Drip Irrigation

This study reports the seasonal assessment of energy balance components and carbon dioxides fluxes over a drip irrigated kiwifruit orchard, with a Leaf Area Index (LAI) of 3 at full canopy development. The most remarkable amount of energy partitioning throughout the whole season was due to latent heat flux that had values approximating to those of sensible heat flux (about

A pilot-scale irrigation scheme was set up in South-West Portugal to investigate the causes of emitter clogging which has been observed when waste stabilisation pond effluents are used for drip irrigation of crops. During field trials over a period of two growing seasons, the ...

This report discusses a statewide survey of irrigation methods conducted in California during 2002. The purpose of the study was to collect information on irrigation methods to determine which methods were used by growers to irrigate their crops in 2001. Reliable information on irrigation methods is an important factor for planning future water demand by agriculture irrigation based on trends. To conduct the survey, one-page survey form was developed to collect irrigated land (acres) by crop and irrigation method. Then a questionnaire was mailed out to 10,000 of the estimated 80,000 growers in California by the California Department of Food and Agriculture. The results from comparing earlier studies with 2001 indicated that the amount of land irrigated by drip irrigation method has increased by about 33%, while the amount of land irrigated by surface methods has decreased by about 31%. The area planted to orchards and vineyards has increased, while that planted to field crops has de...

A field study on cotton (Gossypium hirsutum L., cv.) was carried out from 2005 to 2008 in the Çukurova Region, Eastern Mediterranean, Turkey. Treatments were designated as I100 full irrigation; DI70, DI50 and DI00 which received 70, 50, and 0% of the irrigation water amount applied in the I100 treatment. The irrigation water amount to be applied to the plots

A computer programhas been developed for design of surface drip irrigation system. It could be applied for calculation of small scale fields with an area up to 10 ha. The program includes two main parts: crop water requirements and hydraulic calculations of the system. It has been developed in Graphical User Interface in MATLAB and gives opportunity for selecting some parameters from tables such as: agro- physical soil properties, characteristics of the corresponding crop, climatic data. It allows the user of the program to assume and set a definite value, for example the emitter discharge, plot parameters and etc. Eight cases of system layout according to the water source layout and the number of plots of the system operation are laid into hydraulic section of the program. It includes the design of lateral, manifold, main line and pump calculations. The program has been compiled to work in Windows.

During four growing seasons, 10-year-old apricot trees (Prunus armeniaca L., cv. ‘Búlida’) were submitted to three different drip irrigation regimes: (1) a control treatment, irrigated at 100% of seasonal crop evapotranspiration (ETc), (2) a continuous deficit irrigation (DI) treatment, irrigated at 50% of the control treatment, and (3) a regulated deficit irrigation (RDI) treatment, irrigated at 100% of ETc during the critical periods, which correspond to stage III of fruit growth and 2 months after harvest (early postharvest), and at 25% of ETc during the rest of the non-critical periods in the first two growing seasons and at 40% of ETc in the third and fourth. Soil–plant–water relation parameters were sensitive to the water deficits applied, which caused reductions in leaf and soil water potentials. The longer and severer deficits of the RDI treatment decreased fruit yield in the first two seasons. The RDI treatment pointed to two threshold values that defined the level at which both plant growth and yield were negatively affected with respect to the control treatment: (1) a predawn leaf water potential of around −0.5 MPa during the critical periods, and (2) a 22% drop in irrigation water. The total yield obtained in the DI treatment was significantly reduced in all the years studied due to the lower number of fruits per tree. No changes in the physical characteristics of fruits were observed at harvest. RDI can be considered a useful strategy in semiarid areas with limited water resources.

