pooya hoshyar; Hossein Khademi; Shamsollah Ayoubi; Mehdi Norouzi
Abstract
Parent material and vegetation are two important and influential factors in the formation of soil. Type of elements in the soil and their availability to plants depends deeply on soil parent material. However, type and density of vegetation change with amount of organic matter and mechanism of element ...
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Parent material and vegetation are two important and influential factors in the formation of soil. Type of elements in the soil and their availability to plants depends deeply on soil parent material. However, type and density of vegetation change with amount of organic matter and mechanism of element cycle overshadowed the availability of element in rangeland ecosystem. This study were conducted to investigate profile distribution of nutritional elements affected by rangeland species and different parent material as a factorial trial and completely randomized design with three replications in rangelands around Kuhrang city. Therefore, in the study area, three different parent matter such as fossiliferous marl limestone, fossiliferous dolomitic limestone and red conglomerate and sandstone were selected. In each parent material, three places under Astragalus spp and Daphne and the bare part as a control profile to depth of 100 cm were dug. Then the soil physical and chemical properties and concentrations of nutritional elements in profiles were measured. The results of this study showed that type of parent material have significant effect on amount of soil element while the vegetation in some cases could not make a significant difference in concentration of elements. Red conglomerate parent material because of coarser texture, release fewer element compared to marl and dolomite limestone in soil. Soils in study area except soils derived from red conglomerate parent material, there is no shortage of potassium and phosphorous. Furthermore, concentration of elements in different depths of the profiles obeyed a similar pattern
Hossein Eslami; Ali Salajagheh; Shahram Khalighi sigaroudi; hasan Ahmadi; Shamsollah Ayoubi
Abstract
Rainfall erosivity is the ability of rainfall to detach the soil particles. This study was conducted to evaluate spatial variability of rainfall erosivity indices in Khouzestan Province. The point data of indices (EI30, AIm, KE>1 and Onchev indices) in 74 stations were used to generate spatial erosivity ...
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Rainfall erosivity is the ability of rainfall to detach the soil particles. This study was conducted to evaluate spatial variability of rainfall erosivity indices in Khouzestan Province. The point data of indices (EI30, AIm, KE>1 and Onchev indices) in 74 stations were used to generate spatial erosivity maps through deterministic and geostatistical interpolation methods (Radial Basis Functions, Inverse Distance Weighted, Kriging and Cokriging). Results indicate that cokriging have least error and most correlation with determining coefficient of 0.89, 0.89, 0.48 and 0.49 for EI30, AIm, KE>1 and Onchev indices. Based on the correlation relationships between the basins specific sediment yield (in basins dominating the sedimentation stations) and mean indices of EI30, AIm, KE>1 and Onchev, EI30 index with correlation coefficient of 0.98 (P<0.01) is selected as the appropriate rainfall erosivity index. Based on the prepared map on the basis of Cokriging method with secondary variable of maximum mean monthly rainfall, the east and northeastern regions presented the highest values of EI30 index, while the southern and western regions showed the lowest values of EI30 index. The annual rainfall erosivity (EI30) ranged from 404 to 3064 Mj.mm.ha-1.h-1.y-1.
