Journal of Water and Irrigation Management
Year:2018 | Volume:8 | Issue:1 |Papers Count:12

In managing greenhouse irrigation system, the knowledge of water requirement and crop coefficient tends to be extremely essential at different growth steps. The present study set out to explore the amount of water used in evapotranspiration and to determine crop coefficient in Ocimum basilicum L. in an hourly manner. To this end, the project was implemented in a greenhouse in Urmia University. More specifically, the evapotranspiration level of Ocimum basilicum L. and Lawn (as the reference plant) were measured hourly and daily using lysimetric method. The results revealed that an average 45-day evapotranspiration was 4. 12 mm /day in Ocimum basilicum L. whose total water consumption was found to be 188. 45 mm. Besides, in case of the reference plant, water consumption was determined to be 338. 5 mm during this period. The length of growth stages in Ocimum basilicum L. including the initial, developmental, middle, and final steps were found to be 10, 20, 10, and 5, respectively. The highest crop coefficient in Ocimum basilicum L. occurred on the 39th day after planting in the middle phase. As the evapotranspiration of the reference plant showed, the average crop coefficients of the initial, developmental, middle, and final phases in Ocimum basilicum L. were calculated to be 0. 14, 0. 52, 0. 93, and 0. 83, respectively. Furthermore, the highest hourly evapotranspiration process was conducted in the interval of 15-16 hours, which was calculated to be 0. 13, 0. 41, 0. 70, and 0. 71 at the initial, developmental, middle, and final stages in Ocimum basilicum L., respectively.

Irrigation management is effective on soil salinity variation. Salinity pattern was studied in different soil layer under different irrigation regimes in a pistachio garden equipped to subsurface drip irrigation system. The treatments were three irrigation regimes; control (I1), Irrigation based on irrigation requirement (I2) and I2 plus leaching requirement (I3), three soil depth of 25, 50, and 75 cm from soil surface and before and after irrigation event. According to the results soil salinity change by irrigation regime, time and soil depth layer. The I2 irrigation regime were more effective to move the salinity (ECe) to margin of wetted zone compared to other irrigation regimes. Salinity increased by soil depth and that was higher in 75 cm soil depth with 14. 5 dS/m. Irrigation regimes were not effective in moving the salinity to upper part of dripper lateral line. Bilateral impact of irrigation regimes, soil depth, and time before and after irrigation event was also resulted in higher soil salinity in 75 cm soil depth with 14. 2 dS/m. The I3 irrigation regime applied more salt to the soil by higher irrigation depth but was not effective to leach out the salt.

In order to evaluate the performance of sub-irrigation system using porous clay capsules, the experiment was conducted as factorial plot in base of randomized complete block design with three replications and two irrigation treatments on two different time, 21-MAY-2016 and 21-JUNE-2016 for rice culture. In this study some morphological traits including grain yield, number of empty seeds, number of filled seeds, number of whole seeds, weight of main panicle, main panicle length, 1000-grain weight, plant height, water consumption and water use efficiency were assessed. The results showed that flooding irrigation had no significant effect on the yield increasing compared to sub-irrigation at two sowing dates. Also, the water consumption decreased 30% and 39. 5% using subirrigation in two sowing date (21-MAY-2016, and 21-JUNE-2016) respectively, comparison to flooding irrigation. Based on the result grain yield at two sowing date had significant effect. The grain yield decreased 28 percent in the second date of culture (4463 kg. ha-1) compared the first date of culture (3212 kg. ha-1) at two irrigation methods. Generally, using porous clay capsules technique, rice culture could be provided without yield loss at arid and semiarid regions.

Hydrological modeling plays a valuable role in watershed management. In order to advance this important, in this study, a combination of linear programming, cross-wavelet transform and Kalman filter as a control model for the analysis of nine compound rainfall and runoff events were used in Sufi Chay Basin. The results were compared with modified time area unit hydrograph, and e geomorphologic unit hydrograph. Finally, using the evaluation criteria used in the research, the final performance of these methods was investigated and analyzed. It was revealed that the modified time area method has a relatively weaker performance than the other two methods, which is due to the assumptions used in drawing the isochrones lines. The LP-CW-KF method showed the best performance among the studied methods, which simulated the compound events in the calibration and validation stage with a mean squared error of 2. 47 and 2. 7, respectively. On average, in all the events and the three studied methods, the mean absolute relative error (MARE) was 0. 069 in the time to peak, 0. 131 in the peak discharge and 0. 125 in the base time. Therefore, on average, all methods showed a better performance in estimating time to peak.

