the water application uniformity of a center pivot irrigation system is evaluated.

Soil water availability alter the weed community and its interference on onion crops

Agricultural practices act as an ecological filter of weeds, selecting those more adapted to the agrosystem. The stress conditions due to cultivation preparations shape the weed community, influencing the productive performance of the crops. Among these practices, irrigation can directly affect the establishment of some weeds, and a better-adapted community can intensify the degree of interference with agricultural cultures. This study aims to evaluate the changes in the weed community caused by two irrigation systems (high and low rates of water application) over three onion seasons, and how these changes affect the yield and efficiency of irrigated onion. The γ-, α-, and β diversity pf weeds was altered by onion cultivation over the three seasons. The irrigation system with a higher water supply (micro-sprinkler) favored diversity and weed richness, especially during the second cultivation year, compared to the system with water restriction (drip irrigation). Under the micro-sprinkler system, transition of the weed communities among years took place gradually. The higher level of stress created by drip management stimulated the dominance of Digitaria horizontalis. Non-control of weeds at 12 and 24 days after crop emergence reduced the onion crop yield. Besides that, this reduction in productivity indices was aggravated by the greater weed diversity under the micro-sprinkler system (high water supply). Under drip irrigation (low water supply), dominance intensify the competition of the weed community on the onion crop yield. The density of weeds and C4 species negatively affected onion growth under drip irrigation.

Metabolic behavior in the allocation of biomass of melon cultivars under water deficit conditions

Seeking to understand the mechanisms of tolerance of melon plants under water deficit, this study aimed to evaluate the biochemical behavior of melon cultivars and the allocation of biomass under water deficit. Two experiments were conducted in a shaded environment in the experimental area of the State University of Bahia, Juazeiro / BA; the first was carried out in 2015 and the second in 2016. The experimental design was in randomized blocks, replicated three times, with subdivided plots; the plots consisted of four water application rates (50, 75, 100 and 125% of the crop evapotranspiration), the subplots of two melon cultivars 'Yellow' and 'Piel de Sapo'. The sub-subplots were the sampling periods: 15; 30 and 45 days after transplantation. In the first experiment it was evaluated: total soluble sugars, reducing sugars, total proteins. In the second experiment, in addition to biochemical analyzes, the allocation of biomass of leaves, branches, roots, fruits and root / shoot ratio was evaluated. At the end of both experiments, root proline and aerial part were evaluated. Both cultivars showed similar biochemical behavior, except for the accumulation of proline obtained in the cultivar 'Piel de sapo', which allowed greater biomass allocation to the fruit than the cultivar 'Amarelo'.

Trade-Offs in Net Life Cycle Energy Balance and Water Consumption in California Almond Orchards

Perennial cropping systems, such as almond orchards and vineyards, increasingly dominate California’s agricultural landscape. In California’s leading agricultural region, the Central Valley, woody perennials comprise about half of total farmland. Woody perennial orchards produce high value food crops such as almonds, but also generate significant woody biomass which, where feasible, is used to generate biomass-derived electricity. Because of its semi-arid climate, California agriculture is heavily dependent on irrigation, which in some regions, requires energy-intensive pumping processes for both surface and groundwater. This research study explores the tradeoffs in economic, energy and water efficiency, considering the response of almond orchards to water application rates, using a life cycle basis for calculations and considering water scarcity, to reveal one part of the food-energy-water nexus. Findings indicate economic efficiency, represented by business-as-usual practices by growers, and which prioritizes almond yield, does not correspond to the lowest net-energy consumption (i.e. energy consumption minus bioenergy production). Bioenergy production follows a parabolic relationship with applied water, due to almond yield and growth response to water availability. Thus, the net energy footprint of almond production is minimized at about −45% of business-as-usual applied water, at odds with the economic demands of the almond industry that prioritize high value food production.

Flow Characteristics and Hydraulic Performance of a Gun-Type Impact Sprinkler with and without Aeration

AbstractA water jet aeration method was used to address the problem of high water application rates for rotating impact sprinklers operating at low pressures at the distal end of the wetted radius ...

