Drip / trickle irrigation

Bitter gourd (Momordica charantia), a seasonal vegetable is a source of many essential nutrient and contain low energetic and anti-diabetic property. To increase the self-life, a drying operation was done by using hot air oven dryer at different thickness of fruit slice (3,6 and 9mm) and temperature (60 ,70 and 80°C). The sliced bitter gourds were treated by NaCl solution before drying and dried up to 5 per cent moisture content (MC) on dry basis (db) and grinded to powder for further experiment. The drying rate increases with increase of temperature and decrease of thickness whereas diffusion and activation energy increase with increase of temperature and thickness and they are significantly variable. The maximum value of diffusion coefficient, activation energy, ascorbic acid and the protein were found at 80°C and 9mm thickness (1.9149×10-9 (m 2 s-1), 118.77 KJ kg-mol-1 , 77.65 mg100g-1 and 5.65% (d.b.)) and minimum at 60°C and 3mm (0.0085×10-9 (m 2 s-1), 74.93 KJ kg-mol-1 , 17.65 mg 100g-1 and 3.77% (d.b.)). Losses of nutrients were non-significantly variable.

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.

Simulation models are useful tools for enhancing water management on farm level and optimizing water application efficiency. Focusing on water, as water is the key driver of agricultural production and the critical factor of increasing crop production. Evaluating effects of water saving to optimize water application efficiency under limited conditions to enhance sustainability an (surface drip irrigation and solid-set sprinkler) at the Experimental Farm of d profitability of crop production. HydroCalc model was evaluated under two lateral length (30, 50m) and (0, 0.02) slopes under pressurized irrigation systems Agricultural Production and Research Station, National Research Centre (NRC), El Nubaria, Egypt, (latitude 30.87N, longitude 30.17E and altitude 20 m above sea level). The results obtained declared that: The statistical indicators; the regression coefficient (R² > 0.90) and correlation coefficient confirmed the good performance of HydroCalc in simulating some hydraulic parameters of pressurized irrigation systems. The validation of measured and simulated data clarified it as efficient reliable software to design pressurized irrigation systems to increase the system performance and water application efficiency. The energy savings were (33.18; 27.33%) under slope (0%) and (34.23; 29.54%) under slope (2%) with surface drip irrigation systems when using lateral lengths (30;50m), respectively compared to the solid-set sprinkler irrigation system. It could be concluded to using drip irrigation systems with lateral length 30 m and with slope (2%) downhill for increasing the water application efficiency, decreasing the friction losses along lateral lines and this lead to saving more water head energy.

 (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.

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.

An Abstract-Fertilizers application plays an important in the production of fruits and vegetables. Over-application of fertilizers can slow down the growth and development of fruits and vegetables. The present research work was carried out to check the yield and growth rate of carrot in open field by using drip irrigation along with the application of different rates of poly-feed water soluble NPK (20-20-20) fertilizer. The field study was carried out on randomized complete block design (RCBD) having four different rates of poly-feed water soluble NPK fertilizer, i.e. (T 0 = control, T 1 = 0.7 grams per plant fertigation-1 , T 2 = 1 grams per plant fertigation-1 , and T 3 = 1.4 grams per plant fertigation-1) respectively. All the data analysis and statistical analysis for agronomic parameters were done through ANOVA procedure accordingly. The outcome of the conducted research tantamount that the poly-feed water soluble NPK (20-20-20) fertilizers application with different rates brought a positive effect in carrots cultivation under the open field arrangements. Amongst different treatments rates of NPK, treatment T 3 was observed to be more suitable and economical dose as it took the tallest carrot plants (44.67cm), highest number of leaves (5.52), highest leaf length (44.38 cm), the highest root core diameter (1.76 cm), maximum root shoulder diameter (5.09 cm), highest root length (19.11 cm) and highest root yield (11.07 t/ha) respectively. However, control plots showed unsatisfactory results regarding all the parameters. Therefore, from the current study it may be concluded that application of NPK (20-20-20) (treatment T 3 = 1.4 grams / plant fertigation-1 were suitable for optimum growth and yield of carrot. Application of fertilizers beyond this level seems to be an uneconomical and wasteful practice. Statistical analyses of all the research parameters are elaborated in Table I.

