SEBAL method is one of the most widely used methods for determining evapotranspiration in which physical and empirical relationships have been used. One of the advantages of this approach is a minimum requirement for ground data, which makes this method, despite the limited time and cost and the acceptable results, one of the most widely used methods for measuring evapotranspiration.
Since the plant's water requirement is calculated daily and Landsat 8 images are taken at a time interval of 16 days, and given that the satellite images of the Modis, being available daily, have low spatial resolution, it is possible to have an image that also benefits Landsat 8 (separation A suitable place) and the modis (proper time resolution), the methods of merging images were used.
In this study, Landsat 8 and Modis images were merged with Schmidt algorithm in the 16-day time interval and the actual evapotranspiration of cane sugar was calculated using the 16th day image and the SEBAL method.
The comparison of evapotranspiration from Landsat 8 and lysimetric data showed a high correlation (0.98), comparison of evapotranspiration from the image integration method at the corporation and AmirKabir'sCultivation & Industry, showed a good correlation (0.088) with the company's lysimeter data.
In thepresent survey, also the amount of dry matter produced in the 95-96 cropping season was calculated using the Mantyte model. The average dry matter produced by sugar cane in this period was estimated by using Landsat 8 images, 52/5 t / ha, and the integrated images of 41/14 t / ha. The average water utility from the dry matter produced ratio in relation to the actual evapotranspiration estimated from satellite data for the Landsat 8 images and the merged images was obtained 5.98 and 5/95 kg / m3, respectively.
Eventually, investigating the relationship between age and sugar cane number with performance and evapotranspiration rates calculated by the Mantyte and SEBAL model showed that the effect of sugarcane age on its evapotranspiration is negligible, but the amount of sugarcane evapotranspiration with CP69_1062 variety is more than that of CP48_103 variety. On the other hand, the correlation error and product performance estimation in CP69_1062 is less than that of CP48_103, and as the age of cane rises from cultivation to fourth reproduction, product performance decreases.

Virtual water is a new concept that has attracted the scientists and planners of water sciences at international levels in recent years. Regard to the topic importance in this research, the virtual water was investigated of three irrigation and drainage networks of Shahid Rajaei, Ramshir and Hendijan for three major crop of wheat, barley and sesame. First, the average of crop water requirement were calculated by using metrological data of 10 years (2006-2015) for the mentioned crops by CROPWAT (FAO software). Then, the virtual water of studied networks was determined by using crop productions and existing equations. Also, networks according to virtual water were evaluated by using designed expert questionnaire and analytical hierarchy process (AHP). The results showed that virtual water of wheat in Shahid Rajaei, Ramshir and Hendijan irrigation and drainage networks was 7183.33, 7148.88 and 7501.11 m3/year respectively. The amount of virtual water of barley in the mentioned networks was obtained respectively 8033.33, 8252.78 and 8705.56cm3/years and for sesame in Shahid Rajaei irrigation and drainage network 9836.28 and for Ramshir irrigation and drainage network was 10252.31 m3/year. Comparison between the amounts of calculating data and the delivered water indicated that in Rajaei, Ramshir and Hendijan irrigation and drainage networks had given the water respectively 31, 23 and 28 percent more than actual water requirement. The results of AHP and ranking of mentioned networks by using Super Decisions software with virtual water approach, showed that criterion of field factor in Shahid Rajaei and Hendijan networks and in Ramshir network climate factors had the greatest weight. The least influential factor in three networks was economics factors. Comparing the result of AHP and computational of virtual water indicated that Hendijan network is in the first rank in both methods. Also, qualitative assessment of operation of network utilization according to virtual water and water productivity showed that all three networks are in the undesirable condition.

 In order to investigate the effect of Serially irrigation on properties of soil, an experiment has been preformed with randomized complete design in crop year 2014-2015 at research farm of science and water engineering college (SCU of Ahvaz). The treatments of this study included two types of water (Karun & drained). In this study three part of farm used for cultivation of Maize, Soya and Sunflower were considered that irrigation of first part was with fresh water (Karun river) and next parts with drained water of previous parts. Samplings were done in 4 period of times and 3 depths of soil. The results of chemical analyzes of soil showed that applying treatment in Soya part is statistically significant (p<0/05) for Ca, Mg, Cl, N, P and K ions. Also, in Sunflower part Ca, P and K ions were statistically significant (p<0/05) in two treatments and for the rest of properties had inverse result. Investigation of results of the effect of time dependency in Soya part showed significant differences among after harvesting period with the rest of periods in all properties except pH, P and K. Also, in Sunflower part had same result for all properties except pH, HCO3 and P. Investigation of the effect of depth dependency in Soya part showed that HCO3, N and P ions had maximum value at first layer and for K at second layer. The rest of properties were not statistically significant in soil profile. In Sunflower part, first layer of soil had significant difference in all properties. The statistical indexes results showed that the HYDRUS-1D software had the highest accuracy in simulating HCO3 in Soya part and EC in Sunflower part. For all treatment and properties, the values of R^2 ranged from 0.52 to 0.99. The NSE values in Soya part, in secondary, 3rd and 4th period of simulating had best values for Ca, Mg and HCO3 respectively. Also for Sunflower part HCO3 ion in 2nd and 3rd, also Mg in 4th period had best values of NSE. Results showed that the HYDRUS-1D software had good ability to appropriately simulate salt transport in soil. Therefore, it should be used for better management of irrigation and estimation of soil profile salt in the future.