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Open AccessEditor’s ChoiceArticle

Spatiotemporal Analysis of Maize Water Requirement in the Heilongjiang Province of China during 1960–2015

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Water 2020, 12(9), 2472; https://doi.org/10.3390/w12092472 - 03 Sep 2020

Cited by 10 | Viewed by 1818

Abstract

Climate change will have a significant effect on crop water requirement (ET_c). The spatial and temporal variations of water requirement of maize under climate change are essential elements when conducting a global water security assessment. In this paper, annual reference [...] Read more.

Climate change will have a significant effect on crop water requirement (ET_c). The spatial and temporal variations of water requirement of maize under climate change are essential elements when conducting a global water security assessment. In this paper, annual reference crop evapotranspiration (ET₀) and the crop water requirement of maize were calculated by the single crop coefficient method. The crop water surplus deficit index (CWSDI) and coupling degree of ET_c and effective precipitation (P_e) were calculated to analyze the relationship between ET_c, ET₀, and P_e. The result shows that maize average annual ET₀, ET_c, and precipitation were 552.97, 383.05, and 264.97 mm, respectively. Moreover, ET₀, ET_c, and P_e decreased by 3.28, 2.56, and 6.25 mm every decade from 1960 to 2015. The ET_c decreased less than P_e did, which led to the decreasing of both CWSDI and the coupling degree of ET_c and P_e. The tendency of ET₀, ET_c decreased first and then increased, while P_e and CWSDI increased first and then decreased, from west to east of the Heilongjiang Province. In addition, the highest ET₀, ET_c, and lowest CWSDI and P_e were found in the western part of Heilongjiang Province. This study indicated that even though the water deficit in the western region was alleviated and the water deficit in the eastern region grew gradually serious from 1960 to 2015, the drought situation in western Heilongjiang Province should still be taken seriously. Full article

(This article belongs to the Special Issue Irrigation Management)

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Open AccessArticle

Development and Sensitivity Analysis of an Empirical Equation for Calculating the Amplitude of Pressure Head Loss of Oscillating Water Flow in Different Types of Pipe

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Kai Zhang

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Baoxu Zhang

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Delan Zhu

Water 2020, 12(9), 2421; https://doi.org/10.3390/w12092421 - 28 Aug 2020

Viewed by 1494

Abstract

Low pressure oscillating water flow can reduce the investment and energy consumption of irrigation. It is also effective in reducing the clogging of an emitter and improving the spraying quality of sprinklers. In order to overcome the problem of the complex process in [...] Read more.

Low pressure oscillating water flow can reduce the investment and energy consumption of irrigation. It is also effective in reducing the clogging of an emitter and improving the spraying quality of sprinklers. In order to overcome the problem of the complex process in calculating the amplitude of the pressure head loss of oscillating water flow in different types of pipes, in this study, an empirical equation for the amplitude of the pressure head loss of oscillating water flow in different types of pipe has been developed. Further, validation experiments have been conducted to verify the accuracy of the calculated amplitudes of the pressure head loss by the empirical equation. The results show that average relative error between the measured and the calculated amplitudes of the pressure head loss by the empirical equation is 10.77%. Since the relative errors are small, it is an indication that the amplitudes of the pressure head loss calculated by the empirical equation are accurate. For the empirical equation developed in this study, the sensitivity of the model parameters has been analyzed. The results show that the amplitude of velocity, the internal pipe diameter, and the length of pipe are classified as highly sensitive. The average velocity, the period of oscillating water flow, and the modulus of elasticity of the pipe material are classified as sensitive. The thickness of the pipe wall is classified as medium sensitive. Compared with the calculation models of the existing researches, the empirical equation reduces the number of parameters required to be calculated, by which many complicated calculations are avoided, which greatly improves the computing efficiency. This is conducive to the efficient operation and management of oscillating water flow in irrigation pipe networks and also provides help for the optimal design of irrigation pipe networks. Full article

(This article belongs to the Special Issue Irrigation Management)

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Open AccessArticle

Daily Water Requirement of Container Grown Davallia bullata and Nephrolepis exaltata and Implication in Irrigation Practices

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Richard C. Beeson, Jr.

