Research Paper
N V; E GH
Abstract
In order to evaluate drought tolerance of some genotypes of indeterminite soybean in Uromia, a field experiment using randomized complete block design with split plots was conducted in three replications at Research Farm of Uromia Agricultural High School during 2012. The main plots were allocated ...
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In order to evaluate drought tolerance of some genotypes of indeterminite soybean in Uromia, a field experiment using randomized complete block design with split plots was conducted in three replications at Research Farm of Uromia Agricultural High School during 2012. The main plots were allocated to three levels of drought stress including: no tension i.e. irigation after every 60 mm evaporation from Class A pan; moderate drought stress with irrigation after 110 mm evaporation and severe drought stress, irrigation after 160 mm evapration). Also, three soybean genotypes (Clark, Wiliyams, and Anion) were planted in the sub-plots. Five drought tolerance indices including stress susceptibility index (SSI), stress tolerance index (STI), tolerance index (TOL), Mean Productivity (MP) and geometric mean productivity index (GMP) were calculated based on grain yield in normal and stress conditions. Stress intensity (SI) for mild and severe stress was, respectively, 0.44 and 0.62. The lowest indexes of SSI and TOL in both stress conditions was related to the genotype Williams. Under irrigation after 160 mm evaporation and based on MP, GMP, and STI indices, genotype Williams had the lowest rank and was sensitive to drought stress. In this experiment, under mild and severe drought stress conditions, genotype Anion had the highest MP, GMP, and STI indices, therefore, it was recognized as drought tolerant compared with the other genotypes.
Research Paper
m t; m a; n d; n e
Abstract
This study was carried out to investigate the effects of different irrigation regimes and planting methods on yield, yield components, morphological traits, and storage characteristics of a local onion cultivar, namely, Goli Ghesse. The experiment was conducted as a factorial split plot design with RCBD ...
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This study was carried out to investigate the effects of different irrigation regimes and planting methods on yield, yield components, morphological traits, and storage characteristics of a local onion cultivar, namely, Goli Ghesse. The experiment was conducted as a factorial split plot design with RCBD arrangement in four replications and for three years at Kheirabad Research Station. Irrigation intervals were allocated to the main plots and planting methods were studied in the sub plots. Irrigations were initiated after 40, 70, 100 and 130 mm cumulative evaporation in treatment E1, E2, E3 and E4, respectively. Two planting methods consisting of direct seeding and transplanting were used in this experiment. Seasonal and combined analysis of variance was done and means were compared using Duncan's multiples rang tests. Combined analysis showed that there was significant difference at 5% confidence level among treatments. Assessing effect of different irrigation intervals on average yield revealed that bulb yield in direct planting was 45.54 t/ha, which was 0.6 t/ha more than transplanting method, but this was not significant. Also, results showed that the highest bulb yield (60.8 t/ha) was obtained from E1. In comparison, treatments E2 to E4 had 48.88, 40.23, and 32.21 t/ha bulb yield and were in statistical groups of b, c, and d, respectively. But, cultivation method had no significant effect on yield at 5% probability level. .Effect of planting method on water use efficiency was significant at 5% level and the highest amount was obtained from transplanting method with 10.295 kg onion bulb/m3. Thus, irrigation interval after 70 mm evaporation from Class A pan and transplanting are recommended for Zanjan and other regions with similar climate and soil conditions.
Research Paper
p m; t t; a sh
Abstract
There are different materials and compounds in water that determine its chemical and physical quality. As the result of special conditions such as increase and decrease in discharge, water quality can vary. One of these conditions is drought that decreases discharge, and water quality changes. In this ...
