مجله تحقیقات آب و خاک ایران
سال پنجاه و دوم شماره 10 (پیاپی 70، دی 1400)

Given the advancement of technology and the growing population in the world, the need to recognize and pay attention to the phenomenon of climate change is inevitable. The purpose of this study is to investigate the changes in maize yield for future years in Gorgan with a change in planting date. In this research, the grain yield of maize SC late maturing for future conditions was investigated using WOFOST model in Gorgan city based on different deficit irrigation treatments and different planting dates. Irrigation treatments including 100% (T1), 75% (T2) and 50% (T3) of water requirement. For this purpose, using SDSM statistical model and HadCM3 general circulation model for all scenarios, the fifth microscale report was performed in the next two thirty-year periods (2020-2050 and 2050-2080). Data for the period 1980-1995 were used to calibrate the SDSM model and data for the period 1995-2010 were used for validation. The WOFOST model was calibrated by the measurement data of 1391 and then the data of 1392 were used for validation. Statistical indices of root mean square error (RMSE), compatibility index (d), model efficiency coefficient (E), explanation coefficient (R2) and residual coefficient (CRM) related to grain yield simulation in calibration period was equal to 0.217 tons per hectare, 0.97, 0.94, 0.93 and 0.15, respectively and in the validation period, was obtained 0.241 tons per hectare, 0.98, 0.93, 0.96 and 0.14, respectively. The numbers obtained indicate the good performance of the WOFOST model. Also, the maize grain yield was simulated for four different planting dates in three treatments of T1, T2 and T3. In the period 2020-2050, the lowest yield was predicted 4.3 tons per hectare in T3 treatment under the RCP8.5 scenario on 2 June, which is a decrease of 32.81% compared to the base period. In the period 2050-2080, the lowest yield was predicted 3.3 tons per hectare in T3 treatment under the RCP8.5 scenario on 2 June, which is a decrease of 48.43% compared to the base period. The best planting date for corn in Gorgan city is June 23, which can be used for better management of cultivation and irrigation in Gorgan.

In the present study, three methods of the inverse numerical solution, transfer function, and artificial neural network for estimating soil hydraulic parameters were evaluated. A Double-ring infiltration experiment was conducted in three sites with different soil textures with three replications. Disturbed and undisturbed soil samples were also collected from three depths (0−10, 10−30, and 30−60 cm) for each soil, and some soil physical properties were measured. In this study, HYDRUS- 2D/3D software was used for inverse estimating of hydraulic parameters. The accuracy and reliability of the predictions were evaluated by the mean difference (MSD, m3 m-3), the value of mean differences (MD, m3 m-3), the mean and the standard deviation of the root of mean squared differences (RMSD, m3 m-3) and the Pearson’s correlation coefficient (r). The results showed that inverse estimation of soil hydraulic parameters provided a reliable alternative method for determining the soil water retention curve at the field scale. The soil water retention curves obtained from the RETC fitting had very good correspondence with those derived from inverse modeling. The highest value of determination coefficient (R2) was observed between the measured and estimated volumetric moisture in the inverse numerical solution method (R2 = 0.9363). After that, the estimated volumetric moisture with Rosetta software (R2 = 0.8629) and the PTF of Dashtaki and Homayi (R2 = 0.8401) were respectively.

Given the changes in rainfall and temperature of the regions in recent decades due to global warming, it is necessary to study the temporal changes of sediment in rivers. In the present study, the changes of sediment entering the reservoir of Torogh dam under the influence of the climate change phenomenon were evaluated using the data of the base period (1980-2000) in the period 2076-2056. In this regard, the output of five climate models BCC-CSM-1-1, GFDL-ESM2M, IPSL-CS5A-IR, MICRO-ESM-CHEM, and MRI-CGCM3 and their group implementation under two emission scenarios RCP2.6 and RCP8.5. The IHACRES Rainfall-runoff model was used to simulate the inflow to the dam reservoir, and the sediment measurement curve was used to evaluate sediment changes. The results of flow simulation in the baseline period (1980-2000) indicated that the IHACRES model has a good ability to simulate monthly flow in the study basin. The results of reviewing different climate change scenarios showed that the amount of rainfall in the next period compared to the base period under the RCP2.6 scenario would increase by 7.25%, and under the RCP8.5 scenario will decrease by 1.24%. Both scenarios jointly predicted an upward trend for the average temperature. But the slope of this increase under the RCP8.5 scenario was greater than RCP2.6. The results showed that due to changes in Rainfall and temperature, the amount of discharge in the next period compared to the base period under the RCP2.6 scenario will increase by 13.63% and under the RCP8.5 scenario will decrease by -22.55%. Also, this study showed that the rate of annual changes in suspended sediment load to the Torgh Dam reservoir in the future period compared to the base period under RCP2.6 scenario will increase by 11.58 percent and under RCP8.5 scenario will decrease by -25.32 percent. Therefore, predicting the amount of sediment entering the dam reservoir is strongly a function of the scenario under study.

