TY - JOUR T1 - Different Forms of Iron and Some Physico-Chemical Properties as Soil Development Parameters in a Chronosequence on Karaj River Terraces in Hassan-Abad, Southern Tehran TT - بررسی اشکال مختلف آهن و برخی خواص فیزیکی- شیمیایی به‌عنوان شاخصی از تکامل خاک در یک ردیف زمانی روی پادگانه‌های رودخانه کرج در منطقه حسن‌آباد، جنوب تهران JF - JSTNAR JO - JSTNAR VL - 18 IS - 70 UR - http://jstnar.iut.ac.ir/article-1-2939-en.html Y1 - 2015 SP - 269 EP - 281 KW - Free and amorphous iron oxide KW - Fe-hydr(oxide) KW - Fed-Feo KW - Feo/Fed. N2 - Terraces are old geomorphic surfaces that are not related to present streams and are best places to study the effect of time on soil formation (chronosequence). This research was carried out to study some physico-chemical parameters especially different forms of iron as soil development indices on terraces of Karaj River in Hassan-Abad, southern Tehran. To determine soil development indices in 4 profiles occurring on 4 terraces, some physical and chemical properties were measured and free iron(Fed), aluminum(Ald), silica(Sid) and manganese(Mnd), amorphous Fe(Feo), Al(Alo), Si(Sio), Mn(Mno) and Fe, Al, Si-humus complexes were extracted. Results showed that clay, fine clay/total clay, CEC, the color redness and leaching of calcium carbonate increase toward higher terraces. Contents of Fed, Ald and Sid increases from lower terrace (T1) to the higher terrace (T4). Fed-Feo and Feo/Fed as the most important indices of soil development were enhanced and reduced from lower terrace (T1) to higher terrace (T4) soils, respectively, which indicate an increase in iron oxides crystalinity and soil profile development. Contents of Fed-Feo in the B horizons from T1 to T4 were 600, 800, 1000, and 1400 mg/kg soil, respectively. Calculation of Ferrihydrate and Fe-hydr(oxide) such as goethite and hematite showed that the amounts of these components were increased from T1 to T4 terraces confirming the variation of (Fed-Feo), (Feo/Fed) and (Feo-Fep) indices. M3 ER -