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Roger Kjelgren

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Jianjun Chen

Water 2020, 12(8), 2190; https://doi.org/10.3390/w12082190 - 04 Aug 2020

Cited by 1 | Viewed by 1846

Abstract

Container crop production has become increasingly popular, but daily water requirements of those crops from transplanting to marketable or harvestable stages are largely unavailable. To address this concern, daily water consumption of two container-grown fern species, Davallia bullata and Nephrolepis exaltata from initial [...] Read more.

Container crop production has become increasingly popular, but daily water requirements of those crops from transplanting to marketable or harvestable stages are largely unavailable. To address this concern, daily water consumption of two container-grown fern species, Davallia bullata and Nephrolepis exaltata from initial transplanting to marketable size were studied using a canopy closure model. Daily actual evapotranspiration (ET_A) of D. bullata ranged from 4.6 mL to 76.5 mL with an average of 29.0 mL per plant per day. The mean cumulative ET_A was 13.2 L during 431 days of production spanning from 8 November 2006 to 4 February 2008. Two crops of N. exaltata were produced. Daily ET_A per N. exaltata plant produced in crop 1 varied from 19.0 to 241.2 mL with an average of 69.5 mL, and daily ET_A of crop 2 differed from 5.7 to 136.8 mL with a mean of 74.0 mL. Both crops had a cumulative ET_A of 9.4 L. Such differences in daily ET_A and cumulative ET_A between the two fern species raised further concern of irrigation practices in commercial foliage plant production as multiple species are commonly produced in one greenhouse and share the same irrigation schedule. Comparing daily ET_A and cumulative ET_A values of the ferns with the other studied foliage plants indicated that daily ET_A and cumulative ET_A are species specific. Therefore, to improve irrigation efficiency, daily ET_A and cumulative ET_A values of major container-grown plants should be established. Implementing the research-based daily ET_A and cumulative ET_A in container plant production should reduce irrigation water leaching and runoff and conserving freshwater resources. Full article

(This article belongs to the Special Issue Irrigation Management)

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Open AccessArticle

Nitrogen Fertilization, Container Type, and Irrigation Frequency Affect Mineral Nutrient Uptake of Hydrangea

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Water 2020, 12(7), 1987; https://doi.org/10.3390/w12071987 - 14 Jul 2020

Cited by 2 | Viewed by 1865

Abstract

Mineral nutrient uptake of Hydrangea macrophylla ‘Merritt’s Supreme’ affected by nitrogen (N) fertilization rate, container type, and irrigation frequency was investigated. Rooted liners of hydrangea plants were fertilized twice weekly with a N-free fertilizer plus five N rates including 0, 5, 10, 15, [...] Read more.

Mineral nutrient uptake of Hydrangea macrophylla ‘Merritt’s Supreme’ affected by nitrogen (N) fertilization rate, container type, and irrigation frequency was investigated. Rooted liners of hydrangea plants were fertilized twice weekly with a N-free fertilizer plus five N rates including 0, 5, 10, 15, or 20 mM N from ammonium nitrate (NH₄NO₃), irrigated once or twice daily with the same total irrigation volume, and grown in two types of one-gallon containers: a black plastic container and a biodegradable container (biocontainer), made from recycled paper. Concentrations of calcium (Ca) and magnesium (Mg) averaged in the entire plant, and iron (Fe) and manganese (Mn) in roots had increasing trends with increasing N rate. By comparison, increasing N rate had a dilution effect on root phosphorus (P), stem and root potassium (K), stem Ca and Mg, and leaf boron (B) concentrations. In general, nutrient content of each tested element increased with increasing N rate in each structure, or total in the plant. When there was a significant container type effect, plastic containers consistently had increased nutrient concentrations and content compared to biocontainers. One irrigation per day was beneficial in increasing nutrient concentrations of P, Ca, and zinc (Zn) in different plant structures. Full article

