Showing 7 results for Sedaghat
A. Mohammadi Mohammadabadi, S.j. Hosseinifard, N. Sedaghati,
Volume 12, Issue 43 (spring 2008)
Abstract
Effect of change from the conventional (flooding) to subsurface irrigation system was studied on mature pistachio trees (Cultivar Ohadi) in Kerman pistachio research station for four years. This experiment was carried out in a randomized complete block design including 7 treatments and 3 replications. The experiment also used two irrigation intervals (7&14 days) and three water rates according to pan coefficient (20%, 40%& 60% evaporation from surface of class A pan) for subsurface irrigation system with 6 treatments the conventional (flooding) irrigation system was tested as control. The pipes of subsurface irrigation system were installed at 90cm distance from trees trunk at each side of trees, and 50cm from soil surface. Mean of pressure and discharge in the pipes was 0.8 to 1 atmosphere and 5.4 Lh-1m-1, respectively. Different factors of quantity and quality pistachio yield, current vegetative growth, water use efficiency and soil electrical conductivity were measured. The results showed that change of conventional (flooding) to subsurface irrigation system is possible and the best treatment can have water rate of 7174 m3ha-1y-1 with 14 days irrigation interval. In comparison with other treatments, this treatment has better quantity and quality pistachio yield. Water use efficiency (WUE) of this treatment was 164g dry yield per cubic meter. Nevertheless, application of water rate of 4783 m3ha-1y-1 can result in the deficiency of irrigation water. At this water rate, WUE was 177g dry yield per cubic meter. However, it was found that the application of lower water rate (<4783 m3ha-1y-1) produced severe effects on the treated pistachio trees, e.g. decreasing the growth rate, yield and increasing the early splitting in pistachio fruits. Finally, it is concluded that 14-day interval irrigation is the preferred treatment for pistachio trees. Also, soil salinity showed considerable change in subsurface irrigation treatments after irrigation system was changed, especially in the first year.
K Noohi, F Sahraeian, M Pedram, A Sedaghat Kerdar,
Volume 12, Issue 46 (1-2009)
Abstract
Dates of start and end of frost based on minimum shelter temperature equal to or less than 0°C were studied in Zanjan, Ghazvin and Tehran during 1961-2000. The cause of these frosts was determined by weather parameter values at observation hours and the aid of synoptic maps. Frost series based upon last spring or first fall advection are defined and found to be random and normally distributed. The "potential growing season", defined as the interval between spring last and first fall advection frosts, is found to be 29 days in Zanjan, 23 days in Ghazvin and 10 days in Tehran longer than the "growing season" defined by the interval from last spring to first fall occurrences of minimum shelter temperature of 0°C or less. The numbers of radiation frosts in the interval between first radiation frosts in fall or last radiation frost in spring and related advection frost were counted and found that this parameter is greater in Zanjan. Frostless days between the first two fall frosts and last two spring frosts show that the lengthening of spring season with one night protection is possible for 4 days in Zanjan, 6 in Gazvin and 4 in Tehran, providing that first fall and spring last frost is radiation. Results of this study permit estimating the practicality of frost protection for specialized crops in the area of study.
M Bolandi, F Shahidi, N Sedaghat, R Farhosh, R Ghasemzadeh,
Volume 13, Issue 47 (4-2009)
Abstract
Saffron is one of the most important crops in Iran and the quality of its dried stigma is highly depended on the processing and storage conditions. In this study, the effect of different storage conditions in terms of temperature (20, 30 and 40°C) and water activity (0.32, 0.52 and 0.75) during 12 weeks storage on color strength, aroma and bitterness of saffron were investigated. In order to study of moisture (water activity) different saturated solution of MgCl2, Mg(NO3)2, MgBr2 and NaCl in the various temperatures were used. Results showed the color strength decreased as temperature increased. Increasing of water activity resulted in deterioration of crocin and consequently decreasing of color. Furthermore, after 12 weeks of storage, the color strength had a noticeable decrease, the bitterness also decreased but the aroma increased.
F Hosseini, M Habibi Najafi, N Sedaghat,
Volume 13, Issue 48 (7-2009)
Abstract
In this study, two kinds of packages namely tinplate (TP) can and flexible pouch were used for black cherry in syrup. Samples were taken in the same condition in these two packages. Other variables were temperature (4 levels) 4, 23, 35 and 40°C and time (4 levels) 0, 30, 60 and 90 days after preparation of the samples. Samples were digested according to the approved method of AOAC (AOAC, 1990). The total concentrations of Iron, Tin and lead, were determined by atomic absorption spectrophotometer. The mean concentration of Iron, Tin and Lead was 4/858 ppm, 38/459 ppb, 38/459ppb in TP cans and 3/161 ppm, 387/978ppb, 33/993 ppb in flexible pouches. Statistical analysis showed that at %5 probability level, the mean value of Iron content of the product packed in TP cans were significantly higher than the control the same was true about both lead and Tin content. However, this trend was not proved in flexible pouches. Furthermore, temperature had a significant effect on the metal content of the samples.
