Research Paper
M Dastoorani; S. Poormohammadi; Mohammad Hassan Rahimian
Abstract
Reliable estimation of actual evapotranspiration of the plants plays an important role on planning and optimization of water use especially in dry land environments, where water scarcity is an important problem. In this study, Surface Energy Balance Algorithm for Land (SEBAL) was used for estimation ...
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Reliable estimation of actual evapotranspiration of the plants plays an important role on planning and optimization of water use especially in dry land environments, where water scarcity is an important problem. In this study, Surface Energy Balance Algorithm for Land (SEBAL) was used for estimation of actual evapotranspiration (ETa) in Ardakan pistachio orchards, Yazd province, Iran. For this purpose, a time series of satellite images including 13 cloud free MODIS data were employed to generate actual ET map of pistachio orchards. Results of this study indicated that seasonal ETa for pistachio trees was about 1150 mm, which was significantly less than the applied irrigation depth, Results of this study emphasize the necessity of a proper irrigation scheduling, irrigation interval, and depth in Ardakan pistachio orchards. Consequently, water productivity will improve and considerable amounts of water will be saved as the result of these improvements.
Research Paper
A Ghadami; M. Mirzaei; M Seyedan
Abstract
In this study, combined effects of nitrogen and phosphorus were investigated on the quantity and quality of sugar beet seed (variety 7233) under furrow and trickle irrigation. The experiment had split plot design in completely randomized blocks, adopting split factorial with three replications. ...
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In this study, combined effects of nitrogen and phosphorus were investigated on the quantity and quality of sugar beet seed (variety 7233) under furrow and trickle irrigation. The experiment had split plot design in completely randomized blocks, adopting split factorial with three replications. The main plots were allocated to the two irrigation methods i.e. furrow and trickle (tape) irrigation systems, while the sub plots included 4 nitrogen levels (0, 60, 120, 180 kg/ha) and 3 phosphorus levels (0, 30, 60 kg/ha). The project was conducted at the Ekbatan station of the Agricultural Research Center of Hamedan in 2003- 04.The results of combined analysis showed that the effect of different treatments of N on the quantity of sugar beet seed yield was significant (α =%1).The effects of irrigation method, N, P, and their interactions were not significant on the percentage of the standard seeds. The interaction effect of irrigation method and N as well as the interaction effect of irrigation, P, and environment (year) on seed germination were significant. The results showed that increasing N application up to 88.5 kg/ha increased the amount of standard seed size, whereas higher amounts decreased the standard seed size. With increasing nitrogen fertilizer up to 120 kg, seed germination increased in trickle irrigation. The averages of yield under drip (tape) and furrow irrigation system were 2360 and 2210 kg/ha, respectively. But, with increasing phosphorus rate, changes in the germination percentage under both irrigation methods were not significant. The amount of water use efficiency increased with increase in nitrogen rate, and the difference between different treatments was significant (α =%1). Compared with furrow irrigation, tape irrigation reduced water consumption by about 50 percent. The amount of water use efficiency in trickle irrigation was 0.59 kg.m-3, more than twice the WUE in the furrows. Changing the irrigation method from furrow to trickle irrigation increased net income by about 18.6 million rails. The net value during 15 years was calculated at about 457.3 million Rials. Considering the internal rate of return (43.5%) and the benefit: cost ratio of 1.6, use of drip irrigation for production of sugar beet seed is economical.
Research Paper
Mohiaddin Gousheh; s ghalebi
Abstract
Basically, sever ecological features of Khuzestan Plain such as soil salinity, saline water resources, shallow watertable, heavy clay soils, poor drainage and high temperature as well as significant evaporation rates intensify reductions in crop yield, spacially in cases of inappropriate irrigation regime. ...
