الهه کنعانی

Rural tourism, as a productive and complementary activity, has played a significant role in the redistribution of income and job creation in the process of local development. For this reason, it is considered an effective means of economic and social reconstruction and development in rural areas. In recent years, the use of the metaverse approach has garnered attention from many countries around the world as a key strategy for developing tourism marketing, yielding positive results in the development of rural areas. The Torqabeh district, located in the Razavi Khorasan Province, contains 18 mostly river valley villages with numerous features that attract weekend tourists. Additionally, the proximity of these villages to the metropolis of Mashhad, which faces high demand for tourism from its residents and visitors, has led to increased tourism in the region. The villages in this county not only possess natural attractions and favorable climatic conditions but also have the electronic infrastructure, such as suitable hardware platforms, to promote and enhance tourism due to their closeness to Mashhad city. The research examines the effects of the metaverse on rural tourism marketing in the Torqabeh district of Mashhad County, seeking to address the following key questions: What is the extent of the impact of the metaverse approach on rural tourism marketing in the studied region?

In the present study, in response to the question posed and aimed at providing a robust answer, the study elaborates on the nature and reasons behind the issue and its dimensions. Therefore, this research is applied in terms of purpose and descriptive-analytical in terms of methodology. To collect data, methods such as questionnaires and observations were utilized. Consequently, this research gathered information and data from the studied region to address the research question and assess the validity of the initial research and its realities. In the first step, based on theoretical studies, the indicators of the effects of the metaverse on rural tourism marketing were extracted and identified. As a result, the variable investigating the effects of the metaverse on rural tourism marketing was quantified with 38 indicators. The second step focuses on the practical implementation of the study. Thus, the study area selected for this research is the Torqabeh district of Binalud County, as this region is one of the areas with high potential for rural tourism in Razavi Khorasan province. Binalud County annually welcomes numerous tourists whose primary goal, after visiting the holy shrine of Imam Reza (PBUH), is to explore recreational sites around Mashhad. Figure 1 illustrates the location of the study area and the sample villages. After determining the samples, data were collected through a researcher-created questionnaire based on the variable examining the effects of the metaverse on rural tourism marketing, featuring 38 items. It is noteworthy that two methods were employed to validate the indicators: reviewing prior studies and consulting a specialized panel consisting of university professors and experts. Furthermore, to evaluate the data’s reliability, the Cronbach’s Alpha test was employed, resulting in a high value of 0.93. This indicates that the data is robust and suitable for the research study. The descriptive section of the research examines the average of the items and analyzes the differences in responses among participants using the Chi-square test. In the data analysis phase, exploratory factor analysis was employed in the first stage to classify the indicators. In the second stage, a one-sample t-test was used to examine the mean of the factors obtained from the first phase of the research, all of which were conducted using SPSS software. Furthermore, the Markov model was utilized to prioritize the metaverse approach to rural tourism marketing. The weighting model used in this research is the entropy model.

