By using the temperature of the canopy cover of the plant, a practical parameter called the crop water stress index (CWSI), it was determined that this index is one of the methods of checking the water requirement of the plant and it can be considered as a suitable tool for irrigation management in the field. Therefore, this research was carried out with the aim of determining the water stress index of sugarcane in two methods of surface irrigation (CI) and subsurface drip irrigation (SDI) at research station number one of Khuzestan Research and Training Institute for Development of Sugarcane and Related Industries, in June 2022. The fields included the third field culture (Ratoon 3), of the CP69-1062 variety, and were selected with four repetitions in both methods. First, the equation of upper and lower base lines for the surface irrigation method was determined as (Tc-Ta)ul=1.7 and (Tc-Ta)=-0.09VPD+1.27, respectively. Then, using the equations of the lines based on the surface irrigation method, the average of crop water stress index for subsurface drip irrigation method and surface irrigation was calculated as 0.28 and 0.66, respectively, and the equation was presented according to the irrigation scheduling of the Sugarcane in June.

In this study, water productivity in six vineyards under surface and six under drip irrigation systems was measured in Zanjan Province, then, the effect of modified irrigation schedule to improve water productivity was investigated in two selected vineyards. The average volume of applied irrigation water in vineyards with surface and drip irrigation systems was 6929 and 5418 m3. ha-1, respectively. Also, the average of water productivity indices, Gross Benefit, and Net Benefit were obtained as 2. 9 kg. m-3, 91. 5, and 55. 4 thousand Rials. m-3 in vineyards with surface system and 3. 6 kg. m-3, 112. 4, and 59 thousand Rials. m-3 in vineyards with drip system. In terms of water productivity index, drip irrigation was relatively superior to the surface method. In most of the monitored vineyards, the applied irrigation schedule was not in accordance with the net irrigation requirement. The results of the modified irrigation schedule indicated that water productivity could be improved by 24. 7%.

Increasing of Water Use Efficiency (WUE) is a fundamental remedy to food production under conditions of water scarcity. The aim of this study was to evaluate the potential for water saving and yield improvements with use of ET-HS model and subsurface drip irrigation. For this purpose, four irrigation treatments were installed in a silty loam soil at an experimental farm near Isfahan city of Iran in 2000 and 2001. The treatments were included Surface drip irrigation (DI), Sub surface drip irrigation in 15 cm depth (SDI15), Sub surface drip irrigation in 30 cm depth (SDI30), Furrow irrigation (FI).These treatments were repeated for potato in two genus of Marfona and Navita (which they aordinary genus potato in Isfahan region), tomato and eggplant. In this research, a randomized complete block design of three replications was employed for each crop. Also, in all of these treatments, crops water requirement and time irrigation scheduling were determined by ET-HS model. For this purpose, maximum and minimum temperature were measured daily and filled in the model. Based on the results of this research, SDI15 has the most efficient use of water in the production and it is substantially different from other treatments, which were about 7.84, 3.84, 13.15 and 11.64 kg/m3 in Marfona, Navita, tomato and eggplant respectively. Also, results show that the highest yield was obtained from SDI15 in Marfona, Navita and eggplant and from DI and SDI15 in tomato. A part of this increasing yield in SDI15 was related to better soil moisture in the root zone, less water runoff and less surface evaporation. Additionally, the results showed high reduction surface evaporation was obtained in SDI treatments. Finally, it can be concluded that the subsurface drip irrigation, with drippers installed at a depth of 15cm, and implementation of ET-HS model for estimating irrigation scheduling, is the best condition for Moefona, Navita, tomato and eggplant.