The aims of this study are evaluation of water use management and water use efficiency of Yamchi pressurized irrigation and Ghoorichay low pressurized (hydroflume) canals, with total area 3885 ha and located in Ardabil plain. Annual relative irrigation supply, Annaual relative water supply, relative rainfall supply, water productivity and irrigation water productivity, as physical water use efficiency and parameters pure and impure benefit of water use efficiency and pure and impure benefit of irrigation water use efficiency as economic parameters were calculated. Results showed that, for four years of 2011-12, 2012-13, 2013-14 and 2014-15 mean of irrigation deficit of Yamchi and Ghoorichay canals were calculated 28 and 43 percentage, respectively. For three years of 2012-13, 2013-14 and 2014-15 mean of water productivity in Yamchi and Ghoorichay canals was calculated 1. 52 and 2. 15 kg/m3 and mean of irrigation water productivity was calculated 2. 16 and 4. 08kg/m3, respectively. Mean of water pure and impure benefit for Yamchi canal were estimated 987. 67 and 884. 67 toman/m3 and for Ghoorichay canal were estimated 4028 and 9100 toman/m3, respectively. Mean of irrigation water pure and impure benefit for Yamchi canal were estimated 12669, 1515. 33 toman/m3 and for Ghoorichay were estimated 23988. 33 and 6523. 33 toman/m3, respectively.

One of the non-invasive and remotely sensing method for measuring plant water status, and also irrigation automation, is using canopy temperature as an indicator. This study aimed to evaluate the combined effect of salinity and drought stress on almond water status. The trial was conducted based on randomized complete block design with three replications on a loamy sand soil. Treatments comprised three irrigation salinity levels viz. 2 (T1), 4 (T2), and 5 (T3) dSm-1. Canopy (Tc) and air (Ta) temperatures, relative humidity and integrated volumetric soil water content (SWC) at three depths (0˗ 20, 0˗ 40, and 0˗ 70) were measured at midday (12˗ 14) during the growing season. Results indicated that salinity has significant effect on Tc, Tc-Ta and available water depletion (AWD). Seasonal averages of Tc for treatment T1 to T3 were 31. 9, 32. 7 and 33. 6 oC, respectively. Significant correlation was found between Tc, Tc-Ta, SWC and AWD. Threshold value of Tc for initiating stress in treatment T1 to T3 was obtained to be 31. 6, 30. 3 and 28. 4 oC, respectively. Corresponding SWC for these Tc were 8. 70, 11. 01 and 14. 07 %, respectively. High correlation between Tc and soil water status, shows that midday canopy temperature may be a useful tool for assessment of water status and precision irrigation scheduling of almond orchards.

The controlled drainage is one of drainage methods, which that aim in addition to improve the conditions of the growing space and increase the plant's yield is, reduce the losses of chemical fertilizers and consequently, reduce the pollution of the environment. The present study was conducted to investigate the effect of controlled drainage with constant and variable depth on discharge and salinity changes, as well as transfer of drainage nitrate and phosphorus during the growing season in the dominant products of Moghan plain, barley and corn. For this purpose, three treatment included, Free Drainage (FD) or conventional drainage is used to area, Controlled Drainage with a control level of 70 cm below the soil surface (CD70) and Controlled Drainage with variable control during the growing season (CDch) and each treatment in Three repetitions were considered. The results of the study showed that discharge rate of drainage in barley field in CD70 and CDch treatments was 55. 0 and 44. 9 percent lower than free drainage respectively, and in corn, decreased by 51. 2 and 43. 8 percent, respectively. The amount of nitrate losses in barley filed in the CD70 and CDch treatments was 48. 4 and 42. 4 percent, compared to free drainage and 50. 8 and 46. 0 percent, respectively. Controlled drainage treatments, in addition to reducing the amount of drainage volume, have improved the quality of drainage in terms of nitrate, phosphorus and salinity.

This research was conducted to evaluate the effect of modifiers on water use efficiency, yield and some nutritional elements of carrot in a factorial based on randomized complete blocks with two factors including reformer type (Super absorbent polymer of water crystalline A, zeolite and perlite), and different levels (0, 0. 5, 1, 1. 5 and 2 g/kg soil), and four repetitions in greenhouse conditions. The results showed that interaction between modifiers and different levels has a significant effect on product performance and water use efficiency. Among the modifiers the superabsorbent polymer had the best effect at 2 g/kg on carrot plant performance and water use efficiency, with means 47. 68 grams and 29. 5 g/l, respectively. That in comparison with control treatment showed an increase 2. 8 and 4. 10 times, respectively. Also, Interaction between modifiers and different levels has a significant effect on the concentration of nutrients– such as nitrogen, phosphorus, potassium, sodium, magnesium and calcium– in the carrot plant. The highest nutrient concentrations of nitrogen, phosphorus, potassium, magnesium and calcium– 2. 34, 0. 36, 1. 77 and 1. 55 percent, respectively – were superabsorbent correction at 2 g / kg soil.

