Rahim Kazemi; Hamid Davoudi; Mohammad Jafar Soltani; Amir Sarreshtehdari
Abstract
There are more than 5.5 million date palms in Bushehr province in southern Iran. Repeated droughts and lack of irrigation water in recent years are being the most important factors for yield reduction and low quality of date fruits. Proper utilization of water supplies in order to increase water use ...
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There are more than 5.5 million date palms in Bushehr province in southern Iran. Repeated droughts and lack of irrigation water in recent years are being the most important factors for yield reduction and low quality of date fruits. Proper utilization of water supplies in order to increase water use efficiency and also, identification of more tolerant plants are so sensed according to recent drought crisis in the region. Although, date palm can suffer water shortage for a long time but higher water levels and annual soil temperature between 17 to 45 centigrade degrees would make the highest production. Therefore, a study was conducted in Bushehr Agricultural Research Center to determine the responses of three date palm cultivars of Kabkab, Zahidi and Shahabi to deficit irrigation. This experiment was carried out on randomized complete block design with three replications during 2004 to 2007. The irrigation treatments of this study were water depth in four levels of 35, 50 and 65 percent of irrigation water, which shows the cumulative evaporation of class A pan. Irrigation water was offered to plants under pressured system. Tree responses were evaluated in each year for the following properties: fruits and seeds weight, length and diameter, pulp to seed ratio, TSS, pH and yield. Results showed that cultivar effect was significant in all date palm responses (p>0.01) which can prove different inherent qualitative and quantitative characteristics in date palm cultivars. Zahidi cultivar proved to have higher water use efficiency in water stress conditions during drought periods. Irrigation treatments affected only the yield responses. Although, 65 percent of irrigation water showed to have higher production abut it was classified in the same statistical class with 50 percent of irrigation water. This means that in the situation of water shortage, 50 percent of irrigation water would be the choice. Also, mean water usage during three years of the experiment were 5497, 7758 and 9822 m3 ha-1 per year in the irrigation treatments with 0.544, 0.481 and 0.409 kg m-3 water use efficiency respectively. The sequence of water stress toleration in three date palms was Zahidi > Shahabi > Kabkab.
Ali Akbar Davoodirad; Davood Nikkami; Mehdi Mardian
Abstract
Increasing in production and welfare of rural household along with soil erosion mitigation are the most important objects of a watershed management program. Land use optimization is an efficient approach that leads to a sustainable development plan. In this research, the land use optimization was applied ...
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Increasing in production and welfare of rural household along with soil erosion mitigation are the most important objects of a watershed management program. Land use optimization is an efficient approach that leads to a sustainable development plan. In this research, the land use optimization was applied using a two-objective linear programing model and geographic information systems by Lingo 11.0 software in Adineh-Masjed Shahzand watershed of Markazi province, Iran. The model was defined with three scenarios of current conditions, applying management conditions, and standard conditions for two objectives of maximizing net benefits and minimizing soil erosion. Results showed that the annual soil erosion decreased by 1.27, 18.69 and 26.93% in current land use, land use management, and standard land use conditions, respectively. Also annual net income decreased by 18.56% in current land use; but increased by 48.01 and 220.07% in land use management and standard land use conditions, respectively. Considering weighting value of decreased soil erosion of 1.27% that is less than weighting value of decreased net income in current conditions, land use optimization with no management practices or land standardization is not justifiable.
Ramin Salmasi
Abstract
Heavy metals fixation in-situ by using inorganic amendments is a method for remediation of polluted soils. The goal of this research is to determine five kinds of amendments efficiency for heavy metals fixation of waste-water-irrigated soils of Tabriz city and to suggest the best amendment/amendments. ...
