ali mokhtaran

the current research aims to evaluate the ability of this model to simulate the yield, growth and water productivity of cotton under three irrigation water salinity (S1: 2, S2: 4 and S3: 6 dS.m-1) were investigated. To develop the results of this research, two cultivation dates (D1: March 15 and D2: March 25) and two cotton varieties (C1: Khurshid, C2: Golestan) were also considered. The research farm named L08-20 with an area of 25 hectares was located in the vicinity of the sugarcane industry of Mirza Khokhk Khan, Iran. The results showed that the AquaCrop model had an overestimation error (MBE>0) for simulating the yield, biomass and water productivity of both cotton varieties, but it had good accuracy (NRMSE<0.2) and good efficiency (d>0.99). Was. The accuracy of the AquaCrop model for simulating soil salinity was poor, so that the NRMSE value for three depths of 30, 60 and 90 cm was less than 0.3. Increasing the salinity of irrigation water caused a decrease in the accuracy of the AquaCrop model for simulating the vegetation in Khurshid variety, but ultimately, it did not have much effect on the decrease in the accuracy of the AquaCrop model for simulating both varieties. Changing the planting date did not make a difference in the results of cotton yield and growth simulation. Based on all the results, the AquaCrop model had the ability to simulate the yield and growth of cotton cultivars in different field managements, but it cannot be reliable for simulating soil salinity.

This research aimed to determine rice cultivation map (RCM) for different managements of planting and irrigation (traditional cultivation with permanent flooding and Khoshkeh-kari" with intermittent irrigation) from June to November 2023 in Khuzestan, using vegetation-, temperature- and soil-indicators and remote sensing data. In this research, the temporal-spatial variations of rice water consumption were evaluated and analyzed based on the value of actual water consumption (ETa) and water productivity (WPET). The Random Forest algorithm with Machine Learning technique was used to classify and achieve the rice cultivated area in the province. Sentinel 2, Landsat 9 and WAPOR product bands were used to calculate the indices and WAPOR database was used in the GEE platform environment to determine ETa and WPET. The results showed that the area under rice cultivation for the traditional system in the entire province is 136,770 ha and 43,172 ha for Khoshkeh-kari method. In these conditions, the overall accuracy of rice field separation according to the type of cultivation was around 99.65% and the Kappa coefficient was 0.87. The total ETa of rice in 2023 for Khuzestan Province was 1.62 BCM, with 1.27 BCM for the total ETa of the traditional cultivation and 354 MCM in Khoshkeh-kari. The results showed that, although the farmers tried to avoid crop yield reduction by daily irrigation in the last 45 days of the growth period, the weighted average of ETa reduction and WPET improvement in this technology compared to the traditional method was, respectively, 13% and 8%. Meanwhile, as long as the periodicity of irrigation (Irrigation interval of 2 to 4 days) was observed in the Khoshkeh-kari, the rate of ETa reduction and WPET improvement in this technology was 24% and 16%, respectively. The results of this research, compared to the field data resulting from the applied research works in the province, estimated the efficiency of water use in rice fields with traditional cultivation at 27% and for Khoshkeh-kari at 34%. This shows that if necessary, rice cultivation should be done by Khoshkeh-kari with intermittent irrigation management and in areas that are in good condition in terms of soil, water, underground water level and drainage engineering.

Rice is one of the most important summer crops in Khuzestan province where its cultivation has been limited due to water scarcity in recent years. Water is the most important factor for sustainable production of many agricultural products and changes in soil moisture content during rice growth can affect yield, quality, physicochemical and mechanical properties of its kernel. Considering the severe water resource limitation, this research was conducted on the reaction of the common rice cultivar of this province (Anbarbo) after dry bed seeding and drip strips irrigation method with three different irrigation intervals (every 1, 2 and 3 day/days). Samples were gathered and tested for their geometric properties, gravimetric properties, coefficient of static friction, bending strength, milling yield, chalkiness, gelatinization temperature, whiteness, Amylose and protein. The Results showed that increasing the irrigation period from 1 day to three days could affect negatively on the length, bending strength and one thousand weight of rice. Friction milling system produced significantly higher head rice yield (62.87±2.2%) than abrasive milling system (55.22±6.53%) for anbarbo rice. As the cultivated rice had acceptable properties in all treatments, its production can be explainable due to water scarcity.