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There are different materials and compounds in water that determine its chemical and physical quality. As the result of special conditions such as increase and decrease in discharge, water quality can vary. One of these conditions is drought that decreases discharge, and water quality changes. In this study, droughts of Sistan and Baluchistan province have been analyzed using Standardized Precipitation Index (SPI). On the basis of this index, Sistan and Baluchistan province has experienced alternately different droughts with various intensities in the studied period (1976-2005). Most droughts have been classified as weak with a frequency of 26.7 percent and medium droughts with 20 percent frequency. Then, dry and wet years were identified. Finally, the period of 2000-2004 were selected as representative of dry years. In respect to water quality, results of 4 hydrometrics station for Sianchah, Hirmand, Bampur, and Bahokalat rivers were studied for a period of 10 years (1997-2006). Most changes in cations and anions concentrations were observed at Payab-e- Kohak Dam hydrometric stations, which were about 22 percent. EC also changed in drought index period as compared with long–term average, increasing in Payab–e- Kohak Dam, Daman, Ladiz and Pirdan hydrometeric stations by 12.7%, 2.5%, 0.95%, and 0.03%, respectively. In fact, decrease in river base flow and temperature increase caused increase in EC in drought period. Also, SAR increased in all of the studied stations by about 5.5 percent in the drought period.
Research Paper
r a
Abstract
In order to investigate the effect of domestic wastewater and normal water (well water) on soil chemical properties and alfalfa yield, a research project was conducted for three years in Chahartakhteh Research Station. The experiment was performed in randomized complete blocks design including four treatments ...
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In order to investigate the effect of domestic wastewater and normal water (well water) on soil chemical properties and alfalfa yield, a research project was conducted for three years in Chahartakhteh Research Station. The experiment was performed in randomized complete blocks design including four treatments in three replications. Treatments were as follows: T1: Irrigation with normal water at farmers’ conventional amount; T2: Irrigation with treated wastewater at farmers’ conventional amount; T3: Irrigation with normal water to meet plant water requirement, T4: Irrigation with treated wastewater to meet plant water requirement. The results showed that there were no heavy element in the soil and plants tested, but concentration of elements such as N, P, K, Na, and CI were increased in the plant, and also in 0-30 cm soil depth. However, electrical conductivity, available phosphorus, soluble sodium, magnesium and calcium increased in the treatments using wastewater. Also, in 30-60 cm soil depth, pH, electrical conductivity, total nitrogen and concentration of available iron, copper and sodium increased significantly (p <0.05). Crop yield increased through years of performing the study and results showed that alfalfa mean wet yield was 20367, 28992, 22138, and 29324 kg/ha for T1 to T4 treatments, respectively, while treatment no. 4 had the highest yield. Alfalfa wet yields in treatments irrigated with wastewater were higher than those using normal water (29158 and 21252.5 kg per ha, respectively). In general, results showed that use of effluent of treated domestic wastewater increased crop yield.
Research Paper
f k; o t
Abstract
Population growth as well as global fresh water shortage problem have necessitated the use of unconventional water resources in agricultural sector, as the largest consumer of fresh water, especially in arid and semi-arid regions. In this study, the effect of four irrigation methods on yield, uptake ...
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Population growth as well as global fresh water shortage problem have necessitated the use of unconventional water resources in agricultural sector, as the largest consumer of fresh water, especially in arid and semi-arid regions. In this study, the effect of four irrigation methods on yield, uptake of water and important nutrients, and the salt accumulation in soil was investigated using a completly randomized block design. Treatments included irrigation via fixed furrow with fresh water (FF), irrigation with saline water (SS), irrigation via fixed furrow with saline and fresh water (FFS) and irrigation via alternate furrow with saline and fresh water (AFS). Total crop evapotranspiration during the growing season under FF treatment was 901.2 mm, while for AFS, FFS and SS treatments the values were significantly lower by, respectively, 6.3%, 9.9% and 12.3 percent compared to the control treatment. Despite a significant reduction in the total biomass under FFS (6.34 Mg ha-1) and SS (5.17 Mg ha-1) treatments compared with that for FF treatment (7.89 Mg ha-1), a favorable total biomass under AFS (7.7 Mg ha-1) caused, 13.2% and 33.8 percent increase in water use efficiency under AFS treatments compared with those for FFS and SS treatments, respectively. Although applying SS and FFS treatments caused a significant reduction in crop nutrient uptake, no significant reduction was observed in total crop nutrient content between AFS (150.3 N, 129.6 K and 21.4 P, in terms of kg ha-1) and FF (160.9 N, 134.8 K and 21.4 P, kg ha-1) treatments. Salt accumulation in soil under AFS treatment was also lower than those for FFS and SS treatments. Thus, it could be concluded that applying this irrigation method will lead to 6.3 percent reduction in crop water use, supplying 50 percent of crop water demand by saline water resources, and reduction in crop nutrient demand. This would protect the economic and environmental issues in the irrigated agriculture in the study area.
