Iranian Journal of Irrigation and Drainage
Year:2016 | Volume:10 | Issue:4 |Papers Count:14

In order to study the effect of complementary irrigation on morphological and water productivity of European borage, an experiment was carried out in Rasht in 2013 and 2014. Three irrigation treatments including rainfed (I0), one (I1) and two complementary irrigations (I2) were considered. The results of the first year with basin irrigation showed that irrigation treatments had no significant effect on all factors except of the length of flower, leaf numbers and main branch; for main branch and leaf numbers factors, there was a significant difference between I0 and I2 treatments, also for flower length factor, there was a significant difference between I0 and I1 treatments. Water productivity with I1 had the highest amount being of 0.15 kg/m3.The results of the second year with drip irrigation showed that irrigation treatments had no significant effect on all factors except of flower length, number of flowers and main branch, for the main branch factor as in the first year, there was a significant difference between I0 and I2 treatments; also for flower length and the number of flowers factors there was a significant difference between I1 and I0 treatments. Water productivities of I1 treatment was 0.74 kg/m3, being the maximum amounts.

Considering the increasing development of population and water demand and continuous droughts and lack of rainfall, water crisis especially in the arid regions of Iran has become to a fundamental problem. One of important solutions to deal with this crisis in the urban sector, is the management of demand and water consumption that this requires to recognition of effective mechanisms on consumption and water demand in the consumable sector in order to the realization of managers and planners goals in the field of comprehensive and integrated management of water resources. This study has been done to systematic investigate structural patterns governing on the per capita of municipal water in the Birjand city situated in South Khorasan province and with using Vensim software to achieve the sustainable development of in the field of municipal water during the years 2008-2013. The results show that with existing continued consumption patterns in the region the citizens per capita water consumption is increasing and cause decline in groundwater level Birjand plan. Also can found that the use of government policies in the water sector and also savings in the consumption by citizens at the same time, on average With decreasing 30.03 percent In the per capita urban water compared to the existing consumption pattern, as an effective way in changing of consumption patterns and consequently the control of urban water consumption, significantly can decrease Increasing trend groundwater levels decline in to an average of 28.47 percent in the rigion.

One of the methods to decrease scour around the bridge piers is the use of submerged vanes. Vanes change the regime of bed load movement that led to control place of deposition and erosion. The function of vanes to reduce scour around the bridge piers and sediment movement in the region of vanes due to down flow in front of them are affected by arrays of the vanes. In the present study, physical hydraulic model testing was performed to investigate various angles of attack and Height of convex-flat vanes. Experiments were conducted in a 10m long and 0.3m wide flume and a cylindrical pier of 2.54 cm diameter. Clear-water scour tests with u/uc=0.92 were performed. The length of the vanes was equal the pier width. The highest reduction in scour depth was achieved an angle of 20o for a vane height equal to 0 cm.

Since a significant amount of precipitation in the agricultural watersheds is used by evapotranspiration, so this parameter plays an important role in water budget and water resources management. Therefore, accurate estimation of this component is very important. SEBAL (Surface Energy Balance Algorithm for Land) belongs to the methods of estimating the actual evapotranspiration (ETact) which is based on remote sensing technique. In the structure of this algorithm several indices and empirical coefficients are used, each of them is effective for estimating actual evapotranspiration. In this study the effect of the uncertainty caused by the soil adjusted vegetation index (SAVI) values in the form of SEBAL algorithm was investigated on ETact prediction on the part of Neyshabour watershed. To determine the optimize value of SAVI, 2013 and 2014 MODIS satellite images were used and the effect of SAVI values uncertainty on ETact prediction was discussed in 2014. Comparison between estimated values and microlysimeter measurements of ETact in the discussed polygon showed that the minimum and maximum error of ETact estimation has been obtained for the amount of 0.2 (R2=0.99, RMSE=0.07) and 1 (R2=0.12, RMSE=0.6) for L coefficient in the SAVI index structure. The results of t-test also showed the significant differences at 95% (p<0.05) between measured and predicted values of ETact, using the whole range of L coefficient, except 0.2.