Crop modeling is one of the widely used methods for simulating the crops yield under different farm management. However, paying attention to the sensitivity of these models to the input parameters can improve the calibration operation and reduce the simulation error. For this reason, in the current research, we analyzed the sensitivity of the AquaCrop model under planting date treatments (D1: March 5 and D2: March 15) and irrigation water salinity (S1: Karon water with an average salinity of 2 dS.m-1, S2: combination of Karon water and drains with an average salinity of 4 dS.m-1 and S3: drain with an average salinity of 6 dS.m-1) and cotton cultivars (C1: Khursheed, C2: Golestan, C3: Sajedi and C4: Khordad). For sensitivity analysis, the normalized water productivity (WP*), maximum crop transpiration coefficient (KCTrx), initial crop coefficient (CCo), crop growth coefficient (CGC), crop decline coefficient (CDC) and harvest index (HI) were used. Sensitivity analysis was done using Beven method. The results showed that the highest sensitivity was in parameters of HI (0.69) and WP* (0.6) and the lowest sensitivity was in parameters CDC (0.02) and CCo (0.3). The increase in planting date from D1 to D2 increases the sensitivity of the AquaCrop model to the HI (19%) and WP* (15%), and the increase in salinity from S1 to S3 increases the sensitivity of AquaCrop to the HI (42%) and WP* (50%). Therefore, in the farm management similar to the current research, paying attention to the two aforementioned parameters can cause the accuracy of the results in the calibration (and validation) stage.

Determining water consumption management indicators in order to select irrigation methods with the highest efficiency is one of the most important strategies for large-scale planning for optimal water use in any country. In this study, the effect of five different management methods of border irrigation was evaluated on improving irrigation efficiency with the goal of increasing alfalfa production. The experimental field included five test plots: A, B, C, D and E, where the respective irrigation methods applied were traditional open-end border irrigation as the control, cut-back (flow reduction) border irrigation with open-end,  cut-back border irrigation with closed-end, surge (wave) border irrigation with 5 pulses open-end, and surge border irrigation with 3 pulses open-end. The average reduction of applied water in treatments B, C, D, and E compared to the control (A) were 99, 73, 151, and 11 cubic meters of water per hectare, respectively. Applying methods B, C, D, and E also led to an increase in water advance speed by 20%, 16%, 24%, and 12.5%, respectively, compared to traditional irrigation, resulting in improved uniformity water distribution along the borders and reduced surface runoff losses. The percentage of surface runoff in management methods E, D, C, B, and A was determined to be 31, 27, 0, 14, and 18, respectively, and the percentage of deep percolation losses in these methods was 27, 32, 35, 14.27, and 14.68, respectively. Furthermore, the irrigation efficiency in methods E, D, C, B, and A was calculated to be 45%, 55%, 67%, 71%, and 73%, respectively. The use of 3-pulse surge, 5-pulse surge, cut-back with closed-end, and cut-back with open-end were more effective in water saving and increasing the irrigation efficiency compared to the traditional irrigation method. Meanwhile, the cut-back method with closed-end despite having zero surface runoff, exhibited the highest deep percolation losses. On the other hand, Surge methods had the lowest water losses, with the 5-pulse method showing the least surface runoff. Furthermore, the efficiency of the two models, Surface and WinSrfr, was compared in simulating the hydraulics of each method and estimating water application efficiency. The error of  the average water application  efficiency calculated by the Surface and WinSrfr models, compared to the average field values, was found to be 1.6 and 0.21, respectively, indicating the higher accuracy of the WinSrfr model under this studied conditions.

In the current research, with the aim of identifying the most effective techniques to reduce actual water use (Eta) to help restore the lakes of Urmia, Tashk-Bakhtegan, Fars, and Shadgan Wetland in Khuzestan, monitoring was carried out in the crop year 2021-2022 by applying planting techniques at the level of farmers' fields and orchards. In this research, 55, 17, and 18 farms and orchards were considered from Urmia Lake, Tashk-Bakhtegan and Maron-Jarhari basins, respectively. The results showed that the application of all techniques reduced irrigation water by an average of 24.6%, increased yield by an average of 18.3% and water productivity by an average of 60.4% for all the three catchments. However, not all these techniques were effective in reducing the amount of ETa. Farm monitoring showed that the techniques based on "accurate scheduling based on soil and plant indexes along with the modification and optimal management of the existing irrigation system" were able to reduce ETa by an average of 15.5% and improving the efficiency of water productivity (WPET) by an average of 40% in all the three basins. Therefore, the most effective techniques in Urmia Lake basin were use of two-way furrows of rows of trees in surface irrigation and planning drip irrigation based on soil and plant indexes in row crops and trees, which reduced ETa by 18%. Also, there was 21%, reduction in ETa by making irrigation plots under tree shades for pomegranate and pistachio in the Tashk-Bakhtgan Basin, and 13% reduction by making basins around the shading surface of palm trees along with palm leaf mulch, and 14 % reduction by the water flow cutback management method in the strip surface irrigation in the Maron-Jarahi Basin. These were considered as the most important techniques. Finally, it can be stated that paying attention to monitoring techniques at the level of a basin with local participation and promoting them can be effective in protecting the region's ecosystem while establishing sustainable agriculture.

