جستجوی مقالات مرتبط با کلیدواژه « آبیاری زیرسطحی » در نشریات گروه « آب و خاک »

This study investigated the effect of hydrostatic pressure on clogging of subsurface clay emitters produced by the Plateau Water and Sustainable Development Institute at the Karaj Agricultural Engineering Research Institute. The Plateau Water and Sustainable Development Institute produces and supplies the mentioned emitters for subsurface irrigation of pistachio trees. It is estimated that each ceramic emitter measures approximately 30 cm in length, has an inner diameter of 1.5 cm, an outer diameter of 2.5 cm, and a wall thickness of 0.5 cm. Three groups of seven emitters were selected and tested consecutively for 42 days to investigate the long-term permeability reduction process. The system was operated at hydrostatic pressures of 0.5, 1 and 2 meters. Based on the results of the study, it was found that the amount of seepage from clay emitters decreased in all hydrostatic pressures over time due to a reduction in the participation of pores in the emitter body in water transfer. After 1000 hours of measuring seepage from clay emitters, it was found that water-soluble solutes accumulated in the porous environment of the earthen body over time and caused clogging over time. Based on the very good correlation between the fitted line and the measured points at hydrostatic pressures of 0.5 meters and 2 meters, all analyses performed in the field of occlusion were based upon the data collected at hydrostatic pressures of 0.5 meters and 2 meters. Clogging values measured after 1000 hours of testing at hydrostatic pressures of 0.5 meters and 2 meters were 38.9 percent and 80.3 percent, respectively, and increased logarithmically. Results demonstrated that the higher the hydrostatic pressure in the system, the higher the clogging of the emitter body when a certain amount of water seeped through it.

Increased agricultural activities, the occurrence of successive droughts, and limited freshwater resources, along with increasing population, have made a priority for the importance of protecting water resources in programs of developed and developing countries. Due to the climatic conditions in Iran, which has a wide range of arid and semi-arid characteristics, facing the challenge of water resources crisis, is inevitable. Therefore, the use of wastewater is very important.

This research was conducted in the research farm of Sari University of Agricultural Sciences and Natural Resources (SANRU), which has a silty clay soil texture. The latitude and longitude of the region are 36º 40ʹ N and 53º 04ʹ E, respectively. Its height above sea level is 21 meters. According to Demarten classification, Sari city has a temperate humid climate. The long-term average temperature of Sari is 11.18 °C and the total long-term rainfall is 780 mm. In order to evaluate the wastewater effects on soil chemical characteristics, microelements concentrations, heavy metals accumulation and Maize yield (Single Cross 704), an experiment was carried out as factorial based on a completely randomized design with treatments included; Water source factor (wastewater (A1), well water (A2)), Irrigation (subsurface method (I1) and (drip method (I2)) with three replication in 2018-2019 under lycimetric conditions, at the Sari Agriculture and Natural Resources University (SANRU), Iran.

According to this study results, the effect of type of irrigation source on soil electrical conductivity, soil microelements and heavy metals accumulation of the soil was significantly different (P ≤ 0.01). The highest soil electrical conductivity with a value of 1.8 dS.m-1 was observed in the conditions of using treated wastewater. The highest amount of total nitrogen, phosphorus and potassium were related to the source of treated wastewater with values of 0.086, 24.2 and 222.2 mg.kg-1, respectively. The results showed that the accumulation of soil Pb (0.07) and Cd (0.014 mg.kg-1) in irrigation with treated wastewater increased compare to the well water source by 0.05 and 0.010 mg.kg-1, respectively. Also, the effect of irrigation method and the interaction effect of source and method irrigation on soil chemical characteristics, microelements concentration and heavy metals accumulation were not significant. The use of wastewater by increasing soil stability improves soil physical condition, increases soil fertility, increases photosynthetic products, increases the efficiency of plant photosynthetic system and ultimately improves plant growth. The use of subsurface irrigation resulted in a 67% increase in grain yield and 28% increase in biomass productivity compared to the drip method. Adequate nutrients during the reproductive growth stage of the plant play an important role in grain growth. Therefore, it can be said that the nutrients in the wastewater have increased the grain yield compared to using the well water source. Because the wastewater contains nutrients and micronutrients such as; nitrogen, phosphorus, potassium, calcium, zinc and iron were relative to the well water source and increased maize grain yield. The results showed that the use of effluent compared to well water, caused the absorption of more heavy metals lead and cadmium in the grain, leaf and stem of maize. Due to the use of wastewater water source, the amount of Pb uptake among different parts of the maize, with values of 27.2, 22.5 and 20.5 mg / g, respectively, related to the grain, leaf and stem. However, the uptake of Cd in the grains, leaves and stems was 2.32, 1.35 and 2.01 mg / g, respectively. According to the results, the high concentration of heavy metals Pb and Cd due to the use of wastewater in the grain sector directly threatens human health. Also, the concentration of heavy metals Pb and Cd in the leaf and stem parts of corn, by endangering the health of livestock and poultry, indirectly affects human health.

