Research Paper
H B; A A; A KH
Abstract
In order to investigate the effect of irrigation and straw mulch on yield andyield components of bean, a split-plots experiment with randomizedcomplete block design in three replications was conducted in AstanehAshrafiyeh city during 2012. In this study, irrigation managementtreatments including ...
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In order to investigate the effect of irrigation and straw mulch on yield andyield components of bean, a split-plots experiment with randomizedcomplete block design in three replications was conducted in AstanehAshrafiyeh city during 2012. In this study, irrigation managementtreatments including no irrigation, irrigation frequencies of 6, 12, and18days, and different amounts of straw mulch as 0, 1, 2, and 3 cm thicknesswere examined. The results of the analysis of variance revealed thatirrigation management and different levels of mulch had significant effectson seed yield. But, their interaction was not significant on seed yield. Thetrend of variations indicated that the highest seed yield with 2431.3 kg ha-1was associated with irrigation frequency of 6 days. [n response to the maineffects of mulch levels, the highest average seed yield (1585.6 and 1518.4kg ha-1) was obtained in the 2 and 1 cm treatments, respectively. Also,using straw mulch in irrigation conditions prevented severe seed loss incomparison with no mulch condition. The highest water use efficiencywas in irrigation frequency of 18 days with an average of 0.58 kg m-3.Water use efficiency at straw mulch levels of 1 and 2 cm was observed as0.63 and 0.6 kg m-3, respectively.
Research Paper
M S; M GH; M B
Abstract
To study the effects of industrial effluents on accumulation of heavy metals in soil and cultivated canola, the farms irrigated with the wastewater of Amol Industrial City were selected and samples of wastewater, irrigation water, soil, roots, stems, leaves, and grains of canola were collected. Then, ...
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To study the effects of industrial effluents on accumulation of heavy metals in soil and cultivated canola, the farms irrigated with the wastewater of Amol Industrial City were selected and samples of wastewater, irrigation water, soil, roots, stems, leaves, and grains of canola were collected. Then, the amount of chromium, cadmium, nickel and lead in samples of soil, water and canola organs were determined. The data were analyzed based on statistical factorial analysis in complete randomized block design. Mixing of industrial wastewater with irrigation water increased concentrations of chromium, cadmium, nickel and lead in irrigation water. pH of irrigation water decreased under the effect of industrial wastewater, although EC increased. Industrial wastewater also increased the accumulation of heavy metals in soil. Accumulation of available chromium was affected by wastewater in locations 1, 2, and 3, increasing to 0.11, 0.14 and 0.13 mg/kg, respectively. Accumulation of elements in the surface layer (0-20 cm) of soil was more than the subsurface (20-40 cm). Amounts of total and available cadmium in surface layer of soil in the control site were 1.07 and 0.1 mg/kg, which was affected by wastewater, with the greatest increase in the third location reaching 1.48 and 0.16 mg/kg. Also, nickel and lead increased by wastewater. Accumulation of Cr, Cd, Ni, and Pb in rapeseed organs increased by wastewater application. Accumulation of Cr in leaves and shoot of canola in the second location increased by, respectively, 57.45% [S1] and 2.62 times compared to the control. Transfer factor of metals from soil to shoot was more than the other organs. Accumulation of chromium and nickel in canola leaves exceeded the permissible level. Risk Index of the investigated elements in canola grain increased by irrigation with industrial wastewater. Accumulation of cadmium in canola grain reached dangerous levels. [S1]با متن فارسی مقایسه کنید.
Research Paper
A GH; A SH; M R; H Z
Abstract
Deficit irrigation, as a limiting factor for growth, will affect physiological characteristics of plants. In order to investigate the effects of deficit irrigation on yield, chlorophyll fluorescence, dry weight of stems and leaves, and leaf area index of sunflower, this study was performed at the research ...