In this study, factor analysis was used to interpret the relationships among 38 identified effects and to optimize their combination into 6 meaningful factors. The most significant identified effect in this research is the impact of the metaverse on rural tourism marketing, specifically “information dissemination and awareness”, which accounts for 17.23% of the explained variance. Within this context, the “impact of the metaverse on introducing and promoting rural tourism attractions and facilities” is prioritized first with a correlation coefficient of 0.797. The second effect of the metaverse on rural tourism marketing is “marketing enhancement” where “the impact of the metaverse in motivating you to book rural tourism homes online” ranks second with a correlation coefficient of 0.79. The third impact is “interactive participation” with “the effect of the metaverse in forming partnerships and collaborations to boost rural tourism marketing” ranked third and a correlation coefficient of 0.93. The fourth, fifth, and sixth impacts of the metaverse on rural tourism marketing are “sales growth”, “quality awareness”, and “incentive creation”, respectively. Furthermore, considering the normal distribution and interval properties of the factors derived from the previous section (due to the computation of the items) and having a theoretical median of 3, an analysis of the average indices was conducted using a one-sample t-test. The results of this test indicate that in all dimensions, the real average opinion of all respondents is greater than 3 and is at a medium to high level, with the significance level obtained for all dimensions being less than 0.05. Therefore, the results of the mean analysis of these dimensions are significant and can be generalized to the entire population. Additionally, both the upper and lower limits of all factors are positive, meaning that the average of the population in these dimensions exceeds the tested value. This result indicates that the metaverse has had a positive and significant impact on the development of rural tourism marketing in the Torqabeh area of Binalud County. Thus, the most effective aspect of the metaverse’s influence on rural tourism marketing in the studied villages is sales growth, with an average of 3.78. In second place is marketing enhancement, with an average of 3.75, and in third place, information dissemination and awareness, with an average of 3.71. For the spatial analysis of the metaverse's effects on rural tourism marketing, the multi-criteria decision-making model of Marcus was utilized. The results indicated that the strongest impact of the metaverse on rural tourism marketing belongs to the village of Azghad, while the weakest impact is observed in the village of Dehbar, as the former attracts the highest number of tourists.

The metaverse approach has played a significant role in the sale of traditional and local products, such as indigenous foods, local product packaging, and online product sales. On the other hand, the effects of the metaverse on rural tourism information dissemination and awareness have helped to showcase the diversity of tourism attractions, promote marketing through tourism networks, understand customer behavior, introduce cultural and artistic tourism exhibitions, inform about tourist locations and their safety, and more. Therefore, all of these aspects are crucial for leveraging the effects of the metaverse to enhance rural tourism. These findings align with the results of researchers such as Rezaei et al. (2022), Virantari et al. (2022), Buhalis et al. (2022), and Goursoi et al. (2022). Based on the overall results obtained, it can be said that the metaverse serves as a facilitator for rural tourism marketing, as it provides a pathway for the advancement of rural areas through urban amenities. In conclusion, the findings from this study underscore the importance of the metaverse in tourism marketing.

In spite of the drought conditions and lack of water in most parts of Iran, fodder corn is one of the main producers of silage fodder in the country. For the purpose of investigating the effects of subsurface drip irrigation systems on fodder corn cultivation and determining the efficiency of water consumption, a split plot design was conducted at Jopar Kerman Agricultural Research Station for a period of two crop years using randomized complete block designs with three replications. In the research, three levels of irrigation (I1=100, I2=75, and I3=50 percent of the water requirement) were assessed as the main factor, and two depths of subsurface pipes with drippers (inline) were assessed as the submain factor. Among the treatments of different irrigation levels, the treatment of 100% water requirement obtained the highest yield by producing 77250kg/ha of wet fodder and 15447kg/ha of dry fodder. A 20% and 52% yield difference was observed between the 100% water demand treatment and the 75% and 50% water demand treatments. In terms of WP, there was a significant difference between the two treatments of 30 cm soil depth and 40 cm soil depth; the highest WP was observed in the 30 cm soil depth treatment. In both years of the study, the irrigation treatment of 50% of the water requirement had the lowest WP (average 1.2 kg/m3). Additionally, the average amount of water consumed by the treatments of 50, 75, and 100% of fodder corn water requirements was 3200, 4100, and 5200 m3/ha, respectively. As a result of the results of this research, it has been recommended that for the production of fodder corn in the Jopar Kerman region, a planting depth of 30 cm with a 100% water requirement under subsurface drip irrigation with a water consumption of 5200 m3/ha will be used

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.