Rice is one of the most important summer crops in Khuzestan Province. Due to the severe water limitation, the effect of using strip drip system in the method of direct seeded rice in dry bed was monitored on the yield of common rice cultivars of the province and changes in soil salinity. This research was conducted during 2019-20 and 2020-21, at the Ahvaz Agricultural Research Station on three adjacent plots of land, using split-plot design and randomized complete blocks in three replications. The main factor was irrigation including three levels: daily irrigation, every two days, and three days; and the secondary factor included three cultivars (Red Anbori, Champa, and Daniyal) and one salt tolerant rice line (S2). In the first year, due to the allocation of water outside the cultivation date, the yield of the crop was very low, so, the analysis was done based on the second year. The average volume of irrigation water in the field was measured as 14,800, 15,200, 15,700 and 16,100 m3/ha for, respectively, line S2, Red Anburi, Daniyal, and Champa. The results showed that, in the daily irrigation, the "Red Anburi" local cultivar had the highest yield with 3767 kg/ha and S2 line had the lowest 2541 kg/ha, so that when the irrigation changed from every day to three days, the yield decreased by 56% on average. The highest water productivity was obtained by the "Red Anburi" cultivar (0.25 kg/m3) in the daily irrigation. The reason for this problem can be shown in the monitoring of soil salinity, so that with daily irrigation, the salinity of the saturated extract in all soil layers showed a decreasing trend from 3.77 to 1.8 dS/m. According to the results, use of drip irrigation system would significantly reduce the volume of irrigation water compared to "conventional puddled transplanted rice". This has been an effective strategy in reducing the stress on the water resources of the province and saving the available water to preserve the ecosystem, although significant reduction of rice cultivation area in this province is recommended.

Salinity is one of the most important environmental stresses that affect crop production. In all areas where irrigation is essential for crop production, soil salinity is inevitable . This phenomenon has gradually become a major problem in arid and semi-arid regions of Iran. Among the strategies to deal with abiotic stresses are the development of salinity tolerant cultivars, crop rotation, genetic modification, use of appropriate organic and chemical fertilizers. Quinoa is a promising species of halophyte that has the potential to become a crop. Quinoa, scientifically known as Chenopodium quinoa willd, is a dicotyledonous plant belonging to the Chenopodiaceae family of spinach and is often self-pollinating. Salinity stress has great effects on plant growth, seed quality and grain yield even in saline plants such as quinoa. Due to plant growth salinity, total grain yield, number of seeds, fresh and dry weight of seeds are reduced. Nitrogen is one of the essential nutrients for plant growth. Nitrogen fertilizers play an essential role in increasing yield as well as improving grain quality. Quinoa needs a lot of soil nitrogen and the use of nitrogen fertilizer is very important for crop growth during the vegetative growth period of quinoa.Quinoa cultivation, especially by using drainage in the southern regions of Iran as a salinity-resistant crop, will lead to diversification of crops, sustainable production, and increase farmers' incomes and food security. Considering that agriculture and supply of nitrogen required by the plant is very important in order to increase crop production with optimal yield, the amount of fertilizer used and also the appropriate cultivar need to be investigated and a step to determine the best cultivar and the best level of nitrogen fertilizer and its effect on yield, yield components, grain protein concentration and efficiency of nitrogen application under irrigation conditions of sugarcane fields in the south of Khuzestan province.

This research was carried out in field conditions in the 97th crop year in Mirza Kuchak Khan Sugarcane Cultivation and Industry Company in the form of split plots in a randomized complete block design with three replications. Factors include urea fertilizer at four levels: 0 (control), 75, 150, 225 kg / ha) as the main factor and two quinoa cultivars (Titi Kaka: V1 and Gizavan: V2) as the secondary factor in Was considered.

The results showed that the interaction of nitrogen and cultivar on leaf area index, number of inflorescences per plant, grain yield, biological yield and grain protein were significant. The highest plant height, stem diameter and leaf area index belonged to 225 kg N / ha. The highest grain yield in Gizavan cultivar (2363 kg / ha) was obtained at the level of 150 kg N / ha and then decreased, but in Titi Kaka cultivar the highest grain yield (2372 kg / ha) was obtained at the level of 225 kg N / ha. Obtained and the reaction was linearly reduced to the highest level of nitrogen fertilizer. The highest amount of grain protein was observed in Gizavan cultivar with application of 150 kg N / ha, which was 138% higher than the control treatment. Based on the obtained results, Gizavan Quinoa cultivar can be a very suitable choice for saline and low-yield fields in the south of Khuzestan province.

According to the results of the study, increasing the application of nitrogen fertilizer increased the yield and yield components and grain nitrogen. Application of 150 kg nitrogen per hectare in Gizavan cultivar with an average yield of 2.36 tons per hectare in the climate of southern Khuzestan province along with the application of drainage from sugarcane cultivation produced the highest grain yield. Quinoa due to its high genetic diversity and adaptation to different climates, high nutritional value and high efficiency of resource use, can be a suitable plant for the use of unconventional soil and water resources in the south of Khuzestan province. It is recommended that future tests be performed on quinoa at different locations with different cropping methods and other fertilizer levels to ensure that the results are relatively consistent over time.

