فهرست مطالب بهاره دلسوز خاکی

One of the consequences of the climate change in Khuzestan Province is thedrying up of a large part of the wetlands of this province, including Miangaran and Hoor al-Azim, which has caused dust storms in recent years. In this regard, this research aims to predictclimate changes in the area of Miangaran and Hoor al-Azim wetlands by using the SDSMstatistical microscale model based on HadCM3 B2 and A2 climate scenarios. Considering thespecific conditions of the region and the fact that few studies have been done regardingtemperature change in these areas, knowing the state of temperature change can help bettermanagement of resources, especially water resources management.

These parameters include the average sea level pressure, thegeopotential height of the surface of 850 hectopascals and the average temperature at a heightof two meters. For this purpose, by using the daily data of average temperature, minimum andmaximum temperature in the synoptic stations of Izeh and Bostan as the closest stations to Hooral-Azim and Miangaran wetlands in the periods of 2010-2039, 2040-2069 and 2070-2099,predictions were made and then a comparison was made with the base period (1961-1990). Theselected predictors in climate parameters were chosen using NCEP observational large-scaleparameters and SDSM software. These parameters included average sea level pressure, surfacegeopotential height of 850 hectopascals, and average temperature of two meters above thesurface. Also, with scenarios A2 and B2 until the year 2099, the prediction of the return periodof extreme climatic events in the HadCM3 model was done.

The results of the simulation of the HadCM3 model along withobservational data from the Izeh station, modeled annual average temperature data was 18.47°Cand for the Bostan station, modeled annual data average temperature was 19.10°C. Both stationshad a higher average temperature in the base period, and the maximum temperature in theMiangaran wetland was much higher than Hoor al-Azim wetland in the base period. The resultsshowed that in both stations in scenario A2, the average temperature had significant cycles withreturn periods of 1.2 years and the lowest significant cycles for the two stations were in returnperiods of 2.3 and 1.3 years, respectively. In scenario B2, the average temperature in twostations has significant cycles with return periods of 7.5 years and the lowest significant cyclewith a return period of 1.2 years. The results of examining the cycles in the studied areasindicate that in the A2 scenario, certain climatic conditions in the area have short-term returnperiods. One year was obtained in both scenarios, which indicates a wider range of the returnperiod and a higher probability of extreme temperature events in the B2 scenario. In thecomparison of the two stations, it can be seen that in scenario A2, the average temperature ofthe Miangaran wetland is 1.02 °C and the Hoor al-Azim wetland is 1.08 °C.

The results of the data analysis in the future observation and simulation periodswith scenarios B2 and A2 showed an increase in the mean, minimum, and maximum averagetemperature in the future simulation periods compared to the base period in Izeh and Bostanstations. In Bostan station, the average minimum and maximum annual temperature alsoincreased in the third period compared to the base period. In both scenarios, due to the increasein temperature, the drying process of both wetlands will continue.

Climate has an important role in agricultural activities and can be examined from two perspectives. First, what locations are suitable for a specific plant, and second, what plants are suitable for a climate. The latter approach is less considered; thus in this study, it has been investigated by introducing a standard method (Sys method). The study area is located in Mako city. Climatic suitability evaluation was performed by numerical (parametric) method using the Maku Synoptic Station data for pistachio, almond, pears, plum, sour cherry and sweet cherry. The findings showed that except for pistachio, with marginally suitable class (S3), other plants were classified as moderately suitable class (S2) but the value of climatic index for each crop was different. The introduced method made it possible to identify the most important effective climatic factors for the cultivation of each plant and determine the most limiting factor in the phenological period. Such findings showed that there is a close relationship between crops, phenological period, climatic characteristic and location. Based on this, the most suitable plant or plant species can be selected for a region, using the phenological period of the plant and climatic characteristics. However, for sustainable development, other components of the land, such as soil and/or topography, should also be evaluated. In general, the introduced approach can be used as an efficient tool, both for choosing the most suitable plants in a climate and for choosing the most suitable place (in terms of climate) for specific plants.