Due to the key role of rice crops in food security and employment in Iran, access to on-time information of productivity and water productivity in paddy fields can provide important strategies for planning activities such as harvesting, storage, marketing, and management of resources and inputs. This study aimed to estimate the yield and determine water productivity of paddy fields in the north of Sari city using Landsat 8 satellite data and N type lysimeter. For this purpose, NDVI, SAVI, and RGVI indices were extracted from the images. Using these indices, a suitable regression relationship was created with rice yield. With continuous monitoring of paddy fields and installation of type N lysimeter, water consumption and evapotranspiration of rice data were measured. Finally, the study area's rice water productivity map was obtained by incorporating remote sensing data (yield) and field data (water consumption and evapotranspiration). The results showed that plant indices in the tillering stage have the highest correlation with rice crop yield, and if yield estimation using remote sensing data is considered, plant indices in tillering stage should be used. Among the plant indices, the SAVI index had the best correlation (r=0.94) with yield, and the yield map obtained from this plant index was used to prepare a water productivity map based on water consumption and rice evapotranspiration. Evapotranspiration-based water productivity map provided more realistic data than water consumption-based productivity map, so the SAVI index average productivity was 0.63 kg/m3, and the average measured productivity was 0.68 kg/m3. Findings showed that remote sensing provides useful information for mapping crop yield and water productivity in paddy fields and has good potential for precision and smart agriculture.

Karkheh is one of the most important watersheds for water resources management and croplands in Iran, where the largest dam in Iran and the Middle East is located there. Karkheh is considered as Iran’s food basket and exploring land-use changes in this watershed has highly strategic. In the present study, land-use changes during 1990 and 2020 in the Karkheh basin have been extracted and evaluated using Landsat satellite images and random forest algorithm in the Google Earth Engine platform. In this paper, the changes of 11 classes, including forest, shrubland, grassland, irrigated, rainfed, garden, barren, water body, wetland, urban, and riparian have been quantified. The largest area of the region was belong to grassland and barren. In this research, the classification process has been done separately for each Landsat image scene in the Karkheh basin, and finally, all the scenes have been mosaic together. Using this method, most of the images in a scene are used, and the time series of indexes specific to each class of each scene is used for classification, which achieves more accurate results than the method of classifying the whole area in one place. The results show urban areas have increased by 113%, water bodies by 149%, garden by 163%, riparian by 39%, irrigated by 122%, wetland by 10% and rainfed by 34%. However, forest 22%, barren 20%, and shrubs 20% were reduced. As a result, this statistic indicates an expansion of agriculture and reduction of grassland. The accuracy assessment of the classified images confirmed the overall accuracy and kappa coefficient as being 96% and 95% for 1990, 94%, and 93% for 2020. These indices show the appropriate accuracy of classification maps and the validity of the results.