Due to the critical conditions of Lake Urmia, improving irrigation methods as one the effective solutions is considered by the country's water managers. The present study was conducted to evaluate the effect of improving agricultural activities with the aim of reducing water consumption on greenhouse gas emissions in the provinces of East Azerbaijan (five cities) and West Azerbaijan (six cities) during the autumn and spring crop season on tomato, wheat, and sugar beet crops. The results of autumn wheat cultivation showed that the amount of CO2 produced in East and West Azerbaijan decreased by 22 and 28%, respectively, compared to the control treatment. Carbon footprint in East and West Azerbaijan in the treatment compared to the control shows a decrease of 39 and 35%, respectively. The results of spring cultivation for tomatoes showed that the amount of CO2 produced in the treatment was reduced by 25% compared to the control So that this amount decreased from 3925 in the control to 2917 kg/ha in the treatment. The carbon footprint of tomato production also showed that it was equal to 0.04 in the treatment and equal to 0.06 in the control (Kg CO2/kg) and had a decrease of about 33%. For sugar beet in West Azerbaijan province, the amount of CO2 produced and carbon footprint in the treatment decreased by 11.7% and 28.5%, respectively, compared to the control.

The growing need for food and the increase in agricultural production, and consequently the increasing demand for water on the one hand, and the harmful environmental effects of agricultural drainage water on natural ecosystems and receptive water resources on the other, have led the world to look for methods and techniques that, along with reducing the harmful and adverse consequences of drainage water, make it possible to reuse them to meet part of human needs. In many areas facing water shortages for irrigation, drainage water is used to meet the crop's water requirement. Due to high volume and special quality, agricultural drainage water have a high potential for pollution in the environment, especially water resources. According to water shortage in Iran and population growth and increasing water needs in various uses, planning for the protection and quality management of water resources and optimal use of unconventional water, especially agricultural drainage water as alternative water resources has become more necessary.

For this purpose, the present study investigated the efficiency of a natural reed bed on a real scale in qualitative treatment of incoming drainage water of Khuzestan sugarcane during a period of one year (2010-2011). According to the trend of qualitative changes and wastewater treatment stages at the reed bed level, the length of the reed bed was divided into three parts, namely three stations ST1, ST2, and ST3 with a length and width of 3.5*1.2 hectares, respectively. The efficiency of the natural reed bed was evaluated by measuring parameters such as BOD, COD, PO4, and TP.

The results of the T-Test showed that there are significant differences in terms of BOD values between ST0-ST1, ST0-ST2, ST0-ST3, ST1-ST2, ST1-ST3, and ST2-ST3 study stations. The highest difference in BOD was observed between ST0 and ST3 stations equal to 6.96 mg/l. In addition, the lowest difference in BOD was detected between ST0 and ST1 equal to 1.73 mg/l. At the ST3 station, which is the farthest from the entry point, the highest percentage of BOD removal was obtained. There was a significant difference of 1% for COD between study stations. The largest difference in COD was observed between ST0 and ST3 stations equal to 9.62 mg/L followed by ST1-ST3 stations equal to 7.12 mg/L. There was also a significant difference of 1% levels in PO4 and TP of study stations and the highest difference in PO4 and TP with 0.2724 and 0.3790 mg/l, respectively, between stations. ST0-ST3 was observed. The results showed that the performance of the reed in eliminating the studied parameters was very good and acceptable. The removal efficiency of BOD, COD, PO4, and TP to the last station was noticeable and acceptable in all four seasons. Under different retention times (1.26, 1.10, 1.30, and 1.60 days), the removal percentage of BOD, COD, PO4, and TP was significant in ST1, ST2, and ST3 stations and with increasing the distance from the entry point, of the drain, the reed efficiency increased. Considering the different performances of the three stations in improving the quality of drainage and considering the efficiency target above 50% of all organic matter and phosphorus compounds, the ST2 station can be assumed as the optimal limit in terms of efficiency and cost.

In general, this system can be used as an efficient system in reducing common drainage water pollutants to the level of drainage water treatment standards and acceptable reduction of BOD, COD, PO4, and TP parameters of agricultural drainage water and improving the quality of this drainage water for discharge to surface and groundwater and also reuse for irrigation in agricultural fields.

