Research Paper
A KHARAZMI; M MASHAL; GH ZAREI; M VARAVIPOUR
Abstract
The Guelph Permeameter technique (GP) is one of the proper methods for measuring the saturated hydraulic conductivity (Kfs) above the water table. This study was done by Guelph Permeameter model 2800k1 in 20 auger holes at Research Farm of Abourayhan Campus. Soil texture was determined for the Research ...
Read More
The Guelph Permeameter technique (GP) is one of the proper methods for measuring the saturated hydraulic conductivity (Kfs) above the water table. This study was done by Guelph Permeameter model 2800k1 in 20 auger holes at Research Farm of Abourayhan Campus. Soil texture was determined for the Research Farm, using the hydrometer method. Water outlet flow of the permeameter was measured in four phases under constant ponding heads (H) of 5, 10, 15 and 20 cm, respectively. The field saturated hydraulic conductivity (Kfs) and matric flux potential (Øm), based on successful testing and Guelph analysis, were evaluated by different methods. The results indicated that, in heavy soils, increasing submergence depth of H2 relative to H1, is an appropriate solution for reducing the Guelph's two-head analysis failure in soil hydraulic conductivity estimation. In this study, well shape factor (C) was also calculated by five different methods. Later, the effect of the calculated C factor by various methods was studied in Guelph's two-head analysis. The results showed that using unsaturated effect in the calculations lowers the possibility of obtaining negative values of Kfs and Øm in Xiang Solution. Also, there was a very high correlation between Guelph successful two-head analysis when Xiang and Numeral Solutions were used for calculating C factor (r=0.98).
Research Paper
GH RANJBAR; M.J ROUSTA; A.M CHERAGHI
Abstract
To determine the effects of saline water with and without magnetic treatments on seed emergence and yield of wheat, two experiments were conducted in the National Salinity Research Center, Iran. The first experiment was done under controlled environment conditions with day and night temperatures of 25 ...
Read More
To determine the effects of saline water with and without magnetic treatments on seed emergence and yield of wheat, two experiments were conducted in the National Salinity Research Center, Iran. The first experiment was done under controlled environment conditions with day and night temperatures of 25 ◦C and 15 ◦C, respectively. The emerging wheat seeds were measured under four irrigation water qualities including 2.5, 6, 10 and 12.7 dS/m with and without magnetic device. To determine the effect of magnetic treatment on wheat yield under saline conditions, another experiment was done in 18 fiber glass boxes (0.5 x 0.45 x 0.50 m deep) in the ambient environment for two years. Treatments included use of magnetic device (Model: MAG 4000) and without it and three water qualities (2, 6 and 10 dS/m). Results showed that salinity treatments had no significant effect on final emerged seeds and emergence percentage. However, salinity significantly reduced rate of emergence, coleoptile length, grain yield, plant height, spike length, and the number of kernels per spike. Magnetic treatment and interaction between magnetic treatment and salinity had no effect on the number of emerged plant, emergence rate, emergence percentage, coleoptile length, grain yield, plant height, spike length, and number of kernels per spike. These results were obtained using a specific magnetic device. Probably, using a different magnetic device with different composition of irrigation water applied to various crops may lead to different results.
Research Paper
H SADRGHEIN
Abstract
In Iran, limited water resources and high potential evaporation have led to limited planting of some corps like sugar beet that have long growing season and high water requirements. Sugar beet is a strategic crop planted in most provinces of Iran and its production is very important in agricultural and ...
Read More
In Iran, limited water resources and high potential evaporation have led to limited planting of some corps like sugar beet that have long growing season and high water requirements. Sugar beet is a strategic crop planted in most provinces of Iran and its production is very important in agricultural and industrial aspects. Most of sugar beet farms are irrigated by surface irrigation methods, but the use of drip irrigation can be proposed and developed. This study was based on several researches (specially done in recent years) on using tape drip irrigation systems in sugar beet fields. Results showed that water use efficiency in drip tape irrigation was 1.7 times greater than furrow irrigation. Drip tape irrigation decreased water consumption by 37 - 60 percent. Sowing patterns with 50 x40 cm row spacing and placing each tape for two rows recommended which results in cost reduction of tapes and increased root yields. The increase of yields using tape drip irrigation systems was not significant, but increase of water use efficiency based on root yield and sugar contents was significant (p< 0.01). Water saving with tape systems in fall planting was about two times greater than spring planting. The water stress in root swelling stage was more effective in decreasing of root yield than other growth stages, so using of water stress must not applied by farmers in growth period. Finally, the applicable approach for develop of this system in sugar beet fields is presented.