The results showed that irrigation with treated wastewater due to its richness in nutrients and microelements, improves soil fertility and creates favorable conditions by increasing soil organic matter and mineral for plant growth. Also, according to the permissible threshold values of the concentration of heavy metals Pb and Cd in plants, the accumulation of heavy metals Pb and Cd in the grain, stem and leaf of single cross 704 corn, will not be a problem for consumers. Optimal use of wastewater can increase soil fertility and the ability of plants to absorb nutrients from the soil and ultimately increase plant yield.

Since the sustainable agriculture field is the main water consumer, using techniques in order to increasing water use efficiency is necessary. An investigation was done to evaluate effects of different regimes of urban wastewater on chemicals properties of soil, yield and water productivity of Quinoa plant (cv. Titicaca), at Research Greenhouse of Ferdowsi University of Mashhad, during 2017-2018. The research was based on completely randomized design with three replications in greenhouse conditions and in pots. Five applied treatments were urban fresh water, urban wastewater, alternate wastewater and fresh water, mixture of 50-50 percent wastewater and freshwater, and subterranean irrigation with urban wastewater. The results show that the treatments were significant on K, P, N, and water productivity; grain yield was significant at 1 percent level (P<0.01), but on pH and 1000 kernel weights at 5 percent level (P<0.05). The research shows effects of using urban refined wastewater on an increase in all traits. The treatments of urban wastewater, alternate, mixture of 50-50 and subterranean irrigation resulted in an increase of 30.7%, 8.8%, 20.6% and 36.1% of grain yield, 31.1%, 8.6%, 20.5% and 36.4% of water productivity, 8.8%, 6.7%, 7.5% and 9.6% of 1000 kernel weights, respectively. Furthermore, the results of the experiment show that the use of refined sewage water for irrigation of Quinoa crop can increase the yield of Quinoa, positive effects on the chemical properties of the soils of the studied, and decrease the cost of supplying and using fertilizers, and then save the environment.

Water is one of the most important factors limiting agricultural development. The proper water management on the farm is also significant. To improve the existing conditions, a study aimed at investigating the growth characteristics of replacement corms and photosynthetic levels of saffron plants in response to different irrigation methods under water stress. An experiment was conducted on a farm in Ahmadabad Sheikh village, Torbat - Heydariyeh, from September 2020 to June 2021. In this experiment, the main treatment included three irrigation methods (basin irrigation, drip irrigation, and subsurface irrigation) and the sub-treatment of three irrigation levels (100%, 70%, and 40% of saffron water requirement). On May 1, 2021, to determine the traits related to photosynthetic level (number of leaves, leaf length, leaf width, fresh and dry weight of leaves) were sampled. On June 10, 2021, to study the growth characteristics of replacement corms (number of replacement corms, replacement corm diameter, weight wet and dry replacement corm) sampling was done. The results showed that the effect of method and amount of irrigation on the characteristics of replacement corms and photosynthetic level of the saffron plant was significant. The drip irrigation method significantly increased leaf number, leaf length, fresh leaf weight, leaf dry weight compared to basin irrigation and subsurface irrigation methods. The diameter of the replacement corm, the number of replacement corms, wet weight of replacement corm, and dry weight of replacement corm was reducing the amount of irrigation water from 100% of the water required to 70% and 40% due to drought stress caused a significant reduction in leaf number, leaf length fresh weight, dry leaf weight, replacement corm diameter, number of replacement corms, fresh weight of replacement corms and weight dried replacement. Based on these interpretations, choosing a suitable irrigation method along with a sufficient amount of water is significant.