Among the factors affecting the movement of water in the soil are soil properties (structure and texture). The rate of components of soil minerals and organic material has an effect on its bulk density. As the surface soil has organic matter more than subsurface  soil in general, the bulk density increases with soil depth, so the research aims to study the effect of changing soil bulk density with depth on wetting front advance under a trickle line source. The experimental work included a nine laboratory tests for monitoring the advancement of the wetting front with time, The water advance and water distribution measurement are carried out for three cases of the soil profile with the change of bulk density along soil depth (0.00923,0.00462,0) gm/cm 3/cm: first case with the soil changed bulk density from 1.2 gm/cm 3 at the soil surface and gradually to 1.8 gm/cm 3 at a maximum depth of the profile, the second case with the soil changing bulk density from 1.5 gm / cm 3 to 1.8 gm / cm 3, and the third case homogeneous soil with bulk density 1.2 gm / cm 3.and using three application flow rates 1.3,2.6,3.9 cm 3 / min / cm.
                The study showed that with the increase in the change of bulk density along soil depth there is a small increase in the horizontal advance and almost non-existent this increase in vertical advance while they are clear and tangible in diagonal advance. It also showed that the amount of the increase in the vertical advance is greater than in the horizontal advance and be among in diagonal advance when increasing the application flow rate, and all of the horizontal advance, vertical advance and the diagonal advance of the wetting front increases with the decrease of the application flow rate and that when applied the same volume of water.

A study was conducted at the research farm of Central Soil Salinity Research Institute, Karnal, to evaluate the effect of salinity of irrigation water on the yield of okra (Abelmoschusesculentus L. Moench) under drip irrigation. The experiment was conducted in randomized block design with 4 levels of saline irrigation water (ECiw = 0.2, 2.0, 4.0, 8.0 dS.m-1) in three replications. Significant change in the yield of okra (Var: Mahyco-10 Hy) was observed at 1% level of significance. It was found that even at 8 dS.m-1 irrigation water salinity, 77% of okra yield to the check could be obtained. Highest water use efficiency was with available fresh water of 0.2 dS.m-1 at 0.49, and for the treatments of 2.0, 4.0, 8.0 dS.m-1 it was observed at 0.49, 0.46 and 0.38 t.ha-1.cm-1, respectively.

The effects of water temperature and structural parameters of a labyrinth emitter on drip irrigation hydraulic performance were investigated. The inside structural parameters of the trapezoidal labyrinth emitter include path width (W) and length (L), trapezoidal unit numbers (N), height (H), and spacing (S). Laboratory experiments were conducted using five different types of labyrinth-channel emitters (three non-pressure compensating and two pressure compensating emitters) commonly used for subsurface drip irrigation systems. The water temperature effect on the hydraulic characteristics at various operating pressures was recorded and a comparison was made to identify the most effective structural parameter on emitter performance. The pressure compensating emitter flow exponent (x) average was 0.014, while non-pressure compensating emitter’s values average was 0.456, indicating that the sensitivity of non-pressure compensating emitters to pressure variation is an obvious characteristic (p < 0.001) of this type of emitters. The effects of water temperature on emitter flow rate were insignificant (p > 0.05) at various operating pressures, where the flow rate index values for emitters were around one. The effects of water temperature on manufacturer’s coefficient of variation (CV) values for all emitters were insignificant (p > 0.05). The CV values of the non-pressure compensating emitters were lower than those of pressure compensating emitters. This is typical for most compensating models because they are manufactured with more elements than non-compensating emitters are. The results of regression analysis indicate that N and H are the essential factors (p < 0.001) to affect the hydraulic performance.

A new method to barricade water deep percolation was investigated. This method was called 'The hydraulic barrier technique'. The method involves burying a secondary dripper line under the primary one in order to increase the deep layers' water content whereas to minimize matric potential in these layers. So that to increase the side movement of water from the primary dripper line. The method was validated by a field experiment in Sinai sandy soil. The field experiment tested four burying depths of primary dripper line, with and without the hydraulic barrier, compared with the physical barrier. Two crops were used, Jerusalem artichokes (Tartoufa) as example to tuber roots, and tomato as fibrous root. The results showed that the physical barrier extremely increased both crops more than double its normal in the absence of physical barrier value (2.35 for Tartoufa and 2.19 for Tomato), and the hydraulic barrier existence increased the total crop yield of Tartoufa by about 12% and marketable yield by 47%. Reduction of Tomato yield was found due to existence of hydraulic barrier by about 25%. The Tartoufa yield increased directly proportional to the burying depth of the primary lateral while the situation is inverted in the tomato. The hydraulic barrier acted the same like the physical barrier when the gap between the two dripper-lines getting narrower.

