作 者 ：金继运;高广领;王泽良;王莲池;张乃凤
期 刊 ：植物营养与肥料学报 1994年 1卷 1期 页码：39-48
Keywords:Potassium release, Kinetics, First order reaction, Potassium supply power.,
摘 要 ：应用自行研制的连续流动交换仪研究了取自不同类型的19个土壤样品的钾素释放动力学及其供钾特征。不同土壤钾的释放差异很大,钾的释放持续时间变幅为100～600分钟;最大释放速率变幅为0.46～20.55毫克·千克-1·分-1;平均释放速率变幅为0.009～1.25毫克·千克-1·分-1;总释放量变幅为40～430毫克·千克-1。供试土壤钾的释放过程可以用一级反应方程拟合,表明钾的释放速率主要受交换位上钾离子饱和度的影响。应用一级方程计算出钾的释放速率常数变幅为5.48×10-3～65.62×10-3·分-1。多数土壤的钾释放过程符合单一的一级反应;而以云母类为主,且含有部分绿泥石的土壤的钾释放过程由两个速率不同的一级反应构成,表明不同吸附位上的钾离子可能有不同的释放机制。用供试土壤连续种植玉米幼苗5—7茬进行土壤钾素耗竭试验,结果表明应用连续流动交换仪研究得出的土壤钾素释放的动力学参数可以较可靠地评价土壤的供钾特征。释钾速率快,持续时间长,总释放量大的土壤(如青海栗钙土),在耗竭试验中显出很强的供钾能力;而释钾速率慢,持续时间短,总释放量小的土壤(如广东砖红壤)在盆栽试验中供植物吸收的钾量很低。有的土壤(如四川紫色土)钾的总释放量不低,但释放速度快,持续时间短,在盆栽试验
Abstract:Kinetics of native potassium release and potassium (K) supplying characteristics of 19 soils selected from 16 different soil types were investigated by using a continuous flow apparatus and pot experiments.The soils differed greatly in native K release process. The K releasing time ranged from 100 to 600 minutes. The ranges of maximum and average releasing rates were 0.46-20.55 mg kg-1 min-1, and 0.009-1.25 mg kg-1min-1, respectively. The total amount of K released ranged from 40 mg/kg to 430 mg/kg. The K release process in the soils can be described by first order equations with rate constant ranging from 5.48 × 10-1min-1 to 65.62 × 10-1min-1. Potassium release from most of the soils tested can be well described by a single first order equation. However, K release from soils dominated in mica and with some chlorite existing in the clay fraction showed two distinguished first order reactions with different rates. These may be attributed to different release mechanisms of K at different adsorption sites.Corn seedlings were grown for 5-7 harvests in pot expeifiinents to evaluate K supplying capacity of the soils. Results indicated that the kinstics parameters obtained from the kinetics study in the laboratory can be used to well characterize the K supplying capacity of the soils. Soils with higher total K release, higher releasing rate and longer releasing time, such as a chestnut soil from Qinghai, showed stronger K supplying power in pot experiments, while‘ those with lower total K release, slower releasing rate and shorter releasing time, such as a latosol soil from Guangdong, supplied a small amount of K to plants. A purple soil from Sichuan released a significant amouat of K ia the laboratory study, but it was released at a relatively fast rate in a relatively short time. Results from pot experiments indicated that this particular soil had a notable K supplying intensity initially. But the soil K reserve was depleted quickly with absorption by plants. The amouat of total K released from the soils in K release study was significantly correlated with the total K uptake by plants in pot experiments (r= 0.9056) .
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