Water is one of the main important environmental factors limiting rice cultivation, in arid and semiarid regions like Iran. In order to evaluate the effect of growth inducers on sub-irrigation technology performance in rice water requirement, this field experiment was conducted as a factorial plot, based on completely randomized design with 6 replications, with two irrigation treatments (flooding and sub-irrigation with porous clay capsules), and two inducers (Mycorrhiza and salicylic acid) in 2016 at the research farm of GKU. Salicylic acid was used as seed treatment along with leaf spray in the concentration of 2 mM, two times in vegetative and reproductive growth. Mycorrhiza was used as root inoculation and was also mixed (20 gr.m-3) with the top 40 cm of soil. In this study, some morphological traits including plant height, the main panicle length, the weight of filled seeds, 1000-grain weight, weight of main panicle, the weight of whole panicles, grain yield, biological yield, water consumption, water productivity, water use efficiency and harvest index were measured, calculated, and assessed after harvesting. Grain yield for flood irrigation method for salicylic acid, mycorrhiza and control treatments were 5170, 4710, and 4202 kg.ha-1, respectively. While these values were 4985, 4807 and 4063 kg.ha-1 for the subsurface irrigation method, respectively. The results showed that rice grain yield, biological yield and harvest index were not significant in the two irrigation methods. But the water use efficiency and water productivity index in the subsurface irrigation system were significantly higher than the flood irrigation. Finally, the near-saturated soil matric potential method was able to increase the subsurface irrigation efficiency compared to the flood irrigation method at rice culture.

Water is one of the main important environmental factors limiting plant culture, in arid and semiarid regions like Iran. Providing continuous soil moisture content in the range of field capacity and reducing water losses in near root zone can play a key role in the development of soil and water management programs. Subsurface irrigation system with porous clay capsules are able to release water in the soil at field capacity range. This method is one of the traditional methods to reduce water consumption and increase water use effficiency for providing water requirement of plants in small scale farms at the worlds. There are different types of porous pipes. Clay nozzles are a type of porous clay pipes that allow optimal use of irrigation water due to the moisture supply of field capacity at the roots of plants.

In this study, subsurface irrigation with porous clay capsule nuzzle was used to provide the water  requirement of two fruitful plant (Grapes and Oranges) and measure the volume of water consumption in comparison with drip irrigation method. Porous clay capsule is able to release water into soil about field capacity in low hydroustatic pressure. The soil water content in field capacity was measured by mini soil Tensiometer in 30 kPa soil suction. Soil moisture in field capacity content was 28% for clay soil texture in citrus orchard. In subsurface and surface irrigation methods, 4 porous clay capsules and 2 dripper (8 litr.h-1), were placed for each citrus plant respectively. The volume of water consumed after each irrigation in both methods was measured by a water meter counter with precision +/-1 liter. In citrus plants, to compare the effect of irrigation type the collar diameter and plant height were studied for three consecutive years, and were compared using t-test (P<0.05).

The volume of water used in subsurface irrigation method was less than the surface irrigation method. The results showed that the water supply using buried porous clay capsule irrigation method for citrus plant compared to surface drip irrigation method was associated 42% reduction in water consumption.. Comparison of collar diameter and plant height of citrus plants showed that there was no statistically significant difference (p<0.05) in two irrigation methods. Collar diameter and height growth of citrus trees in subsurface and surface irrigation methods in 2015 compared to 2012 was about 2.5 times.