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Deficit irrigation, as a limiting factor for growth, will affect physiological characteristics of plants. In order to investigate the effects of deficit irrigation on yield, chlorophyll fluorescence, dry weight of stems and leaves, and leaf area index of sunflower, this study was performed at the research farm of Agriculture and Natural Resources University of, Sari, Iran, in 2013. The experimental treatments were arranged as randomized complete block design with three replications. The irrigation regimes consisted of full irrigation (FI), regulated deficit (DI75, DI55), and partial root-zone drying irrigation (PRD75, PRD55). The results indicated that the effect of irrigation treatments on yield, photosynthetic efficiency, maximum fluorescence (Fm), minimum fluorescence (Fo), leaf area index, shoot dry weight, leaf dry weight, and head dry weight was significant. Comparison showed that water stress significantly decreased grain yield, photosynthetic efficiency index and maximum fluorescence (Fm), whereas the minimum fluorescence (Fo) was increased. The maximum seed yield (5148 kg ha-1) was attained in full irrigation treatment and had no difference with PRD75 treatment. The maximum leaf area index at the end of the growing season was 4.3 and recorded in FI and had no difference with PRD75, DI75 and PRD55. Overall, treatment PRD75 is recommended since it reduced water consumption by 16.8 percent relative to FI treatment and had no significant difference with full irrigation treatments (FI) in terms of seed yield, quantum yield, and other growth parameters.
Research Paper
H D; A A; K E; H N
Abstract
Drought stress is one of the main problems regarding agricultural productions throughout the world, especially in arid and semi-arid regions like Iran. Manyresearchers studies various effects of drough stress on root and shoot parts of crop. But, there is not more information about root growth of tomato. ...
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Drought stress is one of the main problems regarding agricultural productions throughout the world, especially in arid and semi-arid regions like Iran. Manyresearchers studies various effects of drough stress on root and shoot parts of crop. But, there is not more information about root growth of tomato. In this study, the effect of drought stress on root growth, yield and yield components of tomato was investigated under greenhouse conditions. The experimental design was a randomized block design with four irrigation treatments comprising 100%, 80%, 60% and 40% of water requirement in three replications. Fruit weight, diameter and quantity, dry weight of shoot part, root volume, wet weight of root, dry weight of root and root length were measured at the end of growing season. Generally, drought stress had significant effect (p<0.01) on yield, yield components and root attributes of tomato. Themaximum fruit weight (602.53 g), fruit quantity (9.33), diameter (4.86 cm), dry weight of shoot part (127.64 g), root volume (0.38 L), wet weight of root (268.97 g), dry weight of root (24.25 g), root length (239386 cm) and root area (33860 cm2) was corresponded to 100% water requirement treatment. In general, the results showed . The root volumehadmaximum correlated with yield and yield components of tomato.
Research Paper
B H; S B; A N
Abstract
The water crisis and the increase in population necessitate improvement of efficiency of water use. Application of new methods of irrigation and irrigation management is a way to optimize the use of available water resources. In order to study effect of different deficit irrigation managements of potato ...
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The water crisis and the increase in population necessitate improvement of efficiency of water use. Application of new methods of irrigation and irrigation management is a way to optimize the use of available water resources. In order to study effect of different deficit irrigation managements of potato in furrow and tape drip irrigation methods on water use productivity and yield of potato, an experiment was performed at Chahar Mahal va Bakhtiari Research Farm of Agricultural and Natural Resources Research Center in 2013. The experiment was based on randomized complete blocks with split-split plot design with three replications. The furrow and tape drip irrigation methods were allocated to the main plots, while the two potato cultivars were in the sub-plots and four deficit irrigation managements including FI(100%), RDI80(80%), RDI65(65%) of available water depletion (AWD), and partial root-zone drying (PRD) during full growth period were in the secondary sub-plots. Analysis of variance showed that there were significant (P≤0.01) differences between deficit irrigation managements for tubers yield, tubers percentage of dry matter, number of tuber per plant and water productivity. Drip irrigation in comparison with furrow irrigation resulted in reduction of irrigation water amount (40%), increase in yield (10%), agronomic water productivity (43%), and economical water productivity (40%). The highest economical water productivity (73240 Rials/m3) belonged to partial root-zone drying (PRD). Due to the limitation of water resources, the best suggestion for optimizing water use is using tape irrigation and deficit irrigation management through partial root-zone drying (PRD) for producing potato.
Research Paper
A O; A S
Abstract
Various tillage systems have different degrading and or beneficial effects on soil structure and aggregates of top layers and, thus, affect infiltration characteristic especially the infiltration rate and the slope of infiltration equation. The objective of this study was to evaluate the effect of tillage ...