Research Paper
m z; r a; h d
Abstract
Due to limitation of conventional water resources, the use of unconventional water for agriculture is unavoidable. Therefore, in order to investigate the effect of using different amounts of municipal wastewater on yield, yield components and water use efficiency of cotton in drip irrigation systems, ...
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Due to limitation of conventional water resources, the use of unconventional water for agriculture is unavoidable. Therefore, in order to investigate the effect of using different amounts of municipal wastewater on yield, yield components and water use efficiency of cotton in drip irrigation systems, a field experiment was carried out during 2010 and 2011 growing season at experimental farm of Jopar Agriculture and Natural Resources Research Center in Kerman province. The treatments were laid out in split plot with a Randomized Complete Block Design (RCBD) with three replications. The treatments were comprised of three levels of irrigation including 100% (control), 80%, and 60 percent of crop water requirement in the main plot, and two water qualities (groundwater and wastewater) as sub plot, under surface drip irrigation system. The results showed reduction of pH and increment of soil salinity due to the high concentration of elements such as Na and K in the wastewater. Also, comparison of 100 percent with 80 percent of water requirement using wastewater showed a water saving of 1800 m3 ha-1, while water use efficiency was increased 18 percent. However, the same treatment caused a decrease of 1.5%, 2.1%, 2.9%, 15.2%, and 11.6 percent in yield, number of boll, boll weight, plant height, and leaf area index, respectively. Considering the results obtained in this study, to cope with the water shortage in the country and increase water use efficiency, make use of wastewater, and conserve water, applying 20 percent less water than the full crop water requirement of cotton is recommendable in Kerman,.
Research Paper
m sh; s m; gh r; f d
Abstract
In order to investigate the effect of wastewater and compost on transport of heavy metals in a soil column, a factorial experiment based on completely randomized design with three replication was conducted. The variables included three types of water: fresh water (W1), treated wastewater (W2) and a composition ...
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In order to investigate the effect of wastewater and compost on transport of heavy metals in a soil column, a factorial experiment based on completely randomized design with three replication was conducted. The variables included three types of water: fresh water (W1), treated wastewater (W2) and a composition of 50% raw wastewater and 50% fresh water (W3). Besides, four levels of compost were also studied: the control without compost: 0 (C1), 40 (C2), 80 (C3) and 120 (C4) t/ha. Soil sampling was done at three depths: 10 (D1), 40 (D2) and 85 cm (D3). Based on these factors: 12 WiCj treatments, 12 WiDj treatments and 9 CiDj treatments were studied. In this regard, 36 volumetric metal lysimeters (30×30×126 cm) were designed. Soil in the lysimeter had three layers: upper (clay), middle layer (clay loam) and bottom layer (sandy clay loam), respectively. After the preparation of lysimeters, basil was planted in them. After harvesting the basil, soil samples were taken from 10, 40 and 85 cm and amounts of Ni, Pb, Cd, Fe, Cu, Zn and Mn were measured. The results showed that the effects of type of water, level of compost, and soil depth on all of the elements were significant (p< 0.05). The dual and trial interactions effects of the factors (except type of water*compost and depth*water type*compost) were significant (p< 0.05) for all elements. The highest concentration of the elements were observed in the W3 C4 D1. In the W3C4 treatment, rates of Pb (474%), Cd (508%), Cu (550%), Zn (463%) and Fe (411%), and in the C4W2 treatment, rate of Ni (563%) and Mn (570%), were increased compared to the control. Based on the results, to reduce risks of long-term environmental impacts of heavy metals from wastewater and compost application, continuous monitoring of soil and water resources is necessary.