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Heavy metals fixation in-situ by using inorganic amendments is a method for remediation of polluted soils. The goal of this research is to determine five kinds of amendments efficiency for heavy metals fixation of waste-water-irrigated soils of Tabriz city and to suggest the best amendment/amendments. For this purpose, solutions containing Cd, Pb, Cu, Ni, and Zn were added to 0.5 gram of five amendments including calcite, hematite, zeolite, illite, and bentonite; and 10 soil samples from around of Tabriz city. After shaking, these five element concentrations were determined in filtered solution by using atomic absorption instrument. Retention capacity percentages of these elements were calculated and the best amendments were determined by using Dunkan method. There were sharp differences of heavy metals retention between amendments. Calcite had the highest retention of Cd, Ni, and Zn; hematite the highest one of Cu and Pb; and the least one was for illite. Calcite, zeolite, bentonite, and hematite had significant (in 5 % level) higher retention capacities of Cd, Ni, and Zn in compared to 10 the soil samples. The highest retention capacities were done by calcite and hematite (without significant differences) for Pb. Calcite hematite, and zeolite had the highest retention of Cu. However, the highest retention was done by illite with significant difference with other two amendments. The retention capacities of calcite and hematite amendments for the five elements were higher than all 10 soil samples in 5% level and can cause low uptake and accumulation of these elements in agricultural crops of polluted soils of around Tabriz city.
Banafsheh Yasrebi; Majid Soufi; Sayed Khalagh Mirnia; Jahangard Mohamadi
Abstract
Gully erosion has an important role in land degradation producing much sediment. Due to development of gully erosion in crop lands of study area, this research deals with assessing the topographic characteristics of bank gullies and assess on effective soil factors controlling gullies advancement in ...
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Gully erosion has an important role in land degradation producing much sediment. Due to development of gully erosion in crop lands of study area, this research deals with assessing the topographic characteristics of bank gullies and assess on effective soil factors controlling gullies advancement in Siekan watershed in Ilam province. For this purpose, 46 bank gullies were selected and morphometric characteristics like initial and advancement contributing area and slope as well were measured. Two compound soil samples were collected from top soil of contributing area and gullies walls then analyzed in the soil lab. Then database formed and effective factors on gullies advancement were recognized by correlation matrix and regression.Correlation matrix results revealed, the higher slope the higher head-cut and gullies volume. A-S relationship is negative and b is 0.31 that shows gullies formed by hortonian overland flow process. Topographic threshold is 0.04 and mean threshold in 10% slope is 0.05 ha and in 2% slope is 2 ha. Critical threshold in 2% slope is 0.07 ha. Correlation matrix showed that increase in gully advancement slope increases head–cut height and gully volume. The index of area of development/ area of initiation is suitablefor gully development stage determination and it has negative relationship with gully length, volume and width/depth index. Increasing in soil organic matter cause an increase in topographical threshold, soil texture and electrical conductivity increase the gully volume. The effect of both topographical parameters and soil material characteristics on total eroded bank gully volume was integrated in multiple regression equations. The models based on all measured parameters explain 85% of the variation ingullies volume.
Abdolrasoul Shafiey Dastjerdi; Mohammad Hossein Mahdian; Kourosh Kamali; Hamid Hoseyni Marandi
Abstract
Entrance of high volume of floodwater containing huge amount of suspended sediments into the floodwater spreading networks which deposits sediments, as well as infiltration of soluble materials and fine grained, gradually changes the infiltration rate of soils. The aims of this project is to study the ...
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Entrance of high volume of floodwater containing huge amount of suspended sediments into the floodwater spreading networks which deposits sediments, as well as infiltration of soluble materials and fine grained, gradually changes the infiltration rate of soils. The aims of this project is to study the quantity and the process of changes made in the soil of Saravan floodwater spreading station. This research has tried to use direct method of infiltration rate measurement, using double ring infiltrometer in two separate time periods of one year each, and to compare it to the experimental area. In order to specify overall situation of infiltration rates in terms of increase or decrease in second period of measurement in comparison to the first one, and as far as data were not distributed normally, Wilcoxon signed-rank test was used. The results showed no significant difference between two separate measurement periods due to few number of floodwater occurrences (three times) in addition to short time interval of one year between the two measurement periods. To determine changing rate of infiltration between strips and between the strips and the experimental field, as far as abnormal distribution of data in this arrangement were concerned, Kruskal-Wallis test was used. Results indicated that the three strips of flood spreading area have no significant difference (at five percent probability level) in two periods of measurement, but the strip related to experimental area has significant difference with other three strips and in both measurement periods. In other words, infiltration rates of all strips under floodwater spreading have been decreased in relation to the experimental area. Moreover, the results were explanatory that only one of the rectangular in both measurement periods had significant difference with experimental rectangular (at five percent probability level) and all the other rectangular have had no significant differences with each other and in comparison to the experimental one, in none of periods of measurement. Main reason of this difference is also related to the thicker sediments deposits in rectangular location, compared to other blocks. Also, infiltration rate decreased by 55.94 percent in flood spreading area compared to experimental area during one-year timeframe and 3.23 percent of reduction.