According to the results of the present study, it can be concluded that the use of porous clay capsules will be one of the most effective traditional methods of optimization and management in water consumption of small scale orchards, especially at arid and semiarid region. An examination of the work done to date on clay nozzles shows that less attention has been paid to the economic aspects and competitiveness of these parts with other nozzles available in the market. It seems that the challenge of sedimentation of water-soluble materials inside the parts or attacking the roots on them has prevented the entry of large private sector investors into this completely economic and high-income environment.

In order to investigate the effect of the type drip of irrigation methods, subsurface irrigation and furrow irrigation on the domestication of Hedysarum criniferum Boiss., an experiment with a  randomized complete block design with three replications was implemented  at Isfahan University of Technology for two years (2016 to 2018) . For this purpose, clay pipes were made and the plant was cultivated on the sides of clay pipes and types. Also, furrow irrigation treatment was applied as the control. During the experiment, all treatments received the same water and finally, some growth parameters were measured. The results of the study showed improvement in height (0.43 and 0.34), canopy cover (0.66 and 0.52), stem number (0.44 and 0.85), chlorophyll index (0.45 and 0.45), seed emergence (0.75 and 0.30), plant survival (0.78 and 0.55), yield (0.23 and 0.35), and water use efficiency (0.25 and 0.25) under type drip irrigation treatment, as compared to subsurface and furrow irrigation, respectively (P<0.05). In general, the type drip treatment is recommended in the early years of planting; however, since the maximum production potential of this plant is in the third year onwards, it is necessary to examine the results in the following years to recommend the proper irrigation method, especially the use of subsurface irrigation.

Sustainable agriculture at arid and semi-arid areas depends on optimized usage of fresh water resources. Evaporation from soil surface and deep percolation categorized as unuseful losses at irrigation, so their reduction could increase the root water uptake efficiency and yield production. Subsurface drip irrigation could provide this situation. Proper depth for installing dripper is the place that reduces soil surface evaporation and deep percolation. The objective of this study was to investigate the effects of various dripper installation depth on soil water content distribution and root water uptake and to choose the proper depth. For this purpose, HYDRUS-2D software was used to investigate the effect of three factors on non-beneficial losses and consumed water in drip irrigation, numerically. These factors were soil texture (loam, clay loam and sandy loam), installation depth (0, 10, 15 and 20 Cm) and dripper discharge (1, 2, 4 and 8 l.h-1). The results showed, although increasing the installation depth could reduce cumulative evaporation up to 40%, but the best installation depth was 15 Cm with discharge rate of 1 l.h-1, according to the amount of deep percolation and consumed water. The effect of soil texture was more than the effect of installation depth on the amount of irrigation water, so that the amount of irrigation water in 2 l.h-1 discharge rate was 2.9, 3.1 and 4.6 m3.m-1 for loam, clay loam and sandy loam soil texture, respectively. Also, for clay loam texture, dripper discharge had the highest effect on root water uptake and the installation depth had the lowest effect on soil surface evaporation.

One of the important goals of irrigation is maximum use of water volume unit in limited conditions of water resources. Subsurface drip irrigation allows the applied water in the garden to be stored in the root zone of the trees in the soil profile and the evaporation losses from the ground to be minimized. In these conditions, the water use efficiency as well as water productivity reaches the maximum possible value. Due to the many advantages such as high efficiency of water consumption in the subsurface irrigation system, this study was conducted to implement the idea of subsurface irrigation without applied dripper below the soil surface. The research plan was implemented in the apricot garden of the water and soil and industry deputy minister of Jehade-Keshavarzi at Alborz province, Karaj city. The age of the apricot trees was 10 years old and three irrigation systems namely surface drip irrigation, subsurface drip irrigation and subsurface sand column were compared with each other in this research project. Crop yield measurement and morphological traits of each treatment were determined separately and then statistical analysis was performed on them with MSTATC and SPSS software. The results showed that the root penetration into dripper in subsurface drip irrigation as well as root accumulation under conductor pipes in subsurface irrigation using sand columns and surface drip blocked water flow from dripper and conductors pipes to soil profile. However, water use efficiency in subsurface irrigation systems using sand columns, subsurface and surface drip irrigation were obtained 1.21, 1.09 and 0.58 kg / m3, respectively and the priority of subsurface irrigation compared to surface drip irrigation was obtained, but root penetration into drip emitters and conductor pipes in subsurface systems has failed the idea of subsurface irrigation.