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Basically, sever ecological features of Khuzestan Plain such as soil salinity, saline water resources, shallow watertable, heavy clay soils, poor drainage and high temperature as well as significant evaporation rates intensify reductions in crop yield, spacially in cases of inappropriate irrigation regime. Besides, saline water is utilized to irrigate crops as an inevitable alternative of scarcely available fresh water resources. In order to cope with drought and salt stresses, an experiment was carried out to investigate the effects of soil salinity on grain yield of spring wheat (Triticum aestivum L.) at three irrigation frequencies, with 30%, 50% and 70% plant available water (PAW), and at three salinity levels of irrigation water (≤2, 3-5, and 6-8 dS.m-1), during 2006-09. Based on the results, electrical conductivity of 5 dS.m-1 could be preferentially recommended for irrigating wheat at studied intervals providing 30% PAW without any significant yield loss under the experimental conditions. Irrigation water with electrical conductivity of 6-8 dS.m-1 substantially reduced the grain yield at all irrigation intervals.
Research Paper
s heshmati; h beigi
Abstract
Groundwater is the only important water resource for irrigation in the Shahrekord plain. Due to over-extraction, the water-table is continuously declining. Drip irrigation has the potential to save water. The main aim of this research was to ...
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Groundwater is the only important water resource for irrigation in the Shahrekord plain. Due to over-extraction, the water-table is continuously declining. Drip irrigation has the potential to save water. The main aim of this research was to investigate the spatial variability and mapping of irrigation water quality of the Shahrekord aquifer. Ninety-seven agricultural wells were sampled three times during 2010 and samples were analyzed. Electrical conductivity (EC), total dissolved solids (TDS), total suspended solids (TSS), and pH were measured and the Langelier index (LI), sodium adsorption ratio (SAR), permeability index (PI), residual sodium carbonate (RSC) and sodium percent (Na%) of each sample were calculated from the measured parameters. The averages of the three samples have been presented here. The mean EC and TDS were 456 µS/cm and 296 mg/l, respectively, placing the groundwater in, respectively, good and relatively good classes for irrigation. According to Wilcox's diagram, almost all groundwater samples were designated as C2S1. Shahrekord groundwater is suitable for irrigation based on Na%, RSC and PI, too. Based on mean pH and TSS of, respectively, 7.6 and 70 mg/l, Shahrekord groundwater has medium potential for dripper clogging. Spatial variability of EC and TDS was best described with a Gaussian model while the other parameters were best described with spherical models. Comparison of the observed and mapped correlations indicated the suitability of the selected variograms and the Kriging method for mapping of parameters. Maps showed that the values of measured and calculated parameters were higher in the southern part of the aquifer. Based on the EC map, the groundwater in most parts, except the southern part of the aquifer, was classified as good and very good. Only in the south of the aquifer did TSS reach 512 mg/l, indicating a medium physical clogging potential in drip irrigation. The pH and TSS maps indicated a medium potential for clogging of drippers, generally across the aquifer. At the same time, the Langelier index across the aquifer was generally negative, indicating the suitability for drip irrigation. The positive LI in some areas of the aquifer may be due to the existence of carbonatic formations and their solubility.
Research Paper
a darzi; m mirlatifi; a shahnazari; f ejlali; m mahdian
Abstract
Proper water management in paddy fields is the most important operations that plays a fundamental role in the usefulness of other inputs in rice cultivation. Construction of drainage systems is very essential for improving water management in paddy fields. The effect of different drainage systems including ...
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Proper water management in paddy fields is the most important operations that plays a fundamental role in the usefulness of other inputs in rice cultivation. Construction of drainage systems is very essential for improving water management in paddy fields. The effect of different drainage systems including three conventional subsurface drainage systems, a bi-level subsurface drainage system, and surface drainage system on the yield of Tarom rice cultivar were compared at the improved and consolidated paddy fields of Sari Agricultural Sciences and Natural Resources University. The experiment was conducted in a randomized complete block design with 5 treatments. At the harvesting time, some crop indices such as plant height, flag leaf length, main panicle length, tillering number, number of lateral branches of the main panicle, straw yield, biological yield, grain yield, and harvest index were determined. Statistical analysisrevealed that many of the determined indices in subsurface drainage treatments were significantly different than those of the control treatment. The grain yield of subsurface drainage treatments was 0.91-1.65 t/ha greater than that of surface drainage treatment. The maximum tillering number, plant height, grain yield, and straw yield belonged to the bi-level drainage plots, while surface drainage treatment had the lowest values for these parameters.