Saeed Nabipay Lashkarian; Seyed Ali Asghar Hashemi; Samad Shadfar
Abstract
Erosion and sedimentation are main challenges in Iran, which cause the reduction of soil quality and quantity. Soil conservation and watershed management activities should be implemented to reduce the impact of these phenomena. Therefore, the knowledge of critical area is necessary through the learning ...
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Erosion and sedimentation are main challenges in Iran, which cause the reduction of soil quality and quantity. Soil conservation and watershed management activities should be implemented to reduce the impact of these phenomena. Therefore, the knowledge of critical area is necessary through the learning the amount of sedimentation and erosion. Because of lack of sediment measurement stations in more watershed outlets in Iran and insufficient data, empirical models are proper tools for data layers generation. Factorial Scoring Model (FSM) is one of the experimental models which has been recently developed out of the country. The main objective of this research is to compare sediment yield estimated by FSM model and observed values. So, in order to evaluate the model, nine small dams of 10 years old with no overflows were selected from in Semnan province. For modeling sediment yield, topography, lithology, gully, catchment shape and vegetation cover of related catchments were studied and required data layers were prepared and scoring indexes were given and finally, the calibrated model was presented. Estimated model values were then compared with measured values. Results showed that main model equation does not have sufficient efficiency. Also, results demonstrated that calibrated FSM model has conformity with observed sediment values at 84 percent.
Mahmood Izadi1; Morteza Pouzesh Shirazi
Abstract
There are more than 5.5 million date palms in Bushehr province in southern Iran. Repeated droughts and lack of irrigation water in recent years are being the most important factors for yield reduction and low quality of date fruits. Proper utilization of water supplies in order to increase water use ...
Read More
There are more than 5.5 million date palms in Bushehr province in southern Iran. Repeated droughts and lack of irrigation water in recent years are being the most important factors for yield reduction and low quality of date fruits. Proper utilization of water supplies in order to increase water use efficiency and also, identification of more tolerant plants are so sensed according to recent drought crisis in the region. Although, date palm can suffer water shortage for a long time but higher water levels and annual soil temperature between 17 to 45 centigrade degrees would make the highest production. Therefore, a study was conducted in Bushehr Agricultural Research Center to determine the responses of three date palm cultivars of Kabkab, Zahidi and Shahabi to deficit irrigation. This experiment was carried out on randomized complete block design with three replications during 2004 to 2007. The irrigation treatments of this study were water depth in four levels of 35, 50 and 65 percent of irrigation water, which shows the cumulative evaporation of class A pan. Irrigation water was offered to plants under pressured system. Tree responses were evaluated in each year for the following properties: fruits and seeds weight, length and diameter, pulp to seed ratio, TSS, pH and yield. Results showed that cultivar effect was significant in all date palm responses (p>0.01) which can prove different inherent qualitative and quantitative characteristics in date palm cultivars. Zahidi cultivar proved to have higher water use efficiency in water stress conditions during drought periods. Irrigation treatments affected only the yield responses. Although, 65 percent of irrigation water showed to have higher production abut it was classified in the same statistical class with 50 percent of irrigation water. This means that in the situation of water shortage, 50 percent of irrigation water would be the choice. Also, mean water usage during three years of the experiment were 5497, 7758 and 9822 m3 ha-1 per year in the irrigation treatments with 0.544, 0.481 and 0.409 kg m-3 water use efficiency respectively. The sequence of water stress toleration in three date palms was Zahidi > Shahabi > Kabkab.
