نشریه فناوری های پیشرفته در بهره وری آب
سال دوم شماره 1 (بهار 1401)

Iran, with a mean precipitation of 230 mm per year, is classified as arid and semi-arid region in the world, facing a water crisis. Since, water resources with high quality for irrigation are limited, therefore the use of supplement irrigation as a method for reducing water consumption is essential in the future. Stevia is a plant with medicinal and anti-diabetic effects, native to the mountainous region of Amoeba, located on the border of Brazil and Paraguay, which is widely cultivated in Shiraz and Isfahan of Iran. The diterpene glycosides in this plant (the main cause of the very sweet taste in plant extracts) are up to 300 times sweeter than sugar used in the pharmaceutical and food industries. In present study, effect of Supplementary irrigation (without Supplementary irrigation, one Supplementary irrigation in flowering and tow Supplementary irrigation in flowering and seeding) were carried out on (Stevia Rebaudiana B.) during two-year period (2017-2018) in greenhouse and research farm. The results showed that supplementary irrigation to prevent reduced sugar yield in the greenhouse and research farm environment was about (18.7, 18.1) and (20.7 and 21.4) irrigation in the first and second year of cultivation, respectively. The result showed that plant tolerance to supplementary irrigation to non- supplement irrigation to avoid reducing sugar yield in greenhouse conditions were obtained as: (18.7 and 18.1), (20.7 and 21.4). According to those results, irrigation of stevia with two supplementary irrigations at the time of flowering and seeding was recommended to increase plant yield.

This study was carried out in a randomized complete block design with four treatments (120, 100, 80 and 60% of field capacity) in order to investigate the effects of deficit irrigation on growth, qualitative, qualitative and water use efficiency of grain maize in Kermanshah. Three replications were designed and conducted in the form of furrow irrigation. The results showed that deficit irrigation effects on grain yield, biomass, leaf area index, harvest index, crop canopy, grain fat productivity, weight of stems, weight of leaves, weight of ears, number of kernels per ear, length of kernels, water use efficiency in grain, water use efficiency in biomass and water use efficiency in fat were significant. The impacts of water stress on the characteristics of maize different in different stages of growth and were higher at the end of the growing season (grain filling stage) so that the application of 40 percent water stress in grain yield, biomass yield, 1000-seed weight and number of grain per ear to the values 3631(Kg), 12143(Kg), 211.66(g) and 288, respectively, reduced 69, 49, 11 and 21 percent compared to the control treatment. The maximum water use efficiency in grain yield ,biomass and fat in the treatment of excess Irrigation was obtained at 1.15, 2.74 and 0.0548 Kg / ha respectively. Therefore, deficit irrigation of maize (KSC 706) is not recommended in Kermanshah.

Regarding the volume of irrigation water in the agricultural sector, the figures presented in the country are very different and there are serious doubts about their accuracy. Therefore, the main purpose of this research project is direct measurement and irrigation water fields of saffron cultivation under farmers' management. Thus, the volume of water used for saffron production in major cities of Khorasan Razavi province (Torbat-e-Heydariyeh, Zaveh and Gonabad) was measured in 18 questionnaires. The results of field measurements showed that the highest volume of saffron irrigation water belongs to surface irrigation at 4691 cubic meters per hectare and the lowest is related to irrigation with Piflex pipes at 3713 cubic meters per hectare and roll irrigation with irrigation water volume of 3900 Cubic meters per hectare was ranked second. The volume of saffron irrigation water in Torbat-e-Heydariyeh, Zaveh and Gonabad cities was 4974, 4816 and 4517 cubic meters per hectare, respectively. The average yield of saffron in Zaveh and Torbat-e Heydarieh counties was 7.3 kg / ha and in Gonabad county was 5 kg / ha. The highest water consumption efficiency in Zaveh city was 0.001669 kg / m3 and the lowest was related to Gonabad city (0.001076 kg / m3). Application efficiency based on ten-year statistics in Zaveh, Torbat-e Heydarieh and Gonabad counties was 51, 49 and 87%, respectively.

A sediment rating curve is the most known method in the hydrological approach for suspended sediment load estimation that is a power equation (or linear equation based on logarithmic data transformation) to relate suspended sediment load to the river discharge. The conventional method to determine the sediment rating curve is ordinary least square (OLS) that outliers can significantly influence. The robust estimations are statistical methods developed to overcome the limitations of OLS. In this study, two robust estimation methods, including MM and least trimmed square (LTS) methods, were investigated for sediment rating curve estimation, and their results were compared with OLS. To compare these three estimators, recorded data sets of four hydrometry stations, Baghou, Alang-Darreh, Anjirab, and Jafakandeh, located in Golestan province with 33-279 pairs of data were used. Coefficient of determination, root mean square error, and mean absolute error as numerical criteria, and graphical criterion was used to compare the results. Assessment of numerical precision criteria showed suitable efficiency for equations estimated based on robust estimator application and revealed their ability to improve OLS estimation. Evaluation of graphical criterion revealed that robust regression estimations could be similar or different to the OLS.

Today, optimizing water consumption is one of the main priorities of agriculture. If on-farm water management is improved, water use efficiency will also increase. Farm water management can be done optimally with the help of simulation models. In this study,. This research is in the form of split plots with the main treatment of urea fertilizer (including 100, 80, and 50% of the fertilizer required for corn (N0, N1, and N2)) and sub-treatment of irrigation water (including irrigation of 100, 80 and 50% of water requirement). The plant (E0, E1, and E2) was executed with four replications. the model had the highest sensitivity to the two parameters of flowering time and pod filling time by seeds. Also, in model calibration to simulate corn yield, normalized water productivity (WP) and cover growth coefficient (CGC) values of 31 (g / m2) and 24.2% were obtained, respectively. In addition, according to the results of this study, the best and weakest corn yield simulations were related to N0E1 and N2E0 treatments, respectively. In general, the model had good simulation in low water and fertilizer stresses, so that in estimating the accuracy of performance simulation (N0E1 treatment), CE, RMSE, d, ME, and CRM values were equal to -0.2, respectively. , 0.32, 0.73, 3.37 and 0.01 were obtained. In general, according to the results of this study, the efficiency of the AquaCrop model for grain corn cultivation in Shush city was considered appropriate and this model can be used to manage water in cornfields.

In the climatic conditions of the country, due to the large volume of groundwater abstraction by wells and also considering the number of wells drilled, especially in recent years, the calculation of privacy in order to apply proper management on the conservation and optimal use of groundwater resources is of particular importance. In this regard, one of the issues that concerns those involved in groundwater protection is the density and proximity of exploitation wells on the one hand and overdraft by exploiters on the other hand. Therefore; in this research, at first, the well function was solved mathematically and the impact radius of each well in the two modes of application of corrective discharge (based on the area under cultivation) and case discharge (exploitation license discharge) was obtained. Then the radius map of the impact of the total wells in the area was drawn and then the areas with privacy interference were identified and drawn. Based on the obtained results, the average discharge of all exploitation wells in the corrective and case discharge mode was calculated to be 18.37 and 11.14 l/s, respectively was obtained. The results also showed that in the most optimistic case, about 20% of the total aquifer area has privacy interference.This causes the local wells to undergo simultaneous operation, severe localized cones and the aquifer to be subjected to unusual stresses, which in the long run causes a permanent and lasting decline in the aquifer and in the long run results to subsidence of the ground.