Research Paper
j nikbakht; m taheri; m sakaki
Abstract
To evaluate deficit irrigation effect on quantity and quality characteristics of olive fruit (Olea europaea L. cv. Koronaiki), this study was carried out in 2009 in Gilvan (49o 5¢ E longitude, 36o 47¢ N latitude, and elevation 330 m above sea level) located in Tarom region in Zanjan province, ...
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To evaluate deficit irrigation effect on quantity and quality characteristics of olive fruit (Olea europaea L. cv. Koronaiki), this study was carried out in 2009 in Gilvan (49o 5¢ E longitude, 36o 47¢ N latitude, and elevation 330 m above sea level) located in Tarom region in Zanjan province, Iran. Soil texture of the farm was loam. The experimental design was randomized complete blocks with 4 replications. The irrigation treatments were T1, =100% (control treatment), T2= 75%, T3= 50%, and T4= 25 % of olive water requirement (OWR). Trees were watered by drip irrigation system with loop layout. OWR was calculated based on Gilvan synoptic weather station data and FAO Penman-Monteith equation and the FAO-56 recommended crop coefficient.
Based on the results, the effect of deficit irrigation on percentage of fruit oil, ratio of fruit length to diameter, percentage of complete flowers, and percentage of secondary fruits were significant at 1% probability, while the effects on percentage of primary fruits produced were significant at 5% probability. However, deficit irrigation effects on the percentage of fruits dry mass and pulp/pit ratio were not significant. The results showed that the percentage of complete flower produced in T4 was the least (42%). Deficit irrigation caused significant difference (P=5%) between T1 and the other treatments in terms of percentage of primary fruits produced (about 31% difference). Also, deficit irrigation caused differences between percentage of the primary and secondary fruits in T4. Based on the results, difference in ratio of fruit length to diameter between T1 and deficit irrigation treatments were significant (P=5%). Therefore, deficit irrigation was not suggested for cannery objectives. The maximum content of fruit oil (28.49%) and the least content (22.73 %) were obtained from 75% and 25% OWR treatments, respectively. Therefore, in the research site, to irrigate olive trees cv. Koroneiki, 25% continuous deficit irrigation (irrigation with 75% OWR) is suggested in order to save on water use.
Research Paper
h ramezani; a liaghat; m parsinejad; m ramezani
Abstract
Agricultural drought occurs when soil moisture is less than that required for the optimized production and damages crop yield. Drought indexes are used for monitoring purposes and in some of these indicators rainfall data are used. But, agricultural droughts indexes use soil moisture data. ...
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Agricultural drought occurs when soil moisture is less than that required for the optimized production and damages crop yield. Drought indexes are used for monitoring purposes and in some of these indicators rainfall data are used. But, agricultural droughts indexes use soil moisture data. Among the most important drought indexes that use soil moisture as input parameter, soil moisture drought index (SMDI) can be noted. Generally, mathematical models are used for soil moisture estimation. The objective of this study was to estimate soil moisture using AquaCrop model and to calculate SMDI with this estimation and compare it with the rainfall-based drought indexes such as PNI, DI, SPI and CZI, using Qazvin synoptic station data of 1982-2008. The results of soil moisture estimation using AquaCrop showed that monthly changes in soil moisture at 5 cm depth were very strong. With increasing depth, soil moisture changes were less and remained constant after 40 cm of depth. Average values of SMDI, PNI, DI, SPI and CZI were, respectively, 0.41.2, 10026.2, 0.042.6, 0.01.0, and 0.01.0. Based on SMDI, the wettest year was 1994 while the driest years were 1997, 1999 and 2008. But, based on other indexes, the wettest and driest years were 1982 and 2008. The main point for SMDI is that, in addition to the current season soil moisture conditions, the index uses soil moisture conditions of the previous year to calculate SMDI. According to our results, SMDI had low coefficient of determination with the other drought indexes, rain, and evaporation.