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Various tillage systems have different degrading and or beneficial effects on soil structure and aggregates of top layers and, thus, affect infiltration characteristic especially the infiltration rate and the slope of infiltration equation. The objective of this study was to evaluate the effect of tillage method and depth on infiltration, penetration resistance, plant available water, and crop yield in Tabriz plain in a clayey textured soil. In this study, four treatments including A1 (chisel plowing at 20 cm depth), A2 (moldboard plowing at 20 cm depth), A3 (moldboard plowing at 30 cm depth) and A4 (no tillage) were compared in three replications using a randomized complete block design. Results indicated that there was significant difference between treatments in infiltration rate at different time increments (1, 2, 5, 10, 30, 60, 120 and 180 min). Based on the slope of infiltration equations, the infiltration rate in A1 decreased more rapidly than the other treatments. Initial infiltration rate in A3 (482.8 mm hr-1) was higher than the other treatments, but differences between the other treatments were not significant. This difference may be attributed to tillage depth. Infiltration rate in A3 was higher than the other treatments but its preference in comparison with A4 (no tillage) just extended until 60 min and then declined rapidly. This result shows that the layer below the tillage depth controls infiltration rate after about 1.5 hr. In all the four measured layers (0-10, 10-20, 20-30 and 30-40 cm), A3 and A4 had the minimum and maximum penetration resistance, respectively. Effect of tillage treatments on plant available water and crop yield was not significant.
Research Paper
A M
Abstract
Reference crop evapotranspiration (ETref) is measured directly (lysimetermethod) or estimated indirectly (mathematical models). In this study, dailyevapotranspiration (ET) was calculated by some mathematical models foralfalfa and was compared with ET data gathered daily from a drainagelysimeter during ...
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Reference crop evapotranspiration (ETref) is measured directly (lysimetermethod) or estimated indirectly (mathematical models). In this study, dailyevapotranspiration (ET) was calculated by some mathematical models foralfalfa and was compared with ET data gathered daily from a drainagelysimeter during six months. To evaluate and select the best model, ETdata values were compared using statistical criteria including R2, NRMSE,MAE, MBE, and d. Results showed that the best models in the daily timeframewere: Hargreaves-Samani (HS), Jensen-Haise (JH) and Turc. Forthe HS model, values of NRMSE and d were 0.126 and 0.930, and MAEwas 0.477 (mm.d-1), respectively. The best models for monthly time-framewere HS, American Society of Civil Engineering-Penman-Monteith(ASCE-PM), and Turc. Generally, HS model had the highest R2 values of0.985, 0.998 and 0.998 for daily and monthly periods, respectively, andASCE-PM had the lowest MBE compared to lysimeter data. To estimatetotal ET during the alfalfa growth period in the Shahrekord plain, resultsshowed that, models have over-estimated, except Turc and Priestley –Taylor models. ASCE-PM had the nearest ET (1161.7 mm) to lysimeterdata (1157.6 mm). In the national document of irrigation, the alfalfairrigation water requirement was reported at 649 mm (in the correspondingperiod), which is much less than the value measured.
Research Paper
M Y; S B; Z I; H S
Abstract
Accurate estimation of evapotranspiration plays an important role inquantification of the water balance at regional scale for better planningand managing water resources. Evapotranspiration can be obtained fromeither estimation of potential ET using data of meteorological stations or,directly, from field ...
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Accurate estimation of evapotranspiration plays an important role inquantification of the water balance at regional scale for better planningand managing water resources. Evapotranspiration can be obtained fromeither estimation of potential ET using data of meteorological stations or,directly, from field measurements. ET is subject to rapid changes in timeand space, attributable to the wide spatial variability of precipitation,hydraulic characteristics of soils, and vegetation types and densities.Therefore, it is nearly impossible to determine its spatial and temporaldistributions over large areas only from lysimeter and precise measuringinstruments. Thus, researchers have used remote sensing data to estimateareal actual ET. In this study, actual evapotranspiration variations ofNeyshabour plain was investigated by algorithm of energy balance of theearth since 2000 to 2013 by using MODIS images and meteorologicaldata. Also, the determined evapotranspiration was compared and evaluatedwith Penman-Monteith and Hargreaves-Samani models. Low amount ofcoefficients of the error between Penman-Monteith model and SEBALalgorithm showed the accuracy of SEBAL model in the estimation ofevapotranspiration and its parameters. The results derived fromcomparison of evapotranspiration and NDVI vegetation index indicated agood correlation between vegetation and evapotranspiration (R2=0.908).Also, the variations of NDVI index, land surface temperature, andevapotranspiration in the studied fields showed that evapotranspirationincreased by lower land surface temperature and higher densities ofvegetation.