Research Paper
m m; a m; a v
Abstract
In the present study, hydraulic properties of low pressure drip irrigation systems in lateral pipes were evaluated by mathematical model with the aid of experimental data resulting from testing of tubes available in Iran. In this regard, emitters discharge were measured in different initial heads from ...
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In the present study, hydraulic properties of low pressure drip irrigation systems in lateral pipes were evaluated by mathematical model with the aid of experimental data resulting from testing of tubes available in Iran. In this regard, emitters discharge were measured in different initial heads from 0.45 to 1.8 m for laterals with outside diameter of 32 mm with different lengths of 89, 60, 30, and 16 meters and also for laterals with the length of 16 meters and external diameters of 32, 25, 20, and 16 mm. the obtained discharge-head relation was q=1.955h0.8421 with R2 of 0.93. On the basis of the ratio of lateral diameter to its length, two relations were proposed for estimating local loss as a function of Reynolds number with R2 of 0.95 and 0.75. Furthermore, experimental results showed that Colebrook-White relation could be used as a good estimation for friction losses. The model was calibrated and evaluated using experimental data and relations which were obtained from experimental results. The model was used for evaluating the effect of different heads, lateral diameters, and length on emitter discharges, which was not possible to evaluate experimentally. The results revealed that the proper length interval in which the uniformity is more than 80% was 40 to 75 meters for laterals with the external diameter of 16 mm under different heads (from 0.45 to 1.8 meters). This length interval for laterals with external diameters of 20, 25, and 32 mm was 50 to 100 m, 70 to 150 m, and 80 to 180 m, respectively. Finally, a relation was developed for designing low pressure drip irrigation system.
Research Paper
m sh; m b
Abstract
In this research, strategies of agricultural water demand management in arid regions was ranked by the proposed hybrid model (MTAHP) of Analytical Hierarchy Process (AHP) and Modified Technique for Order Preference by Similarity to Ideal Solution (MTOPSIS) methods. The proposed hybrid model (MTAHP) uses ...
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In this research, strategies of agricultural water demand management in arid regions was ranked by the proposed hybrid model (MTAHP) of Analytical Hierarchy Process (AHP) and Modified Technique for Order Preference by Similarity to Ideal Solution (MTOPSIS) methods. The proposed hybrid model (MTAHP) uses the strengths of the AHP and TOPSIS and avoids their weaknesses. For this purpose, the AHP model was used for determining relative weights and consistency ratio assessment and, finally, M-TOPSIS model was used for ranking the strategies. To apply the MTAHP model, 35 Iranian experts in the field of agricultural water management participated in the survey. Model results showed that the best strategy for agricultural water demand management in arid regions was training the farmers. The next ranks of strategies in order were: improvement of cropping pattern, land leveling, modernization of irrigation systems in the region, and using recovered water. The lowest ranks belonged to the trade water strategy and virtual water imports. The results of this research showed that the hybrid model of AHP and MTOPSIS can be used in evaluating and prioritizing the strategies for agricultural water demand management.
Research Paper
r z; h m; p d
Abstract
Drainage pipe installation depth, diameter, and spacing are the important variables in subsurface drainage system design. Different combinations of these variables can be applied depending on the objectives of the design. The objective of this research was to investigate the parameters affecting the ...
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Drainage pipe installation depth, diameter, and spacing are the important variables in subsurface drainage system design. Different combinations of these variables can be applied depending on the objectives of the design. The objective of this research was to investigate the parameters affecting the cost of subsurface drainage construction. To this end, steady state flow through the soil to the pipes was studied from midpoint of drainpipes using the governing equation of Hooghout and an optimization algorithm. Information of 50 ha of Salman Farsi Agro-industrial Corporation, Khuzestan, Iran, from two 25 ha units was used. The results of the optimization model showed that reduction in drainage coefficient reduced drainage construction costs, considerably. Also, reduction in drainpipe installation depth increased drain spacing and decreased costs. And, with increasing water table depth, costs increased.