关键词: 西藏土壤, 全钾, 速效钾, 影响因素

Abstract: According to the analysis data of 465 soil samples from 138 soils profiles of 16 soils types, soil potassium and its affecting factors were studied. The contents of soil total potassium(STK) are 17.7~23.4g/kg in surface horizon and 20.3~27.6g/kg in C horizon which are abundant. Parent material which has lower weathering intensity and plentiful potassium is the main effecting factor of STK. In general, organic matter in surface layer makes dilution effect" of the mineral potassium(r=-0.559^**), so that the STK of surface horizon is lower than that in parent material horizon. At the same time the accumulative CaCO₃ makes "dilution effect" of the mineral potassium in alkaline soils. Available potassium contents in most soils types are higher than 100 mg/kg. Correlation coefficient of the soil available potassium(SAK) with soil cation exchange capacity(CEC) with soil organic matter in the soils is the significant(0.547^** and 0.515^**), respectively. The relationship of SAK with soil clay is significant only in several soil types. Moreover, in acid soil the SAK has higher coefficient with base saturation(BS%) than CEC.

Key words: Tibet soils, total potassium, available potassium, the affecting factors