The process of climate change, especially the change in temperature and precipitation, and its effect on the drought phenomenon constitute the most important topic of discussion in environmental sciences. Studying climate change and its effect on the severity and frequency of droughts in the coming decades can considerably contribute to the planning for the proper use of water resources and adapting to the destructive effects of droughts. To this end, based on the SDSM microscale method, precipitation and temperature during the 2020-2100 period were predicted in the present study using the large-scale CanESM2 model, and the effects of climate change on the meteorological drought in Ilam Province were studied using the SPI and RDI indices.

In this study, the required climatic data are obtained through one of the data reporting sites of the IPCC AR5. Twenty one CMIP5 models have been used to predict Precipitation and temperature parameters in the future. The weighting method of observational means was used to investigate the uncertainty caused by using the studied models. Then, using the SDSM model, meteorological data are generated under three scenarios: RCP 2.6, RCP4.5 and RCP8.5 of the CanESM2 model. Model historical data from 1993 to 2005 will be used to analyze the SDSM model using NCEP re-analysis data, and data from 2006 to 2100 will be used to estimate future climate change. The SPI and RDI time series were calculated in three scales of 3, 6 and 12 months for the historical and future period. The intensity, duration and frequency of the drought, according to the run theory for the spi and RDI on scale 3, 6 and 12 months.

According to the results of the uncertainty analysis, the CanESM2 model had the highest weight compared to other models for both temperature and precipitation variables. Analysis of trend in precipitation and temperature data by non - parametric mann - kendall test showed that temperature in scenario rcp8.5 has a significant positive trend ( increasing ) at 0.01 and precipitation has decreasing trend. The results of drought monitoring showed that in both SPI and RDI indices, the frequency of dry period’s decreases with increasing time scale, which is accompanied by an increase in the severity and duration of drought. The RDI index shows higher drought characteristics than SPI due to considering the average temperature in calculating dry periods. The greatest drought in the historical period according to the SPI index on a 12-month scale has an intensity of 38.22 and a duration of 26 months. RDI index on a 12-month scale has an intensity of 39.14 and a duration of 26 months.The study area will experience more severe and longer droughts in the future according to all three scenarios than in the historical period. The severity of droughts produced by RCP4.5 RCP2.6 and RCP8.5 scenarios based on 12-month SPI is 11%, 52% and 65%.

The results of the analysis with the SDSM model and the SPI and RDI drought indices indicated that in the future climatic conditions in the 2020-2100 period, an increase in temperature and a decrease in precipitation are probable. To wit, temperature rises by 3.798 C and precipitation decreases by 6.8%. The results also revealed that the study area will experience more severe and longer droughts in the future than in the historical period under all three RCP2.6, RCP4.5 and RCP8.5 scenarios. As the time scale of the drought index increases, the severity and duration of the drought increases. The RDI index has a high behavioral similarity to the SPI, but the RDI index is sensitive to environmental changes and provides better results.

Development Research Institute during the last three decades has produced clay emitters and has implemented the system on a small scale in several areas of Kerman province in pistachio orchards. Because the hydraulic characteristics of the emitters used in the gardens are unknown and their operating time is also unknown, therefore, it is impossible to evaluate the performance of emitters used in these gardens. In order to evaluate the hydraulic performance of the emitters in terms of the coefficient of construction variation and also changes in the seepage behavior in laboratory conditions. 400 clay emitters were studied at Agricultural Engineering Research Institute of Karaj. To investigate the coefficient of construction variation, the emitters were grouped into groups of 20, and each group was tested at a constant hydrostatic pressure of 1.75 m using water with a quality of 0.83 dS/m. The results showed that the values of the coefficient of variation of the 20 packages under test were in the range of 23 to 73%, which was higher than the declared 20% of the ASAE standard and was found to be unacceptable, and if these emitters are used, the plants in different parts of the farm/garden will not receive equal water. Therefore, in these conditions, the use of these emitters in the subsurface irrigation of plants is not recommended. To investigate the seepage behavior of clay emitters over time, the discharge changes of 7 emitter groups at three hydrostatic pressures of 0.5, 1, and 2 m were tested. Seepage measurements from clay emitters for 1000 hours showed that as water passes through the pores of the emitter’s body, the water-soluble salts precipitate over time in the porous environment of the clay emitters and cause clogging. The average maximum initial seepage of clay emitters in groups of 7 at hydrostatic pressures of 0.5, 1, and 2 meters was 1.537, 2.578, and 4.783 L/hr.m, respectively. After 1000 hours of continuous testing, the values of final seepage reached 0.939, 1.483, and 1.296 L/hr.m, respectively. Descending values of seepage showed that water-soluble salts precipitate over time in the pores of the emitter body and reduce the emitter permeability. Due to the reduction of emission permeability, it is not possible to sustainable use of them to supply the water needed by crops/gardens in the long term.