Water restriction is one of the most important factors inhibiting the crop production. Accordingly, application of pressurized irrigation systems to optimize utilization of water resources is inevitable. This study was conducted in Behbahan Agricultural Research Station during three cropping seasons (2013-2016) and based on a randomized complete block design with a split plot and three replications. The main plots were consisted of Subsurface Drip Irrigation (SDI) system that applied irrigation water at three levels of 75, 100 and 125% of water requirement and a surface Drip Irrigation (DI) system with application of 100% water requirement. The sub-plots were consisted of two varieties of date palm; Khasi and Zahedi. The crop water requirement was estimated based on Penman-Montheith method and using a daily weather information data collected from Behbahan weather station. Analysis of variance showed a significant difference (5%) between water use efficiency of different levels of irrigation water. As, the SDI system with 75% irrigation level showed the highest water use efficiency to be 0. 698 kg/m3. The comparison of interaction effects showed that the water use efficiency of Zahedi dates in 75% SDI system with 0. 744 kg/m3 is higher than that of Khasi dates. In the other hand, the 75% SDI system saved 2509. 6, 5019. 2 and 2630. 3 m3/ha irrigation water as compared with 100% and 125% SDI and 100% DI systems, respectively. According to the results, the interaction impact of irrigation levels and varieties on water use efficiency was significant but the interaction of irrigation systems and varieties were not significant. The stiffness of fruits was measured to be 11. 3 lb per square meter in 75% SDI system which was the highest as compared to those for other treatments. The results of this study showed that the SDI system could be used for palms trees without restriction while use less water without significant impact on yield.

Estimation of wetting front dimensions enhances the water use efficiency and optimal use of water. Since, globally, most of the cultivated lands are not flat, full recognition of the moisture advance front is essential for proper management and operation of surface drip irrigation in these areas. In this study, two physical rectangular cubic models were constructed to measure the soil moisture advance front. The smaller model was used for experiments with lower discharge and the larger model was used for experiments with higher discharge. The experiments were carried out in four different slopes (0, 10%, 20%, and 30%), three soil types with different textures (light, medium, heavy), with three emitter discharges (2, 4 and 6 liters per hour). The results showed that the moisture distribution (for upstream and downstream of the emitter) was different in sloping lands (for different flow rates and different soil texture). Therefore, in relation to the position of the emitter and plant, drip system should be designed differently in the sloping land in comparison to flat lands. According to the nature of the sloping lands, the plant position was downwardly shifted and its exact positions are suggested for different scenarios (for different discharge rates, slopes, and soils) in this study. The results showed that the percent of downstream wetted radius in sloping lands for the three types of heavy, medium, and light textured soils were between 49. 2-81. 5%, 49. 2-76%, and 48. 3-70. 7%, respectively. These values for the percent of the upstream wetted radius of the emitter ranged between 18. 5-50. 8%, 24-50. 8%, and 29. 3-49. 7%, respectively. The results of this study can be used as a general guide in the design of drip irrigation systems in sloping land to determine the plant and emitter position relatively accurately.

Drip irrigation benefits enhanced the worldwide use of this irrigation system. Drip irrigation reduces significantly the wetted soil surface that lead to reduction of evaporative losses. Claimed that wetting pattern is a major parameter in optimizing lateral placement and emitter spacing as well as in selecting emitter’ s discharge. In other word, to achieve proper drip irrigation design, dimensions of the wetted zone (depth and width) should be accurately determined. Therefore, present study was conducted under clay loam soil to investigate the accuracy of numerical (HYDRUS-2D) and empirical (multivariate nonlinear regression) models in estimating wetting pattern for surface drip irrigation. The predicted values of soil moisture, wetted depth and width were compared with those obtained from laboratory experiments. Experimentations included determination of soil moisture, depths and widths of wetted zone after 1, 2, 3, 4, 5, and 6 hour of water application with three different discharge rates (2, 4 and 8 L/h). Statistical parameters revealed that there was no significant difference between models results and observed values. So that the normalized root mean square error (NRMSE) varied from 5. 8 to 8. 2% and 7 to 7. 7% for numerical and empirical models, respectively. The results also showed that the proposed empirical model predicts the wetting pattern with acceptable accuracy.

To study the effect of 3 depth of placement of drip irrigation tape on yield and quality of potato (cultivar Agria), an experiment was conducted in a randomized complete block design, in Fariman region (2010- 2011). Treatments was include, 0, 10 and 20 centimeter, installation depth of drip irrigation tape. The results showed that the yield of potato strips installed on the soil surface were more than installed at depths of 10 and 20 cm and had significant difference at 5% level. But there were not significant differences between the strips that installed at 10 and 20 cm depth. The effect of tape drip irrigation installation depth on the marketability tubers was not significant, but the number of marketability tubers was reduced from 0 to 2 and 3 depth respectively. The effect of depth of drip irrigation tape installed on the mean tubers weight was not significant. The water use efficiency of surface Tape drip irrigation had significant different with subsurface drip irrigation treatments and was more than them. Generally, surface drip tape irrigation was better than subsurface drip tape irrigation.