The objective of this study was to calibrate and validate the AquaCrop (Ver.4.0) model for wheat (variety, Azar2) under rainfed and supplemental Irrigation and definition of the best management scenario in order to enhance yield and WP of rainfed wheat in upper Karkheh basin. The model was calibrated using Matlab software and data collected in research farms in 2005-2006, also the model was validated using data collected in 2006-2007. The on-farm trials included three irrigation treatments (rainfed, single irrigation only at planting time, single irrigation only in spring). The result showed that the model was able to accurately simulate grain yield and biomass of wheat under rainfed and single Irrigation. For grain yield and biomass, RMSE, NRMSE, DIndex and NSE and R2 were obtained equal to (0.16 ton/ ha, 5%, 0.99, 0.99 and 0.86), (0.32 ton/ ha, 4%, 0.99, 0.99 and 0.86) respectively. The result shows that the suitable sowing date in Honam region is between Oct.28 to Nov.2 in 2013-2014. The results indicated by changing sowing dates from Oct.23 to Nov.2, the simulated grain, biomass and the WP were increased up to 7, 6 and 11%, respectively. The results showed that in Honam region the proper depth and time of single irrigation in spring is 50 millimeters and the middle of flowering stage (198 days after planting time), respectively.

Accurate prediction of river daily discharge is a suitable tool for water resources planning and management.Using models that present explicit equation, such as M5 model trees and Genetic expression programming, causes increase efficiency of these models. In this study, the Galikesh basin as one of most flood prone basins in Gloestan Province is considered for the prediction of river daily discharge. Data series used in this study are long term 26 years daily rainfall and river discharge series belong to Galikesh meteorology and hydrometry station.Daily rainfall and river discharge data from 1 to 5 days ahead are used as inputs for prediction by M5 model trees, genetic expression programming and artificial neural network models. The results indicate very good efficiency of the investigated models beside overestimation of the models to predict daily river discharge.Comparison of results of different models leads to selection of M5 model trees as best model among investigated models.

Global warming is a one of the most important natural hazard in the current world which could affect crop yields through affecting plant physiology, soil water balance and crop water requirement via green and blue water. Under such circumstances, achieving water and food security through an optimal usage of water resources and maintaining crop yield level requires measures for adapting with this major environmental challenge in the future periods. Since wheat and its produces has a the most important share in peoples’ food diet, the climate change effect on wheat cropping calendar and its water requirement in Sistan and Baluchestan province was investigated in this research. Also, the influence of managing sowing date on diminishing the negative effects of this global event was assessed. After calibrating and validating LARS-WG, the climatic variables in six synoptic stations of Zabol, Zahedan, Iranshahr, Saravan, Khash and Chabahar were downscaled under three scenarios of A1B, A2 and B1 of HADCAM3 model up to 2100. Crop water requirement was calculated by determining suitable crop cultivation periods based on cardinal temperature and determining the length of initial, developing, mid-season and late-season stages based of growth degree day coefficient. Climate change decrease the length of different growth stages by 1-20 days due to significant temperature increase which led to 0.03-42.7 percentage decrease in wheat water requirement. Although delaying wheat cultivation will intensify the climate change effects and shorten the growing period by 12-25 days, water requirement will increase by 1.27-778 M3 ha-1.Based on the results, the management ofwheat cultivation calendar can be effective way to achieve sustainable agriculture under future climate condition of the Sistan and Baluchestan province.

Both salinity and drought stress induce water limitation for plants and will reduce growth rapidly along with metabolic changes. Pomegranate (Punica granatum L.) is mainly cultured in arid and semi-arid regions, but suitable irrigation regime and accurate water requirements are not identified. Therefore a factorial experiment with irrigation at 5 levels (well water, 10, 20, 30 and 40% well water) and salinity at 3 levels (1.5, 5 and 8 dS.m-1) based on a completely randomized design with 4 replicates was conducted on 4 year old trees in Ferdows town of Iran during 2011-2013. Total yield and other qualitative traits were measured at the end of second year.Results showed a significant decrease in total yield and some other qualitative traits from integrated deficit irrigation and salinity stress. Deficit irrigation decreased fruit yield compared to control treatment. Antioxidant activity increased in response to deficit irrigation, however, it is not considered very important regarding marketability. In addition, fruit yield was observed none-significant among salinity treatments. Hence it generally seems that pomegranate could be classified as a drought sensitive and salinity tolerant plant.