The Effect of Sedimentin Yellow River on Hydraulic Characteristics of Spray Sprinkler

The water shortage has become a great challenge for Yellow River irrigation regions; for the high level of suspended sediment in Yellow River, sprinkler irrigation, which has achieved superior anti-clogging performance, can be an effective solution for water conservation in agriculture management. For the direct utilization of the Yellow River water resource in irrigation land as irrigated by movable sprinkler irrigation systems, a series of experiments about the effect of sediment-water on the hydraulic performance of fixed spray plate sprinkler was conducted. The results showed that peak water precipitation rate appeared as both clean and sediment-water jetting from the groove, and the differences were that sediment-water minimized peak value of water application rate and increased wetted radius efficiently. The water distribution of an individual sprinkler resembled lotus shape with different working conditions, and the application rate nearby sprinkler increased with the increase insediment concentration, resulting in higher water distribution uniformity. In addition, sediment-water increased the spray distance remarkably with a maximum increasing ratio of 7.79%; meanwhile, it led to the transfer of peak application region to the edge of the wetted circle and, consequently, the wetted area increased. The calculation result of the water diffusion coefficient indicated that sediment-water contributed to splintering water jet effectively, but the analysis of variance showed that no significant change was obtained with increasing sediment concentration. All these results suggested that the sediment-water in Yellow River could be directly utilized in agriculture irrigation with superior hydraulic performance, and it would be helpful to protect and maximize the utilization of the Yellow River resource.

Starch gelatinization and drying of paddy using microwave rotary drum dryer: Optimization, kinetics, and cooking studies

The microwave-assisted starch gelatinization was carried out in a semi-pilot microwave rotary drum dryer. Gelatinization experiments were planned using a central composite design and the process was optimized. The effect of microwave power density, time of treatment, and water application rate on final moisture content, crystallinity percentage, and specific energy consumption was studied. The optimized conditions in the starch gelatinization process were found at 1 kW kg−1 power density, 60 min treatment time, and 90 mL/10 min water application rate. Microwave power density and treatment time significantly (p < 0.01) affected the crystallinity percentage and specific energy consumption. Further, the gelatinized paddy was dried in the same dryer at 0.25, 0.50, 0.75, 1.00, and 1.25 kW kg−1 microwave power density levels. The drying characteristics, milling yield, cooking characteristics and cooking kinetics of the milled rice were analyzed. Drying rates were increased with an increase in microwave power density. The head rice yield and specific energy consumption were lower in microwave drying compared with hot air drying. The crystallinity percentage of microwave dried rice was decreased with an increase in power density. At higher power density, the microstructure of starch granules showed formations of internal fissures as well as the effect on the color and cooking rate constants of the rice.

Determination of water application rates required for communities to suppress post‐flashover informal settlement fires based on numerical modelling and experimental tests

SummaryFires originating in informal settlements (ie, slums, ghettos, shantytowns, squatter camps) spread rapidly, due to the presence of densely packed, highly combustible dwellings, thereby making these communities inherently susceptible to large conflagrations. By the time, the fire brigades are notified and can get to the scene of the fire, the resulting conflagrations can be large. Thus, it is necessary to equip communities with the ability to combat smaller fires, although it is acknowledged that this is not ideal. Previous full‐scale testing and firefighter experience have shown that water application through ‘bucket brigades’ can be very effective at suppressing fires. In this article, a model is developed for approximately quantifying the amount of water, and discharge rate, that is, required for communities to suppress fires of various sizes using bucket brigades. This is done to answer the question: based on the water supply infrastructure in an area could a community put out post‐flashover fires of certain sizes? If this is not feasible, it would highlight the importance of communities having readily available pre‐filled water buckets at homes. The model presented is developed in fire dynamics simulator and is calibrated based on full‐scale experiments utilizing the bucket brigade technique. It is shown that standpipe discharge rates of 23 to 40 lpm are suitable for fire sizes of around 3.85 MW, based on a dwelling size of 2.4 x 3.6 x 2.4 m. This means that in communities with a single stand‐pipe (water supply point) with flow rates less than 23 lpm, that fires greater than 3.85 MW (as produced by a home of 2.4 x 3.6 m with a timber fuel load of 25 kg/m2) cannot be suppressed in time without resulting in substantial fire spread to adjacent dwellings.

