جستجوی مقالات مرتبط با کلیدواژه « physiographic units » در نشریات گروه « آب و خاک »

Over the last three decades, there has been a general tendency to change methods in research on soil resource management from conventional and mainly qualitative methods to Quantitative ones based on spatial correlation models which are called digital soil mapping (DSM). The present study was carried out in Shabankareh plain with an area of ​​15,000 hectares with different physiographic units that are mainly used as agricultural farms in Bushehr province, Southern Iran. Target sites (172 points) were selected for soil sampling at depths of 0-30 and 30-60 based on hypothetical networking on satellite images and visual differences observed in the study area. Digital soil texture maps were drawn for both old soil texture triangle (include sand, silt and clay particles) and the new one (include Geometric mean particle diameter and geometric standard deviation of soil particle diameter). Soil texture is considered as one of the most important characteristics in determining the type and density of agricultural activities and types of land use. Two geostatistical programs include GS+ and ArcGIS and various methods of data estimators such as inverse distance weighting and ordinary Kriging method were used in this project. The results showed the strongest spatial structure class was observed in geometric standard deviation of the soil particle diameter (0.48) and the weakest in silt (0.73). The highest and lowest effective range among soil texture parameters were related to soil clay particles and geometric standard deviation of soil particle diameter with 684 and 336 meters, respectively. Number of drilled profiles (11 ones) was based on digital uniformity map. The generated digital maps can provide spatial information of important soil properties such as permeability and drainage, water holding capacity, fertility, soil erosion and salinity which increases the accuracy in the optimal management of agricultural lands.

The optimum and sustainable use of soil is only possible with a correct and complete understanding of its properties. This study was conducted to investigate of should be omitted some physical, chemical, and micromorphology properties of soil formed on the should be added landscapes in the should be added semi-arid region of Lorestan province.

For this study 5 profiles, a long, a should be omitted transect in the direction of slop (plateau, gravelly colluvial fan and pediment plain) were identified in the area, and divided into different physiographic unit based on the type of parent material. At each, physiographic units a profil was excavated, dissected sampled. Physicochemical together with micromorphological observations performed and Soil Taxonomy and WRB were used for soil classification.

The results showed that should be omitted low amounts of organic carbon in the surface and depths of the soil due to the high rate of decomposition of these substances in these areas. The equivalent calcium carbonate in all profiles showed an increasing trend with depth. Thin section investigation showed that there was not much difference between the horizons in terms of the type of voids and the relative distribution of large particles (C/F). Planar, vugh and cannel voids were the most dominant voids of the profiles. Accumulation of calcite was seen in various forms such as coating, infilling, needle- shaped calcite, and nodules calcite which indicates that secondary calcite, and caused a should be omitted crystallite calcite of kind b-fabric. Soil structure in most the horizons of kind angular blocky and sub angular blocky. Also, lenticular plates gypsum was observed on the Bky horizon on the of the gypsum physiographic units plateau. According According to the existence of pedogenic gypsum in the soils of the region, and the important of the gypsum horizon in the soil classification system and its important effect on plant growth. New great groups, and subgroups of Xerepts (Gypsic Calcixerepts) are suggested to be included in soil taxonomy.

Results of the study showed raise in topography and parent material on the variability of soil properties in the area.