According to the growing human need for food production, using of unconventional water is defined as one of the strategies for overcoming the water crisis in the world. Drainage water recirculation for producing economic sustainable agricultural products can be very useful to management of drainage water environmental impact and adapt with water crisis in the world. For this purpose, overcoming on salinity stresses and preservation of soil quality during cultivation are so important. Studying on salinity effect of irrigation water on wheat yield and soil salts has a long history in the world but genotype and climatic conditions are very influential on the results, so do this research can be very useful. This research has been conducted to determination the best genotype of wheat and analysis of soil behavior in the study of solutes in it.

This research was conducted in 2018-2019 in an experimental farm of AmirKabir Agro-Industry Sugarcane Company using split plot design with randomized complete block with three replications, yield reaction of 20 genotypes of wheat to irrigation with sugarcane drainage water farms was investigated. Also applied water volume, farm water requirement and drainage water effect on soil salts were analyzed. Main plots was irrigation water quality with two quality: 1- fresh water with EC=1.3 dS m-1 and 2- sugarcane drainage water with EC=7.0 dS m-1. Sub plots were 20 genotypes of bread and durum wheat which is cultivated in 8 lines and 20 cm distance. Water requirement was determined by 10-years climate data and wheat crop coefficient and calculated using FAO Penman-Monteith method. Field irrigation management was performed based on water requirement information and considering soil physics, leaching requirements and effective rainfall. Extracted information included volume of applied water, salt and moisture soil samples, water and drainage water quality samples, physical soil specifications, grain yield, biological yield, spike per square meter, grain per spike, 1000-grain weight and flowering date. 

Results showed that using sugarcane drainage water reduced the mean yield by 9.7% and decreased irrigation water productivity from 1.08 to 0.97 kg m-3. There is no significant difference between Bow, Shoele, Narin, Bloudan, Sarang, Irna, Spn and Pishtaz varities for using Karun River and drainage water in terms of grain yield, biological yield, spike per square meter, grain per spike, 1000-grain weight and flowering date, so it can be concluded that these genotypes are stable in different environmental conditions. Stress tolerance index varied from 0.57 to 1.22 among different genotypes. 1-63-31 and Narin genotypes had the highest and the lowest tolerance indices, respectively. Bam and Shoele genotypes were in the mean group with 0.92 and 0.89, respectively. Overall, Sistan, 1-63-31, Bow, Shoele, Sirvan, Sarang, Irna, Khalil, Barat, and Pishtaz with an index above the mean index (0.90) are among the most tolerant and it can be concluded that they can be considered as the most tolerant figures. Also Barat genotype had maximum applied water and total water productivity with fresh water irrigation which were 1.35 and 1.14 kg m-3 and Sistan had maximum water productivity for drainage water in these parameters which were 1.16 and 0.98 kg m-3. Soil results showed that using agricultural drainage water for irrigation not only led to changing farm soil from non-saline to saline condition, it closes to become sodic. Under drainage water cultivation conditions, soil quality will be compromised, which will require new development of irrigation management, leaching and cropping patterns. In these conditions, accurate knowledge of the time and amount of water required for wheat, irrigation with high efficiency and application of appropriate amount of leaching water with proper field drainage, can be effective.

This research was conducted to reaction investigation of various genotypes of wheat in condition of using sugarcane drainage water. Due to the fact that in the middle of autumn and late winter, the drainage of sugarcane fields is low and in this period, most of wheat water requirement is supplied by rainfall and the most important irrigation events start after winter in Khuzestan, so wheat had been chosen for this research. Results showed that yield decrease in drainage water farm for 20 studied genotypes was about 9.8% which is varies between 30.6% for ChamranII to 8.6% for Sistan genotypes. Applying drainage water as irrigation water can cause negative effects on farm soil quality in short term and studying of this behavior by using simulating models can be very useful. For reduction of negative effect of drainage water on soil quality, it is necessary to pay enough attention to the amount and time of irrigation at the last 2 or 3 irrigation events.

Due to the scarcity of fresh water resources, one of the main solutions to supply agricultural water resources is the use of unconventional water, including agricultural water drainage, saline water resources and effluents. In Khuzestan province, a total of about four billion cubic meters of drainage water is produced annually. The volume of water in the Karun Basin alone is about two billion cubic meters per year. One of the areas where sugarcane drainage has accumulated and is now a serious concern is the 35,000-hectare sugarcane wetland, located south of Ahwaz on the border with Iraq. Drainage production due to various activities, especially agriculture in Khuzestan province, is one of the serious problems. Sugarcane production and fish farming are the main producers of drainage in southwestern Khuzestan. In order to optimal use of sugarcane drainage, the effect of these waters on the quantitative and qualitative properties of cotton in the Cultivation and Sugarcane Industry of Mirza Kuchak Khan during 2018 and 2019 was investigated.