This study expresses the steps of achievement to the indigenous-executive framework of integrated soil and water management at farm level through a mega project with 19 sub-projects. The projects were carried out during 2013-2020 with active participation of international, national and regional experts as well as local farmers in Honam Sub-basin, Lorestan Province, Iran. To understand the soil and water management problems for agriculture in the same homogeneous units (HSWMUs), farmlands were classified regarding physical, chemical and biological characteristics of soil, making it possible to convert soil maps into thematic maps. In this research, the fertility capability classification (FCC) method that integrates surface and sub-surface soil textures with modifieres was used. In addition, several modifieres were revised for soils of semi-arid regions and new modifieres were introduced for Irrigation Capability Classification (ICC). The required information was collected from 119 soil profiles and 101 surface soil samples in detailed scale of 1:25000 and the corresponding measurements were made. Accordingly, different data layers including detailed soil map were produced via geopedological method icluding land limitation, land suitability, and land production potential (LPP) of major crops, land degradation, location of water withdrawal, land use and agricultural cadastre of 2395 farms were prepared. To evaluate the current soil and water behavior of farmers within HSWMUs, the multidisciplinary team recorded the issues through field visits and open semi-structured questionnaire of 84 selected farmers in 24 villages who were interviewed during 2018-2019. The results showed that 23 and 30 HSWMUs that covered, respectively, 93% and 90% of the irrigated and rainfed areas were delineated on the map. Investigations showed that the sub-basin suffers from problems such as plow pan, phosphorus and zinc deficiencies, poor irrigation scheduling, and three types of farmers. Finally, recommended packages were prepared and validated for each HSWMU, which will be discussed in the part 2.

One of the most common approaches for farm irrigation management is using soil readily available water and allowable depletion coefficient. The objective of this study was to determine wheat crop response coefficients, critical moisture content, and soil allowable depletion coefficient using a physically based method in three dominant soils under wheat cultivation in Khuzestan province. Treatments included full irrigation and water stress at three levels low, moderate, and high. The highest and lowest values of wheat crop response coefficient were related to silty clay loam (Ky=1.26) and clay loam (Ky=0.96), respectively. Critical soil moisture content was observed in loam soil (0.25 cm3cm-3)> silty clay loam (0.23 cm3cm-3)> clay loam (0.22 cm3cm-3), respectively. Despite the higher critical moisture content in loam, the most soil allowable depletion coefficient was also calculated in loam (0.54). Soil allowable depletion coefficient in silty clay loam and clay loam were 0.44 and 0.42, respectively. The results confirmed the simultaneous effects of soil and plant properties on the availability of soil water for the plants.

In order to analyze the temporal and spatial changes in the amount of water required for puddling in rice fields of the Sapidroud Network, daily soil moisture data from the SMAP satellite was obtained and used in a seven-year period (2015 to 2021). The puddling stage (from April 20 to June 10) was analyzed after grouping based on different probability of occurrence (1%, 10%, 25%, 50%, 75%, 90% and 99%) and using raster calculations. In addition, in order to validate the calculations, the predicted values were compared with the saturated soil moisture values of 321 soil samples with specific geographic coordinates that had been measured by the Rice Research Institute of Iran. The comparison was conducted by using the mean absolute error (MAE), mean bias error (MBE), and normalized root mean square error (NRMSE). The results showed that in all moisture scenarios (from the wettest to driest), the foothills had less moisture than the plain and, especially, the low lands, and the soil moisture showed a decreasing trend during the growing period. The rate of this reduction increased gradually and in some areas it reached 2% per day at the end of the puddling period (May 22 to 31). The amount of gross water required for puddling increased from the wettest to the driest year and in the middle of the season (May 3 to 5) it was from 1693 to 2983 square meters per hectare and at the end of the season from 2496 to 3602 m3/ha, respectively. The validation results showed that the calculated MAE, MBE, and NRMSE values were 4.26%, 1.59%, and 15%, respectively, indicating that the accuracy is acceptable. The findings showed that the delay in the start of the puddling operation increases the water required for puddling operation (1.34 m3/ha for each day delay in a normal year). Therefore, in the lands of this network, in all circumstances, especially in dry years, to save water, it is better to release/supply water required for puddling from local reservoirs, wells, or from the Sepidroud Dam in early May.