The developed model 'Drip Chartist' by Ismail et al. (2006a) was verified and validated in field and by comparison to other related model "Hydrus 2D". Field validation resulted showed that the surface system without hydraulic barrier represents the real-condition by 94.99% (correlation coefficient of 0.9746) with under estimation of 0.157. While in the subsurface system with hydraulic barrier represents the realcondition by 81.96% (correlation coefficient of 0.9053) with under estimation of 0.021. Validation to Hydrus2D lead to almost coincidence in predicted values of wetting pattern. Several studies were performed using the model, like studying soil properties such as θsat, θres, Ks, and the retention and conductivity parameters of soil such as α, m, n, λps, and ϒ effect on soil moisture pattern. The effect of soil texture indicated that the heavy textured soils could be simulated faster than light texture soils, while silt texture soil was simulated in longer time compared to other texture classes, solution methods, and other properties were studied as well. In addition, some construction alternatives of the system were studied like the effect of bilateral gap, dripper line burying depth, physical barrier and the emitter discharge on the wetting pattern. The model "Drip Chartist" was proved to act like intended in predicting surface and subsurface drip wetting pattern.

 (البخر – نتج (ET Evapotranspiration

  “كمية الماء المفقودة من التربة (البخر) وعن طريق النبات (نتح). “

 الاستهلاك المائي Consumptive Use

“مقدار الماء المفقود من كل من أسطح النبات والأرض النامي عليها بالإضافة إلى مقدار الماء الداخل في تركيب النبات”.

رطوبة التربة Soil Moisture
النسبة المئوية لوزن الماء المفقود إلى وزن التربة الجاف – فإذا وزنت عينة من التربة ثم جففت في الفرن ثم وزنت ثانية فإن الفاقد هو عبارة عن الماء المفقود الذي كان موجوداً في عينة التربة قبل تجفيفها.

Mathematical modeling considered as one of the influencing means for drip irrigation improvement to develop efficient and economical system designs. Inadequate mathematical models may lead to an underestimation of head losses calculations. This study concerns the factors affect friction head losses in lateral line and to establish the relationship between them.  The accurate design of drip irrigation laterals needs to determine the total energy losses that include the pipe friction losses along the lateral line and minor losses due to emitter connections. Laboratory experiments were conducted to measure friction head losses for emitter spacing from 0.3 to 2.4 m, pipe inner diameter 13.1, 15.6, and 17 mm, protrusion barb area 14.49, 21.375, 28.78 mm2 (for on-line emitters), emitter cylinder length from 30 to 68 mm, and emitter inner diameter from 11.2 to 15.5 mm (for built-in emitters) at values of Reynolds number varied from 6000 to 21000. Two mathematical models were developed to predict the friction head losses in lateral equipped with on-line and integrated built-in emitters. The parameters affecting the friction head losses in lateral defined in dimensionless terms using Buckingham’s Π theorem. The developed models were accounted for 98% of the variation in measured data. The friction head losses were calculated using the developed models and there was an acceptable accuracy comparing with the previously proposed models. A friendly user interface computer program named EGY-DRIP SYSTEMS had developed for drip irrigation system design. The program had written in Microsoft visual basic 2013. EGY-Drip SYSTEMS program carries out hydraulic calculations of a sub-unit design for drip irrigation system. The hydraulic calculation based on data inputs about water supply, soil, evapotranspiration, crop (vegetables, fruit, and field crops), and irrigation system components (drippers, pipes, and fittings). The program supported with an up-gradable Microsoft access database to facilitate data input by the user. EGY-DRIP SYSTEMS program is outfitted with an open source computer aided drafting program (QCAD) for pipeline network layout drafting.

Hazen-Williams equation is used widely by irrigation systems’ designers due to its simplicity.However, Darcy-Weisbach equation is more accurate and reliable. The accuracy of the latter is due to its friction coefficient, which depends on both flow characteristics and pipe surface state. On the other hand, Hazen-Williams’ coefficient (C) depends only on pipe substance and age. A comparative analysis of both models was performed through a simple iterative model. The analysis was based on the real state design procedure of drip laterals. More accurate values of coefficient C were suggested to be used in designing drip laterals. A straightforward equation was developed to compute C depending on emitter flowrate, emitter flow exponent, and pipe diameter.The results reveal that C ranges from 132 to 138 for drip laterals, while it was proved that using C=150 is reasonable for manifolds design.