To investigation and careful study pottery parts, precise laboratory and field tools are needed, which to date has not been defined as a standard tool. The main purpose of this study was to construction and development of standard devices for measuring the emission of porous clay capsule. In this project, first, a twenty-unit percussion measuring device has been constructed, in compliance with the proposed ISO 6775 standard for drip testers. The amount of seepage from each unit of this device, at a hydraulic pressure of 2 meters, is about 0.1. To 0.5 Liters per hour. The maximum hydraulic pressure in the system is less than 5 meters and is selected from the hydrostatic type. The second device developed in this research is a single portable device in the field for measuring pottery seepage. With this device, seepage is measured in the field without removing the pottery from the soil. To test the accuracy of the mentioned devices, a fixed hydraulic head method using a marriott siphon was used to measure the seepage. At constant hydraulic head, a hydrostatic pressure generator equipped with a marriott siphon is used. The results of seepage tests with manufactured devices are compared with the results of fixed hydraulic head methods on twenty pieces of pottery. Comparison of the values obtained from the coefficient of change in laboratory and field devices with Marriott siphon shows that the difference between the coefficient of variation calculated in the mentioned devices with Marriott siphon is between 0.0039 and 0.00053, which is very small and negligible. Therefore, built devices can be used with complete confidence to measure the amount of emissions from emitters in laboratory and field conditions in research projects as well as testing emitters made by different companies.

The clay pipe sub-surface irrigation has been considered due to reduced evaporation from the soil surface and effective use of water in arid and semi-arid regions such as Iran. Due to the ambiguous dimensions of this method of irrigation in different soil texture a two-year study was conducted aimed to investigate the effect of two water qualities with electrical conductivity of 0.346 87 and 3.78 dS/m on emission of clay pipes respectively, under laboratory and field conditions with three types of clay loam, sandy loam and loamy texture at two meters hydrostatic pressure. The laboratory results of emission measurements resulted in a multivariate model for predicting long-term final pipe emission. Also, water salinity significantly changed the parameters of the equation, hence confirming the effect of salinity on pipe emission reduced. The field results of pipe emission were significantly affected by two water qualities. The significant point in this study is the significant reduction in initial emission in saline water use compared to low salinity water. On the other hand, a mathematical regression relationship was found with high correlation between initial and final pipe emission in both water qualities under field conditions for total water volume. Also, the emission reduction rate over time was identical in pipe with different emission follows the regression model with high coefficient of determination in laboratory and field. The study of emission of clay pipes in laboratory and field showed the susceptibility of these pipes to reduced emission even in low salinity water use, even showed that the amount of pipes in the long run will be significantly reduced, which should be replaced according to the salinity of water, irrigation and soil type.

With respect to water shortage during the recent decades, subsurface irrigation method has been considered in arid and semiarid zones. Therefore, experimental design was performed as completely randomized blocks with four repetitions in Isfahan University of Technology. Then, the effects of different irrigation intervals of every day, every other day and once a week under the surface and subsurface irrigation on height, collar diameter, chlorophyll content and stomata conductivity of Zygophyllum fabago L. were investigated. The percentage of plant survival was also recorded six months after planting. The results showed that irrigation interval had a significant effect on height, chlorophyll content and stomata conductivity of the tested plant (P<0.05) and the height, diameter of the collar and stomata conductivity decreased by increasing the irrigation interval. While, the irrigation interval didn’t have a significant effect on the collar diameter (P>0.05). The highest percentage of survival (100%) was observed in subsurface irrigation treatment and control treatment had the lowest percentage of viability (70%). It could be concluded that the improvement of growth parameters and survived of Zygophyllum fabago were better with the subsurface irrigation than the surface irrigation.