Considering the phenomenon of climate change and subsequent changes in plant water requirements, it is crucial to recognize and estimate climate change in the coming decades with the aim of proper environmental planning to adapt to future climate conditions and reduce its effects. The main factor in the consumption of water resources in arid and semi-arid areas is agriculture and, accordingly, evaporation-transpiration, therefore, awareness of the process of changes and its prediction plays an effective role in planning, development, and water resources management. Since evaporation-transpiration accounts for an important part of the water balance of arid and semi-arid regions, its correct estimation is very important in the optimal preservation of water resources. On the other hand, knowledge of evaporation-transpiration process is necessary to estimate plant water consumption and design irrigation systems. According to the conducted research, estimation of evapotranspiration in the present and future periods is one of the basic needs of development managers, therefore, this research aims to evaluate the evapotranspiration potential in the base period (1991-2005), and predict temperature changes, using 3 scenarios (RCP2.6, RCP4.5, and RCP8.5) and evapotranspiration based on CMIP5 models (1.1 BCC-CSM and CCSM4) in the 75 year period (2025-2100) was carried out in Tabriz city.

For this purpose, the Penman-Monteith method was used as a standard algorithm to estimate potential evaporation and transpiration in the basic period (1991-2005). Then, potential evaporation and transpiration in the period of 2025 to 2100 were estimated using 2.6 RCP, 4.5 RCP, and 8.5 RCP scenarios and the LARS-WG6 model. Finally, the predicted values of evaporation and transpiration in future periods were predicted using the statistical indicators and the calculated evaporation and transpiration values for the base period (1991-2005). The ROC skill score curve also was used in order to general assessment of the quality of the estimations.

The results showed an increase in the predicted potential evaporation and transpiration under the RCP scenarios. In all three scenarios, the highest amount of evaporation-transpiration was obtained in July and the lowest amount was obtained in December. Moreover, an increase in the predicted transpiration evaporation was observed in July, August, January and February, compared to the base period. In addition, a decrease in the predicted transpiration evaporation was obtained in November and December, compared to the base period. In the RCP 8.5 scenario, the difference was much higher than in the base period. The evaluation of the model performance showed that for the hot months of the year, the model had a better ability to estimate the amount of potential evaporation-transpiration compared to the cold months, and the lowest RMSE error was in the hot months, so that in January with a value of 0.15 mm, the lowest value Dara showed the error. A comparison between the months indicated the two months of February and August as the best estimation for the estimation of annual evapotranspiration values. Likewise, the results showed that in all future periods and under all scenarios, the average reference evaporation and transpiration in annual scales will increase significantly at the level of 0.01 compared to the base period. The verification results also showed an acceptable ability for the predictions of the potential transpiration evaporation model.

This research amed at investigation of the amount of reference evapotranspiration changes based on RCP radiative forcing scenarios and climate models from 2025 to 2100 in Tabriz. The obtained results indicate the increase of reference evapotranspiration in all RCP scenarios for each of the future periods. In addition, the highest percentage of the reference evapotranspiration changes in the 8.5 RCP scenario is more than other scenarios because this scenario predicts the worst climate conditions and obvious changes in evapotranspiration will occur. The results of this research can be beneficial to solve the challenges of managers and relevant officials in the future periods. Considering this, the water, environment and health sector planners should adopt the necessary solutions for adaptation and reducing the consequences. Reasonable use of water resources is inevitable under the conditions of warming weather in Tabriz. Increasing evaporation and creating important changes in the quality and quantity of water resources, consequently changes in the quantity and quality of agricultural products. This situation determines the necessity of planning changes in the exploitation of water resources and agriculture. The future plans should be such that the upcoming changes have less harmful effects on the water and agriculture sector in this region. It is necessary to consider measures to improve the irrigation system, reduce evaporation, reuse wastewater and improve the cultivation pattern.

