Showing 5 results for Baghernejad
P. Shekari, M. Baghernejad,
Volume 9, Issue 4 (winter 2006)
Abstract
Chenges in the soil characteristics is rather continuously. A method that takes this continuity into account would present a realistic pattern of soil distribution either in taxonomic or geographical space. The fuzzy set theory provides such an approach. In this study, the robustness of fuzzy clustering in soil pattern recognition was evaluated in a subcatchment of western Iran. The clustering carried out on the basis of minimization of an objective function in assigning membership values to each pedon in each fuzzy class. Fuzziness exponent values from 1.15 to 1.5 were used. The following validation of the resulted clusters (classes), optimal number of classes in whole, morphological and particle-size subsets were determined 8, 4, and 5 respectively. Plots of membership values across the landscape indicated class overlap and considerable contiguity. Considering low differentiation of these young soils and the high similarity among their properties, the method indicated a high capacity in recognizing different soil types over the study area. Furthermore, there was relationships between the soil fuzzy classes and landform. Thus, the method is capable in continuous classification, which could be so important in construction of continuous soil maps at low aggregation levels, e. g., pedon.
S. Jafari, M. Baghernejad,
Volume 11, Issue 41 (fall 2007)
Abstract
Sugarcane (Saccharum officinarum L.) and rotational crops have been cultivated without potassium fertilizers for many years in southwestern Iran. Although potassium was removed from this soil, no response has been reported to K fertilizers by crops. This study was conducted to evaluate the effects of wetting and drying, and cultivation systems on potassium fixation in some Khouzestan soils. The results showed that expandable clay mineral was observed in cultivated soils but not in the non-cultivated soils. This may be related to irrigation, and cultivation practices in this soils. By adding K and sequential wetting and drying the amount of K-available increased in sugarcane, rotational cropping and uncultivated soils from 132.6, 226.2 and, 171.6 mgkg-1 to 266, 447 and 628, respectively. These results showed that more K can be fixed after cultivating soils, especially by sugarcane, but available K increased by adding K. All surface soils had higher K fixation capacity than subsurface ones. Also, by application K to these soils, the amount of K fixation decreased with increasing wetting and drying times. The K fixation increased by the increase of cation exchangeable capacity. Significant difference was observed between cultivation system and depth of sampling in 1% levels. High K fixation can be attributed to illite minerals depleted from K. Mica-like minerals formed after adding K, and wetting and drying cycles. Amount of K fixation by clay particle samples was more than the same soil samples but in both the same trend was observed for K fixation. Also, drying and wetting decreased K fixation in the last periods. It may be due to trapping K in the interlayer positions.
R Molavi, M Baghernejad, E Adhami,
Volume 13, Issue 49 (Water and Soil Science 2009)
Abstract
Fire is widely used to clear farms in Iran, while there is little information regarding the effects of fire on the characteristics, especially mineralogy of soils. The objectives of the present study were to 1) compare some physico-chemical properties of burned and unburned soils and 2) evaluate minerals transformation in top soil layer resulting from increasing temperature. Soil samples were taken from 0-5 and 5-15 cm depths of two burned places, an agricultural soil from Takht-e-Jamshid area and Bamoo forest, in four replications. Physico-chemical analyses were carried out on burned and unburned samples. X-ray diffraction technique was used to identify minerals of clay fraction in 0-5 cm depth burned and unburned soil, and also to compare transformation of minerals (if any) after heating at 300˚C and 600˚C for 2, 4, 8 and 12 h. Burning increased soil pH and sand sized fraction in 0-5 cm, and P and K in both depths of Bamoo forest. Changes in soil properties of agricultural filed were negligible. XRD analyses showed the reduction in the intensity peaks of chlorite and illite after burning. Lower relative quantity of chlorite and illite was observed in various times of 300˚C treatment in comparison to control, while they were not observed in 8 and 12 h of 600˚C. No change was observed in the peak of quartz in forest and field soils after burning and after various heat treatments.
S. Shakeri, S. A. Abtahi, N. A. Karimian, M. Baghernejad, H. Owliaie,
Volume 19, Issue 73 (fall 2015)
Abstract
The aim of this study was to assess the kinetics of nonexcheangable potassium release in surface and subsurface soil horizons, using organic and inorganic extractions, in Kohgilouye-va-Boyerahmad Province. Kinetics of K+ release was studied by successive extractions of K from 64 selective surface and subsurface soil samples, using 0.01 M CaCl2 and 0.01 M oxalic acid, for 1948 h, with two replicates. Nonexchangeable K+ release was fitted by Elovich, Pseudo-first order, Power function and Parabolic equations. Result showed that the average nonexchangeable K+ released (extracted by 1M HNO3) was 356 mg/kg, while those extracted by CaCl2 and oxalic acid after 1948 h were only 58% and 52% of the total amount of nonexchangeable K+ of the soils, respectively. In all soil samples, nonexchangeable K+ released by oxalic acid was less than that released by CaCl2, due to the high buffering capacity resulting from high carbonates in the soils. Potassium release rate in Elovich and Parabolic equations were significantly correlated with non-exchangeable potassium and some physical and chemical characteristics. Based on high Coefficients of determination (r2) and low Standard errors (SE), Elovich, Power function, First order and Parabolic equations were selected as the best equations for prediction of K+ release from the soils.
P. Khosravani, M. Baghernejad, A. Abtahi, R. Ghasemi,
Volume 25, Issue 3 (Fall 2021)
Abstract
Soil classification in a standard system is usually defined based on information obtained from properties and their variations in different map units. The aim of this study was to compare soil genesis and morphological characteristics in different landforms with WRB and Soil Taxonomy (ST) Systems. From nine studied profiles, six profiles were selected as representative profiles and dug in Colluvial fans, Piedmont plain, and Alluvial plain physiographic units, respectively. Then, the soils were classified according to the pattern of the two systems. Also, variation analysis of variance (ANOVA) and comparing means were used to quantify interested soil properties. The results of soil physio-chemical properties at different landform positions were significant based on analysis of variance of the effect of physiographic units and soil depth at the level of 1 %. Soil classification results based on WRB indicated that WRB were recognized four reference soil groups (RSG) included Regosols, Cambisols, Calcisols, and Gleysols at the first level of WRB classification in comparison of ST with recognizing two order Entisols and Inceptisols could separate more soils. The soils were located on the alluvial plain with a high groundwater level in the WRB due to the creation of restrictive conditions for root development in contrast to the ST called “Aquepts” in the suborder level but in a WRB is classified as the “Gleysols” RSG. On the other hand, ST, unlike WRB, used the Shallow criteria at the family level to describe the shallowness of soils and the limitations of root development. Generally, the efficiency of each system varies despite the differences in their structure and depending on the purpose of using them.