The aim of localized leaching is to remove accumulatedsalts from the main activeroot zone in orchards and fields under localized irrigation systems and in the absence of sufficient water for leaching.The efficiency of this method has not been examined in subsurface-irrigated orchard or in conditions of localized application of amendments. Therefore, this study was carried out in winter of 1394 in a pistachio orchard in Fath-Abad area in Kerman to evaluate the potential of localized leaching method along with three treatments of irrigation water, gypsum, sulfuric acid with four repetitions to remove soluble salt from the main active pistachio root zone (wet areas around the subsurface pipe). In this leaching technique which was carried out for 5 consecutive days,two lines of low-flow drip tape at a distance of 40 cm from two sides of the tree row were used to leach salt from wet areas around the subsurface clay pipe. To compare leaching efficiency and changes in sodium and EC levels, soil sampling was carried out before and after leaching at 80 (Length)*120 (Depth) cm profile in 20 cm intervals. The results showed that application of 1000 mm of water led to effective salt leaching from the main active pistachio root zone. The application of gypsum increased the sodium and salts removal compare to irrigation water and sulfuric acid treatments. The percentage of sodium and salts leachate in gypsum treatment was about 61 and 58 percentage, respectively.Iirrigation water treatment with 56% leaching efficiency was more than the efficiency of sulfuric acid treatment (45%). Thus, due to the high efficiency of irrigation water compared to sulfuric acid, no significant differencewith gypsum treatment in salt removal and taking into account economic issues related to the amendments,applying irrigation water alone could be recommended as the appropriate strategies for practical reclamation of the studied soil.

In order to study the effects of different levels of irrigation, nitrogen fertilizer, and irrigation methods on yield and yield components of onions, a factorial split plot experiment was conducted in a randomized complete block design with three replications for two years at a research farm in Zahak, Iran. Fertilizer treatments were included four levels of nitrogen fertilizer of from urea fertilizer (130, 97.5, 65 and 32.5 kg/ha). Onion seedlings were planted in 2014 and 2015 and irrigation was carried out in the form of surface gravity irrigation, surface drip irrigation and subsurface drip irrigation. The highest yield and water productivity were obtained in the subsurface drip irrigation system (28.42 ton/ha and 5.9 kg/m3/ha) and the least in surface irrigation (19 ton/ha and 33.3 kg/m3/ha). Reducing the amount of nitrogen fertilizer to less than plant requirement reduced the yield of bulbs and the efficiency of onions. The highest yield and water productivity were observed in 100% nitrogen application (31.59 ton/ha and 4.75 kg/m3/ha) and the lowest was in 25% nitrogen fertilizer treatment (16.12 ton/ha and 2.67 kg/m3/ha).The effect of irrigation water on the yield of onion tubers and its efficiency showed that decreasing the depth of irrigation water to values lower than the water requirement of the plant decreases yield and efficiency, but, no significant effect was observed between treatments 100% and 75% of the plant water requirement. Therefore, according to the results, due to the lack of water in the region, irrigation of this plant can be done with 75% of the plant water requirement, without a significant effect on the yield. Also, due to the high production potential in subsurface drip irrigation and reduction of evapotranspiration, this irrigation method could be used for onions in the region. The best treatment for nitrogen fertilizer use is the 100% nitrogen fertilizer requirement, especially in water tension. Considering the contamination of subsurface waters due to the excessive use of nitrogen fertilizers and the prevention of nitrate accumulation in the bulbs, it seems that using drip irrigation improves nitrogen fertilizer management.