MONITORING XYLEM SAP IN SUGARCANE THROUGH TDR

The TDR can be used to measure water content and nutrients in several media with a potential to monitor the xylem sap flow in plants. The objective of this study was to determine whether there is a correlation between the xylem sap content and water available in the soil for sugarcane cultivation using TDR. The study was conducted in a protected environment with eight boxes (500 L). The boxes were divided into two treatments with different water application rates (1.6 and 3.4 L h-1) through subsurface irrigation. In each box TDR probes were inserted in the medium part of sugarcane stalk, totaling three probes per box to monitoring the sap flow. The soil water content was monitored using 20 net-placed probes. Therefore, the simultaneous monitoring of xylem sap and soil water content occurred for five months. As a result, it was obtained that the xylem content monitoring through TDR is moderately related to soil moisture, with a response to the absorption and translocation of the solution in the stem of sugarcane plants as a consequence of irrigation applications and/or fertirrigation. Thus, it was concluded that there is a weak relations between water contents in the soil and plant, especially for the treatment that used the highest flow rate (3.4 L h-1).

Soil moisture distribution under trickle irrigation: a review

AbstractThe wetting pattern of soil under trickle (drip) irrigation is governed by soil texture, structure, initial water content, emitter spacing, discharge rate and irrigation frequency. For efficient management of trickle irrigation moisture distribution plays an important role. The degree of soil wetted volume in an irrigation system determines the amount of water required to wet the root zone. This article helps in understanding moisture distribution for different lateral spacing, emitter spacing, emitter discharge rates and drip line installation depth for trickle irrigation under various soil conditions all over the world. This review reveals that soil moisture distribution and uniformity within the soil profile were affected by the distance between emitters rather than the distance between drip lines. In drip irrigation systems, the less the dripper spacing, the greater the moisture distribution as well as water use efficiency and crop yield. The radial spread of moisture was greater at lower water application rates, whereas the vertical spread was greater at higher water application rates. The vertical movement of soil moisture was greater than the horizontal movement under surface as well as subsurface drip irrigation systems. Deeper drip tape installations had a potential risk of not providing moisture to shallow rooted crops.

Effects of nitrogen application rate and irrigation regime on growth, yield, and water-nitrogen use efficiency of drip-irrigated winter wheat in the North China Plain

Drip irrigation has been gradually adopted for winter wheat production in the North China Plain (NCP) due to significant saving from using irrigation water and improving water and nitrogen use efficiencies. However, the optimal water and nitrogen application rates for drip-irrigated wheat are still unclear. A field experiment with five nitrogen application rates (0, 120, 180, 240, and 300 kg ha−1, referred as N0, N1, N2, N3, and N4) and three irrigation levels (40, 30, and 20 mm per irrigation, referred as I1, I2, and I3) was conducted during the 2015–2016 and 2016–2017 winter wheat seasons to study the effects of irrigation and nitrogen rates on crop growth, yield, and the water and nitrogen use efficiencies. Results showed that increasing irrigation and nitrogen application rates notably improved actual evapotranspiration, leaf area index, aboveground biomass, grain yield, and water use efficiency (WUE) of winter wheat. However, nitrogen application rates exceeding 240 kg ha−1 were not beneficial for wheat growth, grain yield, WUE, and irrigation water use efficiency (IWUE). The maximum grain yields of 8034 and 8760 kg ha−1 were achieved in N3I1, which had WUE of 2.08 and 2.23 kg m−3, and IWUE of 4.46 and 4.87 kg m−3 in 2015–2016 and 2016–2017, respectively. At the same time, N3I1 did not result in much reduction of nitrogen partial factor productivity (NPFP) (average of 34.99 kg kg−1 in N3I1 for two seasons). Considering comprehensively growth, yield, WUE, IWUE, and NPFP, combination of N rate of 240 kg ha−1 and irrigation quota of 40 mm per irrigation was optimal pattern for drip-irrigated winter wheat. These results may provide a scientific basis for water and nitrogen management of drip-irrigated winter wheat in the NCP.

Extinguishing wildfires by saturation water bombing: A new concept.

To present a new concept for the extinguishment of wildfires by saturation water bombing. Following an exhaustive literature search, a published mathematical model and a published empirical rainfall model were used to estimate the rate at which water would have to be applied to extinguish intense wildfires. Applying the estimated amount by quasi-continuous saturation water bombing was then evaluated. The mathematical model yielded a regression equation that estimates the amount of water to extinguish wildfires of varying sizes as y = 0.1041 x - 5.0096 where y is the quantity of water and x is the size of the fire. The predicted quantities of 1000 metric tonnes ha for intense wildfires vastly exceed the minimum of 50 metric tonnes ha of the empirical rain model, likely due to the limited data available. They nevertheless serve to define the likely range of water application rates that must be applied for wildfire extinguishment. These application rates are shown to be feasible by deploying a team of large, amphibious water scooping aircraft operating in relay continuously day and night. The operating cost of such a team (±$10 million annually) is trivial compared to the potential for reducing the current economic burden of US wildfire of $71.1-347.8 billion annually. The saturation water bombing concept seems promising enough to warrant the commitment of funds to implement field trials on the ground that it could, potentially, result in savings of billions of dollars.