(This article belongs to the Special Issue Irrigation Management)

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Open AccessArticle

Tree-Type Irrigation Pipe Network Planning and Design Method Using ICSO-ASV

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Water 2020, 12(7), 1985; https://doi.org/10.3390/w12071985 - 14 Jul 2020

Viewed by 2382

Abstract

Research on tree-type irrigation pipe networks is an important component of agricultural water-saving projects. The optimal design of tree-type irrigation pipe networks is a key aspect regarding the profitability of irrigated agriculture. Meanwhile, swarm intelligence optimization algorithms have good computational ability and can [...] Read more.

Research on tree-type irrigation pipe networks is an important component of agricultural water-saving projects. The optimal design of tree-type irrigation pipe networks is a key aspect regarding the profitability of irrigated agriculture. Meanwhile, swarm intelligence optimization algorithms have good computational ability and can be applied to solve many optimization problems in agricultural engineering. To identify the lowest investment cost for a pipe network, this study defined the concept of an upper water node to ensure the connectivity of tree-type irrigation pipe networks, and therefore, improve the pipe network planning model without using preliminary network connection diagrams. In addition, this study proposed an improved chicken swarm optimization algorithm (Improved Chicken Swarm Optimization using Adaptive Search and Variation, ICSO-ASV), which was applied to solve 12 test functions of different dimensions. The test results show that, compared to the traditional chicken swarm algorithm and other algorithms in the control group, the ICSO-ASV algorithm could effectively improve the global search capability. Finally, the ICSO-ASV algorithm was used to plan and design 15-node and 40-node pipe networks. The calculation results show that the average investment costs of the two pipe networks generated by the ICSO-ASV algorithm were 42.20% and 31.09% lower than those generated by the traditional chicken swarm algorithm, which further verified the feasibility of applying ICSO-ASV to design tree-type irrigation pipe networks. Thus, the design method proposed in this study can solve the optimal problems of tree-type irrigation pipe networks with varying topologies. The optimal solutions can be generated automatically using the ICSO-ASV algorithm if essential parameters of the pipe network planning model are provided. Full article

(This article belongs to the Special Issue Irrigation Management)

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Open AccessEditor’s ChoiceArticle

Accounting for the Three-Dimensional Distribution of Escherichia coli Concentrations in Pond Water in Simulations of the Microbial Quality of Water Withdrawn for Irrigation

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Water 2020, 12(6), 1708; https://doi.org/10.3390/w12061708 - 15 Jun 2020

Cited by 4 | Viewed by 1894

Abstract

Evaluating the microbial quality of irrigation water is essential for the prevention of foodborne illnesses. Generic Escherichia coli (E. coli) is used as an indicator organism to estimate the microbial quality of irrigation water. Monitoring E. coli concentrations in irrigation water [...] Read more.

Evaluating the microbial quality of irrigation water is essential for the prevention of foodborne illnesses. Generic Escherichia coli (E. coli) is used as an indicator organism to estimate the microbial quality of irrigation water. Monitoring E. coli concentrations in irrigation water sources is commonly performed using water samples taken from a single depth. Vertical gradients of E. coli concentrations are typically not measured or are ignored; however, E. coli concentrations in water bodies can be expected to have horizontal and vertical gradients. The objective of this work was to research 3D distributions of E. coli concentrations in an irrigation pond in Maryland and to estimate the dynamics of E. coli concentrations at the water intake during the irrigation event using hydrodynamic modeling in silico. The study pond is about 22 m wide and 200 m long, with an average depth of 1.5 m. Three transects sampled at 50-cm depth intervals, along with intensive nearshore sampling, were used to develop the initial concentration distribution for the application of the environmental fluid dynamic code (EFDC) model. An eight-hour irrigation event was simulated using on-site data on the wind speed and direction. Substantial vertical and horizontal variations in E. coli concentrations translated into temporally varying concentrations at the intake. Additional simulations showed that the E. coli concentrations at the intake reflect the 3D distribution of E. coli in the limited pond section close to the intake. The 3D sampling revealed E. coli concentration hot spots at different depths across the pond. Measured and simulated 3D E. coli concentrations provide improved insights into the expected microbial water quality of irrigation water compared with 1D or 2D representations of the spatial variability of the indicator concentration. Full article