Increasing green space and afforestation in arid and semi-arid regions has always been accompanied by water shortages. Species with lower water requirements have always been an executive policy in these areas. The aim of this study was to estimate the water requirement of Acer negundo and Pinus eldarica Medw as the main species that applied in green space of arid, outdoors, and greenhouses. For this study, soil field capacity, moisture limit, water requirement, and irrigation frequency of seedlings were determined. Then, the studied seedlings were subjected to two, four, and six water stress days after reaching the allowable point of moisture reduction. The results showed that the mean diameter and height of Afghan pine species at the beginning of the outdoor study period were 6.5 mm and 45.9 cm, and in the greenhouse were 5.6 mm and 46 cm, respectively. In addition, the average diameter and height of ash-leaved maple at the beginning of the experiment in the field were 7.7 mm and 97cm, and in the greenhouse were 9 mm and 80 cm, respectively. At the end of the period, these values were 10.2 and 111.8, 52 and 111 for outdoor space and 6.7 and 13, 52.3 and 104.1 for the greenhouse, respectively. For Afghan pine and ash-leaved maple, the fastest time to reach the allowable point of moisture reduction was 7 and 4 days in the greenhouse, 9, and 6 days in the field, respectively. The highest water consumption of Afghan pine in greenhouse and field on 19 to 20 June and on 1 to 2 May equal to 14.14 and 6.13% by volumetric water content; water content was 10.97 and 4.3% by weight water content. The highest moisture consumption of ash-leaved maple in greenhouses and arenas on 21 to 22 May and on 18 to 19 August equal to 11.58 and 4.03% by volumetric water content; the water content was 8.81% and 2.9% by weight water content. The results of this study showed that Afghan pine, as an evergreen species, has the highest tolerance to water shortage and has the lowest water requirement compared to ash-leaved maple. By knowing the number of water needs and irrigation cycle of species in the green space of metropolitan areas and economic savings in water consumption, we can try to develop new irrigation in these areas facing a water crisis.

The present study was conducted to investigate the effects of culture substrate and silicon on yield and its components in strawberry cultivar Selva under soilless culture in the greenhouse of the Isfahan Agricultural and Natural Resources Research Center in 2019. This experiment was performed in split plots as arandomized complete block design with three replications under greenhouse conditions. The main treatment of culture substrate at four levels included 50% perlite and 50% peat moss, 70% perlite and 30% peat moss, 50% perlite, and 50% vermicompost, 70% perlite, and 30% vermicompost and sub-treatment included the application of silicon at three levels of (0, 50 and  100 mg / l) with plant nutrient solution in strawberry cultivar Selva. Evaluation of the results showed that the application of vermicompost substrate due to the increased salinity caused a significant reduction in yield and its components, but the effect of salinity on traits was different. Application of 50 mg / l of silicon caused the highest yield, total fruit number, number of leaves, chlorophyll index, vitamin C, and fresh and dry weight of roots as well as the lowest acidity of the fruit and fruitless flowers compared to the control, (by 7.01, 4.91, 6.33, 3.64, 8.87, 4.9, 9, 10.71, and 4.67% more than the treatment without application of silicon).

Different viscosity and dielectric constants in petroleum productscause physicochemical interactions in the porous fluid electrolyte system, followed by changes in the physical and mechanical properties of the soil. Shear strength of surface soil is one of the most important mechanical properties influencing determination and prediction of soil erosion as a global problem. Penetration resistance is also another mechanical properties of soil that affects tillage operations, plant growth, and soil biological activities and has an important role in seed germination, root growth and development, and crop yield. This study aimed to investigate the effect of application of 0, 1.5, 3.5, and 4.5% of three types of common petroleum products including crude oil, kerosene, and gasoline on shear strength and penetration resisstance of three calcareous soils with clay loam, loamy sand, and sandy loam textures. Results showed that the mean value of shear strength in loamy and sandy loam soils compared to that of clay loam soils was significantly higher by nearly 100 and 35%, respectively, and the penetration resistance in loamy sand soils compared to that of clay loam and sandy loam soils was significantly lower by nearly 83% and 88%, respectively. The mean value of shear strength in soils mixed with kerosene and gasoline compared to that of the soils mixed with crude oil was significantly higher by nearly 17 and 15%; and penetration resistance was significantly higher by nearly 61 and 53%, respectively. In general, the application of 1.5, 3, and 4.5% of oil products caused a significant increase in soil shear strength by about 58, 47, and 14%, respectively, and also caused a significant increase in soil penetration resistance by about two times in all cases compared to that of control.