Alfalfa canopy water interception under low-pressure sprinklers

Canopy water interception is an important factor in water use efficiency analysis and sprinkler-based fertigation technique development. In the present study, alfalfa canopy water interception and its influence factors were assessed under low wind conditions. The canopy interception capacity for three growth stages of alfalfa (S1, early vegetative stage; S2, late vegetative stage; S3, bud stage) were measured under two types of low-pressure spray sprinklers. The dynamics of canopy interception and interception ratio with irrigation depth were also observed. The total irrigation depth for all measurements was around 8 mm. A weight-based canopy interception measurement device was installed outdoors and integrated with a 20-psi sprinkler at 1 m above the canopy. The alfalfa canopy interception first increased rapidly with irrigation depth, but then stabilized and reached canopy interception capacity (Im). The minimum irrigation depths to achieve the Im values were 2 mm, 3 mm, and 4 mm at the S1, S2 and S3 stages, respectively. Im increased significantly across growth stages, and ranged from 0.46 mm to 1.49 mm. Interception ratio decreased gradually as irrigation depth increased. With an approximately 8-mm total irrigation depth, interception ratio ranged from 5.27 % to 17.59 % over all growth stages. Water application rate had no effect on Im, and Im decreased with droplet diameter. Generally, Im was higher and reached more quickly with the R3000 sprinkler compared to the D3000 sprinkler. Fresh weight, plant height, and LAI of alfalfa had significant positive correlations with canopy interception capacity, and a quadratic regression model was developed with using plant height as a factor. This study provides valuable and basic information for irrigation schedules and fertigation in alfalfa cultivation.

EVALUATING THE PERFORMANCE OF THE GREENHOUSE AS AFFECTED BY SHADOW PAINTING MATERIAL

Indoor experiments and field study were conducted at the Dept. of Agric. & Bio Systems Eng., Faculty of Agriculture, Menoufia University. The indoor experiments concerned with the effect of using shading materials on the performance inside the greenhouse. With each shading material, the atmospheric parameters inside the greenhouse were measured. These parameters were: average air temperature, internal and external radiation. The tested shading materials were: red oxides, Yellow oxides, Ammonium chloride, sodium sulphate and white plastic. The main objective of field experiments was to drive both of cucumber yield and water use efficiency grown under two greenhouses. First was covered by painted plastic with white plastic and the second was covered by an unpainted ordinary plastic. The field experiment was carried out under four levels of water application rate which were: 100%, 90%, 80% and 70% of potential evapotranspiration ETo. The irrigation water was applied by a drip irrigation system which constructed inside each greenhouse. The painted cover with white plastic achieved the lowest radiation transmission coefficient (0.44) and also achieved the highest cucumber yield (15.5 Mg/Fed) at 80% of potential evapotranspiration. It also achieved the highest value of water use efficiency which was 10.23 kg/m3 at the same level of water application rate.

Irrigation Water Demand: Price Elasticities and Climatic Determinants in the Great Lakes Region

This article explores the environmental and market determinants of irrigation management in a five-state Great Lakes region. We found evidence that corn, soybean, and potato irrigators respond to the cost of water at the intensive margin. Evidence of a water-cost effect at the extensive margin was mixed. This article is unique in its geographic focus and its consideration of various temperature effects. We found evidence of a long-run average temperature effect on crop acreage allocation decisions and a short-run extreme heat effect on water application rates.

Experimental study on vertical rigid and flexible polyurethane fire suppression using water spray

A series of vertical fire suppression experiments on rigid polyurethane (RPU) and flexible polyurethane (FPU) with/without water spray were conducted in a standard chamber. A new video processing method was developed to determine the pyrolysis front position of wind-aided flame. Averaged flame height, carbon monoxide/hydrogen cyanide concentration, view factors, and extinguishing time were determined with operating pressure varying from 0.15 MPa to 0.4 MPa. The experimental study showed that water spray would suppress RPU/FPU fire mainly by fuel surface cooling. Furthermore, the perfect water spray pressure for RPU/FPU fire suppression was 0.3 MPa and the corresponding water application rate was 0.7511 mg/(cm2·s).