Experimental cultivation was performed in 8 lines of 30 meters with intervals of 60 x 20 cm. The field soil had a silty to loamy clay texture.. The experimental design was split-split plots with 3 replications. Three planting dates: February 28, March 29 and April 29 as the main plot, three irrigation treatments including sugarcane drainage, Karun river water, and intermittent irrigation with Karun water and drainage (combined) as a sub plot and three cotton cultivars included Golestan, Khorshid and Shayan were considered as sub-plots. The first planting date was 28th February, after plowing, disc and fertilizing. Thus, fuzzy seeds were disinfected using carboxin tiram fungicide and Gachu insecticide and then planted at appropriate depth according to field soil conditions. Irrigation planning was done based on measuring the percentage of soil moisture before irrigation and the depth of root development. Thus, in each irrigation regim, one day before the irrigation operation by measuring soil moisture to a depth of 100 cm, soil moisture deficiency is determined according to the depth of plant development by considering the maximum amount of management allowed deficit (MAD) equal to 60% of soil water holding capacity. In order to measure the yield components, five plants in each treatment were identified and measured on these plants. Cotton was harvested three times. Data were analyzed using MSTATC software and Duncan test. Finally, the best treatments were identified and introduced in terms of planting date, type of irrigation and cultivars that have better yields.

The results showed that the highest yield with 1712 kg/ ha was related to the planting date of 28 Feb. Yield of the first planting date was 42% and 574% higher than the planting dates of 29 March (1204 kg/ha) and 29 April (254 kg/ha), respectively. The total yield of cotton on the date of 29 March was 374% higher than the date of 29 April. The highest percentage of early maturity was related to the first planting date, which was not significantly different from the second and third planting date. There was no significant difference in different dates in terms of early maturity. In terms of mean boll weight, the first planting date had a higher boll weight of 11.5 and 87.6% than the second and third planting dates, but the difference between the date of the first and second crops was not significant in terms of boll weight, but The difference between these two planting dates and the third planting date was statistically significant on boll weight. The number of bolls per plant on the date of the first crop was 35 and 147% higher than the date of the second and third planting date, respectively, while the date of the second planting date had 83% more bolls than the date of the third planting date. There was no significant difference between treatments in terms of lint percentage but the second planting date had a higher lint percentage. Among irrigation water quality treatments, the yield of irrigation treatment with Karun water and intermittent irrigation with Karun water and drainage (combined) were not significantly different. Karun water irrigation had 12% higher yield than drainage irrigation, while the yield of irrigation with Karun water was only 6% higher than combined irrigation, this difference was not statistically significant. Among cotton cultivars, the highest yield with 1159 kg /ha was related to Golestan cultivar, which was 16.8% higher than Shayan cultivar. Shayan cultivar is one of the cultivars in which high temperature caused the flowers to dry out. The reason for the decrease in yield of Khorshid and Shayan cultivars was more withering and falling flowers at higher temperatures than Golestan cultivar. Golestan cultivar was more tolerant to salinity and heat stress than the other two cultivars. For this reason, it had more yield than Khorshid and Shayan cultivars and it seems to be a suitable cultivar for Khozestan. The effect of irrigation water quality treatments on fiber quality properties was not significant so that the highest strength with 26.84 was related to the date of the first planting (Feb.28), which did not differ significantly from the date of the second planting (March 29).. The effect of planting date on fiber strength at the level of 1% was significant. There was a significant difference between cotton cultivars in terms of strength and micronair at the 5% level. Shayan cultivar had the highest strength compared to the other two cultivars. The fiber strength of Golestan and Khorshid cultivars was statistically the same. Among cotton cultivars, Shayan and Golestan cultivars were significantly different from Khorshid cultivar at 5% level and had the lowest micronair. According to the results of this study, the first planting date on Feb 28 and intermittent irrigation with Karun water and drainage (combined) and Golestan cultivar is recommended for Khuzestan region.

Drip irrigation delivers moisture to the soil surrounding the plant root, leaving the uncultivated ridges mostly dry. The dynamics of dryness and moisture can help adjust the soil salinity and redistribute moisture and salinity (Li et al., 2013; Wang et al., 2011). Further, the distribution of soil salinity in arid regions is affected by a multitude of factors, including the water table (Ming et al., 2016), groundwater salinity, (Abliz et al., 2016), irrigation system (Lie et al.,2013;Zhang et al.,2017), and soil texture (Hu et al., 2011; Zhang et al., 2014). Given the complexity of investigating moisture and salinity distribution in the soil and their uptake by plant roots, the subject has been addressed by several studies around the world. The present study attempts to investigate and evaluate the effects of different irrigation regimes (two-, three-, and four-day) using a tape drip irrigation system on the diffusion and distribution of salinity and moisture around the root of summer maize over two crop years (2018–19) in the South Khuzestan region, where a heavy soil texture is predominant.

