Hamed Eskandari Damaneh; Gholamreza Zehtabian; Hassan Khosravi; Hosein Azarnivand; Aliakbar Barati
Volume 28, Issue 3 , October 2021, , Pages 520-536
Abstract
In the present study, the existing land uses in the Minab plain were simulated using the CA-Markov combined method. For this purpose, land use maps for the years 2000, 2010 and 2020 were generated using Landsat satellite images using the maximum probability classification method and after evaluating ...
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In the present study, the existing land uses in the Minab plain were simulated using the CA-Markov combined method. For this purpose, land use maps for the years 2000, 2010 and 2020 were generated using Landsat satellite images using the maximum probability classification method and after evaluating the model, the land use map for 2030 and 2040 was predicted using the combined CA-Markov method. Analysis of land use change patterns in Minab plain showed that during the statistical period 2000-2020 in the level of land uses in this area has changed significantly so that during this 20-year period the area of agricultural land use, urban and man-made areas, saline lands and rangelands and barren lands respectively from 38.91, 25.99, 20.09 and 15 % in 2000 to 40.75, 40.02, 12.44 and 6.80 percent in 2020. Evaluation of the model using kappa index above 90% indicates the high accuracy of the model for predicting land uses. Prediction of changes in 2030 and 2040 show that the use of agricultural lands and urban areas and man-made are increasing at a rate of 0.05 and 0.39 %, respectively, which are advancing from the east of the plain to the west; Meanwhile, the uses of saline areas, rangelands and barren lands are decreasing at a rate of 0.44%, which is more evident in the west and northwest of this plain. Finally, one of the most important executive strategies of planners and officials to prevent land use change and ultimately land degradation in this area, can be to improve the cultivation pattern, new irrigation methods, nourish the bed of this plain and maintain and restore native vegetation.
Ali Tavili; Hamed Eskandari Damaneh
Volume 28, Issue 1 , April 2021, , Pages 93-105
Abstract
Seed germination is usually the most critical factor in determining the success or failure of plant establishment. The most important environmental factors affecting germination, establishment, and growth of plants are temperature and humidity, which have significant effects on germination characteristics ...
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Seed germination is usually the most critical factor in determining the success or failure of plant establishment. The most important environmental factors affecting germination, establishment, and growth of plants are temperature and humidity, which have significant effects on germination characteristics such as germination percentage and rate. For this purpose, to determine the cardinal temperatures of seed germination in Ziziphus spina-christi, in vitro experiment, the germination characteristics of the seeds of this plant at different temperatures were evaluated in a completely randomized design with four replications. Germination response was assessed at the constant temperatures of 5, 10, 15, 20, 25, 30, 35, 40, and 45°C. The cardinal temperatures for the germination of Ziziphus spina-christi seeds were fitted using germination rate and by three models including the beta, segmented, and dent-like models. To select the superior model and measure the accuracy of the model in describing the germination rate of Ziziphus spina-christi seeds for temperature, the statistics of root mean square (RMSE) and coefficient of determination (R2) were used. Accordingly, a higher R2 and a lower RMSE represent a closer correlation of the model with reality. Based on the results, these statistics were better for the segmented model than the other models, so that they were 0.0004 and 98% for this model, respectively. Therefore, based on the segmented model, which was known as the superior model, the basal temperature, the optimum and maximum germination rate of this plant were calculated to be 8.6, 34.3 and 49 ° C, respectively. Then, the response of germination and seedling growth of Ziziphus was explored in another experiment to different levels of salinity and drought stresses at the optimum temperature. In this experiment, the seed germination was studied at four levels of salinity and drought stresses with osmotic potentials of 0, -2, -4, -6, -8, and -10 bars. The results of this experiment showed that salinity and drought stress reduced the germination percentage and rate of Ziziphus spina-christi seeds. Germination percentage for control was 97% while in -10 bar salinity and drought stress was 16% and 0, respectively. In addition, compared to drought, seed germination showed more sensitivity to salinity stress.