A. Mohammadi Orkashvand1, S. Sedaghat Hoor2, H. Jamalpour,
Volume 20, Issue 75 (Spring 2016)
Abstract
In this study, the impact of some organic matters and a moisture super absorbent were investigated on available water and delay of permanent wilting point in a sample soil of Rasht landscape. In incubation stage, 12 Treatments including control (70% v/v soil with 30% of the composted manure) and various amounts of soil, municipal compost, composted manure, olives and rice wastes along with a super absorbent (A200) were used in a completely randomized design. In order to provide water-release curve and to determine the amount of moisture needed for Field Capacity (FC) and Permanent Wilting Point (PWP), filter paper method was used. Three treatments having more available moisture and further delay in permanent wilting point in incubation stage were being applied in greenhouse stage, along with the control treatment. In greenhouse stage, impact of treatments and irrigation period (36, 72 and 168 hours) were studied on plant growth of Lysimachia, in a factorial experiment based on randomized complete block design. Results showed that the greatest weight of shoot dry matter was obtained in 30% municipal waste compost treatment and rice wastes treatment in 36 hours irrigation period, but at 168 hours period, dry matter decreased and the greatest dry matter was obtained from superabsorbent treatment.
H. Nazaripour, Z. Karimi, M. Sedaghat,
Volume 20, Issue 75 (Spring 2016)
Abstract
Drought is a climatic anomaly that associates with a significant decrease (lack) of precipitation and water resources availability, which spreads on vast temporal and spatial scales, and significantly affects various aspects of life and environment. One of the most common methods of drought assessing and monitoring is calculating drought indices (DIs). Drought areal and temporal extent and its severity are determined by these indices. In this study, an aggregate drought index (Hydro-Meteorological) has been developed for the assessment of hydrological and meteorological droughts in Sarbaz river basin located in southeastern of Iran. The Aggregate Drought Index (ADI) comprehensively considers all physical forms of drought (meteorological, hydrological, and agricultural) through selection of variables that are related to each drought type. In this case, monthly values of Stream flow Drought Index (SDI) and Standardized Precipitation Index (SPI) indicators were used for four similar reference periods with principle component analysis and aggregate hydro-meteorological index was defined based on its first component. The study time span was set between 1981-82 to 2010-11, which begins of October in Iran. Results based on the aggregate drought index (ADI) revealed that a long period of hydro-meteorological drought occurred from 1999-2000 to 2005/06 in southeast of Iran, in which, 2003/04 water year has been extremely a drought year. The ADI methodology provides a clear, objective approach for describing the intensity of drought. This index is appropriately able to represent the behavior of Hydro-Meteorological droughts and recommended as an integrated index for assessing and monitoring of regional droughts. Finally, different states of hydro-meteorological drought have been extracted based on conventional regional thresholds, and have been modeled by Markov chain. This made the estimation of drought state transition frequency possible, and made the prediction of next drought state time more real. State transition frequency matrices, are the main instruments for predicting drought states in real time. Results of validation tests and conforming the predicted results with real data indicate that predicting hydrological drought state transitions in the study area using Markov chain method is valid.
M. Nadi, A. Golchin, E. Sedaghati, S. Shafie, S. J. Hosseini Fard, G. Füleky,
Volume 21, Issue 1 (Spring 2017)
Abstract
Soil organic matter is the largest source of organic carbon in the soil surface which played an enormous role in restoring balance, environmental sustainability, soil elements and climatic conditions. Organic materials influence physical, chemical and biological properties of soil and thus soil fertility directly and indirectly. The amount, type and composition of organic matter are different in different soil and climatic conditions. Different soil components can hold different combination of soil organic matter. In this study soil samples were collected from virgin, Populus and Alnus forests from Guilan Province, Iran. The amount of organic matter in the original samples and sand, silt and clay fractions were measured and the quality of organic carbon (13C) and hydrogen (1H) were determined in fractions by Nuclear Magnetic Resonance. Based on the results the amount of organic carbon in the original samples of Alnus forest was highest. among fractions, clay had the highest amount of organic carbon. The result of Nuclear Magnetic Resonance showed presence of different aliphatic and aromatic carbons and hydrogen in different samples. Virgin forest had the highest proportion of alkyl to oxygenated alkyl carbon ratio and Alnus forest showed the highest ratio of aliphatic to aromatic carbon,. Both mentioned ratios was higher in clay fraction than other two fractions.