Located between the 29°57’ N and 33°0’ N relative to the equator, and between 47°40’ E and 50°33’ E relative to the prime meridian, Khuzestan Province occupies 64,057 square kilometers in Southwest Iran. The present study was carried out in a research farm at the Center for Agriculture and Natural Resources Research and Training, Ahwaz, Khuzestan Province, in summers 2018 and 2019. With clay and silty clay soil textures, shallow and saline groundwater (1.5 m depth), and its particular climate, this research farm can be representative of the farmlands of Central and Southern Khuzestan. The required volume of water during each irrigation by the drip tape irrigation system under different irrigation regimes (two-, three-, and four-day) was calculated for different plant development stages and treatments, thus enabling control over the different irrigation hours in different regimes. the farm soil was sampled at four stages, namely before planting, upon germination, during the middle development stage, and after planting), for physical and chemical characterization and monitoring salt levels from three depths (0–25, 25–50, and 50–75 cm) at a 20 cm distance from the tape by manual excavation using an auger (10 cm in diameter and 20 cm in length). Soil salinity and other quality criteria were measured in the lab. Further, the SMC was measured by the weight percent method, which involves weighing and drying the samples.

The present study addressed moisture and salinity distribution in the soil profile around the plant root under different irrigation regimes. The moisture distribution results showed that all irrigation regimes (two-, three-, and four-day) could maintain the moisture around the FC, slowing down the vertical flow and minimizing penetration into depths. The soil salinity results showed that, considering the soil salinity conditions at the start of the growing season, using the drip tape irrigation first reduced and then increased salinity in the first year of cropping. In contrast, in the second growing season, soil salinity at the end of the growing season using two-, three-, and four-day irrigation regimes was cut to a fourth and a third of its initial level. This shift in the behavior was, however, due to the differences in the quality of irrigation water. This outcome shows the susceptibility of using the drip tape irrigation system in soils that are prone to sodicization and salinity, which requires preparing the conditions to ensure the sustainable function of the irrigation system. The final set of samples showed that, under all irrigation regimes, the emitter output effectively reduced soil salinity, and that this reduction is more effective with frequent irrigations, washing the salts further away from the source. Further, the 0–25 cm deep layer was found to have the least salinity among the studied layers. All irrigation regimes (two-, three-, and four-day) were successful in controlling salinity in the root zone, but the two-day treatment, with a shallower irrigation depth and shorter irrigation intervals, offered the best leaching. The results of performance analysis in two years showed that the year did not have a significant effect on grain and dry matter yield. The results also showed that irrigation regimes did not have a significant effect on dry matter yield but significant on grain yield at 5%.

This study was conducted to compare and monitor drip and surface irrigation systems for corn and wheat crops in three planting seasons from summer 2016 to spring 2018 in one of the agricultural research stations in Khuzestan, located in Ahvaz. The source of irrigation water was Karun River with salinity of 3 dS/m in Ahvaz section. This study was performed using randomized complete blocks design with three replications. The basis of blocking in corn cultivation was 2 and 4 days irrigation intervals, and in wheat cultivation, the distances between drip lines were 40, 60, and 75 cm. The results showed that the volume of water used in the drip system for corn and wheat was 24% and 32% lower than the surface irrigation system, respectively. Also, water productivity in the drip system was higher than surface irrigation system by 16% and 21%, for corn forage and grain, respectively, and by 35% for wheat. Wheat water productivity for different distances of drip lines was not significantly different. Therefore, in heavy-textured soils, drip irrigation lines at 75 cm spacing can be used for wheat cultivation. In soil monitoring analysis, the drip system reduced soil quality such that, after three planting seasons, the initial non-saline-sodic soil (ECe = 3.09dS / m, ESP = 6.18%) became saline (ECe = 7.63dS / m, ESP = 12.63%). Despite accumulation of salts at the periphery of the wetted soil under the drippers, the plants had a better growth and yield in the drip system than the surface irrigation, because of the high soil water potential around the roots and under the drippers, which reduced salt effects. The results of this study showed that if a drip system is used for the climate similar to the central and southern regions of Khuzestan, land drainage and leaching operations at the end of the growing season are necessary to protect the soil.