The aim of this study was to investigate the interaction of irrigation regimes and drip-line installation depth on Rapeseed water productivity. The results showed that the effect of different irrigation regimes (I) on all studied traits in Rapeseed (grain yield, 1000-seed weight, number of pods, pod length, number of branches) and water productivity had a significant effect (P <0.01). Increasing the drip-line depth had a negative effect on the Rapeseed yield, yield components and water productivity. So that, the highest amount of each of the mentioned traits was observed at a depth of D1 (30 cm). Differences of 21 and 59% in the first year and 22 and 58.8% in the second year between I2 and I3 treatments with I1 treatment indicate this superiority. The highest water productivity in each of the drip-line depth was allocated to the I2 treatment. It seems that despite the lower consumption of water in the I2 treatment, the performance obtained from this treatment has increased the water productivity compared to the I1 treatment. The interaction effects of different irrigation regimes and drip-line depth showed no significant effect on yield, yield components and water productivity. Considering that the drip-line depth of 30 and 40 cm did not have much effect on the studied traits, however, it is a better choice considering that by placing irrigation pipes at a depth of 40 cm, plowing operations can be extended to depths.

Water scarcity has always been a serious challenge for agriculture and food security, Therefore, agricultural water saving is the most important strategy to overcoming water resource scarcity. Solutions to overcoming the water crisis by looking at the agricultural sector are not simple and the lack of attention and awareness of the water cycle has led to incomplete and incorrect definitions and sometimes overshadowing planning and investment. The main challenge in this regard is the lack of access to sufficient and real information in the agricultural sector. On the other hand, obtaining measured observations of real water savings requires extensive data collection. Some evidence shown that assumed water savings at the local level are in reality often limited at a basin scale context or even increased water consumption. Therefore, using any kind of simple and pragmatic tools to evaluate the impact of interventions used on the farm scale and larger scales can have significant effects on our behavior towards water resources and its consumption. The REWAS (Real Water Savings) tool is developed to undertake a quick impact assessment of detailed field scale experiments (either by models or pilot plots) on basin-scale potential water savings. REWAS is based on proven concepts of water accounting, water productivity and the appropriate water terminology, as promoted by FAO.

The aim of this study was to simulate the effect of micro irrigation systems under mulch conditions on evapotranspiration, soil surface evaporation and plant transpiration of forage maize using AquaCrop model. In this study, the AquaCrop model’s performance was tested using data for silage maize (Zea mays L.) under surface drip, subsurface drip and permeability clay pipe irrigation systems with mulch conditions in the semiarid environment of Karaj, Alborz during 2014. According to the NRMSE index, in the calibration and validation stage (7.74% and 10.7%), the accuracy of this model to simulating forage maize biomass was acceptable, and AquaCrop simulated well the biomass yield (B-yield) of silage maize. The model had moderate efficiency for simulating corn evapotranspiration.The performance of the model in maze evapotranspiration simulation was better in PCI-M1 treatment than other treatments. So that, it had the lowest value of nRMSE and the highest value of R2. There was no good correlation between the observed and simulated values in estimating soil surface evaporation and high nRMSE values in these treatments (2.96 and 3.23%) indicate the inefficiency of the AquaCrop model in estimating soil surface evaporation. The positive MBE index in both DI-M1 and SDI-M1 treatments indicates that the model overestimates the soil surface evaporation and does not estimate close to the observed values. Statistical evaluations between observational values and plant transpiration simulation showed a moderate correlation between observed and simulated values. The value of NRMSE index for canopy cover was calculated to be more than 30% in all treatments, which indicates the poor performance of the model. In these treatments, the maximum amount of canopy cover simulated using the AquaCrop model is more than the observed values.