Heavy metals pollution is one of the main drawbacks of using wastewater for irrigation. Exploring the pollution of heavy metals in a vast area needs frequent experimental measurements, which is mostly time and money consuming. In this study, the image of Sentinell2 satellite was used to evaluate the heavy metals pollution of wastewater irrigated area in south of Tehran, IRAN. For this aim, 30 soil-surface samples were collected from the study area and the concentrations of Pb, Cu and Ni were determined using atomic absorption spectroscopy. Then the relation between the heavy metals concentrations and reflectance in the bands or the ratio of the bands at the corresponded sampling points was determined by applying the stepwise regression method. The developed models were applied on the satellite image for zoning the heavy metals concentrations in the study area. Finally, the accuracy of the developed models was examined by Root-Mean-Square Error (RMSE) and Pearson correlation coefficients. The results showed that the amounts of RMSE for the equations of Pb, Cu and Ni were 1. 90, 2. 54 and 1. 59 ppm respectively while the amounts of R were 0. 81, 0. 75 and 0. 73 for these metals that showed a promising match between estimated and measured results.

Managing nitrogen fertilizers application in the field is an effective tool to mitigate groundwater pollution. The objective of this research was to investigate the effect of various fertigation scenarios on the nitrate leaching and nitrogen absorption by corn in surface tape micro-irrigation system and sandy clay loam soil. For this purpose, HYDRUS-2D model was used to simulate water and nitrogen movement in soil and the requirement data for the model calibration and validation were collected by the field experiments. Then, the nitrogen uptake and nitrate leaching in the different fertigation frequencies were simulated in the calibrated model. The mentioned scenarios in a sandy loam soil were also exerted to compare with the results of the previous stage. The results showed that the nitrate uptake by the plant, leaching and its accumulation at the end of the growth season in the root zone were similar in weekly and biweekly frequencies in the studied soils. Reducing the number of fertigation frequencies to three splits, nitrate uptake by the plant in sandy clay loam soil increased to 73 percent and total losses of leaching and accumulation in the root zone, decreased to 27 percent. However, in three-stage splits in sandy loam soil, the nitrate uptake by the plant decreased to 48 percent and total nitrate losses increased to 52 percent.

Economic development and efficient use of water resources is largely dependent on water as an economic good, and it is to be considered using the economic approach in order to manage it. The main objective of this paper is to determine the economic value of agricultural water based on crop-types and financial efficiency of farmers in seven areasof Markazi province, Iran in the 2012-2013 crop year. For this purpose, a localized developed mathematical model was used to calculate the economic value of water for 4 crops including wheat, barley, alfalfa and corn by three different weighting methods including the volume of water, the area under cultivation and the income from each one of the products. Among the above mentioned methods, the weighting method-which is based on the volume of water-is selected as the most appropriate method. The economic value of water based on this weighting method and for the studied areas including Mahallat, Komijan, Shazand, Saveh, Delijan, Khomein and Ashtian were obtained equal to 5700, 5550, 5000, 6700, 3800, 4800, and 6050 rials per cubic meter of water, respectively. The financial efficiency for all the three alternatives; free water, 10% of the calculated price and the actual price of water from the farmer were calculated. Results revealed that financial efficiency is sensitive to changes in income and it is more sensitive than changes in costs. Irrigation efficiency and financial efficiency are not aligning in all cases. This means that in the first place, in order to increase farmers' financial efficiency, the farmers' incomes should be increased, and secondly, by subsidizing in other conditions, the farmer’ s costs should be reduced.

Determination of the water requirement and crop evapotranspiration is essential for each region of Iran (because of the value of water). One of the best approaches to assess plant water requirement is the determination of the crop evapotranspiration and coefficient, using lysimeters. Chamomile and cumin are two important medicinal plants in Iran. In this study, an experiment was conducted at the Agriculture Faculty of Lorestan University for one year to estimate the transpiration of these two plant species. In the present research, these species and reference grass seeds were sown in mini Lysimeters. Each of the experimental units was irrigated, based on crop capacity and weighing method. The results showed that the amount of evapotranspiration for chamomile was 610. 3 mm for production of 780 Kg/h, and for cumin, evapotranspiration was 416. 4 mm for production of 300 Kg/ha, respectively. Finally, based on the FAO method, The crop coefficient (KC) curves were drawn during different growth periods for both species and, In average, It was concluded that in four stages of plant growth, the KC values for chamomile were 0. 16, 0. 54, 0. 86 and 0. 50 and for cumin they were, 0. 14, 0. 52, 0. 7 and 0. 5, respectively.