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为探索长期不同施肥对土壤钾素固定的影响,采用室内模拟试验对中国主要农田土壤,即红壤、水稻土、灰漠土、塿土、潮土、黑土和紫色土对外源钾固定能力的差异性进行了研究,并对长期施肥条件下土壤钾素固定的影响因素进行了因子分析和逐步回归分析.结果表明,施肥15年后,不同土壤固钾能力大小顺序为:黑土>紫色土>塿土>潮土>水稻土>灰漠土>红壤.土壤主要黏土矿物类型明显影响其固钾能力,此外,对以2:1型黏土矿物为主的土壤而言,其固钾能力还受两个主要因子的影响:因子1包括土壤速效钾、缓效钾和K+饱和度3个因素,因子2包括土壤阳离子交换量(CEC)、土壤有机质(SOM)和<0.002mm黏粒含量3个因素.在外源钾加入浓度较低(0.4～1.6g·L?1)时,因子1和因子2分别主要通过土壤K+饱和度和CEC的变化影响土壤的固钾能力;在外源钾加入浓度较高(2.4～4.0g·L?1)时,因子1和因子2分别主要通过土壤K+饱和度和<0.002mm黏粒含量的变化影响土壤的固钾能力.
In order to explore the effect of long-term different fertilization on soil potassium fixation, indoor simulation experiments were conducted to evaluate the difference of potassium fixation ability of main farmland soils in China, ie red soil, paddy soil, gray desert soil, loam soil, alluvial soil, black soil and purple soil The results showed that after 15 years fertilization, the order of potassium fixation capacity of different soils was: black soil> purple soil> 塿Soil> fluvo-aquic soil> paddy soil> gray desert soil> red soil. The main clay mineral types in soil significantly affect the potassium-fixing ability. In addition, the ability of potassium-fixing soil to be mainly composed of 2: The main factors are as follows: Factor 1 includes three factors: soil available K, K and K + saturation. Factor 2 includes CEC, SOM and <0.002mm clay content (0.4-1.6 g · L -1), K factor 1 and F 2 were mainly affected by potassium K + saturation and CEC, respectively. Under the condition of high concentration of exogenous potassium (2.4 ~ 4.0g · L -1), factor 1 and factor 2 affected the potassium fixation ability of soil mainly through the change of soil K + saturation and <0.002mm clay content, respectively.