Correct cultivar choice of corn and provide an efficient irrigation method to save water and increase production per unit area and the optimal use of water resources is very important. This study was carried out to investigating changes in yield and water productivity in different maize hybrids (KSC 704 and KSC 410) under irrigation management using strip drip and furrow Irrigation methods during two years of 2015-2016 in Jopar research station in Kerman province. The experiment was arranged in a split-plot design over randomized complete block design. The results showed that maize hybrids had significant effect on yield and its components at 1% level. The highest grain yield was observed in KSC 704 (13385 kg/ha) compared to KSC 410. The strip drip irrigation method had the highest grain yield (13376 kg/ha) compared to furrow irrigation method. The effect of interaction between irrigation method and maize hybrids showed that the strip drip irrigation method with maize hybrids, KSC 704 recorded higher yield (14128.5 kg/ha.), and an 11% increase in yield compared to maize KSC 410. Also, the lowest amount of irrigation water was 6765 m3/ha and was observed in KSC 410 under strip drip irrigation method. Strip drip irrigation method reduced water irrigation by 33.5% and 36.25% in KSC 704 and KSC 410 treatments, respectively. Also, the water productivity in the strip drip irrigation and farrow irrigation method was equal 1.84 and 0.98 kg/m3 under water storage condition. To increase water productivity and reduce irrigation water, farmers can benefit from drip irrigation due to the profitability of this irrigation method.

Drought is one of the factors that threatens the performance of agricultural products, especially corn in most parts of the world. Under conditions of water scarcity, the effectiveness and efficiency of fertilizer use is reduced, especially if fertilizer application is not consistent with plant growth. Among fertilizers, nitrogen is one of the most important nutrients for corn, and consumption management of this fertilizer has great importance in order to succeed in increasing the production of corn. Therefore, in conditions of water shortage, balanced and optimal use of fertilizer should be considered to achieve increased yield and water use efficiency.

This study was conducted to investigate the effect of drip irrigation regimes and different levels of nitrogen fertilizer on yield and yield components of corn and soil moisture changes at the Shaheed Zendrh Rouh Jupar in Kerman province during the years of 2012-2014. The experiment was arranged as a split-plot design based on randomized complete block design with five irrigation regimes (I1 = 100, I2 = 80 and I3 = 60% ETc) as the main-factor and five nitrogen fertilizer level N1 = 0, N2 = 50, N3 = 100, N4 = 150 and N5 = 200 kg/ha) as sub-factor. According to the Kerman Meteorological Station, this region has a semi-arid climate with warm summers and mild winters. To calculate the volume of water consumed, potential evapotranspiration (ETo) was determined using daily meteorological information and Penman-Monteith method (PM). A sampling method was used to measure moisture at different depths of soil.