For study of yield, water consumption and water productivity of direct seeded and transplanted corn (basin) in different irrigation regimes, an experiment was carried out during the 2014-2015 growing season in the Agricultural Research and Education Center of KhorasaneRazavi province using a randomized complete block design with a split plot arrangement and four replications. This experiment was including of three irrigation levels treatments (75%, 100%, and 125% of water requirement) as the main plot and three method of planting treatments (transplanting 20-days, transplanting 30-days and direct seeded) as subplots. The results showed that in spring planting, the most water productivity of corn was achieved from the transplanting treatments with different significant at 1% level to direct seeding treatment. The yield of corn and grain in transplanting 20-days and transplanting 30-days were more than direct seeded (a=1%). The water used in the transplanting and direct seeding treatments have a significant difference. The transplanting method can be cause of water saving, but it is better to be done an economic analysis between direct and transplant seeding.

While providing conditions for crop diversification and improving productivity of northern Iran’s paddy fields, subsurface drainage can be a threat to downstream water resources. This research was done to quantify the effects of two types of conventional water management in rice cultivation systems including midseason drainage and alternate irrigation and drainage as well as free drainage in canola growing season on salinity of subsurface drainage effluents. Required experiments were conducted on subsurface drained paddy fields during 4 rice growing seasons and two canola growing seasons (2011- 2015). Each type of management strategy was repeated twice during the study period. Measurements of water table depth and drain discharge were done during drainage periods of different growing seasons. Moreover, drainage water salinity was measured in due times. Alternate drainage and increase in water table depth raised drainage water salinity in rice and canola seasons, respectively.Compared with midseason drainage, alternate irrigation and drainage resulted in 121- 420 kg ha-1 increase in salt loss in different drainage systems. Salt discharge was considerably higher in canola season than rice season due to free drainage condition in canola seasons. Total salt load under midseason drainage, alternate irrigation and drainage and canola cropping through different drainage systems ranged, respectively, 78.4-365, 240- 695 and 3056- 5656 kg ha-1. Based on the results, water table management through installation of shallow- suitable spaced drains can be effective to decrease salt load from subsurface drained paddy fields.

Pressurized irrigation systems are one of the largest energy consumers and they are mainly dependent on the pumping stations. Therefore, optimum design of pumping stations is very important, especially, in view of increasing the efficiency of pumping stations and controlling energy consumption. In this study, variable speed pumps have been examined in Ashrafiyeh agro-industry with an area of 85 ha located in Qazvin province, Iran.Accordingly, the energy consumption during a ten-year period in the five operation scenarios of the pumping stations has been analyzed by MATLAB/SIMULINK software. Results of this study showed that consumed electrical energy by using variable speed pumps is approximately decreased up to about 18 percent as compared with the fixed speed pumps. According to computational model, the average energy consumption to transfer 1 m3 water by variable speed pumps was 0.33 kWh. The results of evaluation of consumed energy showed that current operation circumstance increased the energy losses up to about 60 percent as compared with other operation methods. Furthermore, the initial cost of the variable speed pumps after nine years operation, on average, is dissipated from the saved energy.

Wheat is one of the most important crops in the world and a strategic crop in Iran. The Fars province (south of Iran) is ranked first in the production of Iranian wheat. As the predominant climate of this province is warm and dry and water resources are limited, therefore, identifying suitable areas with the aim of cultivating on dry land and maximizing the utilization of rainfall can significantly optimize the water usage for irrigation. The present study was conducted to investigate the zoning of Fars Province with regard to rain-fed wheat cultivation in autumn. In most previous researches, in order to identifying suitable areas for rain-fed cultivation, only rainfall and no morphological factors such as altitude, slope, soil type and land use of the area have been considered, although these factors play as an important role in water infiltration to the soil and the amount of soil water holding capacity for plants. In the present study, in addition to precipitation, morphological factors were also considered. Also, the use of GIS software to integrate geographic information with high precision has been used in this study. Data of precipitation pertained to 10 years (2003-2013) and were collected from 24 synoptic stations in the province. The SMADA software was applied for the relevant calculations at 50% and 75% probability levels. Maps of elevation and slope angles were obtained by the Digital Elevation Map (DEM), accompanied by a visional resolution of 90 meters. Results showed that the areas located in North and west parts of Shiraz, are suitable for rain-fed wheat cultivation. However, the eastern southeastern and southern regions of the province are placed in unfavorable conditions for rain-fed wheat cultivation. According to the rain-fed wheat map established in this study, it is concluded that the total area suitable for rain-fed cultivation is 1796000 hectares (which counts the good and very good classes at 75% probability level) in the Fars province. This is while statistics provided by the State Institute of Agriculture reported that the average area under rain-fed wheat cultivation has been only 118102 hectares for the past 13 years, which is indicated as non-optimal for dry land cultivation in this province.