【摘要】 用室内模拟和生物耗竭的方法研究了土壤中钾素的变化,试验结果表明,淹水可以减少土壤对外源钾素的固定,淹水比20%田间含水量钾素的固定减少2～29mg/kg。当土壤经过干湿以后,土壤会发生明显的固定钾作用,土壤含钾量越高,固定钾能力越强。棉花吸收的钾素中有80%来自于土壤非交换性钾,盆栽生物耗竭与连续种植10年棉花的田间土壤,具有相同的结果,土壤交换性钾在下降到一定程度后不再下降,而1mol/LHNO3不能提取的钾(层间钾)一直在下降。更多还原

【Abstract】 The change of soil potassium was studied by indoor simulation and biodepletion methods.The study showed that humid soil may reduce soilfixed potassium from potassium fertilizer.Inundated soil reduced the fixed potassium by 229 mg/kg than that of soil containing 20% water.The soil potassium fixation was increased after dry and humid alternation.Soil with higher potassium content had a higher fixation ability.Eighty percent of the potassium taken up by cotton was from nonexchangeable potassium of the soil.Both the pot and the field experiment showed a same result that the content of soil nonexchangeable potassium will no longer decrease when it reached a certain level,while nonextractable potassium with 1 mol/L HNO3 will continue to decline.更多还原