The results showed that the highest yield was due to I1 treatments with 8.85 t/ha, and there was a direct relation between crop reduction and water requirement reduction at all stages of crop production. High nitrogen application had a negative effect on yield. Typically, in soils that lack nitrogen, corn grain yield increased with nitrogen addition. However, after reaching the maximum yield, nitrogen addition has no effect on increase or yield may reduce. The interactions of different levels of water and fertilizer showed that I1N4 and I3N1 treatments had the highest (10.6 ton/ha) and lowest (1.24 ton/ha) value of corn yield, respectively. The highest and lowest grain yield components (thousand grain weight, number of kernels row, number of kernels per row, cob length, cob diameter) were observed in N1 and N3 I1 treatments, respectively. The highest water use efficiency (1.26 kg/m3) was observed in I2N4 treatment and the lowest (0.068 kg/m3) in I3N1 treatment. The results of this study showed that the remaining moisture content in soil decreased by decreasing amount of irrigation water and nitrogen fertilizer in 20 days after planting. At 75 days after planting, reasons such as severe water shortages during growth, reduced root density, high water requirement at this stage of growing season, and the plants need to nutrients have probably caused the roots to absorb as much as possible of the top three water and nutrient. As a result, the moisture that reaches the last layer is less. The results showed that in the last stages of growth compared to other stages, the plant water requirement is reduced and excess water penetrates the lower layers.

According to the results of this study, nitrogen fertilizer at 150 kg/ha with 100% water requirement is the best combination for corn farming in semi-arid climates.

Subsurface drip irrigation is the most suitable irrigation method to provide the water requirements for plants in the root environment. The management of this irrigation method is based on the science of water distribution in wet soil volumes. Simulation models can be used in obtaining this valuable knowledge. In this study, was evaluated simulation the distribution of soil moisture in the plant root zone under subsurface drip irrigation using the HYDRUS-2D model and based on a field research in a pistachio garden, in Sorkhe, Safaeieh, Semnan province, during two years of cultivation 2012-2013. The treatments were three irrigation regimes; control (I1), Irrigation based on irrigation requirement (I2) and I2 plus leaching requirement (I3), three soil depth of 25, 50, and 75 cm from soil surface at before and after irrigation event. The results of this study showed that in the root zone of the plant, the percentage of moisture content measured and estimated were relatively close, and showed that the HYDRUS-2D is able to simulate the soil moisture content in the root zone of the pistachio plant, and has this ability that it estimates conditions the soil moisture with highly accurate, during irrigation under different irrigation regimes at different depths of the soil. Model estimation process in the horizontal and vertical distribution of moisture, it was more than estimated in relation to the measured values. The statistical evaluations also showed that the accuracy of the HYDRUS-2D numerical model with respect to the coefficients of determination between 0.76 to 0.9 and RMSE ranged from 2.23 to 4.01, and the good ability of the model in predicting moisture content in field conditions.

