Wetting Pattern Models for Drip Irrigation: New Empirical Model

Malek, Keyvan; Peters, R. Troy

doi:10.1061/(asce)ir.1943-4774.0000320

Cited by 51 publications

(40 citation statements)

References 30 publications

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“…However, if the drippers had lower discharge rates, we hypothesize that the efficiency of salt removal out of root zone would have been greater. Some investigators developed different methods to allow the estimation of wetting patterns from point sources (Wang et al, 2006;Badr & Taalab,2007;Lazarovitch et al, 2007 andMalek &Peters, 2010).…”

Section: Introductionmentioning

confidence: 99%

Effect of Drip Irrigation System on Moisture and Salt Distribution Patterns under North Sinai Conditions

Rafie¹,

El-Boraie²

2017

Egypt.J. Soil Sci.

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T HE PURPOSE of this experiment is to elaborate the mode of distribution of both moisture and salt under drip irrigation system which is widely regarded as the most promising system in combination with saline water under conditions of El-Sheikh Zewied area-North Sinai (Lithic Torripsamments) during the summer growing season (March -June) 2015. It is just a trial to suggest a suitable irrigation management to increase production of a vegetable crop (Squash, (cucurbita pepo). Two methods of drip irrigation system were applied, i.e., surface and sub-surface with three quantities of irrigation water, i.e., 80, 100 and 120% of evapotranspiration calculated by meteorological equation of Penman-Montieth. Two emitter's discharge rates, i.e., 2 and 4 liter/ hour were used to irrigate squash with saline water (4.5 dS/m). Split -split plot design statistically was applied.1-There is a remarkable decrease in soil moisture content apart from drippers horizontally and vertically. 2-Irrigation water applied as a reference evapotranspiration calculated by penman-Montieth showed that water requirement followed the order increasing as 120 %100 < % < 80 % under 4L/h dripper discharge rate. 3-Surface drip irrigation system cased more soil moisture content than subsurface one. 4-Dripper discharge rate 4L/h surpassed for soil moisture content which increased horizontally, while it increased vertically under 2L/h. 5-Salt concentration in soil increased apart from drippers by increasing irrigation water quantities and dripper discharge rates through growth periods. 6-Surface drip irrigation system help roots to be tolerable salt concentration by moving salts in the two up and down directions apart from roots. 7-Salt concentration significantly increased at 5% level growth season under surface and subsurface drip irrigation system as 90 < 60 < 30 < 1 days, respectively. 8-Biological yield decreased by using salt water under 2L/h dripper discharge and subsurface drip irrigation system, while the best water and salt distribution was conducted in the root zone under surface irrigation system and 100% of irrigation water applied. 9-The maximum squash yield , (significantly increase), was conducted to surface drip irrigation system by applying 100% quantity calculated by reference evapotranspiration approach as 7.59 and 7.4 ton/fed under 4 and 2 L/h dripper discharge rates, respectively. While the minimum yield, (4.4 ton/fed), was found by applying 80 % of water requirements under subsurface drip irrigation with 2L/h dripper discharge rate. 10-Water use efficiency significantly increased with 100% irrigation water requirements and 4L/h dripper discharge rate when applying surface drip irrigation system.

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Section: Introductionmentioning

confidence: 99%

Effect of Drip Irrigation System on Moisture and Salt Distribution Patterns under North Sinai Conditions

Rafie¹,

El-Boraie²

2017

Egypt.J. Soil Sci.

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“…A brief review of empirical equations has been given in the introduction (for more detail, see Amin and Ekhmaj (), Malek and Peters () and Al‐Ogaidi et al . ()).…”

Section: Description Of Experimentsmentioning

confidence: 94%

Experimental and numerical investigations for optimal emitter spacing in drip irrigation

Ghumman

Iqbal

Ahmed

et al. 2018

Irrigation and Drainage

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With the goal of determining optimal emitter spacing in drip irrigation, experiments were performed to examine the effects of emitter discharge on the wetted perimeter and spacing of emitters. Four types of soils were investigated using emitter discharge of 1.0, 2.0, 3.0 and 4.0 l h−1. Wetting diameter was measured at six equal time intervals of water application. An equal volume of water was applied. After 1 h of supply of water, wetted soil was cut to observe the maximum wetted width and depth. Wet soil samples were taken from every patch of 10 × 10 cm to find the percentage of moisture by the gravimetric method. Empirical equations were developed for wetted depth and radius. Additional experiments with emitter discharge of 1–18 l h−1 were performed in sandy loam to obtain more data for accurate estimation of the coefficients of the empirical equations. Two computer programs based on trial and error and the generalized reduced‐gradient non‐linear‐optimized technique were used to find values of the coefficients. Root mean square error between the measured and simulated wetted radius and depth was minimized in optimization. Optimal emitter spacing for each type of soil was determined from the recorded data, which was found to be 35, 40, 40 and 45 cm in sandy loam, loam, clayey loam and clay respectively. © 2018 John Wiley & Sons, Ltd.

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“…However, the physically based models describe the infiltration process in detail, and Richards s model and the Green-Ampt (GA) model are those most commonly used for simulating the infiltration process. The solution to Richards s model requires an iterative implicit numerical technique with fine discretization in time and space; thus, this model is computationally intensive [7][8][9][10]. The GA model [11] is an analytical solution derived from Darcy s equation and is derived indirectly through Richards s model with some simplification [12].…”

Section: Introductionmentioning

confidence: 99%

Approximate Explicit Solution to the Green-Ampt Infiltration Model for Estimating Wetting Front Depth

Nie

Fei

2017

Water

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Obtaining reliable information on the wetting front depth of soil is beneficial to the understanding of one-dimensional (1D) vertical infiltration under border irrigation. This paper presents an approximate explicit solution to the Green-Ampt (GA) infiltration model for estimating the wetting front depth. Moreover, the model proposed in this study, the GA model, the Ali model, and the Stone model were validated and evaluated using laboratory experimental data and HYDRUS-1D simulation. Statistical comparisons (root mean square error-RMSE, mean absolute percent relative error-MAPRE, and percent bias-PB) of the estimated data with the measured and simulated data were conducted. The models were ranked on the basis of their overall performance index (OPI). The results demonstrated that all four models can be used to estimate the wetting front depth of 1D vertical infiltration for a wide range of soil textures; the proposed model provided the most accurate result. According to comparisons of the estimated values with the measured and simulated values, the maximum RMSE, MAPRE, and PB were 1.74 cm, 6.92%, and −6.74%, respectively, for the proposed model. On the basis of the OPI, the optimal model was the proposed model, followed by the Ali, GA, and Stone models.

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Wetting Pattern Models for Drip Irrigation: New Empirical Model

Cited by 51 publications

References 30 publications

Effect of Drip Irrigation System on Moisture and Salt Distribution Patterns under North Sinai Conditions

Effect of Drip Irrigation System on Moisture and Salt Distribution Patterns under North Sinai Conditions

Experimental and numerical investigations for optimal emitter spacing in drip irrigation

Approximate Explicit Solution to the Green-Ampt Infiltration Model for Estimating Wetting Front Depth

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