The present study was conducted to evaluate the efficiency of the HYDRUS model in simulating soil water movement and redistribution of moisture around the roots of maize in homogeneous and heavy soils. This study was carried out in the Agricultural Research Center of Khuzestan Province under drip strip irrigation with three irrigation regimes of 2, 3 and 4 days with three replications during two cropping years. In order to monitor the moisture around the roots, dig a soil profile to a depth of 75 cm perpendicular to the drip irrigation strip. Observed and simulated moisture values were compared byR2,EF, MAE and RMSE statistics. The results showed that the average moisture distribution in each irrigation regime is in the range of crop capacity. RMSE values for different diets ranged from 1.29 to 2.40% and MAE values for different diets ranged from 1 to 2%. Moisture simulations were classified as excellent based on MAE and RMSE values.Also, the results of the coefficient of explanation are between 60 to 90% and the efficiency of the model is between 40 to 90%. Based on the results, the lowest efficiency of the model was in the simulation 24 hours after irrigation and the best simulation was 72 hours after irrigation. The results show the high capability of the model in simulating soil volumetric moisture.

In the new drainage conditions in the center and southwest of Khuzestan Province, by reducing the depth of drainage installation and controlled drainage, studying the dynamics of the mixing zone, understanding the specifications of this region, and its effect on the flow rate of drainage water and salinity is important. In this study, seven groups of piezometers, each consisting of 8 piezometers placed at different soil depths (0.8 to 5m) and at different distances from the drainage water collector were studied in two research farms, namely, field R9-11 Dabal Khazaei agro-industry (with an average drainage depth of 2 m and distances of 65 m) and field R8-7 in Salman Farsi agro-industry (with an average depth of 1.4 meters and 42 meters distances).Water level in piezometers, water salinity in different soil layers, and drainage water flow rate and salinity were monitored daily in three periods of heavy irrigation of sugarcane (March to October of 2013, 2014 and 2017). Results indicated that by starting a heavy irrigation, hydraulic head increased and hydraulic head variance between bottom layer (4 and 5 m) relative to the surface layers, established vertical flow and saline inflow upwards. Reducing the installation depth of drains up to 60 cm from in R9-11 compared to farm R8-7 and moving away from the collector up to 400 m in each farm, reduced the installation depth of drains up to 40 cm, and increased the hydraulic load by an average of 8-12 cm. The thickness of the mixing area was up to one meter and the reduction of the average salinity line in the mixing area was 8%. It was found that in addition to irrigation water salinity, drainage water salinity was affected by groundwater salinity and the difference in drainage depth, position of the impermeable layer, and the presence of sand lenses. By decreasing drainage depth, the drainage water discharge decreased sharply, such that the averag drainage water from each lateral in farm R9-11 was 10 mm/day, and in farm R8-7 it was 3.3 mm/day. The results showed that with increasing the thickness of the salt and fresh water mixing zone due to the optimal reduction of drainage depth, the volume of water consumed in each irrigation cycle decreased due to plant use of this zone, which can be an effective factor in conserving soil and water resources.

< p >  < p >In Khuzestan Province, drainage water production from various activities, especially agriculture, is a serious problem. In order to optimize the use of drainage water, cultivation of salinity resistant crops can be considered as a suitable practice. Therefore, in 2019, a study was conducted to investigate the possibility of recycling drainage water of sugarcane fields for winter cultivation of quinoa  in the Research Farm of Mirza Kuchak Khan Sugarcane Agro-Industry Company in southern Khuzestan. This study was performed as split plots with a complete randomized block design with two factors and three replications. The main factor was the management of irrigation water including the use of Karun river water, drainage water of sugarcane fields, and intermittent-periodic irrigation (alternating application of Karun water and drainage water). The sub-plots were allocated to four genotypes of quinoa including "Giza1, Titicaca, Rosada, and Q26". Interaction of irrigation water type with genotype showed that the highest biomass in terms of dry forage (3645.6 kg/ha) belonged to Giza1 genotype using irrigation with Karun water, which statistically had no difference with the Rozada biomass (2620 kg /ha) using irrigation with drainage water. Monitoring of soil "ECe" and "ESP" during the growing season showed that for the two treatments of irrigation with the water of the Karun River and intermittent-periodic irrigation, the farm soil up to 1 meter depth was non saline and non-sodic. This is while before cultivation of quinova, the soil layer of 0- 25 cm was saline (5.54 dS/m) and the deeper parts were non-saline. In irrigation with drainage water, the 0-25 cm layer soil remained saline due to the effect of evaporation. However, in layers deeper than75 cm, due to the accumulation of salts compared to pre-planting (ECe=2 dS/m), salinity reached ECe=4dS/m and ESP=7%. These results indicate the need for leaching at the end of the growing season and the importance of drainage for salt outflow from agricultural lands to maintain soil salt balance in areas where drainage water recycling is practiced.

 In Khuzestan province, waste water release from various sources, especially from agricultural farms, is a serious problem. The volume of drainage water resulting from irrigation and drainage networks of the Karun river basin is about two billion cubic meters per year, considering sugarcane agro-industries and fish farming as the main sources of drainage water. Time-Averaged salinity of this drainage water, with source of sugarcane agro-industries, is about 6 dS/m which is valuable to irrigate salt-tolerant crops or aquaculture with saline water as part of the solutions for drainage water management and providing sustainable environment. This can also affect the amount of water allocated to irrigation networks and sugar cane industries. In this regard, reusing of agricultural drainage water to produce rice salinity resistant varieties and lines as a high-yielding strategy in Khuzestan, especially in the central and southern areas with high water demand, can be very useful. 