Partitioning of evapotranspiration (ET) into evaporation from the soil (E) and transpiration through the stomata of plants (T) is important in order to assess biomass production and the allocation of increasingly scarce water resources. Generally, T is the desired component with the water being used to enhance plant productivity; whereas, E is considered a source of water loss or inefficiency, and is the basis of the management and organization of water resources. The present investigation was carried out with the objectives evaluation of corn evapotranspiration and its components and relationship between leaf area index and components in surface and subsurface drip irrigation systems.
The pilot farm were located in the water and soil department of the ministry of agriculture in Karaj, Iran (latitude of 51°38 ˊN and longitude of 35°21ˊ W, 1312.5 m above sea level). For implementation project was placed 8 volume micro-lysimeters in the soil, which were filled with soil excavated from the study site. The soil inside of micro-lysimeter and the soil of the surrounding study had the same physical-chemical characteristics. The corn was irrigated with surface drip (DI) and subsurface drip irrigation (SDI) system, that was installed just prior to planting in 2014 in a field that was planted to sprinkler-irrigated corn. Daily crop actual evapotranspiration (ETc) of each micro-lysimeter was calculated by applying the water balance method and soil evaporation was measured with micro-lysimeters. Finally, plant transpiration was calculated from difference between the actual evapotranspiration value and amount of evaporation from the soil surface. Leaf area index (LAI), was measured, and it was measured with the electronic leaf area-meter, CI – 202 seven times during the growing season. This method provides an indication of the plant growth.
The obtained results indicated that actual corn evapotranspiration was 377 and 371.92 mm for surface drip and subsurface drip irrigation systems, respectively. The value of corn evapotranspiration under surface drip and subsurface drip irrigation increased from initial, to middle season stages. The maximum daily values of ETc occurred on 48 days after planting in middle season stages. The total value of transpiration plant was 5.88, 76.82 and 118.21 mmd-1 for surface drip irrigation system and 12.78, 81.31 and 118.95 mmd-1 for subsurface drip irrigation system in the initial, advance, and middle season stages, respectively. Sum evaporation from the soil surface and crop transpiration was 200.81 and 176.02 mm for surface drip irrigation system and 213.04 and 158.81 mm for subsurface drip irrigation system. So, amount of evaporation from the soil surface was 73.02, 65.73 and 37.32 mm for surface drip irrigation system and 65, 58.83 and 34.98 mm for subsurface drip irrigation system in the initial, advance, and middle season stages, respectively. In surface drip and subsurface drip irrigation was allocated approximately 93 and 83 percent of evapotranspiration to evaporation from the soil surface respectively. The minimum daily values of E/ETc were 37 and 34 mm for surface drip and subsurface drip irrigation systems respectively, and occurred in middle season stages. Amount of transpiration was 5.88, 76.82 and 118.21 mm for surface drip irrigation system 12.78, 81.31 and 118.95 mm for subsurface drip irrigation for the initial, advance and middle season stages, respectively. The relationship between T/ETc and LAI was fitted to a polynomial equation with significant correlation coefficients, R2 = 0.95 and 0.89 for surface drip and subsurface drip irrigation systems, respectively. T/ETc started from 0 at sowing, and reached to its maximum at the middle growth stage or when LAI reached to about 3.0. Also, the relationship between E/ETc and LAI was fitted to a polynomial equation with significant correlation coefficients, R2 = 0.97 and 0.88 for surface drip and subsurface drip irrigation systems respectively, and reached to its minimum at the middle growth stage. Also the results showed that subsurface drip irrigation systems have higher biological yield and higher values for plant parameters in compared to surface drip irrigation system that it shows subsurface drip irrigation system due to evaporation reduction, better weed control and direct transport of water to the developmental zone has a significant role in increasing corn yield.
The results of this study indicated that soil evaporation losses in subsurface drip irrigation system had lower than surface drip irrigation system. Also, had higher transpiration in the growth season. This could perform important role on yield of crop. These results should help the precise planning and efficient management of irrigation for these crops in this region.

Subsurface drip irrigation is a highly efficient method to optimal use of water by minimizing water losses through evaporation from the soil surface¡ reduce deep percolation¡ and thus helping to keep water and preserve the nutrients used by crops. This irrigation method have high priority in different parts of the world on different row crops¡ garden and vegetables compared to other methods irrigation such as of surface drip irrigation¡ sprinkler and surface irrigation. In Iran¡ for the crops with cultivated area¡ such as corn¡ were been very productive which may have an important role in the water balance of country''s. In this article¡ the goal is introduction of benefits and limitations of subsurface drip irrigation for corn and provide technical advice for design¡ implementation and operation of this system in corn farming. For this purpose reports and publications on the yield and water productivity of corn under subsurface drip irrigation system were studied. The results showed that depth of dripline due to the soil texture was variable¡ and was in range from 0.15 to 0.45 meters. Also¡ the distance between the dripline was affordable with 1.5 meters for cultivated corn with a row spacing of 0.76 m. Also¡ the results showed that grain yield of corn¡ plant biomass and absorb plant nitrogen fertilizer by fertigation during the growing season has increased under the subsurface drip irrigation system. Generally¡ when we are faced with water shortage and water tension of the product¡ application of subsurface drip irrigation with a proper design and management will increase corn production levels¡ yield and yield components and¡ also increase the irrigation water productivity.