Research Paper
Niazali Ebrahimipak; M MOSTASHARI
Abstract
This study investigated the effect of water stress and different amounts of zinc, manganese, and boron fertilizers on yield components and water use efficiency of sugar beet. The experiment was conducted for three years in Qazvin, Iran, with two-factor factorial design in randomized complete block ...
Read More
This study investigated the effect of water stress and different amounts of zinc, manganese, and boron fertilizers on yield components and water use efficiency of sugar beet. The experiment was conducted for three years in Qazvin, Iran, with two-factor factorial design in randomized complete block and three replicates including irrigation and fertilizer treatments. Irrigation treatments consisted of four intervals i.e. 6, 9, 12 and 15 days (treatments E1 to E4) and fertilizer levels included fertilizers based on soil test (30 kg boric acid/ ha , 40 kg zinc sulfate / ha and 30 kg manganese sulfate /ha,), 30 percent less than the recommended fertilizer (21 kg boric acid/ ha ,28 kg zinc sulfate /ha, 21 kg manganese sulfate /ha) and 30 percent more than the recommended fertilizer (39 kg boric acid / ha , 52 kg zinc sulfate /ha and 39 kg manganese sulfate / ha) treatments, respectively, F1, F2, and F3. Statistical analysis of sugar beet root yield showed significant (at 5% level) differences between irrigation treatments and fertilizer treatments. Treatment E1F3 produced a yield of 64696 kg/ ha, while E4F3 produced 41736 kg/ha that was the lowest yield. Average root yield of F2 treatmentswas more, but, in the case of F1, the amount of sugar level was higher. In the wettest irrigation treatment, root yield increased with increasing fertilizer rates. It is suggested that when water stress conditions occur, use of fertilizer in excess of the recommended levels should be avoided. The volumes of irrigation water applied in irrigation intervals of 6, 9, 12 and 15 days were, respectively, 9659, 8104, 6677, and 5398 cubic meters per hectare. Water productivities for irrigation interval of 15 days and F2, F1, and F3 were, respectively, 8.39, 8.38, and 7.73 kg beetroot per cubic meter of water, reflecting the most efficient use of irrigation water.
Research Paper
A RASOULZADEH; S RAZAVI; M.R NEYSHABOORI
Abstract
Saturated hydraulic conductivity is one of the main soil physical properties used in the modeling of water and solute transport and management of irrigation and drainage problems. Laboratory and field methods for direct measurement of this property are time consuming and costly. Thus, indirect methods, ...
Read More
Saturated hydraulic conductivity is one of the main soil physical properties used in the modeling of water and solute transport and management of irrigation and drainage problems. Laboratory and field methods for direct measurement of this property are time consuming and costly. Thus, indirect methods, such as pedotransfer functions, have been developed to estimate this property. The objective of this study was evaluation of regression-based pedotransfer functions, Rosetta pedotransfer function with artificial neural network approach, and fractal models to estimate saturated hydraulic conductivity. In addition, due to the importance and role of preferential flow of water and chemicals in the soil medium, hydraulic conductivity of large pores was estimated using fractal model. To do so, 31 soil samples with different soil textures and measured saturated hydraulic conductivity by falling head method were selected. Easily measured soil physical properties, such as particle size distribution, bulk density, particle density, and organic matter content were determined in laboratory. Saturated hydraulic conductivity was estimated using the aforementioned models and the measured soil physical properties. For the purpose of comparison and evaluation of pedotransfer functions, fractal model, statistical criteria e.g., deviation time (DT), geometric mean error ratio (GMER) and geometric standard deviation error ratio (GSDER) were calculated for all the models. Results showed that the Wosten et al. and Campbell-Shiozawa models were, respectively, the best and worst estimator of matrix saturated hydraulic conductivity. The statistical criteria indicated that the adjusted fractal model in this study showed the best estimation of macropores saturated hydraulic conductivity.
Research Paper
F ESHRAGHI; S GHASEMIAN
Abstract
Water is one of the most important resources in agriculture. Its scarcity and low irrigation performance in Iran makes it more important. In this study, economic productivity of water use in Golestan province was evaluated for selected irrigated crops including cotton, canola, summer soybean, and rice. ...
Read More
Water is one of the most important resources in agriculture. Its scarcity and low irrigation performance in Iran makes it more important. In this study, economic productivity of water use in Golestan province was evaluated for selected irrigated crops including cotton, canola, summer soybean, and rice. To this end, the gross benefit per unit water use was determined as an index. Furthermore, a new approach in ranking and evaluating the regional productivities was adopted. The results showed that the highest economic productivity in water use of irrigated cotton in Gonbad-e-Kavous was 13496 Toman/m3, irrigated canola in Ag-Ghala with 562 Toman/m3, irrigated summer soybean in Minudasht with 394 Toman/m3, high yield long seed rice in Minudasht with 2108 Toman/m3, high yield rice in Ali-Abad with 988 Toman/m3, and medium yield long seed rice in Kolaleh with 960 Toman/m3. Based on the results, Minudasht, Kalaleh, and Aliabad regions had the highest overall economic productivity in water use, while Gonbad-e-Kavous, Kordkuy and Azadshar regions had the lowest.