Identifying the amount of water used to produce agricultural products is of great importance, and it can be very effective in recognizing and providing appropriate solutions to reduce water consumption in agriculture. In this study, in order to investigate the water consumption of sugarcane in Khuzestan province for sugarcane production, the water footprint index in two 25-hectare farms (free drainage and controlled drainage) from Salman Farsi agro-industry unit was used. Using the collected and available information, the AquaCrop model was calibrated. Then four irrigation scenarios (100, 110, 85, and 70% of water requirement) were implemented. Based on the results, the water footprint index was recalculated. The results showed that the amount of water required for sugarcane production in the field with free drainage was 258 cubic meters per ton. Of this amount, 12% was green water, 72% blue water, and 16% gray water. Using controlled drainage, this amount was reduced to 222 cubic meters per ton, of which green, blue, and gray water were 16, 69, and 15 percent, respectively. The results of the model showed that in scenarios I1 and I2, the water footprint index in controlled drainage is 18% lower than the free drainage.  This value is 18% and 19% for I3 and I4, respectively. Comparison of the results showed that in the controlled drainage condition and supply of 85% of the plant water requirement, the water footprint index decreases by 23% compared to the normal (which is running) condition, which is the best option among the studied scenarios.

In the present study, scour development by wall jets in flowing water in a 90o bend was investigated. To study the secondary flows effect, two different locations for the jet on the outer wall of the bend were considered (1) the beginning of the bend (0o) and (2) the end of the bend (90o). The studied parameters are the flume Froude number (Ff), the jet Reynolds number (Rj), and the jet submergence rate (H/do). The results showed that under the influence of the flume flow, the jet trajectory and the scour profile are deflected to the flume flow direction. With increasing Rj, mound height (hm) and the max scour depth (ds) increase. Due to the secondary currents effect, ds at the end of the bend is as much as the nozzle diameter (1do) greater than ds for the jet at the beginning of the bend. Also, for Rj > 36000, the scour development in the jet direction (ys/B) can make a choking in the flume that for Ff < 0.121, the flume choking is more likely. The findings show that with increasing the ratio of the flume flow velocity to the jet velocity (r), the scour profile development in the flume flow direction (xs/do) increases and can reach 100do. For r < 0.06, with decreasing the flume velocity, ys/B increases and for r > 0.06, increase in the Flume velocity causes an increase in the scour development in the width of the flume. Furthermore, r = 0.06, was introduced as a point with the minimum effect of the jet on the flume, which can be utilized in the design of wastewaters discharge. Finally, some equations with acceptable accuracy were developed to estimate the scour profile development in the length and width of the flume.

Throughout history, architects have always invited water into buildings. The element of water has entered into the construction of the building so that it cannot be separated from architecture in practice, and without it, the spaces will look lifeless and dry. This lofty meaning needs to be honored, manifested, and reflected in our culture and architecture today to remove the dust of antiquity and to belong to the past from its face; But achieving it requires reflection and research. In addition, due to the lack of water in Iran and especially in Birjand, it is necessary to pay special and artistic attention to this vital element and introduce its value to everyone more than before. The purpose of this study is to explain the behavior of water in the formation of the Birjand horticultural system using a qualitative method and with a phenomenological approach and answer these questions: Has water been important in the view of architects in the Birjand horticultural system? Can water, in terms of process, functional and environmental dimensions, make the audience rise and enjoy the horticultural system? For this purpose, the required data by purposeful sampling and in-depth interviews with five experts and skilled people in the field of research (architecture and cultural heritage) who have more than 15 years of experience in the Birjand horticultural system was collected. To determine the reliability of the questionnaires, a pre-test was performed. The Cronbach's alpha value for the water behavior questionnaire was 0.82, and the horticulture system questionnaire was 0.86, which indicates the reliability of the questionnaires. Then data analysis was performed using Maxqda software. The results of data analysis showed (P <0.05) that not only water is important in the view of architects in the Birjand horticultural system but water in terms of process, functional and environmental dimensions can lead to the audience's psychological enjoyment of the horticultural system. According to the obtained results, it is suggested that the traditional system of water supply and circulation in historical gardens be preserved, water functions in the garden be restored, including the agricultural landscape, and now that the agricultural landscape is not as important as it used to be, try to find water for its original functions in the gardens.

