جستجوی مقالات مرتبط با کلیدواژه "dasht" در نشریات گروه "آب و خاک"

Selection of crop pattern is one of the most important factors in achieving water resources Sustainability. Due to the quantity and quality of soil and water, unsuitable and non-native plants may cause saltinification and elevation of groundwater level in the plant growth environment and degrade soil structure. And consequently reduce performance. Based on the dynamics of irrigation and drainage network in the Dasht-e-Abbas, located along the Karkheh Dam and Ilam province, in terms of quantity and quality of water in different scenarios of the crop pattern, using the system dynamics approach has been evaluated. Considering the information needed in this method, the boundaries of the system, the creation of a conceptual model, the determination of causative and causal relationships, the determination of the variables and verification based on observational information, structural testing, boundary test, and statistical parameters and the proposed cultivation pattern have been studied. The conceptual model was considered based on five sub-models of water demand, water supply, environmental stress, water economics and environmental issues. The results of this model show that in sensitivity analysis of input parameters, the coefficient of return of agricultural water to the aquifer has a great effect and its increase will increase the static volume of aquifer and increase the quality of groundwater due to dilution and also reduce the salinity of the soil due to Leaching. From other results of this study, using a crop pattern with an emphasis on increasing forage levels that prevents land drainage in the long time will improve soil construction.

For maintenance of soil fertility and increasing of soil utilization in sustainable agriculture, the information from soil characteristics is necessary. In this research work, effects of landforms on soil morphological and physico-chemical characteristics in Dasht-E-Tabriz were studied and soils were classified. Five profiles in landforms of hill, piedmont, river alluvial plain, playa and lowland were dug and soil moisture and temperature regimes were determined. From hill to lowland, increasing trend of clay, OC, CEC content and depth of soil solum with decreasing of gravel percentage with changing of textural classes showed more development of downstream soils than upstream ones by soil forming processes. This confirmed morphological results, that hill with colorful marn and sandstone parent material and thin solum took place in Entisol order and other landforms with alluvial parent material and thick solum were classified in Aridisol order. Finally, Soils according to Keys to Soil Taxonomy (2014) were classified in Aridisol and Entisol orders, suborder of Calcids, Argids, Salids and Orthent, with great groups of Haplocalcids, Natrargids, Haplosalids and Torriorthentand subgroups of Xeric Haplocalcids, Xeric Natrargids, Typic Haplosalids and Xeric Torriorthent.

Soil is one of the most important natural resources and perhaps is the most fundamental factor in formation of civilization. In addition to food supply، the soil will also provide other human necessities such as clothing، residence، bury wastes، wild life، recreation and etc. Climate plays a very important influence on enhancing and processes of soil formation، and in addition the climatic factors play a considerable influence on plant growth، production and land use. In each region، topographic factor also influence soil characteristics. Its influence on soil development and plant growth depend on its direction and elevation. In other to study the effects of topography and depth of ground water on soil genesis، Dasht-E-Arjan plain with xeric and mesic soil moisture and temperature regimes، were selected. Based on aerial photographs and also topographic maps، the location map of the study area was drawn. Then on two transversal sections، six profiles were dug. Among them four representative profiles were selected for detailed studies. The results of field studies and also profile description showed that Entisols and Inceptisols orders were developed on alluvial-colluvial fans، while on piedmont plains and lowlands only Inceptisols were formed. The physico-chemical characteristics of studied soils showed that، among the studied profiles، there are remarkable differences in soil texture، organic matter، saturation percentage، pH، EC، and CEC. The most important soil forming processes were accumulation of surface soil organic matter and also formation of Cambic and Calcic horizons. Because of extensive cultivation، the color and thickness requirements do not satisfy for the formation of MollicEpipedon، which show great future hazards for all Mollisols of the country. The XRD results of clay minerals showed more smectite mineral with respect to kaolinite، illite and chlorite minerals. This could be due to its higher content in parent materials and also transformation of illite to smectite due to more wetness of low lying physiographies.