Types　of　Crystalline　Iron　Oxides　and　Phosphate　Ad－sorption　in　Variable　Charge　Soils  

作　　者：LIU FAN XU FENG-LIN LI XUE-YUAN WANG YI-JUN and ZENG GUANG-QIAO(Department of Soil and Agrochemistry, Huazhong Agricultural University, Wuhan 430070 (China)) 

出　　处：《Pedosphere》1994年第1期35-46,共12页土壤圈（英文版）

摘　　要：The types, contents and morphologies of crystalline Fe oxides and their relations to phosphate adsorptionon the clay fractions in soils with variable charge in southern China were investigated by means of XRD, TEM,EMA and chemical analysis methods.Results indicated that the types and contents of crystalline Fe oxidesvaried with the soils examined. The dominant crystalline Fe oxide was hematite in the latosols and goethitesin the red soils.In yellow-brown soils, the only crystalline Fe oxide was goethite.The difference between Aldand Alo came mainly from the Al substituting for Fe in the pe oxides. The crystal morphology of goethiteappeared mainly as subrounded flat or iso-dimensional rather than acicular particles. Hematites occurredin plates of various thickness. Their MCDa/MCDc ratios in the latosols and red soils were generally above1.5 and below 1.5, respectively. The MCD values of goethites and hematites were 15-25nm and 20-35nm,and their specific surface areas were 80-120m￣2/g and 35-75m￣2/g, respectively.The goethite crystals weregenerally smaller. Variations of the total amounts of crystalline Fe oxi es in clay fractions were not related tophosphate adsorption. The types, contents and morphologies of crystalline Fe oxides in the soils remarkablyaffected phosphate adsorption characteristics of the soils. The phosphate adsorption of goethite was muchgreater than that of hematite. The higher the MCD /MCDc rotio of hematite, the lower the phosphateadsorption.ＴｙｐｅｓｏｆＣｒｙｓｔａｌｌｉｎｅＩｒｏｎＯｘｉｄｅｓａｎｄＰｈｏｓｐｈａｔｅＡｄ－ｓｏｒｐｔｉｏｎｉｎＶａｒｉａｂｌｅＣｈａｒｇｅＳｏｉｌｓＬＩＵＦＡＮ，ＸＵＦＥＮＧ－ＬＩＮ，ＬＩＸＵＥ－ＹＵＡＮ，ＷＡＮＧＹＩ－ＪＵＮａｎｄＺＥＮＧＧＵＡＮＧ－Ｑ...

关 键 词：crystalline Fe oxides GOETHITE HEMATITE phosphate adsorption variable charge soils 

分 类 号：S153.3[农业科学—土壤学]