The Result of field experiments on surface irrigation in khorasan Razavi province shows that the efficiency application in initial growth stage of plants is very low and less than 10% but after that stage, that maybe bigger than 90%.In order to investigate on the effect of the replacement of current surface irrigation system to drip irrigation on amount of water consumption, yield and water use efficiency (WUE) a study was conducted in some personal farms of Khorasan Razavi province in 2006. The results of analysis showed that the maximum and minimum of yield percentage increased for potato with 21% and sugar beet with 9% respectively. The most saving in water consumption was observed in green com cultivation and the minimum amount of that was happened in tomato farms respectively with 49% and 34%. Water use efficiency in green com increased to 116% and tomato, sugar beet and potato cultivation respectively with 98%, 92% and 83% were located in the next stages. Overall in all farms, the average of used water irrigation, in the total sugar beet, green com, tomato and potato farms, have been reduced from 34% to 49%, whereas the amount of average yield of the four mentioned product increased by 9% to 21%, as well as 83%to 116% (about two time more) for WUE. Surface of planting of sugar beet, potato, green com and tomato increased to 76, 51, 95 and 65 percent respectively and the rate of return of investment of them was 389, 456, 748 and 1304 percent respectively.

Drip irrigation has a priority in selecting an appropriate irrigation method in arid and semi-arid regions because of its potential of precisely applying water and chemicals both in quantity and position. Proper design and management of a drip fertigation system is, to some extent, dependent upon a better understanding of wetting patterns and water and solute distributions in soil under different combinations of soil type and layering, emitter application rate, volume applied and fertigation concentration. In this study, experiments were carried out in a transparent plexiglass tank (0.5 x 1.22 x 3 m) using three different soil textures (light, heavy, and medium). The emitter outflows were considered 2.4, 4, and 6 lit/hr with irrigation duration of 6 hr. The fertigation treatments included treatments with nitrate concentrations of 125, 250, and 375 mg/L. Urea fertilizer (CH4N2O) (46% nitrogen) was used in the fertigation treatments. Then, using the p theorem of Buckingham and Dimension Analysis (DA), equations were developed to estimate the pattern of nitrate distribution pattern (horizontal and vertical) in the three soil textures. The equations developed were functions of initial soil nitrate content, nitrate concentrations in fertigation, initial moisture, radial distance of points, applied water volume, hydraulic conductivity, and emitter outflows. The results of the comparisons between simulated and observed values showed that the equations were capable of predicting the pattern of moisture distribution in different directions. The averages of Root Mean Square Error (RMSE) values in clay soil and for emitter outflows 2.4, 4, and 6 lit/hr were 0.025, 0.105 and 0.093, respectively. These values for loamy soil were 0.032, 0.052, and 0.05, respectively, and for sandy soil were 0.023, 0.038, and 0.035, respectively. Considering these equations in designing surface drip irrigation systems could improve system performance.

Iran is one of the Experienced countries in growing orchards. Traditionally, these orchards are irrigated by surface methods. Due to water scarcity in most parts of Iran, for obtaining higher water use efficiency, application of modern irrigation systemes would be unavoidable. In this study, five irrigation methods including: surface irrigation, bubler, double drip system, spagetti and microjet were tested in aged apple garden located in Semirom region in Esfahan.The systems were compared based on production index, fruit quality, canopy cover and volume of applied water. The study was conducted in a randomized block design with 3 replicates for 3 years. The results indicated siginificant differences among the treatments, in which the double drip system had the maximum yield, while the surface method showed the minimum one. The maximum and minimum trunk diameters , were observed in treatments irrigated with spaghetti and surface methods, respectively. Trees irrigated with double drip system and bubler method had the maximum and minimum height, respectivly.For the main shoot diameter, shading area, and shoots vegetative growth, no significant differences were detected among the treatments. Regarding other vegetative Parameters such as crop yield, qualitative characteristics of fruit, color uniformity, marketing, storage period, sugar content, acidity percentage, and volume of water consumed, double drip and microjet treatments showed the best results.