Since Iran is located in the arid and semi-arid belt in the world, it always confronts low water periods and frequent droughts. In recent years, attention has been paid to the protection of urban water resources, especially green space irrigation. Due to the key role of grass in designing and constructing green space and its high importance in community psychological safety, Maintaining the optimal quality of turf grass throughout the year is essential.
The current experiment is conducted with the aim of optimizing soil moisture using subsurface porous clay capsules in irrigating turf grass. The research was conducted in 2013-2014 in Agriculture Faculty of TarbiatModares University, as split plots in the form of totally random blocks with three treatments and irritations. The main factors include sprinkler irrigation (control), subsurface irrigation using subsurface porous clay capsule, and consolidated Irrigation; secondary factors include the lack of using superabsorbent, using A200 superabsorbent and acrylamide superabsorbent. soil moisture. In this study, indicators of moisture, volume of water consumed, turf color and density and root length, were measured.
The results showed that moisture change diagram represents the same trend in all treatments. In addition, the moisture has been between the plantation capacity and the maximum allowable discharge, and the plant has been under no moisture stress. The results of this experiment showed that the volume of consumed water in the treatments of sprinkler, consolidated and subsurface irrigation has been 7158.4, 4972.6, and 4243.8m3, respectively. In the subsurface and consolidated irrigation treatment , the volume of consumed water increased for 41 and 31% respectively, compared to sprinkler irrigation. This reduction trend was observed in the use of superabsorbent, in such a way that the subsurface irrigation treatment along with superabsorbent has shown the lowest water consumption in irrigation with the reduction of 51%. Irrigation method treatments had a significant effect on the root length. The highest and lowest root length was related to subsurface and sprinkler irrigation treatment, respectively, with the average of 23.56 and 20.50cm, respectively; and the significance level was 5%. In addition, increasing superabsorbent increased the root depth which was significant in 1% level.
Therefore, with regard to the water needs of lawns with subsurface irrigation system using porous clay capsules, this method could be employed as an irrigation method to optimize water consumption and reduce water loss. Yet, to make this system an applied method in turf grass irrigation, regardless of reducing water consumption, It needs to reduce its implementation cost compared with other existing methods.

Clogging of emitters is one of the main problems in subsurface drip irrigation. The objective of this study was investigation of effect of Geocomposite on wetting pattern in subsurface irrigation system. This research was conducted in lysimeters located at Shahrekord University research field. The study was conducted as a factorial experiment based on a completely randomized design with 10 treatments and three replications of three factors. The first factor of experiment was geocomposite shape with the same area on two levels (shape square with dimensions (4 × 4) square centimeters and rectangular with dimensions (2 × 8) square centimeters), the second factor was combination of geocomposite material on two levels (two layers of geotextile on both sides of Geonet and The second level, a layer of geomembrane and a layer of geotextile on both sides of geonet), the third factor of placement in the soil at on two position (horizontal and vertical) and emitter with envelopment (in two position horizontal and vertical) were used as control. The ground wet and wet the maximum of soil depth profiles were measured. The results was showed that geocomposite of shape square with dimensions (4 × 4) square centimeters for a layer of geomembrane and a layer of geotextile on both sides and how to align horizontally in the soil wet ground level by lowering the 21.55 percent and increased 17.1 percent wet the soil deep profile compared to control (emitter with envelopment horizontally in the soil) is the most effective and best conditions on wetting profiles.

In this study reduction in water consumption was evaluated in green space using hydrophobic layer and subsurface irrigation system for ornamental plants Gazanya in Shahrekord University. The experiment was done in a completely randomized design with four treatments and three replications. The treatments included surface irrigation (SI), subsurface irrigation (SSI), subsurface irrigation including hydrophobic layer with thickness of 5 mm (SSILH5) and subsurface irrigation including hydrophobic layer with thickness of 10 mm (SSILH10). During the growing season, factors such as amount of water consumption, leaf length, number of flowers, plant width, flower, peduncle and leaf area were measured. Analysis of variance results due to water consumption showed a significant difference between the treatments in a level of 1%. Maximum and minimum volumes of water consumption were respectively related to surface irrigation treatment (SI) with 656.8 mm and the surface hydrophobic layer one with the thickness of 10 mm (SSILH10) in which the value was 359.3 m. Water consumption reductions in SSI, SSILH5 and SSILH10 treatments comparing to SI were 17.4%, 32.7% and 45.3%, respectively. Analysis of variance results related to plant parameters showed a significant difference between the treatments. The hydrophobic layer treatment with 5 mm thickness had the highest yield.

