长期肥料定位试验中土壤钾素肥力的演变  

VARIATION OF POTASSIUM FERTILITY IN SOIL IN THE LONG-TERM STATIONARY EXPERIMENT

作　　者：范钦桢[1] 谢建昌[1] 

机构地区：[1]中国科学院南京土壤研究所,南京210008

出　　处：《土壤学报》2005年第4期591-599,共9页Acta Pedologica Sinica

摘　　要：利用18个长期定位试验的不施钾和施钾处理土壤,探讨了土壤含钾矿物、Q/I关系和对外源钾固定能力的变化。结果表明:(1)施钾处理的速效钾和缓效钾含量均高于不施钾的,以水云母、蒙皂石为主的土壤,缓效钾含量年均可高7·67mgkg-1;(2)长期不施钾,由于作物吸收消耗了土壤钾,可使水云母→蛭石转化,施用足量的钾可延缓或阻止水云母→蛭石转化;(3)长期不施钾土壤的-ΔK°和ARek降低,PBCk值提高,即土壤易释放钾库变小,土壤对钾的吸附能力增强,土壤供钾能力降低,若要提高土壤溶液中钾素的浓度需要施用较大量的钾;(4)长期不施钾,土壤钾素被消耗,可提高土壤对外源钾的固定能力,不过,一旦土壤中有大量NH4+-N积累时,可降低土壤对外源钾的固定能力。To study variations of soil potassium-bearing minerals, Q/I relation and soil capacity of fixing extraneous K, data from 18 long-term stationary field experiments with K treatments and zero K treatment were cited. The results show that (1) readily available K and slowly available K were higher in Treatment NPK than Treatment NP, with the latter being on average 7. 67 mg kg~ -1 a~ -1 higher in hydromica-or smectite-dominated soils. (2) Due to long-term zero K application, crops depleted soil K, thus making hydromica weather and turn into vermiculite. Application of adequate K could defer or stop the process. (3) As a result of long-term zero K application, soil -ΔK°and AR^k_e were declining while PBC^k ascending, which means that the pool of readily releasable K in soil was getting smaller, K adsorption capacity of the soil higher, and soil K supply capacity lower. A higher rate of K should be applied if K concentration in the soil solution was to be increased. (4) As a result of long-term zero K application, soil K was depleted, which led to strengthened soil K fixation capacity for extraneous K. However, once NH^+_4-N was accumulated in soil to a certain level, soil K fixation capacity for extraneous K would be reduced.

关 键 词：土壤钾素 粘土矿物 Q/I 固钾能力 

分 类 号：S158[农业科学—土壤学]