Research Paper
F A; S A; K KH; J B
Abstract
Evapotranspiration is one of the important components of hydrologicalcycle whose accurate estimate is needed for design and management ofirrigation systems, simulation of crops products, and programming waterresources management. In this research, to predict monthly referenceevapotranspiration, ANFIS ...
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Evapotranspiration is one of the important components of hydrologicalcycle whose accurate estimate is needed for design and management ofirrigation systems, simulation of crops products, and programming waterresources management. In this research, to predict monthly referenceevapotranspiration, ANFIS and GP models were employed and 38 years(1973-2010) of data were collected from six synoptic weather stationslocated in the northwest of Iran. At first, monthly referenceevapotranspiration was estimated by FAO-Penman-Montieth method forthe selected stations and was considered as the output of GP and ANFISmodels. Then, a regression equation between effective meteorologicalparameters and evapotranspiration was fitted and different input patternsfor the models were determined. Relative humidity as the less effectiveparameter was deleted from input of the models. Also, in this study, toinvestigate effect of “memory” on prediction of evapotranspiration, one,two, three and four months lags were used as the input of the models.Results showed that both models estimated monthly evapotranspirationwith high accuracy, but ANFIS model was better than GP model.
Research Paper
M Z; M GH; A H
Abstract
Recently, use of synthetic materials has increased in irrigation and drainage projects due to their environmental advantages. Also, use of geotextile and PLM has been considered in drainage projects instead of granular envelopes. This study was conducted to evaluate the efficiency of geocomposite envelope-drain ...
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Recently, use of synthetic materials has increased in irrigation and drainage projects due to their environmental advantages. Also, use of geotextile and PLM has been considered in drainage projects instead of granular envelopes. This study was conducted to evaluate the efficiency of geocomposite envelope-drain to reduce water-table levels. To simulate natural conditions of a drained land in the laboratory, a soil and sand tank was used that simulated part of a drainage trench in addition to adjusting the height of water table. Three envelope-drains with different geotextile envelope and drainage pipes with granular and PLM (PP450 type) envelopes were tested. In this study, the perimeter of drainage pipe and envelope-drains was equal. The results of this study showed that the performance of envelope-drain in draining excess soil water and lowering water table was similar to the drainage pipe with granular envelope. Under hydraulic head of 110 cm, in the center of the drain, drop in the water surface profile of geocomposite envelope-drain was 14.3% lower than the drainage pipe with granular envelope. By increasing the horizontal distance to the drains, drop in the water table profile of geocomposite envelope-drain was 9.8% lower than the drainage pipe with granular envelope.
Research Paper
A H; A E; H S
Abstract
In on-farm development projects, implementation of subsurface drainagesystem is one of the most important issues. Considering the high costs ofpreparing mineral envelope for subsurface drain pipes, continued executionof such projects, especially in Khuzestan province, has faced somedifficulties. To overcome ...
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In on-farm development projects, implementation of subsurface drainagesystem is one of the most important issues. Considering the high costs ofpreparing mineral envelope for subsurface drain pipes, continued executionof such projects, especially in Khuzestan province, has faced somedifficulties. To overcome such a problem, use of synthetic envelopes or,where soil characteristics allow, subsurface drainage without using envelopemay also be an option. Thus, in this research, in an experimental field of 20ha under wheat in Shadegan region (Khuzestan province), the performance ofsubsurface drainage without using envelope was compared with theconventional drainage by mineral envelope. Each experimental unit had fivesubsurface drain pipes (laterals) spaced at 50 m and installed at depth of1.7m, with a length of 220 m. To study water table condition, somepiezometers were installed perpendicular to the middle laterals of each unit.Also, the rates of drains discharge and drainage water quality of the middlelaterals in each unit were measured in manholes constructed on them. Themaximum salinity of drainage water from drains with mineral envelope(replicates 1 and 2) and drains without envelope were 36.9, 52.1, and 47dS/m, respectively, and the minimum salinities were 25.7, 23.6 and 12.6dS/m. The maximum drain discharge in the first replication of mineralenvelope was 0.59 lit/sec, and for the second one was 0.28 lit/sec and in thedrains with no envelope was 0.23 lit/sec. Investigation of Salt Exit Index(SEI) of soil showed that salt leaching continued during the wheat growingseason. Results of drains discharge showed the acceptable operation of drainswithout envelope and proper performance of drains with mineral envelopeduring the growing season. No sediment discharge was observed in anytreatment.