Considering the limited access to fresh water resources and intense plant respiration and high evapotranspiration in deserts and arid regions, subsurface irrigation seems to be the most appropriate method for cultivation. The aim of this study was finding a proper subsurface irrigation to supply moisture for plant roots using bio-composite water pipes to supply water for panicum. Experimental design was factorial experiment conducted based on completely randomized block design with three replications in the Faculty of Agriculture in Tarbiat Modarres University in 2015. Main factors included subsurface irrigation using three types of bio-composite water pipes manufactured P3, P8, P9, subsurface irrigation using subsurface porous clay capsules and flood irrigation (control treatment). Secondary factors included three drought stress levels of 25, 50, and 100% of soil field capacity (FC). Results showed that, subsurface irrigation treatment using water pipe P8 and drought stress level of 25%, and FC decrease for 12.68%, was the lowest water consumption in irrigation. In addition, in subsurface irrigation, height, wet and dry weights were significantly different at %1 level compared to flood irrigation. Therefore, with regard to responsiveness of panicum water demand to subsurface irrigation using bio-composite water pipes, and considering the results of this research using subsurface irrigation by bio-composite water pipes, it is recommended to optimize water consumption for urban areas located in arid and semi-arid regions.

Information on water soil content and its distribution is vital for field water management in subsurface irrigation. The objective followed in this study was to simulate the extent of wastewater distribution taking into account root water uptake and evaporation from the soil surface under, subsurface drip irrigation system. In this regard, a field experiment was conducted with lettuce as the crop, to collect the required data. Soil hydraulic properties were obtained through an assessment of in-situ soil water pressure heads as well as water contents. Soil matric potentials, under tensiometery range, were obtained by use of tensiometers and the related water contents by a TDR instrument. For the simulation purposes, the HYDRUS-2D model was made use of. The model performance was evaluated by comparing the measured us the predicted values using Root Mean Square Error (RMSE) statistics. The results of the spatial simulation revealed that this model provides more appropriate results in locations farther away, and deeper than The drippers (RMSE=0.03) as compared with the points adjacent to the droppers and less deeper ones (RMSE=0.008). The results of the temporal simulation showed that the model worked more accurately within 48 hrs after irrigation (RMSE=0.005) rather than one following the start of irrigation (RMSE=0.029). Therefore, it can be concluded that soil water content in subsurface drip irrigation system can be reasonably simulated while root water uptake and evaporation processes are both actively going on.

This investigation was conducted on the effects of different drip irrigation (surface and subsurface) and furrow irrigation methods on grain، oil and water use efficiency based on grain black cumin (Nigella sativa L.) as medicinal plants. The research on black cumin was selected because of farmer interest and Agricultural Organization financial supports in Kermanshah province. For this purpose، experiment over the past two years (1388 and 1389) in a randomized complete block was designed in three replications. Treatments in this research were consisting of 50، 75 and 100 % of black cumin annual water requirement with different drip irrigation methods consist of (surface and subsurface) and also the furrow irrigation treatments. The results of this research showed a significant effects of different levels of water stress on different plant parameters such as: grain، oil and water use efficiency in both years of study. The highest and lowest oil percentage was belong to different treatments 100% of subsurface drip tape irrigation and 50% of surface drip tape irrigation systems with 30. 6 and 29. 2% respectively. The highest and lowest average water use efficiency based on seed yield were obtained as 1. 67 and 0. 96 kg/ha/mm for 50% of subsurface and furrow irrigation treatments، respectively. The results of this investigation also showed that by using of subsurface drip irrigation method and by applying of 50% of black cumin annual water requirement، the highest grain water use efficiency could be obtained.