Research Paper
a yadollahi; n teymouri; v abdousi; s sarikhani
Abstract
Considering the arid and semi-arid conditions in Iran, with average rainfall of less than 247mm, development of rainfed orchards has an important role in sustainable development of agriculture. To establish rainfed orchards in Iran in spite of deficiency in water resources, it is necessary to select ...
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Considering the arid and semi-arid conditions in Iran, with average rainfall of less than 247mm, development of rainfed orchards has an important role in sustainable development of agriculture. To establish rainfed orchards in Iran in spite of deficiency in water resources, it is necessary to select suitable plant species and methods of establishing new orchards. Therefore, this study was conducted to evaluate some almond cultivars (Shahrood 7, 10, and 12) and integration of microcatchments and Stockosorb Superabsorbent for establishing rainfed orchards during 2008-2010. The use of Superabsorbent with microcatchment increased relative moisture content of soil in both years. But, in the first year, there was no significant difference between microcatchment treatments with and without Superabsorbent, while both of them showed significant difference with the treatment of Superabsorbent without microcatchment. In the second year, the highest relative moisture content of soil was in microcatchment treatment with Superabsorbent, because of higher seasonal rainfall that caused more vegetative growth in the young almond trees in that treatment compared to the other treatments. Among the almond cultivars studied, Shahrood 7 and 12 seemed more resistant and adaptable to dry conditions than Shahrood 10 cultivar, because of their better vegetative characteristics.
Research Paper
f ejlali; m tavasoli; a asgari
Abstract
Rice, as a main and strategic food, is cultivated in traditional paddies of MazandaranProvince with hard work, high cost, and low yield. Considering the share of this province in national rice production and its important role in view of socio-economic aspects, implementation of paddy fields consolidation ...
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Rice, as a main and strategic food, is cultivated in traditional paddies of MazandaranProvince with hard work, high cost, and low yield. Considering the share of this province in national rice production and its important role in view of socio-economic aspects, implementation of paddy fields consolidation projects is essential to obtain optimum use of soil, water, and labor, and to improve management and productivity of paddy fields. Inasmuch as implementation of such projects as the main infrastructure for increasing rice production requires huge investment, awareness of their performance is essential. In the present research, the characteristics of consolidated paddy fields were compared with those of traditional ones. Based on the results, implementation of this project in the study area increased rice yield per unit area by about 355.7 kg/ha while decreasing one third of the labor requirement.
Research Paper
f dehghani; r r; m.j malakouti; saeed saadat
Abstract
Calcium and magnesium ions are two plant nutrients and are omnipresent in all natural systems. Calcium to magnesium ratio (Ca:Mg) is an important factor in evaluation of water quality for irrigation. A Ca: Mg ratio of less than unity, in particular in saline condition, adversely affects soil physico-chemical ...
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Calcium and magnesium ions are two plant nutrients and are omnipresent in all natural systems. Calcium to magnesium ratio (Ca:Mg) is an important factor in evaluation of water quality for irrigation. A Ca: Mg ratio of less than unity, in particular in saline condition, adversely affects soil physico-chemical characteristics, and could decrease plant yield through nutritional imbalance. Frequent drought and groundwater over-draft have lowered groundwater level and its quality severely, including increase in salinity and, in many cases, relative increase in magnesium ion concentration. In order to assess distribution and changes in Ca:Mg ratio, laboratory analysis data of more than 6200 irrigation water samples were collected from 11 provinces. Data analysis revealed that Ca:Mg ratio was less than unity in about 55% of the samples. It was also found that increase in salinity had a significant correlation with Ca and Mg ions concentrations, but had no relation with their ratio. Correlation analysis indicated that maximum correlation was between Na ion concentration and salinity (R2= 0.86), and 60% of Ca and Mg variation could be explained with variation in salinity. However, no significant relation was found between salinity and Ca:Mg ratio. Using such irrigation water gradually increases exchangeable Mg ion and decreases soil quality (degradation of soil structure and lowering infiltration rate), and causes plant nutritional disorder. Consequently, more detailed assessment of these waters and their effects on soil and plant is enormously important from both economic and environmental points of view.