Agricultural production has forced researchers to focus on increasing water use efficiency by improving either new drought-tolerant plant varieties or water management for arid and semi-arid areas under water shortage conditions. A field study was conducted to determine effects of seasonal deficit irrigation on plant root yield, quality and water use efficiency (WUE) of sugar beet for a 2-year period in the semi-arid region. Irrigations were applied when approximately 50–55% of the usable soil moisture was consumed in the effective rooting depth at the full irrigation (FI) treatment. In deficit irrigation treatments, irrigations were applied at the rates of 75, 50 and 25% of full irrigation treatment on the same day. Irrigation water was applied by a drip irrigation system. Increasing water deficits resulted in a relatively lower root and white sugar yields. The linear relationship between evapotranspiration and root yield was obtained. Similarly, WUE was the highest in DI25 irrigation conditions and the lowest in full irrigation conditions. According to the averaged values of 2 years, yield response factor (k y ) was 0.93 for sugar beet. Sugar beet root quality parameters were influenced by drip irrigation levels in both years. The results revealed that irrigation of sugar beet with drip irrigation method at 75% level (DI25) had significant benefits in terms of saved irrigation water and large WUE, indicating a definitive advantage of deficit irrigation under limited water supply conditions. In an economic viewpoint, 25% saving of irrigation water (DI25) caused 6.1% reduction in the net income.

Mounding often occurs beneath engineering structures designed to infiltrate reuse water. AQTESOLV software and a spreadsheet solution for Hantush, together with soil moisture water balance (SWAGMAN farm model), were used for quantitatively predicting the height and extent of groundwater mounding underground to assess the groundwater-flow simulations of infiltration from a hypothetical irrigation site. Horizontal and vertical permeability, aquifer thickness, specific yield, and basin geometry are among the aquifer and recharge properties inputs. For 2.2 ha sites, the maximum heights of the simulated groundwater mound ranges up to 0.29 m. The maximum areal extent of groundwater mounding measured from the edge of the infiltration basins of 0.24 m ranges from 0 to 75 m. Additionally, the simulated height and extent of the groundwater mounding associated with a hypothetical irrigation infiltration basin for 2.2 ha development may be applicable to sites of different sizes, using the recharge rate estimated from the SWAGMAN farm model. For example, for a 2.2 ha site with a 0.0002 m/day recharge rate, the irrigation infiltration basin design capacity (and associated groundwater mound) would be the same as for a 1.1 ha site with a 0.0004 m/day recharge rate if the physical characteristics of the aquifer are unchanged. The study claimed that the present modelling approach overcomes the complications of solving the Hantush equation for transient flow. The approach utilised in this study can be applied for other purposes such as measuring the feasibility of infiltrating water, attenuation zone, risk mitigation essential for decision-makers and planning regulators in terms of environmental effects and water use efficiency.

This work focused on the determination of equilibrium moisture content (EMC) of some bioplastic materials that could be used for agricultural foil mulch as a source to produce biodegradable drip tubes. Equilibrium moisture content (EMC) is very important to determine the desirable conditions of microorganism’s growth, which causes material deterioration and degradation. Thus, this work aimed to determine the EMC of some commercial bioplastic mulch such as (Bioflex, Ecoflex, Chitosan, Mater-bi, and Bi-OPL). The bioplastic materials were put under different temperature (10-50°C) and relative humidity (43-95%) conditions. The data revealed that changing the relative humidity from 43 to 95% has a great effect on both of Mater-Bi and Chitosan, which the EMC increased by 9.87 and 12.22%, respectively. On the other hand, there is a small effect on the EMC with relative humidity changes on each of Ecoflex (1.41%), Bioflex (2.4%) and Bi-OPL (0.5%). Keywords: EMC, bioplastic, Bioflex, Ecoflex, Chitosan, Mater-Bi, Bi-OPL, relative humidity.