(This article belongs to the Special Issue Irrigation Management)

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Open AccessArticle

Numerical Analysis of Woltman Meter Accuracy under Flow Perturbations

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Water 2019, 11(12), 2622; https://doi.org/10.3390/w11122622 - 12 Dec 2019

Cited by 3 | Viewed by 3221

Abstract

One of the unknowns in the instrumentation for water measurement is what degree of influence other hydraulic elements exert on the velocity profile and, consequently, on the measurement errors. In this work, the measurement errors of a horizontal-axis Woltman meter produced by a [...] Read more.

One of the unknowns in the instrumentation for water measurement is what degree of influence other hydraulic elements exert on the velocity profile and, consequently, on the measurement errors. In this work, the measurement errors of a horizontal-axis Woltman meter produced by a gate valve and by a butterfly valve in different hydraulic configurations were studied using a simplified numerical model. The gate valve was installed beside the meter and three pipe diameters upstream of the meter and were operated with closures of 75%, 50% and 25%, while the butterfly valve was installed at three pipe diameters upstream of the meter with closures of 0° (open) and 30°. The numerical model based on the rotor’s torque balance equations and Computational Fluid Dynamics (CFD) was validated by experimental tests. According to the results, it was concluded that the proposed model is valid and capable of estimating the errors caused by the hydraulic fittings arranged next to the meter. In addition, it is evident that for the analysed operating range, both valves must be installed at least three diameters of straight pipe upstream of the meter. Full article

(This article belongs to the Special Issue Irrigation Management)

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Open AccessArticle

Quantifying Water Quality Improvements through Use of Precision Herbicide Application Technologies in a Dry-Tropical, Furrow-Irrigated Cropping System

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Aaron M. Davis

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Catherine Neelamraju

Water 2019, 11(11), 2326; https://doi.org/10.3390/w11112326 - 07 Nov 2019

Cited by 2 | Viewed by 3103

Abstract

This study compared water quality effects of using precision herbicide application technologies and traditional spraying approaches across several regulated ‘priority’ and alternative pre- and post-emergent herbicides in a northern Australian cane farming system. Use of herbicide banding spray technologies resulted in pre-emergent herbicide [...] Read more.

This study compared water quality effects of using precision herbicide application technologies and traditional spraying approaches across several regulated ‘priority’ and alternative pre- and post-emergent herbicides in a northern Australian cane farming system. Use of herbicide banding spray technologies resulted in pre-emergent herbicide load reductions, extending substantially beyond simple proportionate decreases in the amount of herbicide ingredient applied to paddocks. Aquatic risk assessment from resultant chemical mixtures leaving paddocks, and upscaled to local catchment concentrations, highlighted that precision application technologies could markedly reduce the ecological risk of pre-emergent herbicides. These risk reductions were, however, often complicated by the additional toxicity of post-emergent herbicides in mixtures, some associated with the adoption of band-spraying weed treatments. While the currently regulated priority herbicide, diuron, posed the greatest risk to the environment, alternative herbicides could still pose significant environmental risks, although these relative risks were lower at more ecologically relevant concentrations, typically found in the local freshwater ecosystems. Results underline the need for a carefully considered approach to integrating alternative herbicides and precision application technologies into improved weed management by irrigating cane farmers. Recent government changes to the appraisal of water quality improvement progress, from load-based to ecosystem-based targets, involving a much broader suite of herbicides, also appear likely to complicate assessment of the environmental impacts of practice change adoption for the industry. Full article

(This article belongs to the Special Issue Irrigation Management)

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