This study was conducted at farm code L08-20, in Mirza Koochak-Khan Agro-Industry Company, using split plot in a randomized complete block design with two factors and three replications. Irrigation interval with saline water daily, one-day and two-day alternations were main factors and three salinity-tolerant rice lines were sub factors. Subsequent selections from the International Treasury of rice cultivars, four salinity-tolerant breeding lines, one international control line and local cultivar were subplots. The amount of water applied to the plots was measured throughout the growing season and samples for determination of physical and chemical properties of soil and drainage water before planting until harvesting time for soil monitoring and soil salt balance analysis were collected. In this study, grain yield, biomass and harvest index were determined. Finally, water productivity was estimated as yield per cubic meter of water.  

Due to the average salinity of irrigation water, 6 dS/m, the volume of water consumed during the growing season was estimated to be 30,000 m3/ha, based on water requirement calculations. Based on irrigation management, applied volume of water was estimated about 37500 m3/ha for treatment I0, 19500 m3/ha for treatment I1 and 13200 m3/ha for treatment I3. The average salinity of soil saturated extract was measured about 4 dS/m before cultivation. Except for the first 15 days, when irrigation was carried out with full irrigation for transplanting stage, the trend of soil salinity changes was decreasing, during the rest of the growing season until harvesting. Salinity of soil increased in all three irrigation managements. The rate of salinity changes varied from 50% in the daily irrigation round to 100% in the two-day irrigation round, compared to pre-cultivation soil salinity. During the crop growth from the transplanting, daily, one-day and two-day rounds irrigation managements caused enterance of 190, 99 and 66 tonnes of salt in the top 100 cm of soil profile. Increased salinity over growing time for daily, one-day and two-day round irrigation treatments, were 6, 6.5 and 7.2 dS/m respectively, according to soil salinity, 4 dS/m, before planting. Assuming the  porosity of soil equal to 51%, it could be concluded that 7.6, 9 and 11 tonnes of salts stored in the upper 60 cm of soil profile for daily, one-day and two- day round irrigation management and the rest of the solutes extracted from soil profiles through underground drainage system. This behavior illustrated the importance of drainage, especially underground drainage system, in agricultural drainage reclamation and saline operations for soil conservation. The results showed significant decrease of farm applied water in daily irrigation water management relative to two-day and three-day intervals. Farm yield increased 6% from I0 with an average of 2139.3 to 2248 kg, I1 and then decreased by 30% in the three-day irrigation period. 

The results showed that the highest and lowest water productivity were found in I2 and I0 irrigation treatments, respectively, with values of 0.128 and 0.057kg/m3. ESP monitoring showed that at the end of growing season, soil profile was not sodic and remained in saline condition for two irrigation regimes I0 and I1. However, in I2 irrigation regime, the soil profile status approached to the sodic state, with 17% increasing in ESP and 100% increasing in salinity relative to planting time. The reason for this behavoir was driness of land between two irrigation events which caused salinity moving upward to soil surface layers, so it could be addressed by considering the percentage of leaching at the end of the growing season.   Acknowledgement  The authors gratitude Mirza Koochak-Khan Agro-Industry Company, Khuzestan Water and Power Authority (KWPA), Agricultural Engineering Research Institute (AERI), Rice Research Institute of Iran )RRII), Khuzestan Agricultural and Natural Resources Research and Education Center  for their  overall supports to accomplish the study.

A new approach in drainage design call for the control of shallow water table at vicinity of the crop rootzone for the purpose of proper soil and water conservation. The objective of this study was to evaluate the effect of reducing drainage depth on salinity and water rate of drains. For this purpose، R 9-11 farm with average drainage depth of 2 and distance of 60 meters and a R 8-7 farm with depth of 1. 4 and distance of 40 meters of sugarcane in south Khuzestan were selected. During the study، constructing six pisometers groups in two farms with different distances from drain collector، the daily water table level and outlet drain flow rate and the salinity of groundwater، and outlet drain in each irrigation were measured respectively. Results indicated that by increasing the irrigation water، the difference of hydraulic load between the bottom layers to the top ones in both farms، leads the vertical flow upwards. In addition، by reducing the drain insertion depth، the groundwater rate of salinity reduces، but these changes of salinity depend on the impermeable layer depth. In addition، by reducing that drain salinity was affected by irrigation water and groundwater salinity and the difference of drain insertion depths، location of impermeable layer and sand lenses affect this salinity. In addition، by reducing the drain insertion depth، outlet drain flow rate was intensively reduced such that in R 9-11 and R 8-7 farms، outlet drain reached to 3. 86 and 0. 74 L/s، respectively.