Inadequate oxygen concentration in the root zone is a constraint to plant performance particularly in heavy, compacted and/or saline soils. Sub-surface drip irrigation (SDI) offers a means of increasing oxygen to plant roots in such soils, provided irrigation water can be hyper-aerated or oxygenated. Hydrogen peroxide (HP) at the rate of 5 litre ha−1 at the end of each irrigation cycle was injected through SDI tape to a field-grown zucchini (courgette) crop (Cucurbita pepo) on a saturated heavy clay soil in Queensland, Australia. Fruit yield, number and shoot weight increased by 25%, 29% and 24% respectively due to HP treatment compared to the control. Two pot experiments with vegetable soybean (Glycine max) and cotton (Gossypium hirsutum) compared the effectiveness of HP and air injection using a Mazzei air injector (a venturi), throughout the irrigation cycle in raising crop yield in a heavy clay soil kept at saturation or just under field capacity. Fresh pod yield of vegetable soybean increased by 82–96% in aeration treatments compared with the control. The yield increase was associated with more pods per plant and greater mean pod weight. Significantly higher above ground biomass and light interception were evident with aeration, irrespective of soil water treatment. Similarly cotton lint yield increased by 14–28% in aeration treatments compared with the control. The higher lint yield was associated with more squares and bolls per plant which accompanied greater above ground biomass and an increase in root mass, root length and soil respiration. Air injection and HP effected greater water use, but also brought about an enhancement of water use efficiency (WUE) for pod and lint yield, and increased leaf photosynthetic rate in both species but had no effect on transpiration rate and stomatal conductance per unit leaf area. Aeration-induced enhanced root function was arguably responsible for greater fruit set and yield in all three crops, while in vegetable soybean greater canopy cover, radiation interception and total vegetative biomass were responsible for additional yield benefit. Increased aeration of the root zone in heavy clay soils employing either air injection or HP proved beneficial to SDI irrigated crops, irrespective of the soil water conditions, and can add value to grower investments in SDI.

An interactive computer enabled software namely IRRIPRO was used in order to design and plan viable drip irrigation systems. This software is proficient enough in planning network layout, hydraulic designing and above all simulations to obtain results. This software can also provide requisite cost estimation of new as well as existing drip irrigation. IRRIPRO has the diverse quality to calculate and design many other hydraulic parameters. It is a helping tool for water resource engineers in designing, testing, analyzing any other alternative design on precision and economical parameters. It is equally useful in cost estimation of those systems which are not designed with the help of IRRIPRO software. The research study has been conducted in a greenhouse at western region of Abu Dhabi UAE to check the operational reliability, efficiency, dependability and harmony of the existing drip irrigation system. The comparative study revealed that the drip irrigation achieved high CU and DU which imply that the existing drip irrigation system was designed on the basis of proper scaling and dimensions. The CU on average basis for the system was found to be 96.4990% (observed) and 99.9796% (simulated) respectively. Similarly, the DU on average basis for the system was found to be 94.3605% (observed) and 99.8822% (simulated) respectively. EUa of the system using pressure compensated type emitters with the length of laterals 16 meters with an average observed and simulated value was found 99.2192% and 99.99316% respectively. The comparison of experimental and simulated results confirms that the application uniformity seems to be satisfactory and the existing drip irrigation unit was designed properly.

A field experiment was conducted to study the effect of varying water application and soil pH on the growth parameters during the establishment of litchi (Litchi chinensis Sonn.) plantation in a partially reclaimed alkali environment. The plant growth parameters such as plant height and girth at collar were studied. Hydraulic performance of drip system was monitored by observing the individual and plant wise emitter discharge. The Christiansen's Coefficient of Uniformity (CCU), Wilcox-Swailes Coefficient of Uniformity (WSCU), Statistical Coefficient of Uniformity (SCU), Low Quarter Distribution Uniformity (SDUIq), and Coefficient for Emitter Flow Variation (CEFV) for the rate of water application were determined. The average value of CCU remained close to 0.63 and 0.75, respectively, on emitters' and plant basis when 4 drippers were employed per plant. Different levels of soil pH as experienced by the litchi plants were grouped into seven soil pH groups viz. less than 7.75, 7.75-8.00, 8.00-8.25, 8.25-8.50, 8.50-8.75, 8.75-9.00 and more than 9.00. In each of the above pH groups, different emitter discharges were observed. The plant wise discharges received in each pH group were further sub-divided and grouped in less than 10, 10-15, 15-20, 20-25, 25-30 and above 30 liter per hour (Ih?¹). The plant growth parameters were significantly different at different soil pH levels. The plant mortality was high and plant height and girth at collar reduced when the soil pH exceeded 8.5. A positive linear trend was observed in growth parameters and the application of discharge at or below a pH level of 8.5, after which the trend was reverse.