Research Paper
Z SAADATI; NADER PIRMORADIAN; E AMIRI; M REZARI
Abstract
In order to increase water productivity, a good understanding of crop response to water stress and tools which simplify the complex crop response to various environmental factors, especially to water, are needed.Simulation models that clarify the effects of water on crop yield are useful tools for improving ...
Read More
In order to increase water productivity, a good understanding of crop response to water stress and tools which simplify the complex crop response to various environmental factors, especially to water, are needed.Simulation models that clarify the effects of water on crop yield are useful tools for improving farm level water management and optimizing water productivity. In this study, the WOFOST model was used to simulate two local rice varieties yield response under five irrigation treatments consisting of continuous flooding and irrigation at 0, 3, 6 and 9 days after disappearance of water from the soil surface. The experiment was conducted at Rasht region during two growing seasons of 2003 and 2004. The model was calibrated using the first year data and was validated using the second year data set. According to the results, the relative root mean square errors of grain yield simulation were 12.57% and 5.01% for Binam and Hasani cultivars in 2003, respectively. These values were 7.94% and 13.71% in 2004, respectively. The values of the observed and simulated water productivity based on precipitation and consumed water were close together. The results showed that the WOFOST model could simulate the effect of water on rice yield and water productivity in a humid region. Therefore, this model can be used to explore optimum management options to improve rice water productivity.
Research Paper
H GHAMARNIA; Milad farmanifard; SH SASANI
Abstract
Scarcity of water resources in spite of burgeoning population makes them important and necessitates optimum use of these resources. Shallow groundwater is a resource that has been ignored in irrigation management, while it is an available free source of water which can provide at least part of plants ...
Read More
Scarcity of water resources in spite of burgeoning population makes them important and necessitates optimum use of these resources. Shallow groundwater is a resource that has been ignored in irrigation management, while it is an available free source of water which can provide at least part of plants water requirement. Therefore, a two-year experiment was conducted in 2009-2011 to find the effect of shallow groundwater tables, at 60, 80, and 110 cm depth, on water requirement, water use efficiency (WUE) and yield of three wheat cultivars, namely, W33g, Cross Alborz, and Bahar. Experiments were performed at RaziUniversity lysimeter research station No1 as a randomized complete block factorial experiment with three replications. In these experiments, 45 tubular poly ethylene lysimeters with 1.20m height and 0.30m diameter were fixed in the ground with 1m distance from each other. The highest utilization of groundwater was found for the water table depth of 60 cm and the lowest was found for the 110 cm depth. The 2-year average contribution to different cultivars by groundwater in depths of 60, 80, and 110 cm was 63%, 55% and 45%, respectively. The results for Cross Alborz cultivar showed no significant difference (P<0.01) in WUE between the three water table depth treatments. Overall, the optimum WUE and yield was found at water table depth of 80 cm.
Research Paper
V GHOLAMI; SH DERAKHSHAN; Z DARVARI
Abstract
Scarcity of water resources in spite of burgeoning population makes them important and necessitates optimum use of these resources. Shallow groundwater is a resource that has been ignored in irrigation management, while it is an available free source of water which can provide at least part of plants ...
Read More
Scarcity of water resources in spite of burgeoning population makes them important and necessitates optimum use of these resources. Shallow groundwater is a resource that has been ignored in irrigation management, while it is an available free source of water which can provide at least part of plants water requirement. Therefore, a two-year experiment was conducted in 2009-2011 to find the effect of shallow groundwater tables, at 60, 80, and 110 cm depth, on water requirement, water use efficiency (WUE) and yield of three wheat cultivars, namely, W33g, Cross Alborz, and Bahar. Experiments were performed at RaziUniversity lysimeter research station No1 as a randomized complete block factorial experiment with three replications. In these experiments, 45 tubular poly ethylene lysimeters with 1.20m height and 0.30m diameter were fixed in the ground with 1m distance from each other. The highest utilization of groundwater was found for the water table depth of 60 cm and the lowest was found for the 110 cm depth. The 2-year average contribution to different cultivars by groundwater in depths of 60, 80, and 110 cm was 63%, 55% and 45%, respectively. The results for Cross Alborz cultivar showed no significant difference (P<0.01) in WUE between the three water table depth treatments. Overall, the optimum WUE and yield was found at water table depth of 80 cm.