The impact of climate change as the most important factor affecting agriculture, especially rainfed cultivation has challenged the management of these resources. This study tries to investigate the effect of climate change on the yield and length of the dryland wheat phenological stages in western Iran. For this purpose, two downscaling models, SDSM and LarsWG, were used to simulate the climate over the next 30 years. To model the performance and phonological stages, two models of AquaCrop and DSSAT in the base period and the future period were used, considering the three RCP climate scenarios of 2.6, 4.5, and 8.5. The results showed that the AquaCrop model has better performance and less error than DSSAT. So that the value of the coefficient of determination between observed and simulated data in the base period with AquaCrop model in Kermanshah, Sanandaj, and Ilam stations are 0.86, 0.64, and 0.89, respectively; and RMSE coefficient values are 198.6, 274.6 and 192 kg/ha, respectively. While, in the DSSAT model, the coefficient of determination is 0.90, 0.11, and 0.82, respectively, and the RMSE coefficient is 219.9, 288.1, and 238 kg/ha, respectively. The general results show that in LarsWG downscale model with AquaCrop and DSSAT agronomic model, the lowest yields are allocated to Kermanshah, Sanandaj, and Ilam in 8.5, 4.5, and 8.5 scenarios, respectively, and the highest yields are obtained in 2.6, 2.6, and 4.5 scenarios; which indicates a decrease in performance in the scenario of rising temperature and rising carbon dioxide. However, in the SDSM downscale model, the highest yield of dryland wheat is mainly in scenarios 4.5 and 8.5, and the lowest yield will be in scenario 2.6, which is different from the results of the LarsWG model. According to these results, it can be stated that the type of downscale model and crop model can be effective in the obtained results.

This study aimed to investigate the effect of different intensities (i.e., light, moderate, and heavy) of habitat degradation on soil biological characteristics as the main indicators of soil health in the Khanikan forest of Nowshahr. For this purpose, from each of the different intensities of degradation, 12 samples of topsoil (0-10 cm depth) were transferred to the laboratory. Also, in order to measure the stratification ratio of organic matter, soil samples were taken from a depth of 10-20 cm in addition to 0-10 cm depth. In order to investigate the presence or absence of statistically significant differences between the studied characteristics in different intensities of habitat degradation, a one-way analysis of variance (ANOVA) test in a completely randomized design was employed. In addition, principal component analysis was used to study multiple relationships. According to the results, the highest values ​​of coarse and fine root biomass, number and biomass of epigeics and anecics, number and biomass of total earthworms and the populations of Acarina, collembola, nematodes, protozoa, bacteria and fungi, nitrogen and phosphorus microbial biomass and enzyme (i.e. urease, acid phosphatase, arylsulfatase, and invertase) activities were found in forest cover with light degradation intensity. The number and biomass of endogeics did not show a statistically significant difference in the studied ecosystems, while forest stands with light and moderate degradation intensities had the highest values ​​of basal soil respiration, substrate-induced respiration, and carbon microbial biomass. Principal component analysis results indicate that fertility indices (C/N ratio and available P, available Ca and Mg, available K) and clay content had the greatest effect

Flood routing is an essential and fundamental issue in water resources management and flood control engineering. The Muskingum model is one of the well-known and the most widely used hydrological flood routing approaches. In addition to reasonable accuracy, the linear Muskingum model is also simpler and has a lower cost than that of hydraulic and nonlinear Muskingum models. In this study, a multi-reach linear Muskingum method considering lateral flow is proposed to increase the accuracy and efficiency of the current version of the Muskingum model. To the aim, the river path is divided into a finite number of sub-intervals, and the Muskingum model is then separately applied to each sub-interval successively; in such a way that the input flood hydrograph for each sub-interval is indeed the same as the output flood hydrograph from Muskingum calculations in the previous sub-interval. Here, besides the parameters  and ,  as lateral flow coefficient and  as the number of sub-intervals are also considered as decision variables where the Marine Predators Algorithm (MPA) was used to determine their optimized values. The results showed that the multi-reach approach increased the accuracy of the sum of squared deviation (SSQ) by 70 and 73 percent for Wilson data and Wye river flood, respectively, indicating a higher accuracy for the multi-reach version Muskingum compared to that of single-reach.In addition, the multi-reach Muskingum approach was tested on three flood events of Karun river, in which the calculated statistical criteria, all, show a high accuracy for the proposed method and the MPA.