Changes in evapotranspiration values of rice plants in non-northern regions of the country were estimated for three different planting dates (early, on time and late planting) and with four different probabilities of 75%, 50%, 25%, and 10% (years with low, medium, high, and very high evapotranspiration, respectively), using the Penman-Monteith Equation and meteorological data of 15 stations with a statistical period of 30 years (1990-2020). The crop coefficient of rice in different stages of growth were calculated as an average in 10-day periods based on the Weibull Model. The results showed that, in all non-northern climatic regions, adopting an early planting strategy leads to a reduction in water requirement in all evapotranspiration scenarios. Adopting early planting strategy in years with very high evapotranspiration reduces the water requirement of rice in hot, cold and temperate regions by 125.9, 113.5, and 115 mm, respectively, during the growing season (on average 0.7 to 9. 0 mm per day) compared to late planting. However, in cold and temperate climates, there was no big difference between early planting and timely planting and even late planting. So, it is better to use late planting to avoid the possibility of late frosts. Comparison of the results of evapotranspiration rate of rice plant in all planting dates and different probability levels in cold, moderate, hot and very hot climate regions showed that the highest evapotranspiration rate is related to the hot region at the rate of 1021, and moderate and cold regions have much lower evapotranspiration rate than hot regions with evaporation rates of 784.8 and 729 mm, respectively. Therefore, considering the lack of water resources and the negative effects of climate change in arid or semi-arid regions such as Iran, it is better to avoid rice cultivation in hot regions, especially in years with high evapotranspiration. Also, it is better that in cold and temperate regions, the type of irrigation management and the design of structures and water systems should be adapted to the calculations of years with high evapotranspiration.

One of the practices to improve the agricultural management of paddy fields for sustainable rice production is land equipment, renovation, and integration operations. However, due to some shortcomings, this does not seem to achieve all its goals. Therefore, the purpose of this study was to evaluate the effect of land leveling operations on non-uniformity and severity of changes in soil fertility using fuzzy logic and integrated fertility quality index, in paddy fields of Khosroabad village which is located in fouman city in Guilan province where the land equipment, renovation, and integration operation has been done. In two stages, before and after land leveling operations, 95 and 126 soil samples were prepared from surface horizons, respectively, and then some soil properties related to rice fertility (electrical conductivity, clay, organic carbon, total nitrogen, available phosphorus and available potassium) were measured. In the next step, using fuzzy functions, soil quantitative characteristics were converted into qualitative variables and by using the effect of weight on qualitative variables, the integrated fertility quality index was calculated. The results of measured properties, calculated indices, and the produced maps from them, showed that due to the land leveling operation, the average amount of clay increased (76/9%), and organic carbon, nitrogen, available phosphorus, and available potassium decreased (37, 32%, 41/7 %, and 20/3%, respectively) significantly. One of the main reasons for this is excavation operations and the placement of subsurface soil with more clay and lower concentrations of nutrients in the lower horizon. The integrated fertility quality index also decreased (from an average of 0.31 to 0.18) in most of the studied areas. As a result, it seems that improper implementation of agricultural land equipment, renovation, and integration operations, by reducing the fertility of topsoil, will have long-term negative effects on agricultural land, that elimination of which, will increase the cost of production.

Meeting the demand for rice in the country as a strategic product is of special importance. The objective of this study was to investigate the effect of soil properties on rice yield and their rating to prepare a table of soil and landscape requirements of this crop for use in land suitability assessment studies. For this purpose, 99 rice fields in Mazandaran, Guilan, and Khuzestan provinces were selected. In each farm, a soil profile was studied and a land use questionnaire was completed. After the necessary physical and chemical analyses, a simultaneous multivariate regression between yield and different soil properties was investigated. Then, in order to prepare a table of soil and landscape requirements for rice, simple regression relationships between effective soil characteristics and yield were investigated and rated for different land suitability classes. Verification of the proposed table was performed using data from 18 rice fields (about 18% of the whole data). The results showed that the range of yield, lime, sand, clay and silt in selected fields was extensive, but the percentage of exchangeable sodium and soil salinity were in a more limited range. In multivariate regression, the variables of salinity, ESP, lime, soil reaction, percentage of clay and sand, respectively, were efficient. The coefficient of determination of the proposed equation was about 0.38. Also, the value of the coefficient of determination between yield and soil index for verification data was about 0.71, which indicates the reliability of the proposed table in this study.