Rao, K.V. Ramana, Saxena, C. K. (2014). Advances in Micro Irrigation Systems and Fertigation under Covered and Open Cultivation, ICAR - Central Institute of Agricultural Engineering Bhopal 462 038 (India), Manual No: CIAE/IDED/2014/441, p 333.

India is facing innumerable challenging problems associated with land and water resources. Declining land resource, depleting water resource and decreasing resource productivity are matters of grave concern. While an estimated 8.5 million ha of agricultural lands have turned barren because of excess salts, the receding availability of the fresh quality water for agriculture aggravating over time. Thus, use of water saving technologies and/or technologies that would allow growing crops on salt-affected soils or with the use of poor quality waters would play an increasingly important role in the twin task of utilizing salty land and water resources for agriculture. The use of drip irrigation seems to be the most viable method of irrigation considering the limitations set forth by poor quality land and water resources. The expansion potential of drip irrigation can be gauged from the fact that only 0.36 million ha is currently under drip irrigation against a potential of 27 million ha. Concerted efforts are being made across the country to examine the suitability and adaptability of drip irrigation for growing a wide range of agricultural and horticultural crops under various agro-climatic conditions. A critical review of several research studies has been made to highlight increase in water use efficiency or water saving for several crops. On the basis of drip irrigation experiments conducted across India, the performance of drip irrigation in salt affected soils and water environments has been highlighted. An attempt to develop pitcher irrigation as an indigenous alternative to drip irrigation to minimize initial investment cost is also included.

Abstract: There were some problems that face continuous drip irrigation system in Egypt, such as emitter clogging, due to the narrow paths of water which give small discharge and in sandy soil, the depth of wetting pattern is relatively higher than the width. They cause deep percolation beyond root zone. Thus the need to increase the width of wetting pattern and use of high emitter discharge suggest the use of pulse drip irrigation.
The information on depths and widths of wetted zone of soil plays the greatest role in design and management of drip irrigation system. There is a lack of models to predict wetting pattern under pulse and intermittent flow regime, since the applicability of the available models were limited to continuous flow regime only. Therefore, the objective of this research was to develop a dimensional analysis model to estimate both depth and width of wetting pattern under different flow regimes. Thus, a model was developed using semi-empirical approach and dimensional analysis method for determining geometry of wetted root zone under. The predicted values of wetted depth and width were compared with those obtained through laboratory experiments conducted in same soil. Experiment included determination of maximum depths and widths of wetted zone after 1, 2, 3, 4 h of water application under different flow regimes. Predicted and observed values were compared to test model applicability in laboratory conditions. On the basis of root mean square, mean error and model efficiency parameters model performance was found good. Thus, developed models can be used to predict wetting pattern under continuous, intermittent and pulse flow with line source of water application. Pulse flow results showed that the wetted width increased and wetted depth decreased as the operating on-time decreased for the same amount of applied water. As the pulsed flow was increased from six to twelve times the continuous flow, deep percolation was reduced and horizontal spread increased. This result shows the advantage of pulse flow, for reducing the deep percolation of water under the crop root zone, while obtaining a wide horizontal spread of wetting. This enables using a highly discharge emitter with the same amount of water.

Seepage problem and channel transition efficiency is one of the most important issues in managing and exploiting irrigation networks. Seepage rate should be minimized in the design and construction of irrigation channels. Anyway several methods have been represented to calculate seepage rate. Some methods that are numeral have their own complexity, and some methods are empirical. Due to the fact that the nature of the flow in the channels and the seepage of the walls are spatially varied flow, in this study, the governing dynamical equation is used and combined with the Chahar and Swamee equation. The final differential equation is solved by finite difference method (FDM), and the depth and flow rates of different cross sections of a channel are obtained. From the difference of flow rate in two cross sections, the seepage flow rate can be calculated. The information required for this method is the flow rate and flow depth at a downstream control channel, the hydraulic conductivity of the channel bed, the geometric characteristics of the channel, and the distance between the water table and the bottom of the channel. This model can be used for calculation of the transmission efficiency too.

A field experiment was carried out during the two successive autumn seasons of 2013 and 2014
under open field conditions in protected cultivation site, Agriculture Research Centre, Giza
governorate, Egypt. The study was investigating the effects of different irrigation levels (50, 75 and 100% of crop evapotranspiration (ETc)) and different sources of fertilizers (inorganic fertilizers (control), cattle manure, compost and vermicompost) on some soil chemical characteristics and vegetative growth, yield and water use efficiency of head cabbage. Obtained results showed that soil pH decreased at the end of experiment with a range of 0.08-0.30, compared with before cultivation, with high decreases by 50% of ETc combined with vermicompost. ECe, on the other hand, increased due to different agricultural activities such as adding chemicals and fertilizers,