不同生态条件下长期施钾对土壤钾素固定影响的机理  

Effects of long-term potassium fertilization on potassium fixation in soils under different ecological conditions: A mechanism study.

作　　者：张会民[1] 徐明岗[2] 吕家珑[1] 刘红霞[3] 

机构地区：[1]西北农林科技大学资源环境学院,陕西杨凌712100 [2]中国农业科学院农业资源与农业区划研究所,北京100081 [3]河南科技大学农学院,河南洛阳471003

出　　处：《应用生态学报》2007年第5期1009-1014,共6页Chinese Journal of Applied Ecology

基　　金：国家"十一五"科技支撑计划资助项目(2006BAD05B09;2006BAD02A14).

摘　　要：采用X射线衍射分析技术和室内模拟法,研究了长期施钾对不同生态条件和不同轮作制度下黑土、塿土和灰漠土钾素固定的影响机理.结果表明,长期施钾对水云母含量较低土壤的钾素固定能力影响较大.与不施钾土壤相比,水云母含量较低的黑土和含量较丰富的塿土在外源钾加入浓度在400～4000 mg·kg^-1范围内,对外源钾的固定量分别降低了75～747 mg·kg^-1和16～238 mg·kg^-1,而水云母含量丰富的灰漠土的固钾能力无明显变化.长期施钾主要通过影响土壤含钾矿物组成对土壤固钾能力产生影响,即延缓或阻止水云母向云母-蒙脱石混层层间矿物的转化,使土壤对外源钾的固定能力降低;另外,长期施钾使土壤缓效钾含量和K^＋饱和度增加,土壤固钾能力降低.By using X-ray diffraction and laboratory simulation, this paper studied the effects of long-term potassium （K） fertilization on K fixation in black soil, loess soil, and grey desert soil under different ecological conditions and cropping systems. The results showed that long-term K fertilization had greater effects on the K fixation capacity of soils with lower hydromica content. When the K application rate was 400 to 4 000 mg · kg^-1, the K fixation capacity of black soil and loess soil, whose hydromica contents were low or relatively low, decreased by 75-747 mg · kg^-l and 16-238 mg· kg^-1 desert soil , respectively, compared with no K application, while no change was observed in grey whose hydromica content was high. Long-term K application could affect the changes of soil K-bearing minerals, i. e. , slowing down or holding back the transformation of hydromica into mixed-layered mica-smectite, and consequently, decreased the K fixation capacity of soil. The increase of soil slow-available K content and K^＋ saturation owing to the long-term K application also induced the decrease of the K fixation capacity.

关 键 词：生态条件 长期施钾 钾素固定 

分 类 号：S158[农业科学—土壤学]