Accurate assessment of land suitability for agricultural production plays an important role in reducing the effects of land degradation. The aim of this study was to apply fuzzy, AHP and GIS techniques to determine the degree of land suitability for wheat production in lands of about 61,000 ha located in Qazvin plain. By Investigating the land use maps, geology, topography, slope and satellite image of the region, the delineation of primary soil units was separated, then in the separated units, profiles were excavated and described, and soil horizons were sampled. Based on the characteristics of representative profiles in each map unit, land suitability assessment for wheat cultivation was performed using fuzzy method with AHP and square root method and land suitability map was prepared in GIS environment. According to the results of AHP-fuzzy method 48169.1 ha (78.2%) of the land are moderately suitable (S2), 9086 ha (14.7%) marginally suitable (S3) and 4346.3 ha (7.1%) currently unsuitable (N1). The most important limiting characteristics were slope, pH, ESP, drainage and soil salinity. The results showed that the fuzzy method integrated with AHP was able to evaluate accurately with high value of determination coefficient between land index and yieldcompared to the parametric method of the square root and the modified square root due to determining the appropriate limits of critical points, suitable weights for characteristics, use of fuzzy logic relations and principles and suitable membership functions. Therefore, the mentioned integrative method can be an accurate and effective method for better planning and management of land use for agricultural production.   Identification of Land Potential and Characterizing Limitations for Irrigated Wheat Cultivation in a Part of Qazvin Plain Land Using Fuzzy and AHP Techniques

Multi-variate statistical methods such as principal component analysis (PCA) and regressions could be used to facilitate the interpretation of complex relationships. The objective of this study was to determine the most important soil fertility properties affecting rice yield in the paddy fields. For this purpose, soil samples were taken from the plow layers of 119 points with suitable distribution in the paddy fileds located in Shaft and Fouman cities of Guilan province. Then after, physical and chemical properties of the soil fertility were measured and analysed using descriptive statistics, principal component analysis and regression methods. Results showed that three PCs with eigen values greater than one named as “k and it’s preservation factors”, ”Total N and it’s provider factors” and ”P and Thickness of plow layer” are respectively explained more than 67.4% of the variability in the soil physical and chemical properties and 55% of the yield variability. In addition, the corresponded properties to the PCs explained 80% of the yield variability. Consequently, in order to increase the yield, management practices such as proper fertilizer applications of nitrogen, potassium and phosphorous and proper tillage for creating suitable plow layer are recommended.

Many methods have been developed since the formulation of the FAO framework for land evaluation and several of them still remain in widespread use. The objective of this research was to determine land suitability (using FAO method) and inherent soil fertility quality (using fuzzy membership function) for rice crop in paddy fields of Fouman and Shaft counties in northern Iran. Based on results obtained from FAO method, after climate factor (the limitation of the ratio of sunshine hours to day length i.e. n/N, and mean temperature in the growing cycle[b1] ) which was the major limiting factor for irrigated rice cultivation in the study area, drainage was the most soil-limiting factor. Based on inherent soil fertility quality, thickness of the plow layer, which affected root penetration and available soil volume for nutrients, was the most important limiting factor. Based on FAO method SQRI, 92.4% of the study area were marginal and 7.6% were in moderate suitability class, however, according to CLI, all of studied lands were in moderate suitability class. Also, based on inherent soil fertility quality, most of the study area were in suitable (38%) and highly suitable (27%) classes. Correlation of the FAO (SQRI and CLI) and soil fertility quality calculated indexes showed that the indexes were significantly correlated with each other (r=0.7, p